覃潇敏^,1, 潘浩男¹, 肖靖秀¹, 汤利¹, 郑毅^,1,2,*1云南农业大学, 云南昆明 650201
²云南开放大学, 云南昆明 650599

Effects of maize and soybean intercropping on nodule growth, nitrogen fixation of soybean under low phosphorus condition

QIN Xiao-Min^,1, PAN Hao-Nan¹, XIAO Jing-Xiu¹, TANG Li¹, ZHENG Yi^,1,2,*1Yunnan Agricultural University, Kunming 650201, Yunnan, China
²Yunnan Open University, Kunming 650599, Yunnan, China

通讯作者: * 郑毅, E-mail:zhengyi-64@163.com

收稿日期:2020-10-31接受日期:2021-03-19网络出版日期:2021-04-13

基金资助:

国家重点研发计划项目(2017YFD0200200/207) 国家自然科学基金项目(31760615) 国家自然科学基金项目(31760611) 国家自然科学基金项目(32060718) 云南省科技人才与平台计划项目(2019IC026)

Corresponding authors: * E-mail:zhengyi-64@163.com
Received:2020-10-31Accepted:2021-03-19Published online:2021-04-13

Fund supported:

National Key Research and Development Program of China(2017YFD0200200/207) National Natural Science Foundation of China(31760615) National Natural Science Foundation of China(31760611) National Natural Science Foundation of China(32060718) Science and Technology Talent and Platform of Yunnan Province(2019IC026)

作者简介 About authors
E-mail:qinxiaomin89@163.com



摘要
通过盆栽试验, 探讨在低磷水平(P50)和正常磷水平(P100)下, 玉米与大豆间作对大豆氮磷吸收、根瘤生长与固氮能力的影响。结果表明, 低磷水平(P50)和正常磷水平(P100)下, 与单作大豆相比, 大豆与玉米间作能显著增加根瘤数、根瘤重、根瘤豆血红蛋白含量以及固氮酶活性, 并促进大豆的生长与氮磷吸收。2个磷水平下, 间作大豆根瘤内的氮磷浓度、酸性磷酸酶以及植酸酶活性均显著高于单作大豆, 并且间作P50处理根瘤内酶活性最高。此外, 与正常磷水平(P100)下的单作相比, 间作P50处理的大豆根瘤内磷素浓度并未受到抑制。说明在低磷条件下, 大豆与玉米间作系统主要通过增强根瘤内酸性磷酸酶、植酸酶活性来提高了根瘤内的磷浓度, 以维持根瘤固氮所需的较大磷素, 进而促进大豆生长与氮素吸收。
关键词： 磷水平;玉米与大豆间作;根瘤;固氮能力;氮磷吸收

Abstract
To investigate the effects of maize and soybean intercropping on nitrogen and phosphorus uptake, nodule growth, and nitrogen fixation in soybean, a pot experiment was conducted with two phosphorus (P) rates (low P -P50 and sufficient P -P100). The results showed that, compared with monocropped soybean, intercropping of soybean and maize significantly increased the nodule number, nodule weight, leghemoglobin content, and nitrogenase activity of nodule, and promoted the growth and nitrogen (N) and phosphorus uptake of soybean under P50 and P100 rates. The concentrations of N, P, and the activities of acid phosphatase, phytase in nodules in intercropped soybean were significantly higher than those of monocropped soybean under P50 and P100 rates, and the activities of acid phosphatase and phytase showed the highest values under IS-P50 treatment. In addition, the P concentration in the nodules of intercropped soybean under P50 rate was significantly higher than that of monocropped soybean under P90 rate. so In summary, to maintain the larger phosphorus content for nitrogen fixation of soybean under phosphorus deficiency, the soybean and maize intercropping system increased the phosphorus concentration in the nodules mainly by enhancing the activities of acid phosphatase and phytase in the nodules, and thus promoted the growth and nitrogen uptake of soybean.
Keywords：P rates;maize and soybean intercropping;nodule;nitrogen fixation;N and P uptake


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本文引用格式
覃潇敏, 潘浩男, 肖靖秀, 汤利, 郑毅. 低磷条件下玉米大豆间作对大豆根瘤生长、固氮功能的影响. 作物学报, 2021, 47(11): 2268-2277 DOI:10.3724/SP.J.1006.2021.04237
QIN Xiao-Min, PAN Hao-Nan, XIAO Jing-Xiu, TANG Li, ZHENG Yi. Effects of maize and soybean intercropping on nodule growth, nitrogen fixation of soybean under low phosphorus condition. Acta Agronomica Sinica, 2021, 47(11): 2268-2277 DOI:10.3724/SP.J.1006.2021.04237


磷是植物生长必需的第二大营养元素, 在植物生长发育、代谢活动和高产优质中发挥着不可替代的作用^[1], 更在豆科作物根瘤形成与固氮过程中发挥着极其重要的作用^[2]。然而, 磷素在土壤中极易被固定、难以移动导致土壤中磷的有效性非常低, 造成土壤存在严重缺磷的现象, 尤其在我国南方的酸性土壤中^[3]。国内外大量研究表明, 在低磷胁迫下, 豆科作物根瘤的生长与形成受到明显抑制, 根瘤固氮酶活性和固氮能力显著降低, 进而显著降低根瘤的固氮效率及阻碍植株生长^[4,5,6]。可见, 土壤缺磷已成为阻碍豆科植物生长及结瘤固氮的重要限制因素之一, 严重制约着豆科作物的产量和品质。

在低磷胁迫环境下, 植物自身会通过质子、酸性磷酸酶以及特异根系分泌物的分泌等一系列的生理可塑性机制促进土壤中磷资源的获取^[7,8], 同样豆科作物根瘤内也会通过维持较高的磷浓度来保障其生物固氮过程中需要的大量磷素^[9,10]。Thuynsma等^[11]研究发现, 在缺磷胁迫下, 羽扇豆根瘤内的磷浓度显著高于根系与地上部, 以维持固氮效率。Lazali等^[12]研究发现, 缺磷条件下, 菜豆根瘤内的磷含量显著高于地上部和根系, 提高了固氮效率。目前, 国内外对缺磷胁迫影响豆科作物生长和根瘤固氮性能的研究主要集中在单作种植模式下, 而对间作系统的研究则鲜见报道。

