,1, 马晓1,2, 张子山1, 郭军2, 李月楠1, 梁英1, 宋健民,2, 赵世杰,1Effects of Drought Stress on Photosynthetic Characteristics of Wheat Near-Isogenic Lines with Different Wax Contents
YANG YanHui,1, MA Xiao1,2, ZHANG ZiShan1, GUO Jun2, LI YueNan1, LIANG Ying1, SONG JianMin,2, ZHAO ShiJie,1通讯作者:
第一联系人:
收稿日期:2018-06-4接受日期:2018-09-20网络出版日期:2018-11-16
| 基金资助: |
Received:2018-06-4Accepted:2018-09-20Online:2018-11-16
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杨彦会, 马晓, 张子山, 郭军, 李月楠, 梁英, 宋健民, 赵世杰. 干旱胁迫对蜡质含量不同小麦近等基因系光合特性的影响[J]. 中国农业科学, 2018, 51(22): 4241-4251 doi:10.3864/j.issn.0578-1752.2018.22.003
YANG YanHui, MA Xiao, ZHANG ZiShan, GUO Jun, LI YueNan, LIANG Ying, SONG JianMin, ZHAO ShiJie.
0 引言
【研究意义】小麦是世界上种植最广泛的作物之一,占谷物面积的30%,全球35%—40%的人口以小麦为主食[1,2]。在我国,冬小麦生长季节正值降水稀少的时期,干旱灾害频发,干旱胁迫对小麦的产量影响巨大[3]。研究小麦应对干旱胁迫的机制,对小麦的高产稳产具有重要意义。【前人研究进展】光合作用是作物产量的重要决定因素之一,也是绿色植物对环境最敏感的代谢途径之一。植物光合作用受到干旱胁迫的影响,主要表现在净光合速率（Pn）、蒸腾速率（E）、细胞间CO2浓度（Ci）、气孔导度（Gs）、水分利用效率（WUE）等方面[4]。不同的植物在受到干旱胁迫时光合速率都会有不同程度的降低,随着干旱胁迫程度的加重或者干旱时间的延长,植物光合速率下降的幅度越来越大。史玉炜等[5]认为植物生长及代谢的变化也会对其光合速率产生影响,在相同的干旱胁迫条件下,不同的植物或者同一植物的不同品种对干旱胁迫的响应也是不同的。研究表明,严重干旱可以导致植物叶绿体光合机构的破坏,PSII放氧复合体（OEC）的损伤[6],产生光抑制,直接影响光合作用的电子传递和CO2的同化过程[7]。叶片表皮的角质层具有减少水分散失的生理作用,它能够延迟干旱期间的细胞脱水,被认为是抵御干旱的重要组织[8,9,10]。植物角质层是表皮最外层的部分,由角质和蜡质组成。表皮蜡质可以分成最外层的蜡质晶体层和镶嵌于角质层中的内层蜡质。不同植物或同种植物不同器官的表皮蜡质常存在不同类型的晶体结构,如面包屑状、片状、柱状、管状等。这些不同的蜡质晶体形态是由不同的蜡质化学组分形成的。片状蜡层主要含有较多的伯醇或大量的三萜类成分,管状蜡质主要含有多种β-二酮、仲醇和二醇[11]。在植物生长过程中,蜡质晶体的形态结构会随成分的变化而转变,而表皮蜡质的成分和含量又与生长发育和环境条件密切相关[12,13]。已有研究表明蜡质对于植物抗旱具有重要作用[14,15],YANG等[16]发现,在拟南芥中叶片蜡质含量与抗旱能力呈正相关。VOGG等[17]研究发现,番茄表面蜡质具有蒸腾屏障的作用。过去关于蜡质的研究大多集中在模式植物上,针对蜡质对小麦抗旱性影响的研究较少,而且研究主要采用蜡质含量存在明显差异的不同品种[18,19],无法避免遗传背景对研究结果的影响。前期试验中我们获得了蜡质含量不同的小麦近等基因系,近等基因系是指除了某一两个基因外其他基因都相同的两个遗传材料,通常是经过饱和回交形成的除了目标性状有差异,其他遗传背景完全相同的两个遗传材料（品系）[20],这为我们研究蜡质对小麦干旱抗性的影响提供了材料基础。【本研究切入点】前期研究表明,多蜡质小麦品系对干旱胁迫的抗性明显高于少蜡质品系[21]。但前期研究仅采用单一干旱胁迫条件,不能探究多蜡质小麦品系抵御干旱胁迫的能力范围,且其抗旱机理尚不清楚。【拟解决的关键问题】本研究以蜡质含量不同的2个小麦近等基因系多蜡质品系JM205和少蜡质品系JM204为材料,在人工气候室通过逐渐干旱的方法模拟田间干旱胁迫的过程,研究不同干旱胁迫程度对蜡质含量不同小麦叶片水势及光合性能的影响,为生产中抗旱小麦品种的选择,以及抗旱小麦品种育种提供了理论基础。1 材料与方法
试验于2016年10月至2017年3月在山东农业大学作物生物学国家重点实验室人工气候室进行。1.1 材料种植
试验材料为藁城9411（母本）和ATHLET（父本）杂交选育出的F6代姊妹株系中蜡质含量不同的一对小麦近等基因系：多蜡品系JM205和少蜡品系JM204（图1-A）,通过扫描电镜观察发现JM205叶片表面有较多的蜡质（图1-B）,而JM204表面蜡质较少（图1-C）。前期试验结果表明,多蜡质小麦品系旗叶蜡质含量（平均7.05 mg·g-1）显著高于少蜡质品系（平均为3.38mg·g-1）[21]。2016年10月取饱满的种子育苗后,移栽到直径为32 cm的盆中,土壤为田间土壤与蛭石的混合物,3:2的体积比例混合。每盆种植多蜡质品系JM205和少蜡质品系JM204各2株,共12盆,在室外自然环境下,经过低温春化后于2016年12月转移到人工气候室进行培养。人工气候室日间（12 h）温度26℃,光照强度约800 μmol·m-2·s-1,夜间（12 h）温度17℃。水肥充足培养至开花期。图1
新窗口打开|下载原图ZIP|生成PPT图1两个小麦品系的照片（A）以及扫描电镜图片（B,C）
Fig. 1The photo (A) and scanning electronic microscopy (B, C) of two wheat near-isogenic lines
1.2 干旱处理及土壤相对含水量的测定
开花4 d后选取小麦植株长势良好的6盆,其中3盆正常浇水,作为对照,每天傍晚称重并浇水,使其重量维持不变;其余3盆在傍晚充分浇水至水从盆底流出,第二天上午8：30称盆重,此时重量为土壤饱和重量。从此不再浇水,使其逐渐干旱直至试验结束,在此过程中每天上午8：30称盆重,此时重量为土壤重量,试验结束后将植株和土壤烘干并称重,即为土壤干重。土壤相对湿度=（土壤重量-土壤干重）/（土壤饱和重量-土壤干重）[22]。根据土壤相对湿度（R）的干旱等级[23]指标,可以分为60%<R为无旱,50%<R≤60%为轻度干旱,40%<R≤50%为中度干旱,30%<R≤40%为重度干旱,R≤30%为严重干旱。1.3 旗叶水势的测定
叶片水势的测定采用露点水势仪（PSYPRO,美国WESCOR公司）测定,操作方法参照露点水势仪使用说明书,于每天上午9：00测定旗叶水势。用直径0.6 cm的打孔器打取叶圆片,将叶圆片放入C-52样品室密封,平衡30 min以上,干旱处理的植株叶片平衡1—2 h,然后将样品室连接到露点水势仪主机上测定叶片水势。1.4 旗叶气体交换参数的测定
利用CIRAS-3光合作用测定系统（PP Systems,美国）,在每天上午9：30至下午14：00分别测定旗叶的光合气体交换参数。用内置LED光源照光,光强为1 200 μmol·m-2·s-1,CO2浓度为400 μmol·mol-1,采用大气湿度和温度,仪器自动记录叶片净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、蒸腾速率（E）等参数。处理和对照植株各测定10次重复。1.5 旗叶叶绿素荧光参数的测定
利用FMS-2脉冲调制式荧光仪（Hansatech,英国）测定Fo、Fm、Fm′、Fs等荧光参数。叶片在生长光（约800 μmol·m-2·s-1）下进行光适应后,再用荧光仪内置光源（1 200 μmol·m-2·s-1）对叶片照射300 s,测定光适应条件下的稳态荧光Fs,再打饱和脉冲光（6 000 μmol·m-2·s-1）,测定光适应下最大荧光Fm′,然后对叶片进行暗适应30 min,测定叶片的暗适应下的最小荧光Fo和暗适应下的最大荧光Fm。按照如下公式计算荧光参数：PSⅡ的实际光化学效率ΦPSⅡ=（Fm′-Fs）/Fm′
PSⅡ的最大光化学效率Fv/Fm=（Fm-Fo）/Fm
