Spatial distribution of male and female Populus cathayana populations and its drivers in Xiaowutai Mountains, Hebei, China
MENG Zhen-Si1, XIANG Wei2, SU Guo-Kui1, LI Da-Dong1, DONG Ting-Fa1, PENG Jin-You1, LI Xiao-Dong3, GONG Xiao-Ping3, LIANG Ning3, XU Xiao,1,*通讯作者:
编委: 廖万金
责任编辑: 李敏
收稿日期:2018-07-31修回日期:2018-09-2网络出版日期:2018-12-20
基金资助: |
Received:2018-07-31Revised:2018-09-2Online:2018-12-20
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蒙振思, 向卫, 苏国岿, 李大东, 董廷发, 彭进友, 李晓东, 龚小平, 梁宁, 胥晓. 河北小五台山青杨种群中雌雄群体的空间分布及其成因. 植物生态学报[J], 2018, 42(12): 1145-1153 doi:10.17521/cjpe.2018.0184
MENG Zhen-Si.
植物种群的空间分布研究一直是植物生态学研究的重要领域(钟章成和曾波, 2001; 王本洋等, 2006; 牛翠娟等, 2007)。它不仅能深入阐明该种群的分布现状、规律以及对环境的适应能力, 而且还能有效地预测种群的未来变化趋势。如张璞进等(2017)对鄂尔多斯市的毛刺锦鸡儿(Caragana tibetica)灌丛的空间分布格局与种内关联进行了分析, 发现不同发育阶段的毛刺锦鸡儿种群空间分布格局并不相同, 受到空间尺度的影响; 闫海冰等(2018)采用成对相关函数方法分析了不同气候带下松科、壳斗科和蔷薇科树木的空间分布格局及其关联性, 发现三科树木的空间分布格局及其关联性随径级和尺度发生变化, 并且在不同样地内表现不同; 贺强等(2009)运用典范对应分析方法对盐沼植物的空间分布及其土壤之间的相互关系进行了研究, 发现土壤的pH值、Ca2+、Mg2+含量等对植物个体的分布具有不同的影响; 陈科屹等(2018)对蒙栎(Quercus mongolica)种群的研究结果也表明, 空间尺度大小、种群结构及其发育程度是影响其空间分布的重要因子。尽管有关植物种群空间分布研究的文献众多, 但绝大多数研究工作主要集中在雌雄同株植物种群, 而从雌雄群体角度揭示雌雄异株植物种群的空间分布特征的研究并不多见。
雌雄异株植物是自然生态系统的重要组成部分(Lloyd, 1982; Renner & Ricklefs, 1995)。由于雌雄个体对环境的适应性不同而导致二者在生理(Xu et al., 2008; 胥晓, 2016)、形态(李俊钰等, 2012)、生活史(Charlesworth & Charlesworth, 1978)以及群体结构(Alliende & Harper, 1989)上存在差异, 逐渐成为现代植物生态学关注的一个研究领域。从现有文献来看, 国内外有关该类植物种群的研究主要集中在性比、种群结构及分布生境方面(Dawson & Ehleringe, 1993; Garcia & Antor, 1995; Marques et at., 2002)。如Dawson和Ehleringe (1993)发现生活史特征的差异导致梣叶槭(Acer negundo)雌雄群体的分布生境不同, 雌株在水热充足及土壤肥沃的有利环境下占优势; Marques等(2002)对巴西东南部的雌雄异株灌木Baccharis concinna进行研究后发现, 雌雄植株依据其性别呈聚集分布, 土壤环境对雌树的影响更大, 雌树更偏向于在土壤N:P和Ca:Al较好的低海拔区域分布; 赵亚洲等(2010)对长白山黄连木(Pistacia chinensis)种群的性比及空间分布进行研究后发现, 黄连木幼树、雌树和雄树均呈聚集性分布, 但不同龄级和不同性别的黄连木植株表现出空间分离现象; Hultine等(2013)认为在全球变暖的情况下, 雌雄两性群体可能会发生空间隔离, 资源丰富生境中的雌株个体的生存优势逐渐降低, 而资源贫瘠生境中的雄株个体的生存优势则逐渐增加。王志锋等(2011)发现海拔会影响青杨(Populus cathayana)雌雄群体的分布特征, 但种群总体性比接近1:1。根据Bertiller等(2002)对早熟禾属的雌雄异株植物Poa ligularis的研究结果, 雌雄植株在分布空间上的差异可能是由于性别的分化导致了二者在竞争和生殖成本方面出现差异, 高生殖成本的雌株在高氮的土壤环境下比雄株更具竞争优势。类似的现象也被Chen等(2015)证实, 他们发现氮供应水平显著影响青杨的生长和竞争, 高氮环境下生长的雌株比雄株具有更强的光合能力和竞争能力, 而低氮环境下生长的雄株的竞争能力比雌株更强。总的来说, 上述文献虽然证实了雌雄异株植物种群中的雌雄群体在数量比例、分布生境、空间分异等方面存在差异, 以及土壤环境差异对雌雄植株性比分布空间选择具有重要性, 但出现差异的内在原因还有待进一步阐释。
因此, 本研究以河北小五台山金河沟的青杨天然种群为研究对象, 采用平均最近邻指数、核密度、单因素方差分析等方法分析了青杨雌雄群体的聚集程度、群体密度和分布格局差异以及其与海拔、到河岸的距离(河距)和土壤理化性质间的内在关系, 进一步揭示雌雄群体在空间分布上存在差异的主要原因。由于青杨是我国较为常见的一种雌雄异株植物, 常作为重要的经济树种被广泛用于生态治理、环境改良以及木材加工等方面(王东胜和杨志岩, 2006), 故本研究结果也可为青杨林业资源的保护和管理提供理论依据。
1 材料和方法
1.1 研究区域概况
小五台山国家级自然保护区位于河北张家口蔚县, 114.78°-115.50° E, 39.78°-40.15° N, 属燕山-太行山山系, 海拔1 190-2 882 m, 主峰为东台, 气候类型为温带季风性气候, 年平均气温7.06 ℃, 最冷月气温-18.20 ℃, 最热月气温28.76 ℃, 年降水量为408.48 mm (于澎涛等, 2002)。植被类型主要以针阔混交林为主, 土壤以山地棕壤为主, 在海拔1 300-1 800 m范围内的金河沟谷分布有成片天然青杨林(刘增力等, 2004; 李霄峰等, 2012b), 在低海拔局部地方存在根萌现象。1.2 种群和土壤调查
2016年4月对金河沟谷中青杨种群中接近性成熟(胸径>9 cm)(李霄峰等, 2012a)的所有植株进行每木调查。调查的范围为青杨个体分布的最高海拔1 800 m至分布的最低海拔1 300 m之间、沿河道左右两侧100 m的区域。调查时对每株植株依次进行胸径测定、性别鉴定(根据花序)、挂牌编号, 并用全站仪(SOUTH NTS-362R6, 广州南方测绘科技股份有限公司, 广州)精确测量其地理坐标。总共调查树木6 965株, 其中雄树3 174株, 雌树3 005株, 未能辨识性别的786株。采用网格状法对整个分布区的土壤进行取样, 共设置468个采样点(点间距为30 m)。青杨分布区域为河谷地带, 表土层相当薄(10 cm左右)且其下多为卵石和粗沙, 因此, 取样时在去除地表枯枝落叶和砾石等杂物后, 取10 cm厚度的表土层土壤称质量。室内风干后称干质量计量土壤含水量, 并测定pH值、有机质、全氮(TN)、全磷(TP)、全钾(TK)、有效氮(N)、有效磷(P)和有效钾(K)含量8项土壤理化指标(鲁如坤, 2000)。
1.3 方法和数据处理
采用分段法划分海拔和河距: 改进王志峰等(2011)的方法将海拔划分为低海拔(1 300-1 400 m)、中低海拔(1 400-1 500 m)、中海拔(1 500-1 600 m)、中高海拔(1 600-1 700 m)和高海拔(1 700-1 800 m) 5个梯度, 用于分析海拔对青杨空间分布的影响。基于植株在河滩的实际分布状况, 沿整个海拔范围将河距划分为0-10 m、10-30 m、30-60 m和>60 m 4个梯度, 用于分析河距对青杨空间分布的影响。各海拔段和各河距范围内土壤理化性质的比较均以各梯度或河距范围内涉及的土壤取样点为基础进行统计分析。此外, 我们在核密度分析结果的基础上沿整个海拔范围选择坡度、河距相对一致的雌、雄群体优势生长区各6个, 每个分布区内设置1个50 m × 50 m的样方, 每个样方内选取土壤样点4-5个(取其平均值反映该样方土壤理化性质), 用于分析青杨雌、雄植株的分布与土壤理化性质间的关系。1.3.1 平均最近邻指数
该指数为平均观测距离(dO)与预期(理论)平均最近距离(dE)之比, 反映了最近邻的点的相互邻近程度和空间分布情况。
R = dO /dE
式中, R为平均最近邻指数, dO为地理空间中每个点与之最邻近点之间的欧氏距离平均值, dE为完全随机分布条件下此点的平均最邻近距离。若R = 1, 则点事件随机, 空间呈随机分布; 若R < 1, 则点事件空间彼此邻近, 空间呈集聚分布; 若R > 1, 为点事件空间彼此相斥, 空间呈均匀分布。其显著性水平用p值和Z得分检验, Z得分为标准差的倍数, 其值越大或越小(负值)表示置信度越高(刘昌雪和汪德根, 2016)。
1.3.2 核密度估计
核密度估计(KDE)是预测以事件点为圆心, 半径r范围区域之内事件发生的次数的多少比上该圆的面积n, 表示为在事件点S处的核密度(卢敏等, 2017)。其计算公式如下:
$f(s)=\sum\limits_{i=1}^{n}{\frac{1}{\pi {{r}^{2}}}}k\left( \frac{s-{{s}_{i}}}{r} \right)$
其中r表示带宽, 反映计算的核函数的平滑程度; f(S)表示核函数, 即中心点S到事件发生点Si处的权重大小。越靠近中心S点, 被赋予的权重就越大, 越远离中心点, 被赋予的权重则越小; n表示事件点发生的数量的多少(张桂铭等, 2013)。
1.3.3 方差分析与卡方检验
采用单因素方差分析中的Duncan/Dunnett T3检验不同海拔和不同河距间数据平均值的差异。采用非参数检验法检验雌雄群体优势分布区的土壤理化性质间差异。采用卡方检验性比(♂:♀)是否偏离1:1。上述分析借助统计软件SPSS 22.0完成, 显著性水平均设为α = 0.05。
2 结果和分析
2.1 平均最近邻指数及核密度分析
如表1所示, 该区域青杨种群的平均最近邻指数为0.774 (p < 0.001), 整个种群个体分布为聚集分布。从雌雄群体间的指数差异来看, 无论雄树还是雌树群体的平均最近邻指数均小于1 (R值分别为0.712和0.686), 所以二者都表现为聚集分布。由于雌树的平均最近邻指数小于雄树, 故表现出比雄树更高的分布聚集强度(表1)。Table 1
表1
表1小五台山青杨空间分布的平均最近邻指数分析
Table 1
性别 Sex | 预期平均距离 Expected mean distance (m) | 平均观测距离 Observed mean distance (m) | 平均最近邻指数 Nearest neighbor ration R | Z得分 Score-Z | p |
---|---|---|---|---|---|
雄 Male | 4.767 | 3.394 | 0.712 | -31.045 | < 0.001 |
雌 Female | 4.900 | 3.362 | 0.686 | -32.908 | < 0.001 |
全部 Total | 3.218 | 2.491 | 0.774 | -36.105 | < 0.001 |
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核密度分析的结果表明(图1), 青杨种群主要沿河谷呈狭长带状分布, 尤为在中海拔(1 500-1 600 m)分布最为密集。随着分布范围向低、高海拔延伸, 个体数量逐渐变稀疏。雌雄群体的分布趋势与种群总体分布基本一致, 均集中在中海拔区域, 二者的密集分布区域存在一定程度的重叠(图1)。
图1
新窗口打开|下载原图ZIP|生成PPT图1小五台山青杨种群核密度分布图。
Fig. 1The kernel density distribution map of Populus cathayana populations in Xiaowutai Mountains.