豆科与禾本科作物间作是我国农业实践上最典型的一种间作模式, 在养分高效利用、豆科结瘤固氮方面具有显著的优势^[13,14]。在蚕豆//玉米间作体系中, 间作通过增强作物根系黄酮类物质^[14]、有机酸物质^[15]等分泌, 改善豆科作物固氮能力, 提高间作群体磷的吸收。但是, 在豆科与禾本科作物间作系统中, 施磷水平对豆科作物根瘤固氮特性的影响以及根瘤响应低磷环境的机制鲜见报道。因此, 本研究以玉米与大豆间作系统为研究对象, 通过盆栽试验探讨不同磷水平下间作对大豆氮磷吸收、根瘤生长、固氮能力及其磷素平衡的影响, 并揭示大豆根瘤适应低磷环境的生理机制, 以期为深入理解间作系统豆科作物生物固氮机制开辟新的视野。

1 材料与方法

1.1 试验地点

盆栽试验于2020年5月在云南农业大学资源与环境学院的格林温室大棚中进行。试验所用的土壤采自云南昆明市官渡区小哨村的旱地红壤, 含碱解氮30.87 mg kg^-1、速效磷5.77 mg kg^-1、速效钾135.44 mg kg^-1、有机质7.58 g kg^-1, pH 5.61。

1.2 试验材料

玉米品种是‘云瑞-88’ (Yunrui 88), 大豆选用品种为‘滇豆7号’ (Diandou 7), 均由云南农业科学院粮食作物研究所提供。

1.3 试验设计

盆栽试验以种植模式为主处理, 设大豆单作、玉米//大豆间作和玉米单作3种种植模式, 其中单作处理每盆种植4株大豆或4株玉米, 间作处理按照1行玉米与1行大豆种植(即2株玉米和2株大豆), 每个处理行株距保持一致, 均匀种植。施磷量为副处理, 设置2个施磷水平: 低磷水平(P50 mg kg^-1, 即每盆3.57 g过磷酸钙)和正常磷水平(P100 mg kg^-1, 即每盆7.14 g过磷酸钙), 共6个处理, 每个处理3个重复, 花盆随机排列。试验塑料盆的大小为高230 mm×直径340 mm, 每盆装土10 kg。其余氮钾肥用量: 尿素为每盆3.26 g, 硫酸钾肥为每盆2.88 g。所有大豆植株接种根瘤菌(BNCC336406)菌液(约1×10⁸ cells L^-1), 菌株由北纳创联生物技术有限公司提供。在整个生育期中, 不喷施杀菌剂和杀虫剂, 定期浇水及人工除草, 并定期调换花盆的位置。

1.4 样品采集

于大豆盛花期/玉米大喇叭口期进行采样, 大豆植株分为叶、茎、根3个部位, 烘干称重; 将大豆根系清洗干净并把根瘤全部摘下, 计数, 烘干并称重, 用于氮磷的测定。大豆功能叶、根系及根瘤等鲜样, 置于-80℃冰箱, 用于酶活性的分析测定。

1.5 测定项目和方法

采用H₂SO₄-H₂O₂消煮, 凯氏定氮法测定植株全氮含量; 采用H₂SO₄-H₂O₂消煮, 钒钼黄比色法测定植株全磷含量。豆血红蛋白含量的测定: 取0.25 g (精确到0.0001)的新鲜根瘤, 液氮研磨成粉, 加入1 mL 4℃、0.1 mol L^-1磷酸缓冲溶液(pH 6.8)混合均匀, 在4℃、1000×g条件下离心15 min, 取上清液, 再在4℃、1000×g条件下离心15 min, 上清液在540 nm波长下测量^[16]。采用乙炔还原法测定固氮酶活性。采用苏州格锐思生物科技有限公司(www.geruisi-bio.com)的试剂盒测定酸性磷酸酶活性, 酸性磷酸酶活的定义: 在37℃下, 每克组织每分钟水解1 μmol PNPP产生PNP定义为1个酶活性单位; 采用苏州格锐思生物科技有限公司(www.geruisibio.com)的试剂盒测定植酸酶活性, 植酸酶活性: 在37℃、pH 5.5的条件下, 每克样本每分钟释放1 μmol的无机磷定义为一个酶活力单位。

1.6 数据统计分析

使用Microsoft Excel 2010软件进行数据初步处理、绘制柱状图。采用SPSS 20.0做单因素方差分析ANOVA (LSD法, α=0.05)、Two-Way ANOVA多重比较分析。

2 结果与分析

2.1 低磷条件下玉米与大豆间作对大豆生长的影响

大豆与玉米间作系统生物量变化如表1所示, 在P50和P100水平下, 与单作大豆相比, 间作大豆植株的干物质累积量显著增加71.98%和38.68%, 在P50水平下间作增幅效应较为明显。其中, 叶片干重显著增加71.91%和36.84%, 茎干重显著增加66.69%和37.64%, 根系干重显著增加87.61%和41.84%。此外, 磷肥施用也显著促进了大豆干物质的累积, P100-间作大豆的生物量最大。然而, 在低磷水平(P50)下, 与正常磷水平的单作大豆相比, 间作大豆植株干物质累积量略高7.85%, 但差异不显著。可见, 低磷水平下, 大豆间作种植可以缓解磷养分不足的不利环境, 促进了大豆的生长, 增加了大豆的生物量。

Table 1
表1
表1不同磷水平下玉米与大豆间作对大豆生长的影响
Table 1Effects of maize and soybean intercropping on soybean growth under different P rates (g plant^-1)