用Handy-PEA植物效率仪（Hansatech,英国）测定小麦旗叶的快速叶绿素荧光动力学曲线（OJIP曲线）,测定前将叶片暗适应30 min。OJIP曲线由3 000 μmol·m-2·s-1的红光诱导,测定时间为2 s,记录的初始速率为每秒钟105个数据。按照ZHANG[24]和STRASSER[25]方法,将OJIP曲线进行O-P点和O-J点标准化。O点是10 μs,K点是30 μs,J点是2 ms,P点是荧光最大值对应的时刻。标准化公式如下：
O-P点标准化VO-P=（Ft-Fo）/（Fm-Fo）
O-J点标准化VO-J=（Ft-Fo）/（FJ-Fo）
1.6 统计分析
利用Sigmaplot 12.0软件对相关数据进行绘图,并利用PhotoShop CS 6.0软件对相关图片进行处理。2 结果
2.1 不同程度干旱胁迫下土壤含水量和小麦叶片水势的变化
在充分灌溉情况下,土壤相对含水量保持稳定,一直维持在72%左右。干旱处理后,随着处理时间的延长,土壤相对含水量逐渐降低,第3天降到49%,为中度干旱程度,第6天降到26%左右,达到严重干旱程度（图2-A）。图2
新窗口打开|下载原图ZIP|生成PPT图2干旱过程中土壤相对含水量的变化（A）,不同干旱程度对小麦叶片水势（B）的影响
Fig. 2The change of soil moisture variation (A) during the drought treatment stage and the effects of drought on water potential (B) in leaves of wheat
植物叶片水势是植物水分状况最直接的表现。在正常浇水的条件下,多蜡质品系JM205和少蜡质品系JM204旗叶水势差异不显著（图2-B）。随着干旱胁迫时间的延长,多蜡质品系和少蜡质品系的旗叶水势逐渐下降,但是少蜡品系下降更明显。特别是在处理第3天到第5天,土壤相对含水量在49%—32%时,多蜡品系JM205和少蜡质品系JM204旗叶水势差异显著,如第5天,当土壤相对含水量降至32%时,多蜡品系JM205旗叶水势为-1.42 MPa,而少蜡品系旗JM204叶水势降至-1.845 MPa。当土壤相对含水量进一步下降到26%时,2个品系旗叶水势均大幅度下降,叶片失水严重,出现萎焉,叶片功能受损。
2.2 不同干旱胁迫程度对光合气体交换参数的影响
从图3可见,当土壤相对含水量高于49%时,多蜡质品系JM205与少蜡质品系JM204旗叶的光合速率（Pn）无显著差异,随着干旱程度的加重,多蜡质和少蜡质品系的光合速率都逐渐降低,但少蜡质品系JM204下降幅度更大,如土壤相对含水量下降到32%时,少蜡品系Pn下降了37%,而多蜡品系仅下降了15%,少蜡质品系下降的幅度显著大于多蜡质品系。蒸腾速率（E）和胞间CO2浓度（Ci）变化趋势与光合速率类似;气孔导度（Gs）的变化趋势略有差异,当土壤含水量高于50%时,少蜡质品系JM204的气孔导度高于多蜡质品系,随着干旱程度加重,少蜡质品系和多蜡质品系都逐渐降低,但少蜡质品系Gs下降的更快并逐渐低于多蜡质品系JM205。当土壤含水量为32%时,各气体交换参数差异最显著。随着干旱程度继续加重,各参数急剧下降,当土壤相对含水量下降至28%左右时,所有气体参数都降低得很小,不同品系之间无显著性差异。在整个试验期间,始终保持充足浇水的对照组植株,无论是多蜡质品系JM205还是少蜡质品系JM204,其光合气体交换参数都基本保持稳定。图3
新窗口打开|下载原图ZIP|生成PPT图3充足浇水（CK）与不同程度干旱胁迫（D）对蜡质含量不同小麦近等基因系（JM204,JM205）气体交换参数的影响
Fig. 3Effect of drought stress (D) or sufficient irrigation (CK) on gas exchange parameters of wheat NILs (JM204, JM205) with different wax content
2.3 不同程度干旱胁迫对Fv/Fm和ФPSII的影响
在干旱条件下,随着干旱程度的增加,多蜡质品系JM205与少蜡质品系JM204的Fv/Fm的变化趋势基本相同（图4）。在土壤相对含水量下降初期,无明显变化,随着土壤相对含水量继续下降,最大光化学效率快速降低,少蜡质品系下降出现早、下降速度更快,在土壤含水量约为49%时,少蜡质品系开始出现下降趋势,而多蜡质品系在土壤相对含水量约32%时才开始下降。这表明,在相同干旱胁迫条件下多蜡质品系叶片的PSII光抑制较轻。图4
新窗口打开|下载原图ZIP|生成PPT图4充足浇水（CK）与不同程度干旱胁迫（D）对蜡质含量不同小麦近等基因系（JM204,JM205）旗叶Fv/Fm和ΦPSII 的影响
Fig. 4Effects of different drought treats (D) or sufficient irrigation (CK) on Fv/Fm and ΦPSII of flag leaves from wheat NILs (JM204, JM205) with different wax content
随着土壤相对含水量的减少,多蜡质品系JM205和少蜡质品系JM204的PSII实际光化学效率（ΦPSII）都逐渐降低,但是少蜡质品系JM204降低的幅度更大,当土壤相对含水量低于49%的时候,少蜡质品系JM204与多蜡质品系JM205相比差异显著,随着土壤相对含水量继续下降,二者大幅度下降,表明不同程度干旱条件下多蜡质品系叶片的PSII电子传递更通畅。
在整个试验期间,始终保持充足浇水的对照组植株,无论是多蜡质品系JM205还是少蜡质品系JM204,其Fv/Fm 和ΦPSII都基本保持稳定。
2.4 不同程度干旱胁迫对快速叶绿素荧光诱导动力学曲线的影响
为了进一步研究叶片蜡质是如何缓解PSII光抑制发生的,试验测定了不同干旱程度下旗叶的快速叶绿素荧光诱导动力学曲线（图5—6）。图5
新窗口打开|下载原图ZIP|生成PPT图5不同程度干旱胁迫对多蜡质小麦JM205（A,B）与少蜡质小麦JM204（C,D）旗叶的快速叶绿素荧光诱导动力学曲线O-P段标准化曲线的影响
B、D由图A、C中不同干旱程度时的曲线减去干旱处理前曲线得出。下同
Fig. 5Changes of O-P normalized fast chlorophyll fluorescence induction kinetics curve of JM205 (A, B) and JM204 (C, D) wheat treated with different drought stress
B and D are obtained from the curves of different drought degrees in Figures A and C minus the curve before drought treatment. The same as below
快速叶绿素荧光诱导动力学曲线中蕴含着PSII原初光化学反应的丰富信息,被广泛应用于PSII活性研究[26,27,28]。2 ms的J点被认为反映了PSII受体侧QA向QB的电子传递,J点增加反映了QA向QB的电子传递受阻。在进行O-P点标准化的VO-P曲线中,多蜡质品系JM205与少蜡质品系JM204的OJIP曲线在轻度干旱时均无明显差异（图5）,但随着干旱程度的加重,少蜡质品系J点荧光比多蜡质品系上升更快,当土壤相对含水量降至39%时,少蜡质品系JM204的J点开始逐渐上升,但多蜡质品系JM205无明显变化;当土壤相对含水量低于32%时,2个品系旗叶的J点荧光均大幅增加,且二者无显著差异（图5）。
OJIP 曲线300 μs处被称为K点,K点的上升被作为PSII受体测光抑制的特异性标志[29]。为了更好的观察K点,对OJIP曲线进行了O-J点的标准化（图6）。在不同程度干旱胁迫条件下,土壤相对含水量从72%下降到32%过程中,多蜡质品系JM205和少蜡质品系JM204的K点荧光几乎无变化（图6）,表明此时PSII受体测没有发生明显伤害,当土壤相对含水量低于32%时,继续干旱,K点荧光均上升,但多蜡质品系K点荧光始终低于少蜡质品系。
图6
新窗口打开|下载原图ZIP|生成PPT图6不同程度干旱胁迫对多蜡质小麦JM205（A,B）与少蜡质小麦JM204（C,D）旗叶的快速叶绿素荧光诱导动力学曲线O-J段标准化曲线的影响
Fig. 6Changes of O-J normalized fast chlorophyll fluorescence induction kinetics curve of JM205 (A, B) and JM204 (C, D) wheat treated with different drought stress