2.2 海拔对青杨空间分布的影响
由表2可知, 海拔显著影响了青杨的数量、性比和平均胸径。随海拔从1 300 m上升至1 800 m, 分布区内的青杨雌、雄植株的个体数均呈现“先增后减”的分布趋势(该趋势与核密度分析结果一致), 而平均胸径的变化规律正好相反, 呈现“先减后增”的变化。虽然雄树的平均胸径在各个海拔段均略大于雌树, 但统计结果不显著。此外, 不同海拔区域内的性比显著不同。低海拔区域偏雌(♂:♀ = 0.68, χ2 = 8.09, p = 0.004), 中低海拔区域显著偏雄(♂:♀ = 1.32, χ2 = 26.68, p < 0.001), 而其他海拔段的性比接近1:1 (表2)。Table 2
表2
表2小五台山不同海拔梯度上青杨雌雄群体的个体数、密度、平均胸径和性比(平均值±标准误差)
Table 2
海拔 Altitude | 雄株 Male | 雌株 Female | 性比 Sex ratio | ||||
---|---|---|---|---|---|---|---|
数量 Number | 密度 Density (ind.·hm-2) | 平均胸径 DBH (cm) | 数量 Number | 密度 Density (ind.·hm-2) | 平均胸径 DBH (cm) | ||
低海拔 Low altitude (1300-1400 m) | 88 | 18.87 | 38.90 ± 1.23a | 130 | 27.88 | 38.54 ± 1.16a | 0.68 |
中低海拔 Middle-low altitude (1400-1500 m) | 818 | 130.33 | 32.89 ± 0.42c | 622 | 99.10 | 32.04 ± 0.43c | 1.32 |
中海拔 Middle altitude (1500-1600 m) | 1 462 | 144.83 | 34.17 ± 0.31bc | 1 481 | 146.71 | 32.57 ± 0.29c | 0.99 |
中高海拔 Middle-high altitude (1600-1700 m) | 685 | 130.20 | 36.16 ± 0.46b | 660 | 125.44 | 35.28 ± 0.42b | 1.04 |
高海拔 High altitude (1700-1800 m) | 121 | 61.71 | 38.91 ± 1.30a | 112 | 57.12 | 38.44 ± 1.08a | 1.08 |
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2.3 河距对青杨空间分布的影响
由表3可知, 河距显著影响青杨的个体数、密度、平均胸径和性比。雌雄植株的个体数、密度和平均胸径均表现为随河距增加而逐渐递减的趋势。河距在0-10 m和30-60 m范围内雄株数量多, 密度高, 性比显著偏雄(♂:♀ = 1.15, 1.13; χ2 = 14.85, 4.00; p = 0.000, 0.046), 河距在10-30 m范围内雌株数量多, 密度高, 性比显著偏雌(♂:♀ = 0.9, χ2 = 5.37, p = 0.021), 河距>60 m以后性比接近于1:1 (♂:♀ = 0.99, χ2 = 0.01, p = 0.92)。此外, 无论河距远近, 雄树平均胸径均略大于雌树, 但统计结果差异不显著(表3)。Table 3
表3
表3小五台山与河岸不同距离范围内青杨雌雄群体的个体数、密度、平均胸径和性比(平均值±标准误差)
Table 3
与河岸距离 Distance from river | 雄株 Male | 雌株 Female | 性比 Sex ratio | ||||
---|---|---|---|---|---|---|---|
数量 Number | 密度 Density (ind.·hm-2) | 平均胸径 DBH (cm) | 数量 Number | 密度 Density (ind.·hm-2) | 平均胸径 DBH (cm) | ||
0-10 m | 1 546 | 197.28 | 35.93 ± 0.29a | 1 339 | 170.86 | 34.51 ± 0.29ab | 1.15 |
10-30 m | 882 | 102.85 | 34.43 ± 0.43ab | 982 | 114.51 | 33.90 ± 0.37bc | 0.90 |
30-60 m | 544 | 96.44 | 32.48 ± 0.54cd | 480 | 85.10 | 31.81 ± 0.55de | 1.13 |
> 60 m | 202 | 75.92 | 30.65 ± 0.76ef | 204 | 76.67 | 29.86 ± 0.83f | 0.99 |
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2.4 分布区土壤理化性质的异质性
由表4可知, 土壤理化性质在青杨种群分布区内具有高度异质性, 并与所处的海拔和河距密切相关。低海拔区域的土壤含水量、有机质、TN、TP、有效N、有效P、有效K含量比其他海拔区域含量低; 高海拔区域的土壤含水量、有机质、TN、TP、TK、有效N含量最高; 除了具较低的TK和有效K含量外, 中海拔区域的其他土壤理化指标含量与分布区的整体平均值接近(表4)。Table 4
表4
表4小五台山不同海拔和与河岸距离(河距)区域内的土壤理化性质(平均值±标准误差)
Table 4
指标 Indices | 含水量 Water content (%) | pH | 有机质 Organic matter (%) | 总N Total N (g·kg-1) | 总P Total P (g·kg-1) | 总K Total K (g·kg-1) | 有效N Available N (g·kg-1) | 有效P Available P (mg·kg-1) | 有效K Available K (g·kg-1) | |
---|---|---|---|---|---|---|---|---|---|---|
海拔 Altitude (m) | 1 300-1 400 | 31.24 ± 0.27e | 7.20 ± 0.01a | 6.38 ± 0.05e | 4.00 ± 0.06d | 0.94 ± 0.01d | 13.26 ± 0.04b | 0.25 ± 0.01e | 6.94 ± 0.07e | 0.21 ± 0.01e |
1 400-1 500 | 48.08 ± 0.42b | 7.21 ± 0.01a | 10.89 ± 0.11c | 5.30 ± 0.05c | 1.03 ± 0.01b | 13.04 ± 0.01c | 0.35 ± 0.01d | 9.92 ± 0.12c | 0.33 ± 0.01a | |
1 500-1 600 | 42.38 ± 0.15c | 7.03 ± 0.01c | 10.52 ± 0.03d | 5.32 ± 0.02c | 0.94 ± 0.01d | 13.09 ± 0.01c | 0.39 ± 0.01c | 10.96 ± 0.04b | 0.26 ± 0.01d | |
1 600-1 700 | 40.28 ± 0.23d | 7.02 ± 0.01c | 11.42 ± 0.07b | 5.66 ± 0.04b | 0.96 ± 0.01c | 13.05 ± 0.01c | 0.40 ± 0.01b | 11.74 ± 0.06a | 0.28 ± 0.01c | |
1 700-1 800 | 52.27 ± 0.49a | 7.13 ± 0.01b | 13.48 ± 0.21a | 6.82 ± 0.11a | 1.10 ± 0.01a | 13.81 ± 0.03a | 0.45 ± 0.01a | 9.19 ± 0.11d | 0.29 ± 0.01b | |
平均值 Mean | 43.21 | 7.08 | 10.76 | 5.4 | 0.97 | 13.31 | 0.38 | 10.7 | 0.28 | |
河距 Distance from river (m) | 0-10 | 44.38 ± 0.22a | 7.10 ± 0.01a | 10.91 ± 0.06a | 5.49 ± 0.03a | 0.98 ± 0.01a | 13.02 ± 0.01d | 0.37 ± 0.01c | 10.44 ± 0.06c | 0.28 ± 0.01a |
10-30 | 42.69 ± 0.26b | 7.07 ± 0.11b | 10.79 ± 0.07a | 5.42 ± 0.03a | 0.97 ± 0.01b | 13.08 ± 0.01c | 0.38 ± 0.01bc | 10.79 ± 0.07b | 0.27 ± 0.01b | |
30-60 | 41.47 ± 0.27c | 7.11 ± 0.01a | 10.46 ± 0.08b | 5.21 ± 0.04b | 0.96 ± 0.01b | 13.27 ± 0.01b | 0.39 ± 0.01b | 11.15 ± 0.09a | 0.28 ± 0.01a | |
> 60 | 41.91 ± 0.27bc | 6.91 ± 0.02c | 10.39 ± 0.05b | 5.24 ± 0.04b | 0.92 ± 0.01c | 13.32 ± 0.02a | 0.40 ± 0.01a | 11.02 ± 0.09ab | 0.26 ± 0.01c |
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此外, 随河距的变化各土壤理化性质也呈现出不同的变化。土壤含水量、pH值、有机质、TN、TP和有效K含量随河距增加而减少, 而TK、有效N和有效P含量则随河距的增加而增加(表4)。
2.5 雌雄群体优势分布区域的土壤理化性质差异
由表5可知, 雌雄群体优势分布区的部分土壤理化性质存在显著差异。雌株群体优势分布区的有机质和TN含量显著高于雄株群体优势分布区, 其土壤含水量和有效P含量略高于雄株群体分布区(统计结果不显著), 而pH值、TP、TK、有效N、有效K含量无显著差异。Table 5
表5
表5小五台山青杨雌雄群体优势分布区的土壤理化性质(平均值±标准误差, n = 6)
Table 5
指标 Indices | 含水量 Water content (%) | pH | 有机质 Organic matter (%) | 总N Total N (g·kg-1) | 总P Total P (g·kg-1) | 总K Total K (g·kg-1) | 有效N Available N (g·kg-1) | 有效P Available P (mg·kg-1) | 有效K Available K (g·kg-1) |
---|---|---|---|---|---|---|---|---|---|
雌株 Female | 40.64 ± 2.64 | 7.00 ± 0.09 | 11.23 ± 0.85 | 5.39 ± 0.25 | 0.95 ± 0.03 | 13.01 ± 0.14 | 0.39 ± 0.01 | 12.06 ± 1.12 | 0.23 ± 0.01 |
雄株 Male | 39.78 ± 2.06 | 6.99 ± 0.10 | 8.54 ± 0.45 | 4.10 ± 0.34 | 0.90 ± 0.03 | 13.15 ± 0.17 | 0.34 ± 0.02 | 9.74 ± 0.66 | 0.24 ± 0.02 |
P值 Probability | 0.699 | 0.818 | 0.004 | 0.015 | 0.31 | 0.699 | 0.18 | 0.093 | 1 |
显著性 Significance | ns | ns | ** | * | ns | ns | ns | ns | ns |
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3 讨论
该研究表明, 小五台山的青杨种群主要沿河谷呈狭长带状分布, 雌雄群体均为聚集分布。个体数量在中海拔区域最多、最密集, 随着分布范围向低、高海拔延伸, 个体数量逐渐减少。这种分布特征可能与青杨的生长特性以及小五台山金河沟的地理环境密切相关。青杨是一种喜欢中温、光照、湿润环境的速生高大乔木, 其快速生长的特性需要大量的水分和养分作保障, 往往生长在河滨地带平缓的区域(李贻铨, 1983)。小五台山的气候类型为温带季风性气候, 夏季高温多雨, 降水丰富, 光照充足, 能够为青杨的生长提供良好的气候条件。另外, 金河沟是由狭长深沟切谷发育而成, 两侧坡陡, 沟底较缓, 有利于土壤水分的保持和养分的富集。因此, 形成了青杨种群主要沿河谷底部呈狭长带状分布的现状。该现象与董世林和王战(1988)关于杨树的地理分布特点的研究结果一致。本研究发现海拔和河距是影响青杨雌雄群体的个体数、密度以及平均胸径的主要原因。随海拔增加, 雌雄个体数与密度均表现“先增后减”的特点, 而平均胸径则表现出相反的变化特征。其原因主要在于高海拔区域温度低, 枯枝落叶易于积累, 土壤养分相对富集, 土壤含水量、有机质和矿质元素含量较高, 但由于上游河谷深切严重, 造成两岸地形陡峭, 制约了个体的扩散, 再加上桦树(Betula spp.)等其他乔木的种间竞争, 导致了该区域内雌雄植株的数量和密度偏少(或小)。低海拔区域虽然地形条件相对较好, 但由于汛期河流的冲刷作用导致土壤发育差, 土壤有机质和矿质元素等含量较低, 仅在局部土壤发育较好的斑块内有青杨分布(且雌株偏多), 因此也限制了青杨的生长和分布。中海拔区域比高、低海拔区域更为平坦, 两侧有支沟汇入, 导致河谷更加宽阔, 土壤的水分和养分条件适中, 非常适合青杨个体的生长发育, 因而该区域的个体数和密度最大。但由于受到密度制约作用的影响, 植株的径向生长受到抑制, 平均胸径偏小。而高、低海拔区域由于个体数量少、密度小, 种内竞争小, 平均胸径反而更大, 最终导致群体的平均胸径呈现“先减后增”的变化。此外, 雌雄植株的数量、密度和平均胸径还表现出“随河距增加而逐渐减少”的变化。其原因是靠近河流的区域坡度相对平缓, 水分条件和土壤发育较好, 土壤中的有机质和TN、TP和有效K等矿质元素含量较高(表4), 有利于青杨个体的生长。而随着河距增加, 坡度逐渐变陡, 水分和土壤条件变差, 土壤含水量、有机质以及部分矿质元素含量降低, 限制了青杨个体的生长发育, 最终呈现出逐渐变少(小)的趋势。
此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (王志锋等, 2011), 但我们发现分布区内的局部地方性比并不一致, 往往会受到海拔高低和河距大小的影响。如低海拔区域的性比偏雌(主要由于土壤发育较好的斑块内的雌株处于温暖的环境, 其生长发育比雄株好并呈现聚集分布), 低中海拔区域的性比偏雄。河距在0-10 m范围内性比偏雄, 河距在10-30 m范围内性比显著偏雌。根据Freeman等(1976)的研究, 雌株产生种子往往需要比雄株投入更高的生殖成本, 从而导致其资源需求与雄株显著不同, 这种资源需求差异会进一步影响雌雄个体的分布。与该结论一致, 本研究对比分析青杨雌、雄群体优势分布区域的土壤理化性质后也发现, 雌树更偏向于生长在土壤有机质和TN含量更高的环境(表5), 土壤中氮的多少对雌雄植株的生长以及竞争具有密切联系。类似的结果也被Zhang等(2014)的研究所证实, 他们对土壤缺乏氮、磷环境下生长的青杨雌雄植株的形态、生理及叶绿体超微结构进行研究后发现, 缺乏氮、磷对雌株造成的负面影响大于雄株, 雄株比雌株具有更强的光合作用、更高的光合氮和磷利用效率, 以及更完整的叶绿体超微结构等。同时, Song等(2017)也发现氮可以控制贡嘎山冰川退缩迹地上冬瓜杨(Populus purdomii)与川滇柳(Salix rehderiana)的种内和种间竞争, 并驱动原生演替。另一方面, 还有研究报道雌雄植株对外界环境的适应能力有差异(Dawson & Ehleringe, 1993; Li et al., 2005, 2007; Xu et al., 2008, 2009; Hultine et al., 2013)。雄株个体在土壤干燥、养分贫瘠、海拔较高等恶劣生境中生长良好, 而雌株个体在湿润、肥沃、低海拔或低洼等生境中生长良好(胥晓等, 2007)。因此, 这种性别间的适应能力差异也可能会影响雌雄个体的分布。与高海拔区域相比, 金河沟低海拔区域更加温暖, 雌株生长占优势, 故性比偏雌。类似的现象也被Grant和Mitton (1979)在Populus tremuloides种群中发现。此外, 小五台山河流每年的春汛和夏汛期间, 水流湍急, 河流冲刷力强, 在距河道0-10 m范围均处于水淹状态。根据杨鹏和胥晓(2012)的研究, 青杨雄株在水淹状况下可以通过维持更高的光合作用和增加不定根数量来维持比雌株更强的耐涝性。因而在距河道0-10 m范围内雄株个体存活数较多, 性比偏雄。在距河道10-30 m范围内由于避开了河流冲刷, 不存在水淹胁迫, 再加上土壤养分相对富集, 更适合雌株生长, 故性比偏雌。因此, 海拔和河距只是改变了区域内的土壤理化性质以及生长环境这两种外在因素, 而雌雄植株对资源需求以及对环境适应能力的性别差异才是决定性比的内在原因。
综上所述, 小五台山的青杨种群主要沿河谷呈狭长带状分布, 雌雄群体均为聚集分布。个体数量在中海拔区域最多, 密度最大。随着分布范围向低、高海拔延伸, 个体数量逐渐减少。海拔和河距对青杨雌雄群体的个体数、密度以及平均胸径均有影响。随海拔增加, 雌雄个体数与密度均表现“先增后减”的特点, 而平均胸径受密度效应的影响则表现出相反的变化特征。随河距增加, 个体数量、密度和平均胸径表现为“逐渐减少”的特点。局部区域由于海拔和河距影响了土壤理化性质和生长环境, 在资源需求和环境适应力存在差异的内因驱动下, 雌雄植株性比会发生偏倚。
参考文献 原文顺序
文献年度倒序
文中引用次数倒序
被引期刊影响因子
, 77,
DOI:10.2307/2260821URL [本文引用: 1]
(1) The distribution of individuals of Salix cinerea was mapped in a site in Angelsey, N. Wales. The age structure of individual genets was estimated from morphological characteristics and used to describe the age structure of the whole population. The sex ratio and the spatial distribution of the two sexes and of juvenile (non-flowering) individuals were determined. (2) The colonization of the study site apparently commenced when two female trees became established before 1967. The population increased rapidly until 1980, after which few new individuals became established and these were restricted to a few small areas on the site. (3) The overall sex ratio was female biased, with a ratio of 2:1. The sex ratio of each age cohort was also female biased, except at age 6. At other sampled sites the sex ratio was also female biased, with one exception. (4) There was no evidence of spatial segregation of the sexes, but juvenile plants tended to be spatially segregated from adults. (5) Analysis of the distribution of individuals by Thiessen polygons showed few differences between the area occupied by male and female plants. The younger male plants were further from neighbours, and male plants overall had higher polygon displacement values than females. The polygon areas of juvenile plants were smaller than those of reproductive plants of the same age. (6) Nearest-neighbour distance was the density measure best correlated with plant performance. Measures of plant growth were more strongly correlated with measures of density in female and juvenile plants than in males. (7) No differences in size were detected between male and female plants. Reproductive individuals were usually larger than juveniles.