磷水平 P rates	种植模式 Planting patterns	叶 Leaf	茎 Stem	根 Root	全株 Whole plant
P50	MS	4.09±0.20 c	4.05±0.32 c	1.16±0.11 d	9.44±0.13 c
	IS	7.04±0.69 b	6.76±0.81 b	2.17±0.15 c	16.23±1.16 b
P100	MS	6.39±0.33 b	6.01±0.27 b	2.48±0.18 b	15.04±0.39 b
	IS	8.75±0.44 a	8.27±0.63 a	3.52±0.15 a	20.85±0.76 a

MS: 单作大豆; IS: 间作大豆; P50: 低磷水平; P100: 正常磷水平。同列数据后不同小写字母表示不同处理的差异显著性(P < 0.05)。
MS: monocropping soybean; IS: intercropping soybean; P50: low P rate; P100: sufficient P rate. Values followed by different lowercase letters in a column indicate significant difference among different treatments at the 0.05 probability level.

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2.2 低磷条件下玉米与大豆间作对大豆根瘤生长及固氮能力的影响

根瘤生物量在一定程度上间接表明根瘤固氮能力的大小, 即根瘤生物量越大, 根瘤的固氮能力相对较强。从表2和图1可以看出, 间作显著促进了大豆根瘤的生长与形成, 根瘤数和根瘤干重较单作大豆分别显著增加88.60%和85.16%, 其中在P50和P100水平下分别增加91.63%、86.63%和99.41%、106.25%。磷肥显著影响大豆根瘤的形成与生长, P100水平的大豆根瘤数和根瘤干重分别较低磷水平(P50)显著提高47.66%和24.37%。此外, 施磷水平和种植模式对大豆根瘤数的增加具有显著的交互作用, 而对根瘤重的影响没有明显的交互作用。

Table 2
表2
表2间作和磷水平对大豆根瘤生长及固氮能力的影响
Table 2Effects of intercropping and P rates on growth and nitrogen fixation ability of soybean nodules

磷水平 P rates	种植模式 Planting patterns	根瘤数 Nodule number	根瘤干重 Nodule dry weight	豆血红蛋白 Leghemoglobin	固氮酶活性 Nitrogenase activity
P50		29.04 b	0.197 b	4.56 b	1.53 b
P100		42.88 a	0.245 a	5.74 a	2.02 a
	MS	24.92 b	0.155 b	4.76 b	1.62 b
	IS	47.00 a	0.287 a	5.55 a	1.92 a
磷水平 P rates (P)		**	**	**	**
种植模式 Planting patterns (PP)		**	**	**	**
P×PP		*	ns	ns	ns

缩写和处理同表1。同列数据后不同小写字母表示不同处理的差异显著性(P<0.05)。*表示在0.05水平差异显著; **表示在0.01水平差异显著; ns表示不显著。
Abbreviations and treatments are the same as those given in Table 1. Values followed by different lowercase letters in a column indicated significant difference among different treatments at the 0.05 probability level. *: significant difference at the 0.05 probability level; **: significant difference at the 0.01 probability level; ns: not significant.

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图1

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图1不同磷水平下间作对大豆根瘤生长及固氮能力的影响

缩写和处理同表1。不同大小写字母分别表示在P50和P100水平下单作与间作之间的差异显著性(P < 0.05)。
Fig. 1Effects of intercropping on growth, nitrogen fixation ability of soybean nodules under different P rates

Abbreviations and treatments are the same as those given in Table 1. Different uppercase and lowercase letters mean significant difference between monocropping and intercropping at the 0.05 probability level under P50 and P100 rates, respectively.


豆血红蛋白是根瘤中特异存在的一种蛋白, 其含量与根瘤固氮功能强弱的紧密相关。与单作大豆相比, 间作显著提高了大豆根瘤豆血红蛋白的含量16.60%, 其中在P50水平下增加26.30%。磷肥显著影响大豆根瘤中的豆血红蛋白含量变化, P50水平的大豆根瘤豆血红蛋白含量显著低于P100水平20.56%。

固氮酶活性与根瘤固氮能力紧密相关, 其活性高低反映了根瘤固氮能力的大小。间作能显著增强大豆根瘤的固氮酶活性, 较单作显著提高18.52%。适当施磷显著增强大豆根瘤的固氮酶活性, 比P50水平提高了32.03%。同样, 施磷量和种植模式对大豆根瘤豆血红蛋白的含量与固氮酶活性的增加均没有显著的交互作用。综上亦说明, 大豆与玉米间作在一定程度上可以改善根瘤的固氮性能。

2.3 低磷条件下玉米与大豆间作对大豆不同组织氮、磷吸收量的影响

从表3可以看出, 与单作大豆相比, 间作显著提高了大豆植株氮素吸收量50.82%, 其中使叶片、茎部、根系以及根瘤的氮素吸收量分别显著增加57.88%、33.43%、79.74%和109.27%。施磷显著促进了大豆的氮素吸收, P100水平的大豆氮素吸收量较P50水平显著提高60.08%, 其中叶片氮素吸收量增加51.11%, 茎部氮素吸收量增加66.11%, 根系氮素吸收量增加121.29%, 根瘤氮素吸收量增加37.06%。但施磷量和种植模式对大豆各组织氮素吸收量的增加没有明显的交互作用。可见, 大豆与玉米间作可以促进大豆的氮素吸收。

Table 3
表3
表3不同磷水平下玉米与大豆间作对大豆不同组织氮素吸收量的影响
Table 3Effects of maize and soybean intercropping on N uptake of soybean different organs under different P rates (mg plant^-1)