2.5 不同程度干旱胁迫对植株干重的影响
本研究发现,在充足浇水情况下,蜡质含量不同的小麦品系的生物量无明显差异（图7）。在6 d干旱胁迫处理后,多蜡质小麦品系JM205的干重与充足浇水的对照组相比没有明显变化,而少蜡质小麦品系JM204的干重则明显低于充足浇水的对照组（图7）。这表明少蜡品系在干旱下较低光合机构的活性限制了其干物质的积累。图7
新窗口打开|下载原图ZIP|生成PPT图7不同程度干旱胁迫对不同蜡质含量小麦近等基因系干重的影响
*表示P<0.05水平差异显著
Fig. 7Effect of drought stress on drought weight of wheat NILs (JM204,JM205) with different wax contents
* indicates significant difference at P<0.05
3 讨论
表皮蜡质层在植物抗旱过程中起着重要的作用,大量研究发现,表皮蜡质可以作为植物表皮细胞内水分或溶解物向外扩散的屏障,其含量和厚度会影响植物的水分蒸腾[30,31,32]。但是,这些研究所用的材料来自不同的国家和地区,遗传背景差异较大。而本试验所用的研究材料为两个蜡质含量不同的小麦近等基因系,其遗传背景相同。前期试验发现多蜡质小麦品系旗叶保水能力强,蜡质能够减轻干旱胁迫造成的光抑制,使旗叶维持较高的光合速率[21]。本研究进行不同程度的干旱胁迫,探讨多蜡质小麦的抗旱范围和抗旱机理。为了减少天气变化对试验的影响,试验在人工气候室控制温度、湿度和光照条件下进行,采用逐渐干旱的方式,从开始干旱至完全干旱期间测定了6个不同时间点的干旱梯度,在一定程度上模拟田间干旱的过程。前人对于蜡质抗旱性的研究往往只设置1个或者2个干旱梯度,很难得出蜡质对抗旱的有效范围,而本研究包含了从开始干旱至严重干旱的所有过程,较详细的描述了蜡质在不同干旱程度下对小麦光合性能的影响,明确了多蜡质品系和少蜡质品系各自的抗旱能力范围,对于抗旱小麦品种的选育和田间栽培均有借鉴意义,并对进一步的研究提供了建议。叶片水势是表示植物水分亏缺或水分状况的一个直接指标[33],通过研究不同土壤供水条件下的植物水势的变化特征,可以了解植物的抗旱特性以及植物对环境变化的生理适应特点。笔者之前的研究发现,在干旱条件下,小麦叶片蜡质含量与旗叶水势、光合速率、蒸腾速率呈显著正相关[21],表明蜡质具有一定的抗旱功能,本研究发现当土壤相对含水量为49%—32%时抗旱效果最明显。根据FARQUHAR等[34]提出的光合速率气孔限制的判断标准,光合速率与气孔导度同时下降时,如果Ci也下降,则说明光合速率的下降是气孔限制。笔者的研究表明,随着干旱程度加重,Pn和Gs下降,同时Ci也下降,这表明光合速率下降的原因是气孔限制而不是叶肉因素的限制。多蜡质品系旗叶光合作用在干旱胁迫处理后下降的幅度小,气孔限制轻。这可能是由于蜡质含量多的品系,旗叶细胞膜的结构相对稳定,干旱胁迫后,失水较慢,叶片水势相对较高,气孔导度下降慢,因此保持了较高的光合速率、蒸腾速率及水分利用效率。本研究结果与黄玲等[3]的研究结果部分一致,但与郭彦军等[35]研究结果不同,这可能与不同试验的胁迫程度和其他环境因素不同有关,也可能与品种间气孔调节的遗传差异有关,这也说明蜡质和抗旱节水性状的关系非常复杂,还有待深入研究。
植物本身的生理变化如衰老以及逆境的干旱[36]、高温[37]、低温[38]和盐胁迫[39]等都能够直接或间接地影响植物PSⅡ的功能。前人的研究表明,干旱胁迫主要伤害PSII反应中心,通过调节电子传递速率和光化学速率,降低光合同化力。本研究结果表明,随着干旱程度加重,多蜡质及少蜡质品系Fv/Fm和ФPSⅡ均下降,说明天线色素吸收的光能被反应中心捕获的概率降低,叶片吸收的光能不能有效转化为化学能,但多蜡质品系JM205下降幅度小,少蜡质品系JM204下降幅度大,说明干旱胁迫下,多蜡质品系对光能的捕获和转化能力受干旱胁迫影响较小,可维持相对较高的光合能力。PSII是光抑制的主要场所,JIP-test可以解析PSII光能吸收、转换、电子传递、PSII作用中心以及受体侧和供体侧的活性、电子传递体氧化还原状态动态变化,是目前常用的非破坏性技术手段。本研究结果表明,随着干旱程度的加重,OJIP曲线J点和K点的荧光均上升,但J点荧光上升更明显,而且多蜡质品系比少蜡质品系上升速度慢,说明干旱胁迫后受体侧受伤害程度重于供体侧,QA到QB的电子传递受阻,使电子传递活性降低。PSII的破坏常伴随着Mn2+的丧失,脂肪酸的增加及ATP和蛋白质的降解[40],因此PSII受到损害,必然影响到光合作用的正常进行。但多蜡质品系可以在干旱胁迫条件下维持相对较高的光能转换效率和实际光化学效率,电子传递更通畅,更多的能量被反应中心捕获并进入电子传递链,过剩光能少,减少了活性氧的产生,具有相对较高的光合能力。因此,有利于光合产物的积累,从而维持较高的产量[21]。
关于蜡质与植物抗旱性关系方面,近年来已有较多研究,大多数研究者认为蜡质与植物的抗旱节水性密切相关[41,42,43],但也有一些研究者认为,蜡质含量与植株蒸腾速率及抗旱性没有必然的联系[44]。本研究发现,在干旱条件下,多蜡质品系较少蜡质品系旗叶水势更高,PSII电子传递更通畅,光合能力更强,蜡质含量对提高小麦的抗旱性有积极影响。通过模拟田间充分灌水后土壤逐渐干旱的过程,笔者发现在轻度干旱胁迫条件下,蜡质的抗旱效果并不明显,但在中度和重度干旱胁迫条件下,即土壤相对含水量约为49%—32%时,蜡质的抗旱节水性更加显著。所以前人关于蜡质在抗旱方面的争议也有可能是由于干旱程度的差异引起的。
4 结论
轻度干旱胁迫条件下,多蜡质品系JM205抗旱优势不明显,但是随着干旱程度逐渐加重,多蜡质品系旗叶的水势和光合速率都高于少蜡质品系,Pn和Gs下降的同时,Ci下降,可见光合速率的下降主要是由气孔因素导致的。中度干旱胁迫条件下,多蜡质品系比少蜡质品系具有更高的ΦPSII和Fv/Fm,表明多蜡质品系电子传递更通畅,叶片光抑制较轻,抗旱功能较强。JIP-test分析发现OEC受伤害程度小于QA到QB电子传递受阻程度,表明PSⅡ电子传递主要是受体侧受到抑制。经不同程度干旱胁迫处理分析,当土壤相对含水量在49%—32%时,多蜡和少蜡品系各项指标差异最大,抗旱效果最明显,这对于抗旱小麦品种的选育和田间栽培均有借鉴意义。（责任编辑 杨鑫浩）
参考文献 原文顺序
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被引期刊影响因子
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We produced a reference sequence of the 1-gigabase chromosome 3B of hexaploid bread wheat. By sequencing 8452 bacterial artificial chromosomes in pools, we assembled a sequence of 774 megabases carrying 5326 protein-coding genes, 1938 pseudogenes, and 85% of transposable elements. The distribution of structural and functional features along the chromosome revealed partitioning correlated with meiotic recombination. Comparative analyses indicated high wheat-specific inter- and intrachromosomal gene duplication activities that are potential sources of variability for adaption. In addition to providing a better understanding of the organization, function, and evolution of a large and polyploid genome, the availability of a high-quality sequence anchored to genetic maps will accelerate the identification of genes underlying important agronomic traits.