, 11,
DOI:10.1023/A:1014084024145URL [本文引用: 1]
We examined the effect of environmental patchiness on the spatial segregation of the sexes in the dioecious anemophilus grass Poa ligularis . Because the species is sensitive to grazing, a better understanding of environmental factors that control its spatial distribution and abundance could improve conservation efforts. We hypothesized that (i) males and females are spatially segregated in the microenvironments created by plant patches as the result of sexual specialization in habitat and/or resources use, (ii) sexual specialization is related to different tolerance to competition and reproductive costs of males and females, and (iii) changes in patch structure affect the microenvironment and the intensity of spatial segregation of the sexes. We analyzed the spatial distribution of sexes at three sites with different plant and micro-environmental patchiness and performed a controlled competition experiment with different substitution of males and females. Our results showed that large plant patches created larger sheltered soil fertility islands than small patches. As patch size and their area of influence increased, the density and the spatial segregation of the sexes of P. ligularis also increased, resulting in biased habitat-specific sex ratios. In accordance with their higher reproductive costs, females were more frequent in sheltered (low air evaporative demand) and nitrogen-rich areas inside patch perimeters than males. Females were also better able to tolerate inter-sexual competition than males. In contrast, males tolerated low nitrogen concentration in soil and low sheltering, probably gaining advantage in pollen dispersal. Inter- and intra-sexual competition, however, affected the reproductive output of both sexes. From the point of view of conservation, environmental patchiness is important to the status of P. ligularis populations. The reduction of patch size limits the available microsites, biases the sex ratio towards males inside patches, increases inter- and intra-sexual competition, and it might be expected to decrease overall seed and pollen production and consequently potential recruitment.
112,
DOI:10.1086/283342URL [本文引用: 1]
A model for the evolution of gynodioecy from the hermaphrodite or monoecious condition is described, taking into account the effects of partial selfing and inbreeding depression. It is shown that a mutant causing male-sterility can be selected even if the female plants have the same ovule output as the hermaphrodites, but that the conditions for this are very stringent: The product of the selfing rate and the inbreeding depression must exceed one-half. If the females have an increased ovule output, gynodioecy can evolve with lower values of the selfing and inbreeding depression parameters. Expressions for the equilibrium frequency of females and of the male-sterility gene in both the dominant and the recessive case are given. By a similar technique, conditions for the evolution of androdioecy are derived. In a selfing population, these conditions are much less easily satisfied than those for gynodioecy, though in a randomly mating population the conditions are similar: If ovule production is abolished, pollen production must be more than doubled, or vice versa. Since androdioecy is known to be a very rare condition, it seems likely that avoidance of selfing has played a role in the evolution of gynodioecy. Using the equilibria derived for gynodioecy, the conditions for the evolution of subdioecy or dioecy, by means of a partial or total female-sterility mutation, are studied. In contrast to the situation in a hermaphrodite population, a female-sterility gene can be selected in a gynodioecious population if it confers a moderate increase in pollen output; some increase in pollen output is essential. The fate of such a female-sterility gene also depends on its linkage with the male-sterility gene. If this is recessive, and the female-sterility gene is dominant and has an effect in the females as well as the hermaphrodite individuals, then the second mutation will usually be eliminated unless it occurs at a locus tightly linked to the first gene. In other cases there is no such "linkage constraint," though in all situations there may be selection for tighter linkage between the loci; this will result in an initially subdioecious population becoming more fully dioecious. These results agree with some of the facts known about the evolution of dioecy in plants. First, since gynodioecy is more often controlled by a recessive than a dominant gene, male heterogamety should be commoner than female, as is observed. Second, subdioecy should be common, since full dioecy requires not only the correct phenotypic effects of the two genes but also complementary dominance relations and tight linkage; subdioecy is indeed known in many species. The equilibria reached by our model have only one type of female in appreciable frequency, whereas the polleniferous individuals may fall into several genotypic classes; it is often observed that in subdioecious species the males are more variable than the females, regardless of which is the heterogametic sex. Finally, the equilibria generated by our model agree closely with the results of genetical studies of those dioecious species with male-determining Y chromosomes that have been investigated, in which both male-and female-sterility factors have been found, showing complementary dominance relations and no crossing-over between the loci, so that just two gamete types exist. Such a situation can be explained by the operation of the linkage constraint, which ensures that only linked mutations become established and does not require that unlinked genes have been brought together. This is consistent with the fact that dioecious species often have the same chromosome numbers as their bisexual relatives.
38,
DOI:10.1111/pce.12477URLPMID:25366665 [本文引用: 1]
Abstract Several important dioecious species show sexual spatial segregation (SSS) along environmental gradients that have significant ecological effect on terrestrial ecosystem. However, little attention has been paid to understanding of how males and females respond to environmental gradients and sexual competition. We compared eco-physiological parameters of males and females of P opulus cathayana under different sexual competition patterns and nitrogen (N) supply levels. We found that males and females interacting with the same or opposite sex showed significant differences in biomass partition, photosynthetic capacity, carbon (C) and N metabolism, and leaf ultrastructure, and that the sexual differences to competition were importantly driven by N supply. The intersexual competition was enhanced under high N, while the intrasexual competition among females was amplified under low N. Under high N, the intersexual competition stimulated the growth of the females and negatively affected the males. In contrast, under low N, the males exposed to intrasexual competition had the highest tolerance, whereas females exposed to intrasexual competition showed the lowest adaptation among all competition patterns. Sexual competition patterns and N supply levels significantly affected the sexual dimorphism and competitiveness, which may play an important role in spatial segregation of P . cathayana populations.
[本文引用: 1]
, 38,
[本文引用: 1]
74,
DOI:10.2307/1940807URL [本文引用: 3]
In the semiarid Intermountain West, boxelder, Acer negundo, var. interior, a deciduous, dieocious tree, exhibits significant habitat-specific sex ratio biases. Although the overall sex ratio (male/female) does not deviate significantly from one, the sex ratio is significantly male biased (1.62) in drought-prone habitats, while it is significantly female biased (0.65) in moist, streamside habitats. The causes underlying gender-specific habitat associations in this species are not known. We hypothesized that spatial segregation of the sexes is maintained by differences in gender-specific photosynthetic behavior, water relations characteristics, and both instantaneous and integrated water-use efficiency. Gender-specific physiological characteristics were measured and related to growth, reproduction, population age structure, and habitat distribution of male and female trees. Under both field and controlled-environment conditions, males and females differed significantly in a number of physiological traits. Males maintained lower stomatal conductance to water vapor (g), transpiration (E), net carbon assimilation (A), leaf internal CO"2 concentration (c"i), carbon isotope discrimination (@D; an index of time-integrated c"i and water-use efficiency), and higher instantaneous (A/E) and long-term (@D) water-use efficiency than females. Furthermore, male trees exhibited greater stomatal sensitivity to both declining soil water content and increasing leaf-to-air vapor pressure gradients, a measure of evaporative demand. Higher rates of carbon fixation in female trees were correlated with higher g, higher leaf nitrogen concentrations, and greater stomatal densities. For females growing in both wet and dry habitats, vegetative shoots had higher growth rates than reproductive shoots, while for males, growth rates of the two shoot types did not differ. In streamside habitats, female trees exhibited significantly greater vegetative shoot growth when compared to male trees. In contrast, males showed slightly greater vegetative and much greater reproductive shoot growth in non-streamside habitats. Regardless of habitat or growing conditions, females allocated proportionately more of their aboveground biomass to reproduction than did males. These results suggest that (1) gender-specific physiological traits can help explain the maintenance of habitat-specific sex ratio biases in A. negundo along a soil moisture gradient, and (2) that the combination of the gender-specific physiology, growth, and allocation differences contribute to differences in the size (=age) structure of male and female plants within the population. Gender-specific physiological differences may have evolved as a product of selection to meet significantly different costs associated with reproduction in male and female plants.
URL [本文引用: 1]
正 杨树的许多优良特性(生长快、易繁殖、适应性强、轮伐期短、用途广)使人们对它的经营、栽培十分感兴趣,在解决木材供求矛盾,实现大地园林化方面起着重要作用。因此,对它的研究已经引起许多****的关注。笔者在研究国产杨树分类的同时,对国产杨树地
, 7(
URL [本文引用: 1]
正 杨树的许多优良特性(生长快、易繁殖、适应性强、轮伐期短、用途广)使人们对它的经营、栽培十分感兴趣,在解决木材供求矛盾,实现大地园林化方面起着重要作用。因此,对它的研究已经引起许多****的关注。笔者在研究国产杨树分类的同时,对国产杨树地
193,
DOI:10.1126/science.193.4253.597URL [本文引用: 1]
( 156,
[本文引用: 1]
33,
DOI:10.1111/j.1558-5646.1979.tb04744.xURLPMID:28568430 [本文引用: 1]
Field studies of dioecious clones of quaking aspen, Populus tremuloides Michx., in the Colorado Rockies, demonstrated significant spatial segregation of sexes over elevational gradients. Female clones are numerically predominant at lower elevations, and male clones are overwhelmingly more common at high elevations. Annual radial growth increment measurements show that growth rates of female clones decrease more rapidly with increasing elevation than do growth rates for male clones. Yet over all elevations, female clones show a consistently higher radial growth increment than males. This result runs counter to previously published accounts which attribute higher vegetative growth rates to males because of the presumably higher cost of sexual reproduction for females. These results clearly could not have been predicted from current sex ratio or resource allocation theory alone and argue that an empirical approach to adult sex ratio and energy partitioning strategies is an essential ingredient in developing a sound understanding of these aspects of population biology.