磷水平 P rates	种植模式 Planting patterns	叶 Leaves	茎 Stems	根 Roots	根瘤 Nodules	全株 Whole plant
P50	MS	13.76±1.51 a	11.61±1.78 a	1.24±0.09 a	1.22±0.01 a	27.83±1.07 a
	IS	25.05±2.46 a	17.31±0.36 a	2.80±0.32 a	2.72±0.19 a	47.88±2.87 a
P100	MS	24.03±1.58 a	21.36±0.61 a	3.41±0.15 a	1.81±0.20 a	50.60±0.97 a
	IS	34.63±1.86 a	26.67±2.20 a	5.53±0.24 a	3.59±0.32 a	70.43±3.52 a
施磷量 P rates
P50		19.41 b	14.46 b	2.02 b	1.97 b	37.86 b
P100		29.33 a	24.02 a	4.47 a	2.70 a	60.51 a
种植模式 Planting pattern
	MS	18.90 b	16.48 b	2.32 b	1.51 b	39.22 b
	IS	29.84 a	21.99 a	4.17 a	3.16 a	59.15 a
显著性 Significance
磷水平 P rates (P)		**	**	**	**	**
种植模式 Planting patterns (PP)		**	**	**	**	**
P×PP		ns	ns	ns	ns	ns

缩写和处理同表1。同列数据后不同小写字母表示不同处理的差异显著性(P < 0.05)。**表示在0.01水平差异显著; ns表示不显著。
Abbreviations and treatments are the same as those given in Table 1. Values followed by different lowercase letters in a column indicated significant difference among different treatments at the 0.05 probability level. **: significant difference at the 0.01 probability level; ns: not significant.

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由表4可以看出, 与单作大豆相比, 间作使大豆全株、叶片、茎部、根系以及根瘤的磷素吸收量分别显著提高79.07%、77.24%、70.74%、93.00%和117.02%。与低磷水平(P50)相比, P100水平的大豆全株及各组织磷素吸收量分别显著提高了63.59%、58.10%、59.91%、136.66%和37.06%。另外, 施磷量和种植模式对大豆根系磷素吸收量的增加具有明显的交互作用, 而对其他各组织磷素吸收量则无显著的交互作用。表明大豆与玉米间作可以促进大豆的磷素吸收。

Table 4
表4
表4不同磷水平下玉米与大豆间作对大豆不同组织磷素吸收量的影响
Table 4Effects of maize and soybean intercropping on P uptake of soybean different organs under different P rates (mg plant^-1)

磷水平 P rates	种植模式 Planting patterns	叶 Leaves	茎 Stems	根 Roots	根瘤 Nodules	全株 Whole plant
P50	MS	12.13±0.56 a	7.66±0.78 a	1.75±0.25 a	1.55±0.07 a	23.09±0.61 a
	IS	26.39±2.15 a	15.35±1.91 a	4.46±0.47 a	3.55±0.33 a	49.75±0.57 a
P100	MS	23.74±2.18 a	14.41±0.94 a	5.39±0.67 a	2.17±0.24 a	45.71±3.27 a
	IS	37.16±1.54 a	22.36±1.79 a	9.32±0.15 a	4.60±0.22 a	73.45±0.43 a
施磷量 P rates
P50		19.26 b	11.50 b	3.11 b	2.55 b	36.42 b
P100		30.45 a	18.39 a	7.36 a	3.38 a	59.58 a
种植模式 Planting pattern
	MS	17.93 b	11.04 b	3.57 b	1.88 b	34.40 b
	IS	31.78 a	18.85 a	6.89 a	4.08 a	61.60 a
显著性Significance
磷水平 P rates (P)		**	**	**	**	**
种植模式 Planting patterns (PP)		**	**	**	**	**
P×PP		ns	ns	*	ns	ns

缩写和处理同表1。同列数据后不同小写字母表示不同处理的差异显著性(P < 0.05)。*表示在0.05水平差异显著; **表示在0.01水平差异显著; ns表示不显著。
Abbreviations and treatments are the same as those given in Table 1. Values followed by different letters in a column indicate significant difference among different treatments at the 0.05 probability level. *: significant difference at the 0.05 probability level; **: significant difference at the 0.01 probability level; ns: not significant.

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2.4 低磷条件下玉米与大豆间作对大豆不同组织氮、磷含量的影响

大豆与玉米间作系统中氮素含量的变化见表5和图2, 与单作相比, 间作使大豆叶片、根系及根瘤的氮素含量分别显著提高5.68%、16.53%和12.97%, 但P50和P100水平下单作与间作之间没有显著差异。P100水平显著提高了大豆叶片、根系及根瘤的氮素含量, 分别较P50水平显著增加11.57%、24.20%和10.11%。而且, 施磷量和种植模式对大豆各组织氮素含量的增加没有明显的交互作用。此外, 在大豆叶片、根系、根瘤3个部位中, 以根瘤内的氮素含量最高, 约是叶片和根系的2~8倍, 其次是叶片、根系, 可见在根瘤是氮素贮存的一个重要场所。

Table 5
表5
表5间作和磷水平对大豆氮磷浓度的影响
Table 5Effects of intercropping and P rates on N and P concentrations of soybean organs

磷水平 P rates	种植模式 Planting patterns	氮素浓度N concentrations			磷素浓度P concentrations
		叶Leaf	根系Root	根瘤Nodule	叶Leaf	根系Root	根瘤Nodule
P50		34.58 b	11.86 b	98.07 b	3.36 b	1.78 b	12.63 a
P100		38.58 a	14.73 a	107.98 a	3.98 a	2.41 a	13.43 a
	MS	35.57 b	12.28 b	96.75 b	3.34 b	1.84 b	11.93 b
	IS	37.59 a	14.31 a	109.30 a	4.01 a	2.35 a	14.14 a
磷水平 P rates (P)		**	**	*	**	**	ns
种植模式 Planting patterns (PP)		*	*	*	**	**	**
P×PP		ns	ns	ns	ns	ns	ns

缩写和处理同表1。同列数据后不同小写字母表示不同处理的差异显著性(P < 0.05)。*表示在0.05水平差异显著; **表示在0.01水平差异显著; ns表示不显著。
Abbreviations and treatments are the same as those given in Table 1. Values followed by different lowercase letters in a column indicate significant difference among different treatments at the 0.05 probability level. *: significant difference at the 0.05 probability level; **: significant difference at the 0.01 probability level; ns: not significant.