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为了进一步了解植物叶片蜡质含量与植物抗旱节水性的关系，本试验对6个小麦品种在灌浆后期的旗叶蜡质含量与抗早生理指标进行了相关分析，结果表明，干早条件下小麦灌浆后期叶片蜡质含量与光合速率、叶温、叶片水分利用效率和产量呈显著正相关．蜡质含量高的品种叶片温度高、蒸腾速率大，这与传统现点不同．分析认为蜡质含量高的品种在干早胁迫条件下可能叶片细胞膜稳定性强，气孔不容易发生关闭，因此其叶片水分利用效率和产量较高．蜡质含量除了受遗传因素决定外，还受环境因素影响．
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为了进一步了解植物叶片蜡质含量与植物抗旱节水性的关系，本试验对6个小麦品种在灌浆后期的旗叶蜡质含量与抗早生理指标进行了相关分析，结果表明，干早条件下小麦灌浆后期叶片蜡质含量与光合速率、叶温、叶片水分利用效率和产量呈显著正相关．蜡质含量高的品种叶片温度高、蒸腾速率大，这与传统现点不同．分析认为蜡质含量高的品种在干早胁迫条件下可能叶片细胞膜稳定性强，气孔不容易发生关闭，因此其叶片水分利用效率和产量较高．蜡质含量除了受遗传因素决定外，还受环境因素影响．
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本研究在土壤相对含水量分别为90%,70%,50%,30%,10%时,探讨了刚毛柽柳(Tamarix hispida)同化枝中可溶性蛋白、可溶性糖和脯氨酸含量的变化规律,并分析了三者之间的关系。结果表明,在土壤相对含水量逐渐减少时,刚毛柽柳同化枝中可溶性糖、脯氨酸含量持续升高,但前者的增幅明显小于后者。可溶性蛋白的变化规律则有所不同,土壤相对含水量从90%减小到70%时,可溶性蛋白含量开始小幅增加;随着水分胁迫加深,可溶性蛋白急剧增加,在土壤相对含水量为30%时达到最大;而当土壤相对含水量下降到10%时,可溶性蛋白开始分解,含量迅速下降。蛋白质的双向电泳图谱表明,当土壤相对含水量从70%减小到50%时,刚毛柽柳中出现了至少4个新的蛋白点。水分胁迫下可溶性糖和脯氨酸的积累为刚毛柽柳体内与抗旱有关的新蛋白的表达提供了物质基础,增强了刚毛柽柳的抗旱性。
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本研究在土壤相对含水量分别为90%,70%,50%,30%,10%时,探讨了刚毛柽柳(Tamarix hispida)同化枝中可溶性蛋白、可溶性糖和脯氨酸含量的变化规律,并分析了三者之间的关系。结果表明,在土壤相对含水量逐渐减少时,刚毛柽柳同化枝中可溶性糖、脯氨酸含量持续升高,但前者的增幅明显小于后者。可溶性蛋白的变化规律则有所不同,土壤相对含水量从90%减小到70%时,可溶性蛋白含量开始小幅增加;随着水分胁迫加深,可溶性蛋白急剧增加,在土壤相对含水量为30%时达到最大;而当土壤相对含水量下降到10%时,可溶性蛋白开始分解,含量迅速下降。蛋白质的双向电泳图谱表明,当土壤相对含水量从70%减小到50%时,刚毛柽柳中出现了至少4个新的蛋白点。水分胁迫下可溶性糖和脯氨酸的积累为刚毛柽柳体内与抗旱有关的新蛋白的表达提供了物质基础,增强了刚毛柽柳的抗旱性。
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Peanut is an important edible oil crop plant whose quality and yield are greatly affected by drought. The process and molecular mechanisms of recovery from drought are also critical to its productivity, but are currently poorly characterized. Here, we investigate the involvement of peanutAhGLK1in recovery from drought, and in particular its relationship withAhPORA, which encodes a key enzyme in chlorophyll biosynthesis. We found that chlorophyll content, chlorophyll fluorescence, AhPORA protein level and genes related to chlorophyll biosynthesis and photosynthesis declined markedly under drought conditions, but all increased during recovery. Consistent with this,AhGLK1expression decreased during water stress and increased when the stress was removed. WhenAhGLK1was transformed into Arabidopsisglk1glk2mutant, it increased the survival rate of the mutant during recovery from drought and fully rescued the mutant pale-green phenotype. In addition, chlorophyll content and fluorescence, and the expression of genes related to chlorophyll biosynthesis and photosynthesis, were all increased. Bioinformatics analysis and experimental evidence suggested that AhGLK1 augments the expression ofAhPORAby binding to its promoter. Our findings confirm that AhGLK1 plays a role as a transcription factor that upregulates expression ofAhPORAduring post-drought recovery, thereby stimulating chlorophyll biosynthesis and photosynthesis.
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干旱胁迫使冬小麦可变荧光与最大荧光比(<i>F<sub>v</sub>／F<sub>m</sub></i>)、可变荧光与最小荧光比(<i>F<sub>v</sub>／F<sub>o</sub></i>)、稳态荧光(<i>F<sub>t</sub></i>)、初始荧光到最大荧光1／2点的时间(T<sub>l/2</sub>)均明显降低，表明干旱胁迫使冬小麦叶片光系统Ⅱ(PSⅡ)质子醌库(PQ库)容量变小，光系统Ⅱ原初光能转换效率、光系统Ⅱ潜在活性受到抑制，干旱胁迫直接影响了光合作用的电子传递和C0<sub>2</sub>同化过程。
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扼要地介绍了植物发生滞绿突变的类型、生理生化特征及遗传机理。
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Plant surfaces are the interfaces of the organisms with respect to their environment. In the micro-dimension they show an enormous variety of functional three-dimensional structures. Their materials and structures developed over millions of years by evolutionary processes in which their functionality has been proven and selected by environmental pressures. As a result, nature developed highly functional materials with several amazing properties like superhydrophobicity and superhydrophilicity. These functional structures are built up by a complex biopolymer called cuticle. The cuticle is mainly composed of a three-dimensional network of cutin, and integrated and superimposed lipids called “waxes”. Superimposed waxes are also called “epicuticular waxes”. Epicuticular waxes often form two- and three-dimensional structures, in dimensions between hundreds of nanometers and some micrometers, which influence the wettability, self-cleaning behaviour and the light reflection at the cuticle interface. This review gives a brief introduction into the functions of the plant epicuticular waxes and summarises the current knowledge about their morphologies, crystal structures, growth by self-assembly and provides an overview about the microscopy and preparation techniques for their analysis.
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14 varieties of tall fescue in field as the experiment material,epidermis wax content,net photosynthesis rate,transpiration rate,stomatal conductance and intercellular CO_2 concentration of leaves were mensurated under drought and high temperature conditi
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Magsci [本文引用: 1]
DOI:10.1007/s00299-010-0940-7URLPMID:20976458 [本文引用: 1]
The GRAS proteins are a family of transcription regulators found in plants and play diverse roles in plant growth and development. To study the biological roles of GRAS family genes in Brassica napus , an Arabidopsis LAS homologous gene, BnLAS and its two homologs were cloned from B. napus and its two progenitor species, Brassica rapa and Brassica oleracea . Relatively high levels of BnLAS were observed in roots, shoot tips, lateral meristems and flower organs based on the analysis of the transcripts by quantitative RT-PCR and promoter-reporter assays. Constitutive overexpression of BnLAS in Arabidopsis resulted in inhibition of growth, and delays in leaf senescence and flowering time. A large portion of transgenic lines had darker leaf color and higher chlorophyll content than in wild type plants. Interestingly, water lose rates in transgenic leaves were reduced, and transgenic plants exhibited enhanced drought tolerance and increased recovery after exposed to dehydration treatment. The stomatal density on leaves of the transgenic plants increased significantly due to the smaller cell size. However, the stomatal aperture on the leaves of the transgenic plants reduced significantly compared with wild type plants. More epidermal wax deposition on transgenic leaves was observed. Furthermore, several genes involved in wax synthesis and regulation, including CER1 , CER2 , KCS1 and KCS2 , were upregulated in the transgenic plants. Our results indicate a potential to utilize BnLAS in the improvement of drought tolerance in plants.