DOI:10.3321/j.issn:1000-0933.2009.02.016URL [本文引用: 1]
以黄河河口盐沼实地调查的67个样地19个植物种的重要值,运用双向指示种分析将黄河河口盐沼植被分为柽柳-翅碱蓬+补血草+碱蓬群落、翅碱蓬群落、柽柳-芦苇+翅碱蓬群落、芦苇群落、穗状狐尾藻+芦苇群落和旱柳-芦苇+荻群落。利用典范对应分析(CCA)分析了土壤盐分、pH、Na^+、K^+、Ca^2+、Mg^2+、Cl^-、全氮、全磷、全碳、有机质等11个土壤化学因子与黄河河口盐沼植被分布的相关关系。CCA排序结果表明,土壤盐分和土壤pH是影响黄河河口盐沼植被分布的主要土壤化学因子。CCA排序第一轴与土壤盐分呈显著正相关关系(P〈0.001),第二轴主要和土壤pH呈显著负相关关系(P〈0.001)。柽柳-翅碱蓬+补血草+碱蓬群落排列于排序图的右上部,与生境土壤中高含盐量及中等pH相对应,穗状狐尾藻+芦苇群落和芦苇群落分布于第一排序轴的最左端,主要与土壤低含盐量相关,翅碱蓬群落位于第二排序轴的下侧,与较高的土壤pH相关,柽柳-芦苇+翅碱蓬群落和旱柳-芦苇+荻群落,土壤pH和盐分均较低。通过物种丰富度R、香农维纳多样性H′、物种均匀度E等指数与土壤化学因子的相关分析,发现黄河河口盐沼植物物种多样性与土壤盐分没有呈现出与土壤盐分很好的负相关关系,物种丰富度R、香农维纳多样性H′、物种均匀度E均与土壤盐分呈现显著正相关关系;R、H′与土壤pH呈现出十分显著的负相关关系;R、H′与土壤Ca^2+、Mg^2+含量呈现极为显著正相关关系。
, 29,
DOI:10.3321/j.issn:1000-0933.2009.02.016URL [本文引用: 1]
以黄河河口盐沼实地调查的67个样地19个植物种的重要值,运用双向指示种分析将黄河河口盐沼植被分为柽柳-翅碱蓬+补血草+碱蓬群落、翅碱蓬群落、柽柳-芦苇+翅碱蓬群落、芦苇群落、穗状狐尾藻+芦苇群落和旱柳-芦苇+荻群落。利用典范对应分析(CCA)分析了土壤盐分、pH、Na^+、K^+、Ca^2+、Mg^2+、Cl^-、全氮、全磷、全碳、有机质等11个土壤化学因子与黄河河口盐沼植被分布的相关关系。CCA排序结果表明,土壤盐分和土壤pH是影响黄河河口盐沼植被分布的主要土壤化学因子。CCA排序第一轴与土壤盐分呈显著正相关关系(P〈0.001),第二轴主要和土壤pH呈显著负相关关系(P〈0.001)。柽柳-翅碱蓬+补血草+碱蓬群落排列于排序图的右上部,与生境土壤中高含盐量及中等pH相对应,穗状狐尾藻+芦苇群落和芦苇群落分布于第一排序轴的最左端,主要与土壤低含盐量相关,翅碱蓬群落位于第二排序轴的下侧,与较高的土壤pH相关,柽柳-芦苇+翅碱蓬群落和旱柳-芦苇+荻群落,土壤pH和盐分均较低。通过物种丰富度R、香农维纳多样性H′、物种均匀度E等指数与土壤化学因子的相关分析,发现黄河河口盐沼植物物种多样性与土壤盐分没有呈现出与土壤盐分很好的负相关关系,物种丰富度R、香农维纳多样性H′、物种均匀度E均与土壤盐分呈现显著正相关关系;R、H′与土壤pH呈现出十分显著的负相关关系;R、H′与土壤Ca^2+、Mg^2+含量呈现极为显著正相关关系。
19,
DOI:10.1111/gcb.12230PMID:23666790 [本文引用: 2]
Air temperatures in the arid western United States are predicted to increase over the next century. These increases will likely impact the distribution of plant species, particularly dioecious species that show a spatial segregation of the sexes across broad resource gradients. On the basis of spatial segregation patterns, we hypothesized that temperature increases will have a greater negative impact on female plants compared with co-occurring male plants of dioecious species. This hypothesis was tested by examining the whole-plant carbon and water relations of 10-year-old female (n = 18) and male (n = 13) Acer negundo Sarg. trees grown in a common garden in Salt Lake City, UT. The trees were established from cuttings collected where the growing season temperature averaged about 6.5 C cooler than at the common garden. During May and June, stem sap flux (Js) was similar between genders, but averaged 25% higher in males during the warmer months of July and August. Daytime canopy stomatal conductance (gs) per unit leaf area was 12% higher in females in May : June, but was 11% higher in males in July : August. We combined measurements of sap flux caled transpiration with measurements of tree allometry and 13C of leaf soluble sugars to estimate whole-tree carbon assimilation (Atree) and water use efficiency (WUE) (Atree : Etree). Atree was similar between genders until late August when Atree was 32% higher in male trees. Atree : Etree was on average 7% higher in females than in males during the growing season. Patterns of Js, gs, Atree and Atree : Etree in the present study were in contrast to those previously reported for A. negundo genders under native growing season temperatures. Results suggest that the spatial segregation of the sexes could shift under global warming such that female plants lose their dominance in high-resource habitats, and males increase their dominance in relatively lower-resource habitats.
, 27,
DOI:10.1093/treephys/27.3.399URLPMID:17241981 [本文引用: 1]
Abstract In most woody plants, leaf morphological and physiological characteristics are extremely variable across environmental gradients, particularly across altitudinal gradients. Hippophae rhamnoides L., a dioecious and deciduous shrub species, occupies a wide range of habitats in the Wolong Nature Reserve, southwest China. We measured growth, sex ratio and morphological and physiological characteristics of leaves in male and female H. rhamnoides individuals along an altitudinal gradient. Shoot height (HT), leaf N concentration per unit dry mass (N(mass)), leaf N concentration per unit area (N(area)) and leaf carbon isotope composition (delta(13)C) were higher in males than in females, whereas females had higher specific leaf area (SLA), stomatal length (SL) and stomatal index (SI) (i.e., total stomatal length per unit leaf area) than males along the altitudinal gradient. Females also had higher values of stomatal density (SD) at all altitudes except 2800 m. The male:female ratio (MFR) was biased toward males at all altitudes except at 2800 m. Changes in HT, MFR, SLA, SD, SL, SI, N(mass), N(area) and delta(13)C along the altitudinal gradient were nonlinear. Below 2800 m, HT, SLA, SD, SL and SI increased with increasing altitude, but above 2800 m they decreased with increasing altitude. In contrast, MFR, N(mass), N(area) and delta(13)C showed the opposite patterns with altitude. Consequently, we confirmed our hypotheses: (1) stressful environments have a more negative impact on females than on males in a variety of ways; (2) under optimal growth conditions the sex ratio is even, but becomes male-biased as resources become limited; and (3) there is an optimum altitudinal range at around 2800 m for the growth of H. rhamnoides in the Wolong Nature Reserve.
168,
DOI:10.1016/j.plantsci.2005.02.001URL [本文引用: 1]
Sexual differences in cold acclimation and freezing tolerance development of two contrasting sea buckthorn ( Hippophae rhamnoides L.) ecotypes from northern and southern regions in China were recorded after exposure to short day photoperiod (SD) and low temperature (LT). The results demonstrated that cold acclimation could be triggered by exposing the plants to SD or LT alone, and that a combination of both treatments had an additive effect on freezing tolerance in all plants tested. However, development of freezing tolerance was dependent on the sex of plants under SD and LT, the males were clearly more responsive to SD and LT than the females in both ecotypes studied. On the other hand, development of freezing tolerance was also ecotype-dependent, the northern ecotype was more responsive to SD and LT than the southern ecotype, resulting in earlier cold acclimation under SD and higher freezing tolerance under LT. Moreover, development of freezing tolerance induced by SD and LT was accompanied by changes in ABA levels. These alterations in ABA levels were different in different treatments, ecotypes and sexes. Therefore, the differences in SD and LT-induced physiological responses showed that the different ecotypes and the different sexes might employ different survival strategies under environmental stress.
URL [本文引用: 1]
This paper studied the sex-specific differences of male and female kg). Under the effects of aluminum, the malonaldehyde (MDA) and soluble protein (Pr) contents of the male and female seedlings increased significantly () of both male and female seedlings decreased significantly (=0.001), and the transpiration rate () of the female seedlings decreased (=0.007) and the instant water use efficiency (WUE) increased significantly, while no significant variations were observed in the and WUE of the male seedlings. The total chlorophyll and chlorophyll a contents and chlorophyll a/b ratio of the females decreased significantly, resulting in a significantly higher chlorophyll a/b ratio of the males. The specific leaf area (SLA) of the females decreased but that of the males increased significantly. No significant variation was observed on the leaf- and stem dry mass. Comparing with the females, the males had higher Pr and chlorophyll contents and higher active antioxidant enzymes activity to maintain higher , and thus, had greater resistance against aluminum stress.
, 23,
URL [本文引用: 1]
This paper studied the sex-specific differences of male and female kg). Under the effects of aluminum, the malonaldehyde (MDA) and soluble protein (Pr) contents of the male and female seedlings increased significantly () of both male and female seedlings decreased significantly (=0.001), and the transpiration rate () of the female seedlings decreased (=0.007) and the instant water use efficiency (WUE) increased significantly, while no significant variations were observed in the and WUE of the male seedlings. The total chlorophyll and chlorophyll a contents and chlorophyll a/b ratio of the females decreased significantly, resulting in a significantly higher chlorophyll a/b ratio of the males. The specific leaf area (SLA) of the females decreased but that of the males increased significantly. No significant variation was observed on the leaf- and stem dry mass. Comparing with the females, the males had higher Pr and chlorophyll contents and higher active antioxidant enzymes activity to maintain higher , and thus, had greater resistance against aluminum stress.
DOI:10.3969/j.issn.1002-204X.2012.05.001URL [本文引用: 1]
对小五台山地区青杨种群进行野 外调查和数据分析研究,发现雌雄植株的性成熟条件具有差异。雌株性成熟的最小年龄(17 a)小于雄株(21 a),而雄株性成熟时的最小胸径和株高都大于雌株,不同性别的青杨其性成熟条件存在差异,雌株性成熟时间一般早于雄株,并且其成熟时的个体也小于雄株。
, 53,
DOI:10.3969/j.issn.1002-204X.2012.05.001URL [本文引用: 1]
对小五台山地区青杨种群进行野 外调查和数据分析研究,发现雌雄植株的性成熟条件具有差异。雌株性成熟的最小年龄(17 a)小于雄株(21 a),而雄株性成熟时的最小胸径和株高都大于雌株,不同性别的青杨其性成熟条件存在差异,雌株性成熟时间一般早于雄株,并且其成熟时的个体也小于雄株。
DOI:10.3724/SP.J.1258.2012.00109URL [本文引用: 1]
通过野外样方调查和室内种子萌发实验两种方法,对河北小五台山天然青杨(Populus cathayana)种群的更新方式进行了研究,以揭示落叶层的化感作用和机械阻挡作用对青杨种子萌发的干扰机理。结果显示:1)种群样方中的幼苗都为无性繁殖的克隆分株,种子繁殖的幼苗年自然存活率为0%;2)落叶层对种子幼苗的存活率有显著影响。50mg·mL-1浓度的落叶水浸液可使青杨种子发芽率降低41%,使主根长度减少95%,100mg·mL-1浓度的落叶水浸液则完全抑制种子萌发;单层和多层落叶对种子萌发产生的影响差异不显著,都能完全阻碍种子的根系正常生长,导致幼苗脱水干枯死亡。结果表明,在高海拔山区的青杨天然林中,由于不断积累的落叶层通过化感作用和机械阻挡作用严重影响种子的萌发、定根以及正常生长,从而导致种子更新的途径受阻,而只能通过无性繁殖来完成正常的种群更新。
, 36,
DOI:10.3724/SP.J.1258.2012.00109URL [本文引用: 1]
通过野外样方调查和室内种子萌发实验两种方法,对河北小五台山天然青杨(Populus cathayana)种群的更新方式进行了研究,以揭示落叶层的化感作用和机械阻挡作用对青杨种子萌发的干扰机理。结果显示:1)种群样方中的幼苗都为无性繁殖的克隆分株,种子繁殖的幼苗年自然存活率为0%;2)落叶层对种子幼苗的存活率有显著影响。50mg·mL-1浓度的落叶水浸液可使青杨种子发芽率降低41%,使主根长度减少95%,100mg·mL-1浓度的落叶水浸液则完全抑制种子萌发;单层和多层落叶对种子萌发产生的影响差异不显著,都能完全阻碍种子的根系正常生长,导致幼苗脱水干枯死亡。结果表明,在高海拔山区的青杨天然林中,由于不断积累的落叶层通过化感作用和机械阻挡作用严重影响种子的萌发、定根以及正常生长,从而导致种子更新的途径受阻,而只能通过无性繁殖来完成正常的种群更新。
URL [本文引用: 1]
正杨属(Populus sp.)是一种分布范围较广的泛域性树种.世界上天然杨树分布界限大致界于北回归线(N23.5°)至北极圈线(N67.5°)之间.南半球除个别地区外,很少见其分布.白杨派的山杨派分布偏北,从北极圈到40°均见存在.胡杨跨越的纬度也宽,从北纬45°1′至赤道的肯尼亚均见其足迹.我国是杨树分布的中心,分布于北纬25—53°,东经80°—134°范围之内.滇杨(Populus yunnanensis)广泛分布于云贵高原坝子地区.向南可达北纬25°左右.杨树在垂直分布上所占的空间也较宽阔.从滨海平原直到高山均有分布,如藏青杨(P.szechuanica var.tibetica)可分布在青藏高原海拔4000多米的河谷阶地.昆仑山2400—3600米之间的山麓下部有苦杨(P.IaurifoliaLedeb)分布.可见,无论从水平和垂直分布来看,杨树所占的地域和空间是非常广泛的,如果考虑到人栽
, 15,
URL [本文引用: 1]
正杨属(Populus sp.)是一种分布范围较广的泛域性树种.世界上天然杨树分布界限大致界于北回归线(N23.5°)至北极圈线(N67.5°)之间.南半球除个别地区外,很少见其分布.白杨派的山杨派分布偏北,从北极圈到40°均见存在.胡杨跨越的纬度也宽,从北纬45°1′至赤道的肯尼亚均见其足迹.我国是杨树分布的中心,分布于北纬25—53°,东经80°—134°范围之内.滇杨(Populus yunnanensis)广泛分布于云贵高原坝子地区.向南可达北纬25°左右.杨树在垂直分布上所占的空间也较宽阔.从滨海平原直到高山均有分布,如藏青杨(P.szechuanica var.tibetica)可分布在青藏高原海拔4000多米的河谷阶地.昆仑山2400—3600米之间的山麓下部有苦杨(P.IaurifoliaLedeb)分布.可见,无论从水平和垂直分布来看,杨树所占的地域和空间是非常广泛的,如果考虑到人栽
DOI:10.11821/dlyj201605014URL [本文引用: 1]
随着创意经济的兴起和旅游者需 求的变化,发展创意旅游日益成为消费热点和推动旅游业转型升级的有效途径。创意旅游资源是创意旅游发展的基础,其产生的空间效应是区域旅游研究的重要内 容,对提升区域旅游竞争力具有重要意义。以苏州中心城区为例,综合运用最近邻指数、不平衡指数、核密度分析和使用者温度计量模型等方法,深入研究城市创意 旅游资源空间效应。结果显示:1创意旅游资源的融入使苏州中心城区整体和各区域的旅游资源空间分布集聚度增大,但各区域增大程度和资源空间分布状态变化不 同;2融入创意旅游资源后苏州中心城区整体旅游资源区域分布呈集中态势,且分布的均衡度降低;3创意旅游资源的融入促进了区域旅游资源空间效应的发挥,苏 州中心城区由以姑苏区为"单核心"的"众星拱月"空间格局转变为以姑苏区—工业园区为"双核心"的"日月同辉"空间格局,从而实现苏州中心城区"双核"旅 游空间发展模式。
, 35,
DOI:10.11821/dlyj201605014URL [本文引用: 1]
随着创意经济的兴起和旅游者需 求的变化,发展创意旅游日益成为消费热点和推动旅游业转型升级的有效途径。创意旅游资源是创意旅游发展的基础,其产生的空间效应是区域旅游研究的重要内 容,对提升区域旅游竞争力具有重要意义。以苏州中心城区为例,综合运用最近邻指数、不平衡指数、核密度分析和使用者温度计量模型等方法,深入研究城市创意 旅游资源空间效应。结果显示:1创意旅游资源的融入使苏州中心城区整体和各区域的旅游资源空间分布集聚度增大,但各区域增大程度和资源空间分布状态变化不 同;2融入创意旅游资源后苏州中心城区整体旅游资源区域分布呈集中态势,且分布的均衡度降低;3创意旅游资源的融入促进了区域旅游资源空间效应的发挥,苏 州中心城区由以姑苏区为"单核心"的"众星拱月"空间格局转变为以姑苏区—工业园区为"双核心"的"日月同辉"空间格局,从而实现苏州中心城区"双核"旅 游空间发展模式。
DOI:10.3321/j.issn:1005-0094.2004.01.017URL [本文引用: 1]
通过野外群落调查,分析了小五台山北坡植物物种多样性的垂直梯度变化。结果表明:(1)小五台山北坡的物种丰富度随海拔的升高逐渐减小,物种组成趋于简单,乔木树种渐少。d多样性指数变化较小,但呈现出随海拔升高先增大、后减小的趋势。(2)β多样性指数很好地反映了群落之问的变化。相异系数峰值出现在海拔1.400-1500m处灌丛向森林的过渡带和海拔2600—2700m处森林向亚高山草甸的过渡带。海拔1400-1500m处出现的Cody指数极大值反映了灌丛群落向森林群落的变化,而Cody指数在海拔2100—2200m的极大值反映了阔叶林和针叶林之间的过渡。(3)作为小五台山两种最为重要的阔叶树种,白桦(Betula platyphylla)和红桦(Betula albosinensis)沿海拔梯度出现明显的替代现象,随着海拔的升高,白桦逐渐为红桦所取代。
, 12,
DOI:10.3321/j.issn:1005-0094.2004.01.017URL [本文引用: 1]
通过野外群落调查,分析了小五台山北坡植物物种多样性的垂直梯度变化。结果表明:(1)小五台山北坡的物种丰富度随海拔的升高逐渐减小,物种组成趋于简单,乔木树种渐少。d多样性指数变化较小,但呈现出随海拔升高先增大、后减小的趋势。(2)β多样性指数很好地反映了群落之问的变化。相异系数峰值出现在海拔1.400-1500m处灌丛向森林的过渡带和海拔2600—2700m处森林向亚高山草甸的过渡带。海拔1400-1500m处出现的Cody指数极大值反映了灌丛群落向森林群落的变化,而Cody指数在海拔2100—2200m的极大值反映了阔叶林和针叶林之间的过渡。(3)作为小五台山两种最为重要的阔叶树种,白桦(Betula platyphylla)和红桦(Betula albosinensis)沿海拔梯度出现明显的替代现象,随着海拔的升高,白桦逐渐为红桦所取代。
120,
DOI:10.1086/284014URL [本文引用: 1]
In the majority of the populations of seed plants, there is a single morph, a "cosex," which combines maternal and paternal functions in the same individuals. Fewer than 10% of populations are dimorphic, with differentiated males and females specializing in one sexual function. Evolution of sex conditions has been principally from cosexuality to separate sexes. Conditions under which unisexual mutants invade cosexual populations are examined. The advantages of cosexuality include the facilitation of mating, reproductive economies, noninterchangeable diminishing returns imposed on paternal and maternal fitness by Bateman''s Principle and the distinct spatial distribution of maternally and paternally derived offspring, and bet-hedging. Females and males share an ability to reproduce more efficiently than cosexes under certain conditions. Females (but not males) may gain benefits from increased outcrossing, or they may gain better seed dispersal of their more massive crops, while males can conceivably obtain better pollen transfer than cosexes under certain circumstances. The overwhelming predominance of gynodioecy over androdioecy, and the higher incidence of separate sexes in larger plants and in plants pollinated by generalist insects or by wind are considered to be primarily associated with the advantages of outbreeding for females. Alternative hypotheses to explain the recently discovered correlation between separate sexes and bird dispersal are discussed.