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图2

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图2不同磷水平下玉米与大豆间作对大豆不同组织氮素浓度的影响

缩写和处理同表1。不同大小写字母分别表示在P50和P100水平下单作与间作之间的差异显著性(P < 0.05)。
Fig. 2Effects of maize and soybean intercropping on N concentration of soybean organs

Abbreviations and treatments are the same as those given in Table 1. Different uppercase and lowercase letters mean the significant difference between monocropping and intercropping at the 0.05 probability level under P50 and P100 rates, respectively.


由表5可以看出, 间作显著提高了大豆叶片、根系和根瘤的磷素含量, 分别较单作大豆增加20.06%、27.72%和18.52%。其中, 在P50水平下, 间作大豆叶片、根系的磷素含量显著高于单作大豆26.82%和35.89%; P100水平下, 间作大豆根系、根瘤的磷素含量显著高于单作大豆22.10%和22.01% (图3)。与正常磷水平(P100)相比, 低磷水平(P50)下大豆叶片和根系的磷含量分别降低15.58%和26.14%, 而根瘤磷含量没有明显下降趋势, 说明根瘤内的磷浓度在低磷与正常磷水平之间保持相对稳定。同样, 施磷量和种植模式对大豆各组织磷素含量的增加同样没有明显的交互作用。同样, 在大豆的叶片、根系和根瘤3个部位中, 同样以根瘤内的磷素浓度最大, 约是叶片、根系磷含量的3~10倍, 说明根瘤同样是磷素的主要贮藏器官。

图3

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图3不同磷水平下玉米与大豆间作对大豆不同组织磷素浓度的影响

缩写和处理同表1。不同大小写字母分别表示在P50和P100水平下单作与间作之间的差异显著性(P < 0.05)。
Fig. 3Effects of maize and soybean intercropping on P concentration of soybean organs under different P rates

Abbreviations and treatments are the same as those given in Table 1. Different uppercase and lowercase letters mean the significant difference between monocropping and intercropping at the 0.05 probability level under P50 and P100 rates, respectively.

2.5 低磷条件下玉米与大豆间作对大豆根瘤酶活性的影响

由表6可知, 与单作大豆相比, 大豆与玉米间作分别显著增强大豆叶片、根系及根瘤内酸性磷酸酶、植酸酶的活性14.02%、27.01%、11.88%和16.81%、17.60%、13.88%。其中, 在P50水平下, 间作大豆叶片、根系内的酸性磷酸酶活性较单作大豆显著增加11.68%和22.73%, 叶片、根系及根瘤内植酸酶活性均显著增加20.21%、20.88%和18.28%; P100水平下, 间作大豆叶片、根系及根瘤内的酸性磷酸酶活性较单作大豆显著增加16.68%、32.24%和9.76%, 而各组织内植酸酶活性无显著增加(图4)。

Table 6
表6
表6间作和磷水平对大豆根瘤酶活性的影响
Table 6Effects of intercropping and P rates on enzyme activities of soybean organs

磷水平 P rates	种植模式 Planting patterns	酸性磷酸酶Acid phosphatase			植酸酶Phytase
		叶Leaf	根系Root	根瘤Nodule	叶Leaf	根系Root	根瘤Nodule
P50		21.19 a	7.74 a	28.89 a	37.17 a	10.00 a	52.84 a
P100		18.37 b	6.38 b	25.35 b	26.67 b	7.80 b	40.56 b
	MS	18.48 b	6.22 b	25.60 b	29.45 b	8.18 b	43.67 b
	IS	21.07 a	7.90 a	28.64 a	34.40 a	9.62 a	49.73 a
磷水平 P rates (P)		**	**	**	**	**	**
种植模式 Planting patterns (PP)		**	**	**	**	**	**
P×PP		ns	ns	ns	ns	ns	ns

缩写和处理同表1。同列数据后不同小写字母表示不同处理的差异显著性(P < 0.05)。**表示在0.01水平差异显著; ns表示不显著。
Abbreviations and treatments are the same as those given in Table 1. Values followed by different lowercase letters in a column indicated significant difference among different treatments at the 0.05 probability level. **: significant difference at the 0.01 probability level; ns: not significant.

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图4

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图4不同磷水平下间作对大豆根瘤酶活性的影响

缩写和处理同表1。不同大小写字母分别表示在P50和P100水平下单作与间作之间的差异显著性(P < 0.05)。
Fig. 4Effects of maize and soybean intercropping on enzyme activities of soybean organs under different P rates

Abbreviations and treatments are the same as those given in Table 1. Different uppercase and lowercase letters mean significant difference between monocropping and intercropping at the 0.05 probability level under P50 and P100 rates, respectively.


与正常磷水平(P100)相比, P50水平使大豆叶片、根系及根瘤内的酸性磷酸酶活性分别显著提高15.35%、21.32%和13.96%, 植酸酶活性分别显著提高39.37%、28.21%和30.28% (表6)。但是, 施磷水平和种植模式对大豆各组织内酸性磷酸酶、植酸酶活性的影响没有明显的交互作用。此外, 在大豆叶、根系及根瘤等3个部位中, 根瘤内的酸性磷酸酶、植酸酶活性最强, 显著高于叶片和根系, 以间作P50处理各组织内的酸性磷酸酶、植酸酶的活性均表现最强。