DOI:10.1093/jxb/erh149URLPMID:15133057 [本文引用: 1]
Cuticular waxes play a pivotal role in limiting transpirational water loss across the plant surface. The correlation between the chemical composition of the cuticular waxes and their function as a transpiration barrier is still unclear. In the present study, intact tomato fruits (Lycopersicon esculentum) are used, due to their astomatous surface, as a novel integrative approach to investigate this composition unction relationship: wax amounts and compositions of tomato were manipulated before measuring unbiased cuticular transpiration. First, successive mechanical and extractive wax-removal steps allowed the selective modification of epi- and intracuticular wax layers. The epicuticular film consisted exclusively of very-long-chain aliphatics, while the intracuticular compartment contained large quantities of pentacyclic triterpenoids as well. Second, applying reverse genetic techniques, a loss-of-function mutation with a transposon insertion in a very-long-chain fatty acid elongase -ketoacyl-CoA synthase was isolated and characterized. Mutant leaf and fruit waxes were deficient in n-alkanes and aldehydes with chain lengths beyond C30, while shorter chains and branched hydrocarbons were not affected. The mutant fruit wax also showed a significant increase in intracuticular triterpenoids. Removal of the epicuticular wax layer, accounting for one-third of the total wax coverage on wild-type fruits, had only moderate effects on transpiration. By contrast, reduction of the intracuticular aliphatics in the mutant to approximately 50% caused a 4-fold increase in permeability. Hence, the main portion of the transpiration barrier is located in the intracuticular wax layer, largely determined by the aliphatic constituents, but modified by the presence of triterpenoids, whereas epicuticular aliphatics play a minor role.
DOI:10.3969/j.issn.1674-5906.2009.03.064URL [本文引用: 1]
植物表面蜡质的最初角色是防止植株体内水分的散失和外界水分的进入,其分布的部位、化学成分和结构的复杂性与复杂的生态角色相对应。植物表面蜡质的物理化学特性能够抵抗各种各样生物与非生物侵害,这些侵害包括真菌病害、植食性昆虫、太阳射线、冻结温度等。植物表面蜡质还是植物、植食性昆虫及其捕食者和寄生者相互作用的竞技场,其特有的化学成分和形态学特征赋予它特有的生态机能,这些机能之一便是植物与植食性昆虫之间相互作用的媒介。植物表面蜡质的物理结构和数量能够影响植食性昆虫的附着和移动。表面蜡质可通过影响天敌对植食性害虫的捕食,从而间接影响植食性害虫的行为。表面蜡质提取物和单一的蜡质成分能够刺激或者抑制植食性昆虫产卵、活动和取食。烷烃、蜡酯、游离脂肪醇和酸等脂肪族化合物是表面蜡质的主要成分,在植食性昆虫选择寄主植物中,长链脂肪族化合物起着尤为重要的作用 芳香族化合物也影响昆虫对寄主植物的选择。植食性昆虫较少在光滑蜡质少表现型的作物上取食,在光滑蜡质少表现型的作物上,表面蜡质的数量少,化学组分和形态学特征也不同。研究光滑蜡质少作物抗虫的分子生物学机制,有助于阐明植物表面蜡质在植物与昆虫之间所起的作用。表面蜡质的理化特性能够改变害虫与寄主植物间的相互作用,具有重要的农业影响,已成为一个活跃的研究领域。
DOI:10.3969/j.issn.1674-5906.2009.03.064URL [本文引用: 1]
植物表面蜡质的最初角色是防止植株体内水分的散失和外界水分的进入,其分布的部位、化学成分和结构的复杂性与复杂的生态角色相对应。植物表面蜡质的物理化学特性能够抵抗各种各样生物与非生物侵害,这些侵害包括真菌病害、植食性昆虫、太阳射线、冻结温度等。植物表面蜡质还是植物、植食性昆虫及其捕食者和寄生者相互作用的竞技场,其特有的化学成分和形态学特征赋予它特有的生态机能,这些机能之一便是植物与植食性昆虫之间相互作用的媒介。植物表面蜡质的物理结构和数量能够影响植食性昆虫的附着和移动。表面蜡质可通过影响天敌对植食性害虫的捕食,从而间接影响植食性害虫的行为。表面蜡质提取物和单一的蜡质成分能够刺激或者抑制植食性昆虫产卵、活动和取食。烷烃、蜡酯、游离脂肪醇和酸等脂肪族化合物是表面蜡质的主要成分,在植食性昆虫选择寄主植物中,长链脂肪族化合物起着尤为重要的作用 芳香族化合物也影响昆虫对寄主植物的选择。植食性昆虫较少在光滑蜡质少表现型的作物上取食,在光滑蜡质少表现型的作物上,表面蜡质的数量少,化学组分和形态学特征也不同。研究光滑蜡质少作物抗虫的分子生物学机制,有助于阐明植物表面蜡质在植物与昆虫之间所起的作用。表面蜡质的理化特性能够改变害虫与寄主植物间的相互作用,具有重要的农业影响,已成为一个活跃的研究领域。
URLMagsci [本文引用: 1]
采用气质联用(GC-MS)和生物测定法,探讨了不同小麦品种(系)叶片 表面蜡质对麦长管蚜和禾谷缢管蚜取食的影响.结果表明:SN80、SN18和ZM12叶片表面蜡质对2种蚜虫取食具有刺激作用,而SN87叶片表面蜡质无 刺激作用.对4种小麦材料叶片表面蜡质进行GC-MS分析发现,其表面蜡质化学组分有所不同, 但主要组分均为长链烷烃,其它组分包括7-十四碳烯、8-十五烷酮、十四烷酸乙酯和十六烷酸乙酯等.生物测定结果表明:长链烷烃(＞C17)、7-十四碳 烯及8-十五烷酮对两种蚜虫取食具有显著的刺激作用;而乙基柠檬酸、十四烷酸乙酯和十六烷酸乙酯对麦长管蚜取食无刺激作用;十四烷酸乙酯和十六烷酸乙酯对 禾谷缢管蚜取食也无刺激作用.
URLMagsci [本文引用: 1]
采用气质联用(GC-MS)和生物测定法,探讨了不同小麦品种(系)叶片 表面蜡质对麦长管蚜和禾谷缢管蚜取食的影响.结果表明:SN80、SN18和ZM12叶片表面蜡质对2种蚜虫取食具有刺激作用,而SN87叶片表面蜡质无 刺激作用.对4种小麦材料叶片表面蜡质进行GC-MS分析发现,其表面蜡质化学组分有所不同, 但主要组分均为长链烷烃,其它组分包括7-十四碳烯、8-十五烷酮、十四烷酸乙酯和十六烷酸乙酯等.生物测定结果表明:长链烷烃(＞C17)、7-十四碳 烯及8-十五烷酮对两种蚜虫取食具有显著的刺激作用;而乙基柠檬酸、十四烷酸乙酯和十六烷酸乙酯对麦长管蚜取食无刺激作用;十四烷酸乙酯和十六烷酸乙酯对 禾谷缢管蚜取食也无刺激作用.