URL [本文引用: 1]
随着信息技术的发展,点状专题数据激增,需要突破传统制图方法的表达局限,利用海量点群数据对专题信息进行快速、直观、综合的制图表达。文中以南京市银行的ATM网点数据以及全国KTV营业点分布为制图数据源,探讨了点群数据核密度估计图以及三维核密度曲面图的制作方法,并对其中的关键技术作了深入的研究。研究表明,基于核密度估计的网点密度制图方法,消除了边界分隔对密度计算精度的影响,能更好反映点群数据的空间分布密度、区域差异、动态变化等特征,具备更丰富的表现力。
, 26,
URL [本文引用: 1]
随着信息技术的发展,点状专题数据激增,需要突破传统制图方法的表达局限,利用海量点群数据对专题信息进行快速、直观、综合的制图表达。文中以南京市银行的ATM网点数据以及全国KTV营业点分布为制图数据源,探讨了点群数据核密度估计图以及三维核密度曲面图的制作方法,并对其中的关键技术作了深入的研究。研究表明,基于核密度估计的网点密度制图方法,消除了边界分隔对密度计算精度的影响,能更好反映点群数据的空间分布密度、区域差异、动态变化等特征,具备更丰富的表现力。
[本文引用: 1]
[本文引用: 1]
4,
DOI:10.1055/s-2002-20441URL [本文引用: 2]
Abstract: This study focuses on the sex ratio and spatial distribution of males and females in three populations of the endemic and restricted tropical dioecious shrub, Baccharis concinna (Asteraceae) in the mountainous region of Serra do Cip , southeastern Brazil. The proportion of female plants in the population at lower elevation (1000 m a.s.l.) was significantly greater than of male plants. At this elevation of P/N and Ca/Al ratios in the soil were also greater indicating better nutritional status of the soils. The concentration of aluminium increased significantly with the elevation ( p < 0.001), perhaps rendering soils less conducive to female plants at higher elevations. Female plants are possibly adversely affected to a greater extent by soil quality than male plants. The spatial distribution of the populations within habitat was tested by the K(t) function, where the neighbourhood of a given individual was defined by a circle with a radius (t) up to 3 m. Despite the strong tendency for aggregation, the distribution of the sexes within habitats was random and the hypothesis was not supported. The independent distribution of the sexes within habitats may be explained by nutrient homogeneity of the soils, as well as by an absence of antagonism between the sexes. Nevertheless, we found a trend for males and females to be aggregated according to their gender.
[本文引用: 1]
[本文引用: 1]
82,
DOI:10.1002/j.1537-2197.1995.tb11504.xURL [本文引用: 1]
, 37,
[本文引用: 1]
DOI:10.17521/cjpe.2006.0117URL [本文引用: 1]
该文根据“空间代替时间”的原则和对马尾松(Pinus massoniana)种群的重要值-平均胸径的变动趋势的分析,确定5个森林群落为广东省黑石顶自然保护区森林群落演替的一个时间序列;并在此基础上,运用分形理论的计盒维数和信息维数,对演替过程中马尾松种群空间格局的动态进行了分形分析.结果表明,马尾松种群的计盒维数和信息维数2个参数值均呈递减趋势,与其个体数、重要值变动趋势一致.在群落的演替过程中,马尾松种群的空间占据能力不断下降,种群呈衰退趋势.随其在群落中的优势地位逐渐被其它种群取代,群落将由以马尾松占绝对优势的单优群落演替为多优常绿阔叶林群落.分析结果同时表明,分形分析是群落演替过程中种群空间格局动态研究的有效方法,分形维数则能反映种群格局的尺度变化规律.
, 30,
DOI:10.17521/cjpe.2006.0117URL [本文引用: 1]
该文根据“空间代替时间”的原则和对马尾松(Pinus massoniana)种群的重要值-平均胸径的变动趋势的分析,确定5个森林群落为广东省黑石顶自然保护区森林群落演替的一个时间序列;并在此基础上,运用分形理论的计盒维数和信息维数,对演替过程中马尾松种群空间格局的动态进行了分形分析.结果表明,马尾松种群的计盒维数和信息维数2个参数值均呈递减趋势,与其个体数、重要值变动趋势一致.在群落的演替过程中,马尾松种群的空间占据能力不断下降,种群呈衰退趋势.随其在群落中的优势地位逐渐被其它种群取代,群落将由以马尾松占绝对优势的单优群落演替为多优常绿阔叶林群落.分析结果同时表明,分形分析是群落演替过程中种群空间格局动态研究的有效方法,分形维数则能反映种群格局的尺度变化规律.
[本文引用: 1]
[本文引用: 1]
URL [本文引用: 3]
以小五台山天然青杨种群为试验对象,通过在其分布海拔范围内(1400-1700 m)设置样方的方式研究青杨雌雄群体的平均胸径、密度、性比、大小级结构和空间分布的差异。结果显示:雌株群体的平均胸径在整个海拔梯度上无显著差异,而海拔1700 m处的群体密度显著低于其它海拔;雄株群体的平均胸径在海拔1700 m最大,显著高于其它海拔,而群体密度在各海拔梯度间无显著差异。在海拔1600 m,雌雄群体的平均胸径最接近,同时密度也最接近。从整个海拔范围来看,青杨雌雄个体的比例(雄/雌)为0.80∶1,性比不偏离1∶1(χ 2 = 2.94, P > 0.05)。但在不同海拔梯度上性比有所不同,低海拔性比为0.44,显著偏雌(χ 21400 = 5.91, P < 0.05),而高海拔性比为2.55,显著偏雄(χ 21700 = 6.56, P < 0.05);随着海拔接近1600 m,性比逐渐趋于1∶1(χ 21600 = 0, P > 0.05)。除海拔1700 m为下降型外,青杨雌雄群体的大小级结构在其它海拔主要表现为稳定型。而最稳定群体结构的分布海拔在雌雄群体间不同。在海拔1400 m,雌株群体中Ⅰ级和Ⅱ级植株占群体比例最大;雄株群体Ⅰ级和Ⅱ级植株占群体比例最大的海拔是1600 m。群体空间分布以聚集分布为主,彼此间无明显差异;但群体间聚集强度的变化在海拔梯度上各有不同,主要表现为雌株群体的 PAI 随海拔的升高逐渐增加,而雄株群体的 PAI 则随海拔的升高呈现出先增加后减少的趋势。研究结果表明了青杨雌雄群体的分布特征沿海拔梯度的变化明显不同,中等海拔区域可能为青杨种群的最适繁衍区。;Dioecious plant species are an important component of terrestrial ecosystems. However, little is known about their ecology, including the factors affecting their distribution. We investigated the ecology of Populus cathayana Rehd, a dioecious and deciduous species that occupies a wide range of habitats in China. We measured the mean diameter at breast height (DBH), population density, sex ratio, size structure, and spatial distribution of male and female P. cathayana populations in a series of forest plots along an altitudinal gradient (1400-1700 m) in the Xiaowutai Mountains. The results showed that the trends in mean DBH and density were significantly different for males and females. There was no significant difference in mean DBH along the altitudinal gradient in female populations and the population density at 1700 m was lower than at other altitudes. Compared with females, the maximum mean DBH for males was observed at 1700 m and was significantly larger than at other altitudes. However, there was no variation in the population density of males associated with altitude. The mean DBH in male and female populations was nearly equal at 1600 m and the density at this altitude was also very similar among male and female populations. The sex ratio (male∶female) tended to increase along the altitudinal gradient. Although the sex ratio was close to 1∶1 (χ 2 = 2.94, P > 0.05) for the entire population (1400-1700 m), the ratio was biased towards females (χ 21400 = 5.91, P < 0.05) at low altitudes and biased toward males (χ 21700 = 6.56, P < 0.05) at high altitudes. The sex ratio approached 1∶1 (χ 21600 = 0, P > 0.05) as the altitude tended towards 1600 m. Furthermore, the size structure of all male and female P. cathayana populations revealed a steady-state distribution along the altitudinal gradient (except for a decline-state distribution at 1700 m). However, the distribution of the size classes differed between male and female P. cathayana populations. A large proportion of class Ⅰ and Ⅱ were observed at 1400 m in female populations but at 1600 m in male populations. In addition, we also found that the distribution of male and female populations was affected by altitude. We observed a random distribution pattern at low altitudes and a clumped distribution pattern in most male and female populations at other altitudes, though we did not detect a difference among the sexes. However, the aggregation intensity between male and female P. cathayana populations differed markedly along the elevation gradient. The aggregation intensity of female populations increased gradually along the elevation gradient whereas the change in aggregation intensity was nonlinear in male populations. Below 1500 m, the aggregation intensity increased with increasing altitude, but then decreased with increasing altitude above 1500 m. This phenomenon may be explained by differences in the adaptability of male and female P. cathayana plants. In summary, we showed that differences in the distribution of male and female P. cathayana populations along an altitudinal gradient. And we conclude that P. cathayana populations are likely to reproduce and survive best at moderate altitudes.