3 讨论

禾本科/豆科间作被广泛认为是一种可持续的农业生产体系, 可以通过改善豆科作物的结瘤与固氮, 促进群体的氮素吸收, 从而获得高产并减少氮肥的投入^[17,18,19]。Liu等^[20]在小麦与蚕豆间作体系中, 间作显著提高了蚕豆的根瘤数、根瘤重以及固氮酶活性, 促进了群体的氮素吸收。赵雅姣等^[21]研究发现, 与单作相比, 间作显著提高了苜蓿的根瘤数、根瘤重以及固氮酶活性, 促进了玉米的氮素吸收与累积。在本试验中, 在低磷与正常磷水平下, 与单作大豆相比, 间作均显著提高了大豆根瘤数、根瘤干重、根瘤豆血红蛋白含量与固氮酶活性, 并显著促进了其氮素吸收, 说明大豆与玉米间作能够改善大豆结瘤与固氮能力, 提高了氮素吸收, 这与前人的研究结果相符合。

本试验还表明, 与正常磷水平的单作相比, 在减磷1/2处理(P50)下间作大豆的氮吸收量并未出现明显降低, 同时大豆根瘤的生长以及固氮性能亦未受到明显的抑制, 说明大豆与玉米间作可以缓解低磷环境对大豆根瘤生长与固氮性能造成的不利影响, 并有利于氮素吸收。

磷在豆科作物的结瘤与固氮过程中发挥着十分重要的作用, 而土壤中磷素低有效性已成为限制豆科作物根瘤生长发育的一个重要环境因素^[22,23,24]。和植物一样, 根瘤在低磷胁迫环境下也形成一些适应性机制, 如维持根瘤内磷素浓度的相对平衡^[25]。研究表明, 根瘤是一个较强的P库, 低磷胁迫时根瘤的磷浓度远高于植株地上部或根系的磷浓度, 以维持根瘤磷素浓度的相对平衡, 从而保障了低磷条件下根瘤的固氮效率^[26,27,28]。在本试验条件下, 无论单作还是间作条件下, 大豆根瘤内的磷浓度同样显著高于叶片和根系, 根瘤磷浓度在低磷与正常磷水平之间的变化相对平稳, 并且间作大豆根瘤内的磷浓度显著高于单作大豆, 说明大豆与玉米间作更有利于维持根瘤内的磷浓度平衡, 进而保障自身的固氮能力。同样, 低磷条件(P50)下间作大豆根瘤内的磷浓度较正常磷水平的单作大豆显著增加, 说明在低磷环境下, 大豆与玉米间作具有提高根瘤内磷素浓度相对平衡的潜力, 有利于改善了大豆的固氮能力。

植物体内磷的再活化也是其响应低磷胁迫的一种生理生化反应, 从而维持细胞内相对平稳的磷浓度^[29,30]。Araújo等^[31]研究亦表明, 缺磷条件下, 菜豆通过增强根瘤内的酸性磷酸酶与植酸酶活性来维持根瘤内相对较高的磷浓度, 以保障固氮的效率。Lazali等^[32]研究发现, 在低磷胁迫下, 芸豆通过增强根瘤内的植酸酶、酸性磷酸酶活性以及植酸酶基因的表达来提高根瘤内的磷浓度, 维持较高的固氮效率, 进而促进菜豆的生长与氮磷吸收。在本试验中, 间作大豆根瘤组织内的酸性磷酸酶、植酸酶的活性显著高于单作大豆, 并且低磷条件下间作大豆根瘤组织内酸性磷酸酶、植酸酶的活性最强, 说明大豆与玉米间作通过增强根瘤内酸性磷酸酶、植酸酶的活性来再活化体内的有机磷以维持根瘤内较高的磷浓度, 改善了根瘤的固氮能力, 有助于大豆的生长与氮吸收, 尤其在低磷条件下。综上结果表明, 间作特别是间作低磷条件下, 大豆通过增强根瘤内酸性磷酸酶、植酸酶的活性维持体内磷浓度的相对平衡, 保证根瘤固氮过程对磷素的较大需求, 改善了根瘤固氮的能力, 从而促进间作群体的氮素营养。

4 结论

在低磷水平(P50)和正常磷水平(P100)下, 大豆与玉米间作较单作大豆显著提高大豆氮磷素的吸收, 同时显著增加大豆根瘤数、根瘤重、根瘤豆血红蛋白含量以及固氮酶活性。间作大豆根瘤内的氮磷浓度、酸性磷酸酶及植酸酶活性均显著高于单作大豆, 且在低磷条件下酶活性最高。根瘤内酸性磷酸酶、植酸酶活性的增强是驱动低磷条件下间作维持大豆根瘤磷浓度平衡以及改善大豆固氮能力的重要原因。玉米-大豆间作具有减少磷肥投入的空间以及改善豆科结瘤固氮性能的潜力。

参考文献 View Option 原文顺序
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被引期刊影响因子

[1] Cordell D, White S. Life’s bottleneck: sustaining the world’s phosphorus for a food secure future
Annu Rev Environ Resour, 2014, 39: 161-188.
DOIURL [本文引用: 1]

[2] Zhang Z L, Liao H, Lucas W J. Molecular mechanisms underlying phosphate sensing, signaling, and adaptation in plants
J Integr Plant Biol, 2014, 56: 192-220.
DOIURL [本文引用: 1]

[3] 李杰, 石元亮, 陈智文. 我国南方红壤磷素研究概况
土壤通报, 2011, 42: 763-768.
[本文引用: 1]

Li J, Shi Y L, Chen Z W. Research on phosphorus in southern red soils in China
Chin J Soil Sci, 2011, 42: 763-768 (in Chinese with English abstract).
[本文引用: 1]

[4] 苗淑杰, 乔云发, 韩晓增, 王树起, 李海波. 缺磷对已结瘤大豆生长和固氮功能的影响
作物学报, 2009, 35: 1344-1349.
[本文引用: 1]

Miao S J, Qiao Y F, Han X Z, Wang S Q, Li H B. Effects of phosphorus deficiency on growth and nitrogen fixation of soybean after nodule formation
Acta Agron Sin, 2009, 35: 1344-1349 (in Chinese with English abstract).
[本文引用: 1]