DOI:10.3969/j.issn.0517-6611.2012.05.006URL [本文引用: 1]
[目的]概述小麦近等基因系的构建方法及其应用进展,为近等基因系的合理利用提供参考。[方法]介绍了多代回交转育、基于目标性状位点杂合个体自交和从突变体中分离等构建小麦近等基因系的方法,阐述了近等基因系在小麦多系品种培育、抗病机制研究和品质基础研究等方面的应用,并展望了其应用前景。[结果]近等基因系是研究单个基因效应、克隆目标基因、基因精细定位及分子标记辅助育种的理想材料,随着小麦不同性状近等基因系的不断培育,其将有更广泛的应用。[结论]该研究为小麦近等基因系的构建及其进一步的合理利用提供了参考。
DOI:10.3969/j.issn.0517-6611.2012.05.006URL [本文引用: 1]
[目的]概述小麦近等基因系的构建方法及其应用进展,为近等基因系的合理利用提供参考。[方法]介绍了多代回交转育、基于目标性状位点杂合个体自交和从突变体中分离等构建小麦近等基因系的方法,阐述了近等基因系在小麦多系品种培育、抗病机制研究和品质基础研究等方面的应用,并展望了其应用前景。[结果]近等基因系是研究单个基因效应、克隆目标基因、基因精细定位及分子标记辅助育种的理想材料,随着小麦不同性状近等基因系的不断培育,其将有更广泛的应用。[结论]该研究为小麦近等基因系的构建及其进一步的合理利用提供了参考。
DOI:10.3724/SP.J.1006.2016.01700URLMagsci [本文引用: 5]
<p>于2013—2014和2014—2015年度，以多蜡质和少蜡质的4个小麦近等基因系为材料，采用田间旱棚方式控制土壤水分，研究了蜡质含量与小麦抗旱性的关系。结果表明，干旱处理后，多蜡质小麦品系旗叶的蜡质含量平均为15.15 mg g?1，较少蜡质小麦品系(8.43 mg g?1)高79.8%；多蜡质小麦品系旗叶的水势较高，干旱处理后下降幅度明显小于少蜡质小麦品系，水分散失率也显著低于少蜡质品系(P< 0.05)；多蜡质小麦品系旗叶的光合速率平均下降7.5%，而少蜡质小麦品系下降9.8%；多蜡质小麦品系旗叶PSII最大光化学效率(Fv/Fm)平均下降幅度为3.4%，少蜡质小麦品系下降幅度达到5.8%；多蜡质小麦品系的籽粒产量高于少蜡质品系，平均高3.7%；多蜡质小麦品系的抗旱指数和干旱敏感指数均显著低于少蜡质小麦品系(P< 0.05)。以上结果表明，蜡质能够提高小麦的抗旱性，旗叶蜡质含量可以作为抗旱小麦品种的选择指标。</p>
DOI:10.3724/SP.J.1006.2016.01700URLMagsci [本文引用: 5]
<p>于2013—2014和2014—2015年度，以多蜡质和少蜡质的4个小麦近等基因系为材料，采用田间旱棚方式控制土壤水分，研究了蜡质含量与小麦抗旱性的关系。结果表明，干旱处理后，多蜡质小麦品系旗叶的蜡质含量平均为15.15 mg g?1，较少蜡质小麦品系(8.43 mg g?1)高79.8%；多蜡质小麦品系旗叶的水势较高，干旱处理后下降幅度明显小于少蜡质小麦品系，水分散失率也显著低于少蜡质品系(P< 0.05)；多蜡质小麦品系旗叶的光合速率平均下降7.5%，而少蜡质小麦品系下降9.8%；多蜡质小麦品系旗叶PSII最大光化学效率(Fv/Fm)平均下降幅度为3.4%，少蜡质小麦品系下降幅度达到5.8%；多蜡质小麦品系的籽粒产量高于少蜡质品系，平均高3.7%；多蜡质小麦品系的抗旱指数和干旱敏感指数均显著低于少蜡质小麦品系(P< 0.05)。以上结果表明，蜡质能够提高小麦的抗旱性，旗叶蜡质含量可以作为抗旱小麦品种的选择指标。</p>
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DOI:10.1007/s10535-012-0100-8URL [本文引用: 1]
The effects of inhibition of mitochondrial alternative oxidase (AOX) respiratory pathway on photosynthetic apparatus in Rumex K-1 leaves were studied. Under high irradiance, the inhibition of AOX pathway caused over-reduction of photosystem (PS) 2 acceptor side, a decrease in the energy transfer in the PS 2 units, damage of donor side of PS 2 and decrease in pool size of electron acceptors. The inhibition of AOX pathway also decreased photosynthetic performance index (PI ABS ), actual photochemical efficiency (桅 PS2 ), photochemical quenching (qP) and photosynthetic O 2 evolution rate. The results demonstrate that mitochondrial AOX pathway plays a vital role in photoprotection of photosynthetic apparatus.
URL [本文引用: 1]
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DOI:10.1016/j.bbabio.2010.09.001URLPMID:20840840 [本文引用: 1]
78The effect of high temperature on wheat leaves on the two types of PSII heterogeneity (including α, β, γ and Q B-reducing and Q B-non-reducing type of heterogeneities) simultaneously has never been explored so extensively till yet. 78Both antenna size and reducing side heterogeneity are greatly affected with increasing temperature. It is concluded that certain environmental stimuli like high temperature stress evoke interconversions of α centers into β and γ centers and the active Q B-reducing centers into inactive Q B-non-reducing centers. 78The plant adapts to high temperature stress by temporary interconversions of PSII heterogeneity up to temperature of 40 °C. 78The changes in energy flux in response to high temp leads to increased dissipation of energy and untrapped photons which may protect the plant from oxidative stress transiently. 78High temperature stress led to incidental changes in PS II heterogeneity which may be one of the adaptive mechanisms to cope with high temperature stress.
DOI:10.3321/j.issn:0513-353X.2008.01.001URLMagsci [本文引用: 1]
以6年生‘金太阳’杏(Prunus armeniaca lJ.‘Jin Taiyang’)叶片为试材,通过同时测定叶绿素荧光快速诱导动力学曲线和对820 nm光的吸收曲线,分析了黑暗脱水条件下,杏叶片光系统Ⅱ(PSⅡ)和光系统Ⅰ(PSⅠ)功能的变化及相互影响。结果表明,叶片在黑暗中脱水能对光合结构造成严重伤害。黑暗脱水对PSⅡ供体侧的影响不明显。在相对含水量(RWC)降到59%时,快速叶绿素荧光诱导动力学曲线和820 nm光吸收曲线的形状已有非常明显的变化,但对PSⅡ最大光化学效率(Fv/Fm)和反映PSⅠ活性的ΔI/Io的影响较小。这说明RWC大于59%时,PSⅡ供应电子的能力和PSⅠ接受电子的能力可以保持相互匹配,即PSⅡ和PSⅠ的活性之间是协调的。RWC低于59%时,PSⅠ与PSⅡ之间的上述协调关系被打破,ΔI/Io的下降早而且大于Fv/Fm的变化,表明叶片脱水对PSⅠ的伤害比PSⅡ严重。与Fv/Fm相比,以吸收光能为基础的光合性能指数(PI_(ABS))可以较全面地反映两个光系统间光合电子传递的变化。
DOI:10.3321/j.issn:0513-353X.2008.01.001URLMagsci [本文引用: 1]
以6年生‘金太阳’杏(Prunus armeniaca lJ.‘Jin Taiyang’)叶片为试材,通过同时测定叶绿素荧光快速诱导动力学曲线和对820 nm光的吸收曲线,分析了黑暗脱水条件下,杏叶片光系统Ⅱ(PSⅡ)和光系统Ⅰ(PSⅠ)功能的变化及相互影响。结果表明,叶片在黑暗中脱水能对光合结构造成严重伤害。黑暗脱水对PSⅡ供体侧的影响不明显。在相对含水量(RWC)降到59%时,快速叶绿素荧光诱导动力学曲线和820 nm光吸收曲线的形状已有非常明显的变化,但对PSⅡ最大光化学效率(Fv/Fm)和反映PSⅠ活性的ΔI/Io的影响较小。这说明RWC大于59%时,PSⅡ供应电子的能力和PSⅠ接受电子的能力可以保持相互匹配,即PSⅡ和PSⅠ的活性之间是协调的。RWC低于59%时,PSⅠ与PSⅡ之间的上述协调关系被打破,ΔI/Io的下降早而且大于Fv/Fm的变化,表明叶片脱水对PSⅠ的伤害比PSⅡ严重。与Fv/Fm相比,以吸收光能为基础的光合性能指数(PI_(ABS))可以较全面地反映两个光系统间光合电子传递的变化。
DOI:10.1016/j.jplph.2009.04.013URLPMID:19473728 [本文引用: 1]
The purpose of this study is to demonstrate the heterogeneous behavior of PSII in soybean ( Glycine max) leaves and identical maximum PSII photochemistry efficiency ( F V/ F M) under different high temperature treatments. We observed that, with an identical decrease in F V/ F M in soybean leaves caused by different high temperature treatments, chlorophyll a fluorescence differed significantly, indicating different behaviors in the photosynthetic apparatus. The quantitative analysis showed that, with an identical F V/ F M, leaves treated at 48 °C showed a higher W K, an indicator of damage to the oxygen-evolving complex along with a lower O 2 evolution rate compared with leaves treated at 45 °C. This demonstrated that the donor side of PSII was damaged more severely at 48 °C than at 45 °C despite the same decrease in F V/ F M in the two heat-treated leaves. The ratios of Q A- and Q B-reducing PSII reaction centers to total PSII reaction centers were both lower in leaves treated at 48 °C than in leaves treated at 45 °C with an identical F V/ F M, indicating that the acceptor side of PSII was also more damaged by heat treatment at 48 °C than at 45 °C. However, when damage to the donor side of PSII was similar in leaves treated at two different temperatures, the acceptor side of PSII was damaged less severely at 48 °C, which accounted for higher electron transport rate at the acceptor side of PSII in leaves treated at 48 °C than in leaves treated at 45 °C.
DOI:10.1093/jxb/43.12.1569URL [本文引用: 1]
A held experiment was conducted with a non-irrigated water stress treatment and an irrigated control using four sorghum (Sorghum bicolor L. Moench) cultivars. We investigated the effects of water deficits on leaf water relations, osmotic adjustment, stomatal conductance, cuticular conductance, cell membrane stability (CMS) measured by the polyethylene glycol (PEG) test, epicuticular wax load (EWL), cytoplasmic lipid content, solute concentration in cell sap, and growth. Osmotic adjustment was observed under water deficit conditions. Lower osmotic potential enabled plants to maintain turgor and decreased the sensitivity of turgor-dependent processes. Sugar and K were identified as the major solutes contributing to osmotic potential in sorghum. Sugar and K concentrations in cell sap increased by 37.4% and 27%, respectively, under water deficit conditions in favour of decreasing osmotic potential. Stomatal conductance and cuticular conductance were lower in the non-irrigated plants. A wide range in CMS among four cultivars was observed. CMS increased with increasing water deficits. EWL increased on leaves of water deficient plants and was positively correlated with cuticular conductance and CMS. Membrane phospholipid content increased in water-stressed plants. CMS as measured by the PEG test, was influenced by EWL, cuticular thickness, and osmotic concentration of leaf tissues. The cultivars which maintained higher CMS, higher EWL, lower cuticular conductance, higher turgor and higher osmotic adjustment under water deficit conditions were identified as drought tolerant.