, 31,
URL [本文引用: 3]
以小五台山天然青杨种群为试验对象,通过在其分布海拔范围内(1400-1700 m)设置样方的方式研究青杨雌雄群体的平均胸径、密度、性比、大小级结构和空间分布的差异。结果显示:雌株群体的平均胸径在整个海拔梯度上无显著差异,而海拔1700 m处的群体密度显著低于其它海拔;雄株群体的平均胸径在海拔1700 m最大,显著高于其它海拔,而群体密度在各海拔梯度间无显著差异。在海拔1600 m,雌雄群体的平均胸径最接近,同时密度也最接近。从整个海拔范围来看,青杨雌雄个体的比例(雄/雌)为0.80∶1,性比不偏离1∶1(χ 2 = 2.94, P > 0.05)。但在不同海拔梯度上性比有所不同,低海拔性比为0.44,显著偏雌(χ 21400 = 5.91, P < 0.05),而高海拔性比为2.55,显著偏雄(χ 21700 = 6.56, P < 0.05);随着海拔接近1600 m,性比逐渐趋于1∶1(χ 21600 = 0, P > 0.05)。除海拔1700 m为下降型外,青杨雌雄群体的大小级结构在其它海拔主要表现为稳定型。而最稳定群体结构的分布海拔在雌雄群体间不同。在海拔1400 m,雌株群体中Ⅰ级和Ⅱ级植株占群体比例最大;雄株群体Ⅰ级和Ⅱ级植株占群体比例最大的海拔是1600 m。群体空间分布以聚集分布为主,彼此间无明显差异;但群体间聚集强度的变化在海拔梯度上各有不同,主要表现为雌株群体的 PAI 随海拔的升高逐渐增加,而雄株群体的 PAI 则随海拔的升高呈现出先增加后减少的趋势。研究结果表明了青杨雌雄群体的分布特征沿海拔梯度的变化明显不同,中等海拔区域可能为青杨种群的最适繁衍区。;Dioecious plant species are an important component of terrestrial ecosystems. However, little is known about their ecology, including the factors affecting their distribution. We investigated the ecology of Populus cathayana Rehd, a dioecious and deciduous species that occupies a wide range of habitats in China. We measured the mean diameter at breast height (DBH), population density, sex ratio, size structure, and spatial distribution of male and female P. cathayana populations in a series of forest plots along an altitudinal gradient (1400-1700 m) in the Xiaowutai Mountains. The results showed that the trends in mean DBH and density were significantly different for males and females. There was no significant difference in mean DBH along the altitudinal gradient in female populations and the population density at 1700 m was lower than at other altitudes. Compared with females, the maximum mean DBH for males was observed at 1700 m and was significantly larger than at other altitudes. However, there was no variation in the population density of males associated with altitude. The mean DBH in male and female populations was nearly equal at 1600 m and the density at this altitude was also very similar among male and female populations. The sex ratio (male∶female) tended to increase along the altitudinal gradient. Although the sex ratio was close to 1∶1 (χ 2 = 2.94, P > 0.05) for the entire population (1400-1700 m), the ratio was biased towards females (χ 21400 = 5.91, P < 0.05) at low altitudes and biased toward males (χ 21700 = 6.56, P < 0.05) at high altitudes. The sex ratio approached 1∶1 (χ 21600 = 0, P > 0.05) as the altitude tended towards 1600 m. Furthermore, the size structure of all male and female P. cathayana populations revealed a steady-state distribution along the altitudinal gradient (except for a decline-state distribution at 1700 m). However, the distribution of the size classes differed between male and female P. cathayana populations. A large proportion of class Ⅰ and Ⅱ were observed at 1400 m in female populations but at 1600 m in male populations. In addition, we also found that the distribution of male and female populations was affected by altitude. We observed a random distribution pattern at low altitudes and a clumped distribution pattern in most male and female populations at other altitudes, though we did not detect a difference among the sexes. However, the aggregation intensity between male and female P. cathayana populations differed markedly along the elevation gradient. The aggregation intensity of female populations increased gradually along the elevation gradient whereas the change in aggregation intensity was nonlinear in male populations. Below 1500 m, the aggregation intensity increased with increasing altitude, but then decreased with increasing altitude above 1500 m. This phenomenon may be explained by differences in the adaptability of male and female P. cathayana plants. In summary, we showed that differences in the distribution of male and female P. cathayana populations along an altitudinal gradient. And we conclude that P. cathayana populations are likely to reproduce and survive best at moderate altitudes.
[本文引用: 1]
, 37,
[本文引用: 1]
, 28,
DOI:10.1093/treephys/28.11.1751URLPMID:18765380 [本文引用: 2]
Abstract We investigated sex-related photosynthetic responses to drought in the dioecious species, Populus cathayana Rehd. Plants were subjected to two watering regimes (100% and 30% of field capacity) in a semi-controlled environment. Drought significantly decreased leaf area (LA), total number of leaves (TNL), specific leaf area (SLA), relative water content, net photosynthetic rate (P(n)), transpiration (E), stomatal conductance (g(s)), intercellular CO(2) concentration (C(i)), light saturation point (L(SP)), apparent quantum yield (Phi), carboxylation efficiency (CE), light-saturated photosynthetic rate (P(max)), maximum efficiency of PSII (F(v)/F(m)) and maximum effective quantum yield of PSII (Yield), and increased the total chlorophyll concentration (TC), CO(2) compensation point (Gamma), non-photochemical quenching coefficient, peroxidase (POD) activity and carbon isotope composition (delta(13)C). Moreover, differences between males and females were detected in many of these responses. In the drought treatment, males exhibited significantly higher LA, TNL, TC, concentration of carotenoids (Caro), P(n), E, g(s), C(i), L(SP), Phi, CE, P(max), F(v)/F(m), photochemical quenching coefficient, POD activity and delta(13)C, but a lower SLA, chlorophyll a/b ratio, carotenoids/total chlorophyll ratio and Gamma than females. However, Caro, L(SP), Gamma, Phi, CE and POD activity were apparently associated with sex-related resource demands, because significant differences in these traits were detected between the sexes under well-watered conditions. Our results indicate that drought stress limits photosynthetic capacity more in females than in males.
URL [本文引用: 1]
从温度、CO2、水分以及生境变化4个方面综述了雌雄异株植物的雌雄个体在环境胁迫下出现的不同生理、生态和生化差异.温度胁迫将导致雌雄个体在气孔导度、净同化作用、耐冻性形成以及ABA含量等方面出现不同的生理响应,响应大小受限于外界条件.雄株植物的净光合速率高于雌株,而且随着CO2浓度的增高,二者的光合作用受到明显的促进,生物量均显著增加.水分胁迫使雌雄个体在干物质积累、净光合速率、蒸腾速率、水分利用效率和碳同位素值等生理指标以及部分形态指标呈现显著差异.多数植物的雄株个体在干旱环境中具有较高的水分利用效率,对水分胁迫的抗性更大.不同生境中雌雄异株植物雌雄个体的适应性各不相同.在土壤干燥、养分贫瘠、海拔较高、坡度较大的生境中,雄性植株生长良好,数量较多;而在湿润、肥沃、低海拔或低洼的生境中,雌性植株生长良好.
, 18,
URL [本文引用: 1]
从温度、CO2、水分以及生境变化4个方面综述了雌雄异株植物的雌雄个体在环境胁迫下出现的不同生理、生态和生化差异.温度胁迫将导致雌雄个体在气孔导度、净同化作用、耐冻性形成以及ABA含量等方面出现不同的生理响应,响应大小受限于外界条件.雄株植物的净光合速率高于雌株,而且随着CO2浓度的增高,二者的光合作用受到明显的促进,生物量均显著增加.水分胁迫使雌雄个体在干物质积累、净光合速率、蒸腾速率、水分利用效率和碳同位素值等生理指标以及部分形态指标呈现显著差异.多数植物的雄株个体在干旱环境中具有较高的水分利用效率,对水分胁迫的抗性更大.不同生境中雌雄异株植物雌雄个体的适应性各不相同.在土壤干燥、养分贫瘠、海拔较高、坡度较大的生境中,雄性植株生长良好,数量较多;而在湿润、肥沃、低海拔或低洼的生境中,雌性植株生长良好.
, 136,
DOI:10.1111/j.1399-3054.2009.01222.xURLPMID:19453505 [本文引用: 1]
The acclimation of plants to water deficit is the result of many different physiological and biochemical mechanisms. To gain a better understanding of drought stress acclimation and tolerance mechanisms in Populus cathayana Rehder, we carried out an integrated physiological and comparative proteomic analysis on the drought stress responses of two contrasting populations originating from wet and dry regions in western China. The plantlets were subjected to continuous drought stress by withholding soil water content at 25% of field capacity (FC) for 45 days, while the control treatments were kept at 100% FC. Drought stress significantly inhibited plant growth, decreased net photosynthetic rate and stomatal conductance of leaves, increased the relative electrolyte leakage and malondialdehyde (MDA) content, and, at the same time, accumulated soluble sugars and free proline in both populations tested. The population from the dry climate region exhibited stronger tolerance to drought stress compared with the wet climate population. The proteomic analyses resulted in the identification of 40 drought-responsive proteins. The functional categories of these proteins include the regulation of transcription and translation, photosynthesis, cytoskeleton, secondary metabolism, HSPs/chaperones, redox homeostasis and defense response. The results suggest that poplars' tolerance to drought stress relates to the control of reactive oxygen species (ROS) and to osmoprotective capacity. The differential regulation of some drought-responsive proteins, such as HSPs and the enzymes related to redox homeostasis and regulation of secondary metabolism, plays an important role in poplars' tolerance and acclimation to drought stress. In conclusion, acclimation to water deficit involves changes in cellular metabolism and the regulation of gene networks. The present study not only provides new insights into the mechanisms of acclimation and tolerance to drought stress in different poplar populations but also provides clues for improving poplars' drought tolerance through breeding or genetic engineering.
DOI:10.13287/j.1001-9332.201802.040URL [本文引用: 1]
以温带长白山(CBS)、暖温带关帝山(GDS)、亚热带黑石顶(HSD)样地监测数据为基础,采用成对相关函数g(r)分析了3个样地共有的3科(松科、壳斗科、蔷薇科)树木的空间分布格局及其关联性.结果表明:不同样地3科树木分布数量及结构特征存在差异.松科在GDS分布数量较多,呈双峰型径级结构,在CBS和HSD分布数量少,径级结构近似正态分布;壳斗科在CBS和GDS分布数量少,分别呈双峰型和偏正态径级结构,在HSD分布数量多,呈倒“J”型径级分布;蔷薇科在GDS分布数量多,呈“L”型径级分布,在CBS和HSD分布相对较少,径级结构分别呈倒“J”型和“L”型分布.3科树木空间分布格局在不同样地表现也不同,松科的大径级个体在CBS和GDS小尺度上呈均匀分布,在HSD呈聚集分布,中、小径级在3个样地均呈聚集分布;壳斗科在CBS以大径级个体为主,呈近似随机分布,在GDS和HSD以中、小径级为主,呈聚集性分布格局;蔷薇科在3个样地均为聚集分布.3科树木的聚集程度均随尺度增加而降低.大径级的壳斗科个体在CBS和HSD与松科呈不相关或小尺度负相关关系,中、小径级的壳斗科在CBS和GDS与松科呈负相关关系,但在HSD与松科表现为正相关;松科与蔷薇科在3个样地均表现为负相关;中、小径级的壳斗科与蔷薇科在CBS和GDS呈正相关关系,但在HSD呈负相关关系.总之,3科树木空间分布格局及关联性随径级、尺度而变化且在不同样地内有不同表现.
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DOI:10.13287/j.1001-9332.201802.040URL [本文引用: 1]
以温带长白山(CBS)、暖温带关帝山(GDS)、亚热带黑石顶(HSD)样地监测数据为基础,采用成对相关函数g(r)分析了3个样地共有的3科(松科、壳斗科、蔷薇科)树木的空间分布格局及其关联性.结果表明:不同样地3科树木分布数量及结构特征存在差异.松科在GDS分布数量较多,呈双峰型径级结构,在CBS和HSD分布数量少,径级结构近似正态分布;壳斗科在CBS和GDS分布数量少,分别呈双峰型和偏正态径级结构,在HSD分布数量多,呈倒“J”型径级分布;蔷薇科在GDS分布数量多,呈“L”型径级分布,在CBS和HSD分布相对较少,径级结构分别呈倒“J”型和“L”型分布.3科树木空间分布格局在不同样地表现也不同,松科的大径级个体在CBS和GDS小尺度上呈均匀分布,在HSD呈聚集分布,中、小径级在3个样地均呈聚集分布;壳斗科在CBS以大径级个体为主,呈近似随机分布,在GDS和HSD以中、小径级为主,呈聚集性分布格局;蔷薇科在3个样地均为聚集分布.3科树木的聚集程度均随尺度增加而降低.大径级的壳斗科个体在CBS和HSD与松科呈不相关或小尺度负相关关系,中、小径级的壳斗科在CBS和GDS与松科呈负相关关系,但在HSD与松科表现为正相关;松科与蔷薇科在3个样地均表现为负相关;中、小径级的壳斗科与蔷薇科在CBS和GDS呈正相关关系,但在HSD呈负相关关系.总之,3科树木空间分布格局及关联性随径级、尺度而变化且在不同样地内有不同表现.
DOI:10.3724/SP.J.1258.2012.00081URL [本文引用: 1]
AimsMethodsImportant findings), chlorophyll content, super-oxide dismutase (SOD) activity, plant height, basal diameter, total leaf area, specific leaf area (), root biomass, leaf biomass, stem biomass, total biomass and root/shoot ratio (R/S). Moreover, the waterlogging treatment significantly increased MDA content but decreased SOD activity, , carotenoids (Caro) content, chlorophyll a/b ratio, , root biomass and R/S in female plants, and males had higher stomatal conductance (), intercellular CO concentration (), transpiration rate (), more adventitious roots and greater plant height than females. The results indicated that morphological growth and physiological progress of the P. cathayana seedlings were seriously inhibited by the waterlogging treatment. Males may possess greater waterlogging resistance than females with higher photosynthetic capacity and number of adventitious roots maintaining plant growth under waterlogging stress.
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DOI:10.3724/SP.J.1258.2012.00081URL [本文引用: 1]
AimsMethodsImportant findings), chlorophyll content, super-oxide dismutase (SOD) activity, plant height, basal diameter, total leaf area, specific leaf area (), root biomass, leaf biomass, stem biomass, total biomass and root/shoot ratio (R/S). Moreover, the waterlogging treatment significantly increased MDA content but decreased SOD activity, , carotenoids (Caro) content, chlorophyll a/b ratio, , root biomass and R/S in female plants, and males had higher stomatal conductance (), intercellular CO concentration (), transpiration rate (), more adventitious roots and greater plant height than females. The results indicated that morphological growth and physiological progress of the P. cathayana seedlings were seriously inhibited by the waterlogging treatment. Males may possess greater waterlogging resistance than females with higher photosynthetic capacity and number of adventitious roots maintaining plant growth under waterlogging stress.