[5] Vardien W, Mesjasz-Przybylowicz J, Przybylowicz W, Wang Y D, Steenkamp E T, Valentine A J. Nodules from Fynbos legume Virgilia divaricata have high functional plasticity under variable P supply levels
J Plant Physiol, 2014, 171: 1732-1739.
DOIURL [本文引用: 1]

[6] Valentine A J, Kleinert A, Benedito V A. Adaptive strategies for nitrogen metabolism in phosphate deficient legume nodules
Plant Sci, 2017, 256: 46-52.
DOIPMID [本文引用: 1]
Legumes play a significant role in natural and agricultural ecosystems. They can fix atmospheric N and contribute the fixed N to soils and plant N budgets. In legumes, the availability of P does not only affect nodule development, but also N acquisition and metabolism. For legumes as an important source of plant proteins, their capacity to metabolise N during P deficiency is critical for their benefits to agriculture and the natural environment. In particular for farming, rock P is a non-renewable source of which the world has about 60-80 years of sustainable extraction of this P left. The global production of legume crops would be devastated during a scarcity of P fertiliser. Legume nodules have a high requirement for mineral P, which makes them vulnerable to soil P deficiencies. In order to maintain N metabolism, the nodules have evolved several strategies to resist the immediate effects of P limitation and to respond to prolonged P deficiency. In legumes nodules, N metabolism is determined by several processes involving the acquisition, assimilation, export, and recycling of N in various forms. Although these processes are integrated, the current literature lacks a clear synthesis of how legumes respond to P stress regarding its impact on N metabolism. In this review, we synthesise the current state of knowledge on how legumes maintain N metabolism during P deficiency. Moreover, we discuss the potential importance of two additional alterations to N metabolism during P deficiency. Our goals are to place these newly proposed mechanisms in perspective with other known adaptations of N metabolism to P deficiency and to discuss their practical benefits during P deficiency in legumes.Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

[7] Wen Z H, Li H B, Tang X M, Xiong C Y, Li H G, Pang J Y, Ryan M H, Lambers H, Shen J B. Trade-offs among root morphology, exudation and mycorrhizal symbioses for phosphorus-acquisition strategies of 16 crop species
New Phytol, 2019, 223: 882-895.
DOIURL [本文引用: 1]

[8] 张丽梅, 郭再华, 张琳, 贺立源. 缺磷对不同耐低磷玉米基因型酸性磷酸酶活性的影响
植物营养与肥料学报, 2015, 21: 898-910.
[本文引用: 1]

Zhang L M, Guo Z H, Zhang L, He L Y. Effects of phosphate deficiency on acid phosphatase activities of different maize genotypes tolerant to low P stress
J Plant Nutr Fert, 2015, 21: 898-910 (in Chinese with English abstract).
[本文引用: 1]

[9] Magadlela A, Kleinert A, Dreyer L L, Valentine A. Low-phosphorus conditions affect the nitrogen nutrition and associated carbon costs of two legume tree species from a Mediterranean-type ecosystem
Aust J Bot, 2014, 62: 1-9.
DOIURL [本文引用: 1]

[10] Magadlela A, Beukes C, Venter F, Steenkamp E, Valentine A. Does P deficiency affect nodule bacterial composition and N source utilization in a legume from nutrient-poor Mediterranean-type ecosystems?
Soil Biol Biochem, 2017, 104: 164-174.
DOIURL [本文引用: 1]

[11] Thuynsma R, Valentine A, Kleinert A. Phosphorus deficiency affects the allocation of below-ground resources to combined cluster roots and nodules in Lupinus albus
J Plant Physiol, 2013, 173: 1-7.
[本文引用: 1]

[12] Lazali M, Bargaz A, Carlsson G, Ounane S M, Drevon J J. Discrimination against ¹⁵N among recombinant inbred lines of Phaseolus vulgaris L. contrasting in phosphorus use efficiency for nitrogen fixation
J Plant Physiol, 2014, 171: 199-204.
DOIURL [本文引用: 1]

[13] Ahmed A, Aftab S, Hussain S, Cheema H N, Liu W G, Yang F, Yang W Y. Nutrient accumulation and distribution assessment in response to potassium application under maize-soybean intercropping system
Agronomy, 2020, 10: 725-731.
DOIURL [本文引用: 1]

[14] Li B, Li Y Y, Wu H M, Zhang F F, Li C J, Li X X, Lambers H, Li L. Root exudates drive interspecific facilitation by enhancing nodulation and N₂ fixation
Proc Natl Acad Sci USA, 2016, 113: 6496-6501.
DOIURL [本文引用: 2]

[15] Zhang D, Zhang C, Tang X, Li H G, Zhang F S, Rengel Z, Whalley W R, Davies W J, Shen J B. Increased soil phosphorus availability induced by faba bean root exudation stimulates root growth and phosphorus uptake in neighbouring maize
New Phytol, 2016, 209: 823-831.
DOIURL [本文引用: 1]

[16] 左元梅, 刘永秀, 张福锁. 与玉米混作改善花生铁营养对其根瘤形态结构及豆血红蛋白含量的影响
植物生理与分子生物学学报, 2003, 29: 33-38.
[本文引用: 1]

Zuo Y M, Liu Y X, Zhang F S. Effects of improvement of iron nutrition by mixed cropping with maize on nodule microstructure and leghemoglobin content of peanut
J Plant Physiol Mol Biol, 2003, 29: 33-38 (in Chinese with English abstract).
[本文引用: 1]

[17] Hu F, Zhao C, Feng F C, Chai Q, Mu Y P, Zhang Y. Improving N management through intercropping alleviates the inhibitory effect of mineral N on nodulation in pea
Plant Soil, 2017, 412: 235-251.
DOIURL [本文引用: 1]

[18] Liu Y C, Yin X H, Xiao J X, Tang L, Zheng Y. Interactive influences of intercropping by nitrogen on flavonoid exudation and nodulation in faba bean
Sci Rep, 2019, 9: 1-11.
[本文引用: 1]