DOI:10.2135/cropsci2007.02.0119URL [本文引用: 1]
Sorghum (Sorghum bicolor (L).Moench.) is one of the most drought tolerant and water efficient grass species. A distinctive feature of sorghum is the profuse deposition of epicuticular wax or bloom on the abaxial side of the leaf and sheaths which has been proposed as one of the possible trait contributing to the species over all abiotic stress tolerance. However, the role and contribution of epicuticular wax to drought tolerance has been inconclusive. In this study, we characterized a bloomless mutant, (KFS2021 developed via gamma irradiation) using a combination of genetic and physiological approaches and provided evidence for the contribution of epicuticular wax in reducing night transpiration. Phenotypic segregation for the bloomless trait in an F2 population developed from a cross between KFS 2021 and BTx623, suggest that in this cross, the bloomless phenotype is a result of mutation in a single nuclear recessive gene. The bloomless parent and F2 progenies had lower frequency of guttation, more leaky cuticular layer (measured based on chlorophyll leaching in 80% ethanol) and higher rate of seedling water loss than the wild type and bloom progenies. More important, bloomless progenies consistently showed 3 to 6- fold higher night time transpiration based on measurement of night time conductance. Genetic correlation analysis of traits showed significant associations which indicate the important role of epicuticular wax in the various physiological traits analyzed in this study. Taken together these results suggest that sorghum epicuticular wax or bloom may enhance water use efficiency by depressing night time water loss.
DOI:10.1007/s11103-010-9656-xURLPMID:20593223 [本文引用: 1]
Abstract Epidermal cell layers play important roles in plant defenses against various environmental stresses. Here we report the identification of a cuticle membrane mutant, wilted dwarf and lethal 1 (wdl1), from a rice T-DNA insertional population. The mutant is dwarf and die at seedling stage due to increased rates of water loss. Stomatal cells and pavement cells are smaller in the mutant, suggesting that WDL1 affects epidermal cell differentiation. T-DNA was inserted into a gene that encodes a protein belonging to the SGNH subfamily, within the GDSL lipase superfamily. The WDL1-sGFP signal coincided with the RFP signal driven by AtBIP-mRFP, indicating that WDL1 is an ER protein. SEM analyses showed that their leaves have a disorganized crystal wax layer. Cross-sectioning reveals loose packing of the cuticle and irregular thickness of cell wall. Detailed analyses of the epicuticular wax showed no significant changes either in the total amount and amounts of each monomer or in the levels of lipid polymers, including cutin and other covalently bound lipids, attached to the cell wall. We propose that WDL1 is involved in cutin organization, affecting depolymerizable components.
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DOI:10.1146/annurev.pp.33.060182.001533URL [本文引用: 1]
URLMagsci [本文引用: 1]
选用2个抗旱性不同的紫花苜蓿品种,敖汉(强抗旱)和三得利(弱抗旱),设置空气湿度(45%-55%和75%-85%)和土壤水分胁迫(75%和35%田间持水量)处理,分析紫花苜蓿叶表皮蜡质含量、组分及晶体结构、气体交换参数、水势及脯氨酸含量的变化规律。结果表明,单独土壤水分胁迫时,紫花苜蓿叶表皮蜡质晶体结构及蜡质总量无显著变化;敖汉蜡质组分中烷类、酯类含量增加,醇类含量下降;三得利醇类含量下降,烷类、酯类含量变化不显著。低空气湿度胁迫时,两品种蜡质总量无显著变化,烷类和酯类含量显著增加,醇类含量显著下降,叶表皮片状蜡质晶体结构熔融呈弥漫性,扩大了对叶表面积的覆盖,其蒸腾速率显著低于正常湿度。复合胁迫处理时,叶表皮片状蜡质晶体结构继续呈弥漫性,烷类、酯类、未知蜡质组分含量均高于单独胁迫处理,醇类含量最低,而蜡质总量除三得利显著高于对照外,其余均无显著差异。紫花苜蓿叶表皮蜡质各组分含量(除醇类)及蜡质总量与光合速率呈显著负相关,与蒸腾速率无显著相关关系。蜡质总量与叶水势呈显著正相关。总体上,敖汉蜡质总量显著高于三得利,蜡质组分中烷类物质的增加有助于提高植株的抗旱性。在复合胁迫下,强抗旱品种主要通过气孔因素控制水分散失,而弱抗旱品种通过气孔和非气孔因素共同控制植物水分散失。
URLMagsci [本文引用: 1]
选用2个抗旱性不同的紫花苜蓿品种,敖汉(强抗旱)和三得利(弱抗旱),设置空气湿度(45%-55%和75%-85%)和土壤水分胁迫(75%和35%田间持水量)处理,分析紫花苜蓿叶表皮蜡质含量、组分及晶体结构、气体交换参数、水势及脯氨酸含量的变化规律。结果表明,单独土壤水分胁迫时,紫花苜蓿叶表皮蜡质晶体结构及蜡质总量无显著变化;敖汉蜡质组分中烷类、酯类含量增加,醇类含量下降;三得利醇类含量下降,烷类、酯类含量变化不显著。低空气湿度胁迫时,两品种蜡质总量无显著变化,烷类和酯类含量显著增加,醇类含量显著下降,叶表皮片状蜡质晶体结构熔融呈弥漫性,扩大了对叶表面积的覆盖,其蒸腾速率显著低于正常湿度。复合胁迫处理时,叶表皮片状蜡质晶体结构继续呈弥漫性,烷类、酯类、未知蜡质组分含量均高于单独胁迫处理,醇类含量最低,而蜡质总量除三得利显著高于对照外,其余均无显著差异。紫花苜蓿叶表皮蜡质各组分含量(除醇类)及蜡质总量与光合速率呈显著负相关,与蒸腾速率无显著相关关系。蜡质总量与叶水势呈显著正相关。总体上,敖汉蜡质总量显著高于三得利,蜡质组分中烷类物质的增加有助于提高植株的抗旱性。在复合胁迫下,强抗旱品种主要通过气孔因素控制水分散失,而弱抗旱品种通过气孔和非气孔因素共同控制植物水分散失。
[本文引用: 1]
DOI:10.3724/SP.J.1006.2013.01060URLMagsci [本文引用: 1]
<div ><span >以水稻结实期的人工控温试验测定不同温度处理下水稻旗叶光合速率、叶绿素荧光参数的动态变化，并结合</span><span >Western</span><span >印迹与</span><span >胶体金标记技术对叶肉细胞</span><span >类囊体膜中</span><span >D1</span><span >蛋白的表达检测与活性定位，探讨了高温胁迫对</span><span >D1</span><span >蛋白存在形态与活性分布的影响，以及</span><span >D1</span><span >蛋白表达与叶片光合速率、</span><span >PSII</span><span >荧光参数的联系。结果表明，高温处理下叶片</span><span >净光合速率下降、</span><span >PSII</span><span >潜在活性</span><span >(<em>F</em><sub>v</sub></span><em><span >/</span></em><em><span >F</span></em><sub><span >o</span></sub><span >)</span><span >和</span><span >PSII</span><span >光能转化效率</span><span >(</span><em><span >F</span></em><sub><span >v</span></sub><em><span >/</span></em><em><span >F</span></em><sub><span >m</span></sub><span >)</span><span >降低，</span><span >且</span><span >随</span><span >着高温胁迫时间的持续和叶片功能的衰退，类囊体膜结构损伤越严重，</span><span >光能转化效率</span><span >越低；在</span><span >D1</span><span >蛋白的两类存在形态中，非磷酸化</span><span >D1</span><span >蛋白和磷酸化</span><span >D1</span><span >蛋白在高温胁迫下的表达量均有所下降，但前者下降更明显；高温处理下控制</span><span >D1</span><span >蛋白表达的叶绿体</span><em><span >psbA</span></em><span >基因在转录水平呈下调表达，使</span><span >D1</span><span >蛋白合成及周转过程受到抑制，进而类囊体膜</span><span >PSII</span><span >反应中心的功能受</span><span >损与叶绿体光合效率下降，揭示高温胁迫对叶片</span><span >PSII</span><span >系统的伤害受</span><span >D1</span><span >蛋白磷酸化过程和</span><em><span >psbA</span></em><span >基因表达变化的共同作用，进而影响不同水稻品种在高温胁迫下的光合速率和耐热性。</span></div>
DOI:10.3724/SP.J.1006.2013.01060URLMagsci [本文引用: 1]
<div ><span >以水稻结实期的人工控温试验测定不同温度处理下水稻旗叶光合速率、叶绿素荧光参数的动态变化，并结合</span><span >Western</span><span >印迹与</span><span >胶体金标记技术对叶肉细胞</span><span >类囊体膜中</span><span >D1</span><span >蛋白的表达检测与活性定位，探讨了高温胁迫对</span><span >D1</span><span >蛋白存在形态与活性分布的影响，以及</span><span >D1</span><span >蛋白表达与叶片光合速率、</span><span >PSII</span><span >荧光参数的联系。结果表明，高温处理下叶片</span><span >净光合速率下降、</span><span >PSII</span><span >潜在活性</span><span >(<em>F</em><sub>v</sub></span><em><span >/</span></em><em><span >F</span></em><sub><span >o</span></sub><span >)</span><span >和</span><span >PSII</span><span >光能转化效率</span><span >(</span><em><span >F</span></em><sub><span >v</span></sub><em><span >/</span></em><em><span >F</span></em><sub><span >m</span></sub><span >)</span><span >降低，</span><span >且</span><span >随</span><span >着高温胁迫时间的持续和叶片功能的衰退，类囊体膜结构损伤越严重，</span><span >光能转化效率</span><span >越低；在</span><span >D1</span><span >蛋白的两类存在形态中，非磷酸化</span><span >D1</span><span >蛋白和磷酸化</span><span >D1</span><span >蛋白在高温胁迫下的表达量均有所下降，但前者下降更明显；高温处理下控制</span><span >D1</span><span >蛋白表达的叶绿体</span><em><span >psbA</span></em><span >基因在转录水平呈下调表达，使</span><span >D1</span><span >蛋白合成及周转过程受到抑制，进而类囊体膜</span><span >PSII</span><span >反应中心的功能受</span><span >损与叶绿体光合效率下降，揭示高温胁迫对叶片</span><span >PSII</span><span >系统的伤害受</span><span >D1</span><span >蛋白磷酸化过程和</span><em><span >psbA</span></em><span >基因表达变化的共同作用，进而影响不同水稻品种在高温胁迫下的光合速率和耐热性。</span></div>