URL [本文引用: 1]
On the basis of field investigations,the timberline range of Beitai,the Xiaowutai Mountains was carved up, and the changes in the makeup and diversity of plants with the altitude were discussed.The results showed that the timberline with gradual changes in the northern slope of Beitai ranged from 2620 2800m.In timberline,herbaceous plants were rich,and the diversity was higher than that in coniferous forest and sub alpine meadow zones.The turnover rates of species were gradually hoisting from the centre of timberline to sub alpine meadow and forest zones,and highest at the edge of timberline. Betula,Picea meyreri and Larix principis-ruprechtii species were the ecological indicator for research on environmental changes.Climate indication significance of these arbor species distributed in and near the timberline was also discussed.
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URL [本文引用: 1]
On the basis of field investigations,the timberline range of Beitai,the Xiaowutai Mountains was carved up, and the changes in the makeup and diversity of plants with the altitude were discussed.The results showed that the timberline with gradual changes in the northern slope of Beitai ranged from 2620 2800m.In timberline,herbaceous plants were rich,and the diversity was higher than that in coniferous forest and sub alpine meadow zones.The turnover rates of species were gradually hoisting from the centre of timberline to sub alpine meadow and forest zones,and highest at the edge of timberline. Betula,Picea meyreri and Larix principis-ruprechtii species were the ecological indicator for research on environmental changes.Climate indication significance of these arbor species distributed in and near the timberline was also discussed.
DOI:10.5846/stxb201208221185URL [本文引用: 1]
生境适宜度制图能提供动物适宜生境的空间分布信息,对野生动物种群管理、保护地规划等非常重要.生境适宜度制图的关键是构建生境适宜度模型(habitat suitability model,HSM),只基于动物出现位置数据构建HSM的方法在实践中得到了非常广泛的应用.然而现有的只基于动物出现位置数据构建HSM的方法还不能很好地直接表达动物生境适宜度和环境因子之间具有生态学意义的数量关系,因此也就不能很好地体现环境因子对动物生境利用的生态学作用.提出了一种基于核密度估计构建HSM的方法,在地理信息系统技术支持下,通过运用核密度估计从代表性的动物出现位置数据中估计出动物出现对各个环境因子的概率密度函数来直接表达生境适宜度与各个环境因子之间的数量关系,以体现环境因子对动物生境利用的生态学作用,在此基础上对生境适宜度与各个环境因子之间的数量关系进行综合构建了具有明确生态学意义的HSM用于动物生境适宜度制图.以美国Voyageures国家公园的白尾鹿(Odocoileus virginianus)生境适宜度制图为例,基于365个出现位置点位数据并结合积雪深度、地表覆被类型、森林边界长度和坡度等环境因子数据,开展了该方法的案例研究.通过交叉验证计算连续Boyce指数对制图结果进行评价,结果表明:基于核密度估计方法构建的HSM预测能力强,所得出的生境适宜度图经10次交叉验证,连续Boyce指数平均值为0.75,标准差为0.11,达到了较高精度.此外,由于基于核密度估计的方法能以“生境适宜度和环境因子之间具有生态学意义的数量关系”的形式来直接体现环境因子对动物生境利用的生态学作用,就模型的可解释性而言,该方法要优于现有的其他构建HSM的方法.
, 33,
DOI:10.5846/stxb201208221185URL [本文引用: 1]
生境适宜度制图能提供动物适宜生境的空间分布信息,对野生动物种群管理、保护地规划等非常重要.生境适宜度制图的关键是构建生境适宜度模型(habitat suitability model,HSM),只基于动物出现位置数据构建HSM的方法在实践中得到了非常广泛的应用.然而现有的只基于动物出现位置数据构建HSM的方法还不能很好地直接表达动物生境适宜度和环境因子之间具有生态学意义的数量关系,因此也就不能很好地体现环境因子对动物生境利用的生态学作用.提出了一种基于核密度估计构建HSM的方法,在地理信息系统技术支持下,通过运用核密度估计从代表性的动物出现位置数据中估计出动物出现对各个环境因子的概率密度函数来直接表达生境适宜度与各个环境因子之间的数量关系,以体现环境因子对动物生境利用的生态学作用,在此基础上对生境适宜度与各个环境因子之间的数量关系进行综合构建了具有明确生态学意义的HSM用于动物生境适宜度制图.以美国Voyageures国家公园的白尾鹿(Odocoileus virginianus)生境适宜度制图为例,基于365个出现位置点位数据并结合积雪深度、地表覆被类型、森林边界长度和坡度等环境因子数据,开展了该方法的案例研究.通过交叉验证计算连续Boyce指数对制图结果进行评价,结果表明:基于核密度估计方法构建的HSM预测能力强,所得出的生境适宜度图经10次交叉验证,连续Boyce指数平均值为0.75,标准差为0.11,达到了较高精度.此外,由于基于核密度估计的方法能以“生境适宜度和环境因子之间具有生态学意义的数量关系”的形式来直接体现环境因子对动物生境利用的生态学作用,就模型的可解释性而言,该方法要优于现有的其他构建HSM的方法.
DOI:10.17521/cjpe.2015.0448URL [本文引用: 1]
灌丛化草原的形成机制和群落结构与功能是植被生态学研究的一个重要科学问题。植物种群空间格局分析是研究植物种群相互作用及种群与环境关系的重要手段。灌丛化草原是内蒙古草原的主要类型。该文选择分布在鄂尔多斯市的毛刺锦鸡儿(Caragana tibetica)灌丛化草原为研究对象,布设一个64 m×64 m的样方,采用“三线定位法”确定样方中灌木的空间位置,用点格局的方法分析灌木空间分布格局与种内关联。结果显示:(1)毛刺锦鸡儿种群为增长型种群,成熟毛刺锦鸡儿个体在半径〈3.7 m的范围内为均匀分布,范围增大则呈随机分布;毛刺锦鸡儿幼年个体在0.3–20.4 m之间为聚集分布,其他范围表现为随机分布;死亡个体在0.7–1.4 m范围为聚集分布,其他范围则随机分布。(2)毛刺锦鸡儿存活个体对死亡个体在0–9.9 m范围内为不明显的正相互作用,其他范围无相关关系;成熟个体对幼年个体在〈2.2 m范围表现为负相互作用,在〉2.2 m范围表现为不相关。研究显示,毛刺锦鸡儿灌丛化草原不同发育阶段的毛刺锦鸡儿种群空间分布格局是不同的,并随空间尺度的变化而变化,如果在干旱区采用毛刺锦鸡儿对退化草原进行恢复重建,灌木间的株行距以4 m为宜。
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DOI:10.17521/cjpe.2015.0448URL [本文引用: 1]
灌丛化草原的形成机制和群落结构与功能是植被生态学研究的一个重要科学问题。植物种群空间格局分析是研究植物种群相互作用及种群与环境关系的重要手段。灌丛化草原是内蒙古草原的主要类型。该文选择分布在鄂尔多斯市的毛刺锦鸡儿(Caragana tibetica)灌丛化草原为研究对象,布设一个64 m×64 m的样方,采用“三线定位法”确定样方中灌木的空间位置,用点格局的方法分析灌木空间分布格局与种内关联。结果显示:(1)毛刺锦鸡儿种群为增长型种群,成熟毛刺锦鸡儿个体在半径〈3.7 m的范围内为均匀分布,范围增大则呈随机分布;毛刺锦鸡儿幼年个体在0.3–20.4 m之间为聚集分布,其他范围表现为随机分布;死亡个体在0.7–1.4 m范围为聚集分布,其他范围则随机分布。(2)毛刺锦鸡儿存活个体对死亡个体在0–9.9 m范围内为不明显的正相互作用,其他范围无相关关系;成熟个体对幼年个体在〈2.2 m范围表现为负相互作用,在〉2.2 m范围表现为不相关。研究显示,毛刺锦鸡儿灌丛化草原不同发育阶段的毛刺锦鸡儿种群空间分布格局是不同的,并随空间尺度的变化而变化,如果在干旱区采用毛刺锦鸡儿对退化草原进行恢复重建,灌木间的株行距以4 m为宜。
, 34,
DOI:10.1093/treephys/tpu025URLPMID:24739232 [本文引用: 1]
Previous studies have shown that there are significant sexual differences in the morphological and physiological responses of Populus cathayana Rehder under stressful conditions. However, little is known about sex-specific differences in responses to nutrient deficiencies. In this study, the effects of nitrogen (N) and phosphorus (P) deficiencies on the morphological, physiological and chloroplast ultrastructural traits of P. cathayana males and females were investigated. The results showed that N and P deficiencies significantly decreased plant growth, foliar N and P contents, chlorophyll content, photosynthesis, and instantaneous photosynthetic N- and P-use efficiencies (PNUE and PPUE) in both sexes. Males had higher photosynthesis, higher PNUE and PPUE rates, and a lower accumulation of plastoglobules in chloroplasts than did females when exposed to N-and P-deficiency conditions. Nitrogen-deficient males had higher glutamate dehydrogenase and peroxidase activities, and a more intact chloroplast ultrastructure, but less starch accumulation than did N-deficient females. Phosphorus-deficient males had higher nitrate reductase, glutamine synthetase and acid phosphatase activities, but a lower foliar N : P ratio and less PSII damage than did P-deficient females. These results suggest that N and P deficiencies cause greater negative effects on females than on males, and that the different sexes of P. cathayana may employ different strategies to cope with N and P deficiencies.
URL [本文引用: 1]
研究了100m×140m固定样地内黄连木种群的性比格局和空间分布。结果表明,调查样地中dbh≥4cm的黄连木植株共有2116株,其中包括526株雌树,1200株雄树,性别未确定植株390株。黄连木性比(雄/雌=2.28)显著偏雄(P〈0.001)。雌树和雄树平均胸径分别为7.34和7.81cm,雄树胸径显著大于雌树胸径(P〈0.05)。黄连木幼树、雌树和雄树均呈显著聚集性分布。黄连木幼树与雌树、幼树与雄树均在较小尺度上表现为相互吸引;雌树与雄树则在空间上相互排斥,即雌树与雄树存在空间分离现象;黄连木不同大小以及不同性别植株之间主要表现为相互排斥。
, 29,
URL [本文引用: 1]
研究了100m×140m固定样地内黄连木种群的性比格局和空间分布。结果表明,调查样地中dbh≥4cm的黄连木植株共有2116株,其中包括526株雌树,1200株雄树,性别未确定植株390株。黄连木性比(雄/雌=2.28)显著偏雄(P〈0.001)。雌树和雄树平均胸径分别为7.34和7.81cm,雄树胸径显著大于雌树胸径(P〈0.05)。黄连木幼树、雌树和雄树均呈显著聚集性分布。黄连木幼树与雌树、幼树与雄树均在较小尺度上表现为相互吸引;雌树与雄树则在空间上相互排斥,即雌树与雄树存在空间分离现象;黄连木不同大小以及不同性别植株之间主要表现为相互排斥。
DOI:10.3969/j.issn.1000-5471.2001.02.026URL [本文引用: 1]
对植物种群生态学近 2 0年在其各个领域所取得的进展及其动态作如下归纳 :(1)植物种群生理生态学在向宏观方向发展的同时 ,由于分子生物学和生物技术的兴起 ,也向器官细胞和分子水平发展 . (2 )植物种群繁殖生态主要集中于繁殖分配与繁殖投资 ,分配通货 ,生殖值 ,生活史进化 ,繁殖时间与频率等 . (3)无性系种群生态学主要集中于无性系性 ,生理整合 ,克隆生长格局 ,无性系生长型 ,等级选择模型和空间拓展性等 . (4)植物构件生态主要集中于植物构件种群动态和形态结构与构件的关系 . (5 )遗传生态学主要集中在种群遗传结构 ,变异、分化、适应及其与环境的关系 ,生态型及其遗传基础 ,多态性等 . (6 )植物行为生态学主要对植物觅源生态学研究 ,并集中在资源分配格局 ,表型可塑性 ,资源异质性以及觅源行为和进化 .种群统计学主要涉及图解模型和转移矩阵模型 .植物种群生理生态、生殖生态、遗传生态以及种群数量动态均与分子机制相关联 ,因而成为种群生态研究的前沿
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DOI:10.3969/j.issn.1000-5471.2001.02.026URL [本文引用: 1]
对植物种群生态学近 2 0年在其各个领域所取得的进展及其动态作如下归纳 :(1)植物种群生理生态学在向宏观方向发展的同时 ,由于分子生物学和生物技术的兴起 ,也向器官细胞和分子水平发展 . (2 )植物种群繁殖生态主要集中于繁殖分配与繁殖投资 ,分配通货 ,生殖值 ,生活史进化 ,繁殖时间与频率等 . (3)无性系种群生态学主要集中于无性系性 ,生理整合 ,克隆生长格局 ,无性系生长型 ,等级选择模型和空间拓展性等 . (4)植物构件生态主要集中于植物构件种群动态和形态结构与构件的关系 . (5 )遗传生态学主要集中在种群遗传结构 ,变异、分化、适应及其与环境的关系 ,生态型及其遗传基础 ,多态性等 . (6 )植物行为生态学主要对植物觅源生态学研究 ,并集中在资源分配格局 ,表型可塑性 ,资源异质性以及觅源行为和进化 .种群统计学主要涉及图解模型和转移矩阵模型 .植物种群生理生态、生殖生态、遗传生态以及种群数量动态均与分子机制相关联 ,因而成为种群生态研究的前沿
Demographic studies of a dioecious tree. I. Colonization, sex and age structure of a population of Salix cinerea
1
1989
... 雌雄异株植物是自然生态系统的重要组成部分(
Spatial sex segregation in the dioecious grass Poa ligularis, in northern Patagonia: The role of environmental patchiness
1
2002
... 雌雄异株植物是自然生态系统的重要组成部分(
A model for the evolution of dioecy and gynodioecy
1
1978
... 雌雄异株植物是自然生态系统的重要组成部分(
Sexual competition and N supply interactively affect the dimorphism and competiveness of opposite sexes in Populus cathayana.