[19] Li B, Li Y Y, Wu H M, Zhang F F, Li L. Root exudates drive interspecific facilitation by enhancing nodulation and N₂ fixation
Proc Natl Acad Sci USA, 2016, 113: 6496-6501.
DOIURL [本文引用: 1]

[20] Liu Y C, Qin X M, Xiao J X, Tang L, Wei C Z, Wei J J, Zheng Y. Intercropping influences component and content change of flavonoids in root exudates and nodulation of Faba bean
J Plant Interact, 2017, 12: 187-192.
DOIURL [本文引用: 1]

[21] 赵雅姣, 刘晓静, 童长春, 吴勇. 紫花苜蓿/玉米间作对紫花苜蓿结瘤固氮特性的影响
草业学报, 2020, 29(1):95-105.
[本文引用: 1]

Zhao Y J, Liu X J, Tong C C, Wu Y. Factors influencing nodulation and N fixation ability of alfalfa in a simulated alfalfa/maize intercropping system
Acta Pratac Sin, 2020, 29(1):95-105 (in Chinese with English abstract).
[本文引用: 1]

[22] Esfahani M N, Kusano M, Nguyen K H, Watanabe Y, Ha C V, Saito K, Sulieman S, Herrera-Estrella L, Tran L S P. Adaptation of the symbiotic Mesorhizobium-chickpea relationship to phosphate deficiency relies on reprogramming of whole-plant metabolism
Proc Natl Acad Sci USA, 2016, 22: 4610-4619.
[本文引用: 1]

[23] Chen Z J, Cui Q Q, Liang C Y, Sun L L, Tian J, Liao H. Identification of differentially expressed proteins in soybean nodules under phosphorus deficiency through proteomic analysis
Proteomics, 2011, 11: 4648-4659.
DOIURL [本文引用: 1]

[24] 齐敏兴, 刘晓静, 张晓磊, 刘艳楠. 不同磷水平对紫花苜蓿光合作用和根瘤固氮特性的影响
草地学报, 2013, 21: 512-516.
[本文引用: 1]

Qi M X, Liu X J, Zhang X L, Liu Y N. Effects of different phosphorus levels on photosynthesis and root nodule nitrogen-fixing characteristic of alfalfa
Acta Agrest Sin, 2013, 21: 512-516 (in Chinese with English abstract).
[本文引用: 1]

[25] Sulieman S, Tran L S P. Phosphorus homeostasis in legume nodules as an adaptive strategy to phosphorus deficiency
Plant Sci, 2015, 221: 1-8.
[本文引用: 1]

[26] Sulieman S, Van Ha C, Schulze J, Tran L S P. Growth and nodulation of symbiotic Medicago truncatula at different levels of phosphorus availability
J Exp Bot, 2013, 64: 2701-2712.
DOIPMID [本文引用: 1]
Medicago truncatula is an important model plant for characterization of P deficiency on leguminous plants at the physiological and molecular levels. Growth optimization of this plant with regard to P supply is the first essential step for elucidation of the role of P in regulation of nodulation. Hence, a study was carried out to address the growth pattern of M. truncatula hydroponically grown at different gradual increases in P levels. The findings revealed that M. truncatula had a narrow P regime, with an optimum P level (12 μM P) which is relatively close to the concentration that induces P toxicity. The accumulated P concentration (2.7 mg g(-1) dry matter), which is normal for other crops and legumes, adversely affected the growth of M. truncatula plants. Under P deficiency, M. truncatula showed a higher symbiotic efficiency with Sinorhizobium meliloti 2011 in comparison with S. meliloti 102F51, partially as a result of higher electron allocation to N2 versus H(+). The total composition of free amino acids in the phloem was significantly affected by P deprivation. This pattern was found to be almost exclusively the result of the increase in the asparagine level, suggesting that asparagine might be the shoot-derived signal that translocates to the nodules and exerts the down-regulation of nitrogenase activity. Additionally, P deprivation was found to have a strong influence on the contents of the nodule carbon metabolites. While levels of sucrose and succinate tended to decrease, a higher accumulation of malate was observed. These findings have provided evidence that N2 fixation of M. truncatula is mediated through an N feedback mechanism which is closely related to nodule carbon metabolism.

[27] Schulze J, Temple G, Temple S J, Beschow H, Vance C P. Nitrogen fixation by white lupin under phosphorus deficiency
Ann Bot, 2006, 98: 731-740.
DOIURL [本文引用: 1]

[28] Lu M Y, Cheng Z Y, Zhang X M, Huang P H, Fan C M, Yu G L, Chen F L, Xu K, Chen Q S, Miao Y C, Han Y Z, Feng X Z, Liu L Y, Fu Y F. Spatial divergence of PHR-PHT1 modules maintains phosphorus homeostasis in soybean nodules
Plant Physiol, 2020, 10: 1-19.
[本文引用: 1]

[29] Bargaz A, Faghire M, Abdi N, Farissi M, Sifi B, Drevon J J, Ikbal M C, Ghoulam C. Low soil phosphorus availability increases acid phosphatases activities and affects P partitioning in nodules, seeds and rhizosphere of Phaseolus vulgaris
Agriculture, 2012, 2: 139-153.
DOIURL [本文引用: 1]

[30] Lazali M, Drevon J J. Role of acid phosphatase in the tolerance of the rhizobial symbiosis with legumes to phosphorus deficiency
Symbiosis, 2018, 76: 221-228.
DOIURL [本文引用: 1]

[31] Araújo A P, Plassard C, Drevon J J. Phosphatase and phytase activities in nodules of common bean genotypes at different levels of phosphorus supply
Plant Soil, 2008, 312: 129-138.
DOIURL [本文引用: 1]

[32] Lazali M, Zaman-Allah M, Amenc L, Ounane G, Abadie J, Drevon J J. A phytase gene is overexpressed in root nodules cortex of Phaseolus vulgaris-rhizobia symbiosis under phosphorus deficiency
Planta, 2013, 238: 317-324.
DOIURL [本文引用: 1]