DOI:10.1104/pp.116.2.571URLPMID:9490760 [本文引用: 1]
Abstract Measurements of the quantum efficiencies of photosynthetic electron transport through photosystem II (phiPSII) and CO2 assimilation (phiCO2) were made simultaneously on leaves of maize (Zea mays) crops in the United Kingdom during the early growing season, when chilling conditions were experienced. The activities of a range of enzymes involved with scavenging active O2 species and the levels of key antioxidants were also measured. When leaves were exposed to low temperatures during development, the ratio of phiPSII/phiCO2 was elevated, indicating the operation of an alternative sink to CO2 for photosynthetic reducing equivalents. The activities of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, and superoxide dismutase and the levels of ascorbate and alpha-tocopherol were also elevated during chilling periods. This supports the hypothesis that the relative flux of photosynthetic reducing equivalents to O2 via the Mehler reaction is higher when leaves develop under chilling conditions. Lipoxygenase activity and lipid peroxidation were also increased during low temperatures, suggesting that lipoxygenase-mediated peroxidation of membrane lipids contributes to the oxidative damage occurring in chill-stressed leaves.
DOI:10.1078/0176-1617-00839URLPMID:12756920 [本文引用: 1]
The effects of high salinity (0-400 mmol/L NaCl) on photosystem II (PSII) photochemistry and photosynthetic pigment composition were investigated in the halophyte Artimisia anethifolia grown under outdoor conditions and exposed to full sunlight. High salinity resulted in an inhibition in plant growth and a significant accumulation of sodium and chloride in leaves. However, high salinity induced no effects on the actual PSII efficiency, the efficiency of excitation energy capture by open PSII reaction centres, photochemical quenching, and non-photochemical quenching at midday. High salinity also induced neither changes in the maximum efficiency of PSII photochemistry, the efficiency with which a trapped exciton can move an electron into the electron transport chain further than Q A and the quantum yield of electron transport beyond Q A, nor changes in absorption, trapping and electron transport fluxes per PSII reaction centre. No significant changes were observed in the levels of neoxanthin, lutein, -carotene, violaxanthin, antheraxanthin, and zeaxanthin expressed on a total chlorophyll basis in salt-adapted plants. Our results suggest that Artimisia anethifolia showed high resistance not only to high salinity, but also to photoinhibition even if it was treated with high salinity as high as 400 mmol/L NaCl and exposed to full sunlight. The results indicate that tolerance of PSII to high salinity and photoinhibition can be viewed as an important strategy for Artimisia anethifolia, a halophyte plant, to grow in very high saline soil.
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DOI:10.1007/BF00024805URL [本文引用: 1]
Cultivars of common wheat ( Triticum aestivum L.) and durum wheat ( T. turgidum L. var. durum) were evaluated for epicuticular wax content and its relationship with spectral reflectance. Epicuticular wax is associated with drought tolerance. Highly significant differences (1.51 to 2.80 mg/dm 2 ) were found in the amount of epicuticular wax (EW) among the cultivars. Water stress significantly enhanced the level of EW. EW content under stress and control conditions were positively correlated (r=0.85, p<0.01) suggesting that selection for this trait could be practised in either environment. Surface reflectance was reduced when the waxy layer from the leaf was removed with chloroform. The reduction for the abaxial surface was twice that for the adaxial surface indicating that the abaxial surface was more waxy than the adaxial one. The mean reduction (both surfaces) termed ‘δ’ was positively correlated with the amount of EW (r=0.59, p<0.01).
DOI:10.2307/2446150URLPMID:21708662 [本文引用: 1]
Interactive effects of increasing atmospheric CO2with resource limitations on production of surface wax in plants have not been studied. Pinus palustris seedlings were grown for 1 yr at two levels of soil N (40 or 400 kg N ha-1 yr-1) and water stress (-0.5 or -1.5 MPa xylem pressure potential) in open-top field chambers under two levels of CO2(365 or 720 mol/mol). Needle surface wax content was determined at 8 mo (fall) and 12 mo (spring) and epicuticular wax morphology was examined using scanning electron microscopy (SEM) at 12 mo. Wax content expressed on both a leaf area and dry mass basis was increased due to main effects of low N and water stress. No main effects of CO2were observed; however, a CO2x N interaction at 12 mo indicated that under low soil N the elevated CO2treatment had less wax (surface area or dry mass basis) compared to its ambient counterpart. Morphologically, low N needle surfaces appeared rougher compared to those of high N needles due to more extensive wax ridges. Although the main effect of water treatment on wax density was not reflected by changes in wax morphology, the CO2x N interaction was paralleled by alterations in wax appearance. Decreases in density and less prominent epicuticular wax ridges resulting from growth under elevated CO2and limiting N suggest that dynamics of plant/atmosphere and plant/pathogen interactions may be altered.
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DOI:10.1007/s12892-009-0119-3URL [本文引用: 1]
Sesame ( Sesamum indicum L.) is one of the most important oil seed crops, which has been used as a traditional health food. The objective of this study was to investigate the changes of leaf cuticular waxes during plant growth from 5 to 75 days after seedling emergence, and the variation of leaf waxes with different leaf position; top, middle, and lower positions, using four Korean sesame cultivars, Ahnsan, Danbaeck, Hanseom, and Kyeongheuk. Alkanes in lower leaves and aldehydes in top leaves among leaf positions were the most abundant, with alkanes being with major portion in all leaf position of four sesame cultivars. Total leaf wax load decreased around three-fold between 5 and 30 days, and then remained constant up to day 75. The percentages of alkanes and aldehydes increased between 5 and 15 days and then changed little or increasingly, showing minor variation depending on sesame cultivars. The rate of increase of alkanes was slightly higher than that of aldehydes. Chain length of alkanes and aldehydes became longer from 5 to 30 days, and then remained almost constant till day 75. The major homologue in alkanes was the C29 at day 5 and the C33 constituent after day 30, while the major homologue in aldehydes was the C32 constituent continuously during leaf development. The results demonstrated that the chain length for alkane and aldehyde constituents changed increasingly by chain elongation and wax biosynthesis during leaf development of sesame.