1
2015
... 雌雄异株植物是自然生态系统的重要组成部分(
天然次生林蒙古栎种群空间格局
1
2018
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
天然次生林蒙古栎种群空间格局
1
2018
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
Gender-specific physiology, carbon isotope discrimination, and habitat distribution in boxelder, Acer Negundo.
3
1993
... 雌雄异株植物是自然生态系统的重要组成部分(
... ).如
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
中国杨树地理分布规律的研究
1
1988
... 该研究表明, 小五台山的青杨种群主要沿河谷呈狭长带状分布, 雌雄群体均为聚集分布.个体数量在中海拔区域最多、最密集, 随着分布范围向低、高海拔延伸, 个体数量逐渐减少.这种分布特征可能与青杨的生长特性以及小五台山金河沟的地理环境密切相关.青杨是一种喜欢中温、光照、湿润环境的速生高大乔木, 其快速生长的特性需要大量的水分和养分作保障, 往往生长在河滨地带平缓的区域(
中国杨树地理分布规律的研究
1
1988
... 该研究表明, 小五台山的青杨种群主要沿河谷呈狭长带状分布, 雌雄群体均为聚集分布.个体数量在中海拔区域最多、最密集, 随着分布范围向低、高海拔延伸, 个体数量逐渐减少.这种分布特征可能与青杨的生长特性以及小五台山金河沟的地理环境密切相关.青杨是一种喜欢中温、光照、湿润环境的速生高大乔木, 其快速生长的特性需要大量的水分和养分作保障, 往往生长在河滨地带平缓的区域(
Differential resource utilization by the sexes of dioecious plants
1
1976
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
Age and size structure in populations of a long-lived dioecious geophyte:
1
1995
... 雌雄异株植物是自然生态系统的重要组成部分(
Elevational gradients in adult sex ratios and sexual differentiation in vegetative growth rates of Populus tremuloides Michx.
1
1979
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
黄河河口盐沼植被分布、多样性与土壤化学因子的相关关系
1
2009
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
黄河河口盐沼植被分布、多样性与土壤化学因子的相关关系
1
2009
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
Gender specific patterns of carbon uptake and water use in a dominant riparian tree species exposed to a warming climate
2
2013
... 雌雄异株植物是自然生态系统的重要组成部分(
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
Sex-related differences in leaf morphological and physiological responses in Hippophae rhamnoides along an altitudinal gradient
1
2007
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
Sexual differences in cold acclimation and freezing tolerance development in sea buckthorn (Hippophae rhamnoides L.) ecotypes.
1
2005
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
铝胁迫对青杨雌雄幼苗生理生态特征的影响
1
2012
... 雌雄异株植物是自然生态系统的重要组成部分(
铝胁迫对青杨雌雄幼苗生理生态特征的影响
1
2012
... 雌雄异株植物是自然生态系统的重要组成部分(
a). 天然青杨种群性成熟条件及性别间差异
1
2012
... 2016年4月对金河沟谷中青杨种群中接近性成熟(胸径>9 cm)(
a). 天然青杨种群性成熟条件及性别间差异
1
2012
... 2016年4月对金河沟谷中青杨种群中接近性成熟(胸径>9 cm)(
小五台山森林落叶层对天然青杨种群更新方式的影响
1
2012b
... 小五台山国家级自然保护区位于河北张家口蔚县, 114.78°-115.50° E, 39.78°-40.15° N, 属燕山-太行山山系, 海拔1 190-2 882 m, 主峰为东台, 气候类型为温带季风性气候, 年平均气温7.06 ℃, 最冷月气温-18.20 ℃, 最热月气温28.76 ℃, 年降水量为408.48 mm (
小五台山森林落叶层对天然青杨种群更新方式的影响
1
2012b
... 小五台山国家级自然保护区位于河北张家口蔚县, 114.78°-115.50° E, 39.78°-40.15° N, 属燕山-太行山山系, 海拔1 190-2 882 m, 主峰为东台, 气候类型为温带季风性气候, 年平均气温7.06 ℃, 最冷月气温-18.20 ℃, 最热月气温28.76 ℃, 年降水量为408.48 mm (
杨树生长的土壤条件
1
1983
... 该研究表明, 小五台山的青杨种群主要沿河谷呈狭长带状分布, 雌雄群体均为聚集分布.个体数量在中海拔区域最多、最密集, 随着分布范围向低、高海拔延伸, 个体数量逐渐减少.这种分布特征可能与青杨的生长特性以及小五台山金河沟的地理环境密切相关.青杨是一种喜欢中温、光照、湿润环境的速生高大乔木, 其快速生长的特性需要大量的水分和养分作保障, 往往生长在河滨地带平缓的区域(
杨树生长的土壤条件
1
1983
... 该研究表明, 小五台山的青杨种群主要沿河谷呈狭长带状分布, 雌雄群体均为聚集分布.个体数量在中海拔区域最多、最密集, 随着分布范围向低、高海拔延伸, 个体数量逐渐减少.这种分布特征可能与青杨的生长特性以及小五台山金河沟的地理环境密切相关.青杨是一种喜欢中温、光照、湿润环境的速生高大乔木, 其快速生长的特性需要大量的水分和养分作保障, 往往生长在河滨地带平缓的区域(
城市创意旅游资源空间效应及发展模式——以苏州市中心城区为例
1
2016
... 式中, R为平均最近邻指数, dO为地理空间中每个点与之最邻近点之间的欧氏距离平均值, dE为完全随机分布条件下此点的平均最邻近距离.若R = 1, 则点事件随机, 空间呈随机分布; 若R < 1, 则点事件空间彼此邻近, 空间呈集聚分布; 若R > 1, 为点事件空间彼此相斥, 空间呈均匀分布.其显著性水平用p值和Z得分检验, Z得分为标准差的倍数, 其值越大或越小(负值)表示置信度越高(
城市创意旅游资源空间效应及发展模式——以苏州市中心城区为例
1
2016
... 式中, R为平均最近邻指数, dO为地理空间中每个点与之最邻近点之间的欧氏距离平均值, dE为完全随机分布条件下此点的平均最邻近距离.若R = 1, 则点事件随机, 空间呈随机分布; 若R < 1, 则点事件空间彼此邻近, 空间呈集聚分布; 若R > 1, 为点事件空间彼此相斥, 空间呈均匀分布.其显著性水平用p值和Z得分检验, Z得分为标准差的倍数, 其值越大或越小(负值)表示置信度越高(
河北小五台山北坡植物物种多样性的垂直梯度变化
1
2004
... 小五台山国家级自然保护区位于河北张家口蔚县, 114.78°-115.50° E, 39.78°-40.15° N, 属燕山-太行山山系, 海拔1 190-2 882 m, 主峰为东台, 气候类型为温带季风性气候, 年平均气温7.06 ℃, 最冷月气温-18.20 ℃, 最热月气温28.76 ℃, 年降水量为408.48 mm (
河北小五台山北坡植物物种多样性的垂直梯度变化
1
2004
... 小五台山国家级自然保护区位于河北张家口蔚县, 114.78°-115.50° E, 39.78°-40.15° N, 属燕山-太行山山系, 海拔1 190-2 882 m, 主峰为东台, 气候类型为温带季风性气候, 年平均气温7.06 ℃, 最冷月气温-18.20 ℃, 最热月气温28.76 ℃, 年降水量为408.48 mm (
Selection of combined versus separate sexes in seed plants
1
1982
... 雌雄异株植物是自然生态系统的重要组成部分(
基于核密度估计的点群密度制图应用研究
1
2017
... 核密度估计(KDE)是预测以事件点为圆心, 半径r范围区域之内事件发生的次数的多少比上该圆的面积n, 表示为在事件点S处的核密度(
基于核密度估计的点群密度制图应用研究
1
2017
... 核密度估计(KDE)是预测以事件点为圆心, 半径r范围区域之内事件发生的次数的多少比上该圆的面积n, 表示为在事件点S处的核密度(
1
2000
... 采用网格状法对整个分布区的土壤进行取样, 共设置468个采样点(点间距为30 m).青杨分布区域为河谷地带, 表土层相当薄(10 cm左右)且其下多为卵石和粗沙, 因此, 取样时在去除地表枯枝落叶和砾石等杂物后, 取10 cm厚度的表土层土壤称质量.室内风干后称干质量计量土壤含水量, 并测定pH值、有机质、全氮(TN)、全磷(TP)、全钾(TK)、有效氮(N)、有效磷(P)和有效钾(K)含量8项土壤理化指标(
1
2000
... 采用网格状法对整个分布区的土壤进行取样, 共设置468个采样点(点间距为30 m).青杨分布区域为河谷地带, 表土层相当薄(10 cm左右)且其下多为卵石和粗沙, 因此, 取样时在去除地表枯枝落叶和砾石等杂物后, 取10 cm厚度的表土层土壤称质量.室内风干后称干质量计量土壤含水量, 并测定pH值、有机质、全氮(TN)、全磷(TP)、全钾(TK)、有效氮(N)、有效磷(P)和有效钾(K)含量8项土壤理化指标(
Distribution of adult male and female Baccharis concinna( Asteraceae) in the rupestrian fields of Serra Do Cipó, Brazil
2
2002
... 雌雄异株植物是自然生态系统的重要组成部分(
... )雌雄群体的分布生境不同, 雌株在水热充足及土壤肥沃的有利环境下占优势;
1
2007
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
1
2007
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
Dioecy and its correlates in the flowering plants
1
1995
... 雌雄异株植物是自然生态系统的重要组成部分(
Nitrogen-controlled intra- and interspecific competition between Populus purdomii and Salix rehderiana drive primary succession in the Gongga Mountain glacier retreat area
1
2017
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
植被演替过程中种群格局动态的分形分析
1
2006
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
植被演替过程中种群格局动态的分形分析
1
2006
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
1
2006
... 因此, 本研究以河北小五台山金河沟的青杨天然种群为研究对象, 采用平均最近邻指数、核密度、单因素方差分析等方法分析了青杨雌雄群体的聚集程度、群体密度和分布格局差异以及其与海拔、到河岸的距离(河距)和土壤理化性质间的内在关系, 进一步揭示雌雄群体在空间分布上存在差异的主要原因.由于青杨是我国较为常见的一种雌雄异株植物, 常作为重要的经济树种被广泛用于生态治理、环境改良以及木材加工等方面(
1
2006
... 因此, 本研究以河北小五台山金河沟的青杨天然种群为研究对象, 采用平均最近邻指数、核密度、单因素方差分析等方法分析了青杨雌雄群体的聚集程度、群体密度和分布格局差异以及其与海拔、到河岸的距离(河距)和土壤理化性质间的内在关系, 进一步揭示雌雄群体在空间分布上存在差异的主要原因.由于青杨是我国较为常见的一种雌雄异株植物, 常作为重要的经济树种被广泛用于生态治理、环境改良以及木材加工等方面(
青杨雌雄群体沿海拔梯度的分布特征
3
2011
... 雌雄异株植物是自然生态系统的重要组成部分(
... 采用分段法划分海拔和河距:
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
青杨雌雄群体沿海拔梯度的分布特征
3
2011
... 雌雄异株植物是自然生态系统的重要组成部分(
... 采用分段法划分海拔和河距:
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
植物根系识别研究
1
2016
... 雌雄异株植物是自然生态系统的重要组成部分(
植物根系识别研究
1
2016
... 雌雄异株植物是自然生态系统的重要组成部分(
Drought inhibits photosynthetic capacity more in females than in males of Populus cathayana
2
2008
... 雌雄异株植物是自然生态系统的重要组成部分(
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
雌雄异株植物对环境胁迫响应的性别差异研究进展
1
2007
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
雌雄异株植物对环境胁迫响应的性别差异研究进展
1
2007
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
Physiological and proteomic responses of two contrasting Populus cathayana population to drought stress
1
2009
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
不同区域典型树木的空间分布格局及关联性
1
2018
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
不同区域典型树木的空间分布格局及关联性
1
2018
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
淹水胁迫对青杨雌雄幼苗生理特性和生长的影响
1
2012
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
淹水胁迫对青杨雌雄幼苗生理特性和生长的影响
1
2012
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
小五台山北台林线附近的植被及其与气候条件的关系分析
1
2002
... 小五台山国家级自然保护区位于河北张家口蔚县, 114.78°-115.50° E, 39.78°-40.15° N, 属燕山-太行山山系, 海拔1 190-2 882 m, 主峰为东台, 气候类型为温带季风性气候, 年平均气温7.06 ℃, 最冷月气温-18.20 ℃, 最热月气温28.76 ℃, 年降水量为408.48 mm (
小五台山北台林线附近的植被及其与气候条件的关系分析
1
2002
... 小五台山国家级自然保护区位于河北张家口蔚县, 114.78°-115.50° E, 39.78°-40.15° N, 属燕山-太行山山系, 海拔1 190-2 882 m, 主峰为东台, 气候类型为温带季风性气候, 年平均气温7.06 ℃, 最冷月气温-18.20 ℃, 最热月气温28.76 ℃, 年降水量为408.48 mm (
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1
2013
... 其中r表示带宽, 反映计算的核函数的平滑程度; f(S)表示核函数, 即中心点S到事件发生点Si处的权重大小.越靠近中心S点, 被赋予的权重就越大, 越远离中心点, 被赋予的权重则越小; n表示事件点发生的数量的多少(
基于核密度估计的动物生境适宜度制图方法
1
2013
... 其中r表示带宽, 反映计算的核函数的平滑程度; f(S)表示核函数, 即中心点S到事件发生点Si处的权重大小.越靠近中心S点, 被赋予的权重就越大, 越远离中心点, 被赋予的权重则越小; n表示事件点发生的数量的多少(
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1
2017
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1
2017
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
Sexually different physiological responses of Populus cathayana to nitrogen and phosphorus deficiencies
1
2014
... 此外, 尽管前期的研究表明了整个青杨种群的性比不偏离1:1 (
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1
2010
... 雌雄异株植物是自然生态系统的重要组成部分(
雌雄异株树种黄连木种群性比及空间分布
1
2010
... 雌雄异株植物是自然生态系统的重要组成部分(
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1
2001
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(
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1
2001
... 植物种群的空间分布研究一直是植物生态学研究的重要领域(