大豆叶片光合氮利用效率与氮分配对水分的响应

马晓芳; 白怡菲; 刘倩; 张方敏

文章摘要

马晓芳,白怡菲,刘倩,张方敏.大豆叶片光合氮利用效率与氮分配对水分的响应[J].农业环境科学学报,2025,44(10):2508-2516.

大豆叶片光合氮利用效率与氮分配对水分的响应

Response of photosynthetic nitrogen use efficiency and nitrogen partitioning to water conditions in soybean leaves

投稿时间：2024-11-20

DOI：10.11654/jaes.2024-1005

中文关键词: 光合氮利用效率氮分配比例 CO₂扩散导度水分

英文关键词: photosynthetic nitrogen use efficiency nitrogen partition ratio CO₂ diffusive conductance moisture

基金项目:江苏省碳达峰碳中和科技创新专项（BE2023400）；江苏省研究生科研与实践创新项目（KYCX22_1161）；国家重点研发计划项目（2023YFF0805402）

作者	单位	E-mail
马晓芳	南京信息工程大学气象灾害预报预警与评估协同创新中心/应用气象学院江苏省农业气象重点实验室, 南京 210044
白怡菲	南京信息工程大学气象灾害预报预警与评估协同创新中心/应用气象学院江苏省农业气象重点实验室, 南京 210044
刘倩	南京信息工程大学气象灾害预报预警与评估协同创新中心/应用气象学院江苏省农业气象重点实验室, 南京 210044
张方敏	南京信息工程大学气象灾害预报预警与评估协同创新中心/应用气象学院江苏省农业气象重点实验室, 南京 210044	fmin.zhang@nuist.edu.cn

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中文摘要:

为探究水分减少条件下大豆叶片光合氮利用效率与氮分配的关系，在大田条件下设置5种水分处理：全生育期供水（CK）、全生育期轻度干旱（W1T1）、全生育期中度干旱（W2T1）、苗期充分供水+开花期到成熟期中度干旱（W2T2）、苗期和开花期充分供水+成熟期中度干旱（W2T3），测定计算了各处理下大豆叶片的光饱和净光合速率（A_max′）、单位叶面积氮含量（N_area）、CO₂扩散导度[气孔导度（g_s）与叶肉导度（g_m）]和氮分配比例[Rubisco氮分配比例（P_R）、生物力能量学氮分配比例（P_B）与捕光系统氮分配比例（P_L）]等参数，分析了光合氮利用效率（PNUE）随水分的变化趋势及 PNUE与其他参数的关系。结果表明：与 CK相比，W2T1的PNUE、A_max′和N_area分别下降了32.2%、42.6%和11.9%，W2T1和W2T3处理下的g_s显著低于CK，分别为CK的56.0%和52.0%（P<0.05）；W2T1和W2T3的g_m为CK的60.9%和78.3%，g_s与PNUE之间呈显著正相关关系（P<0.01）；叶绿素含量（cchl）随水分亏缺呈下降趋势，W2T1的cchl降幅最大，达到25.6%（P<0.05）；P_R与P_B随水分减少而显著降低（P<0.05）；所有水分处理（W1T1、W2T1、W2T2、W2T3）的 P_L均较 CK显著下降（P<0.05），处理组间没有显著差异；大豆叶片 P_R和 P_B与 PNUE呈显著正相关关系，说明 P_R和 P_B是PNUE随水分变化的重要因素。研究表明，水分胁迫显著降低大豆叶片A_max′、N_area及PNUE；水分减少不仅削弱了CO₂向叶片内部的传输能力，同时造成叶绿素含量降低，还引发了光合系统与非光合系统之间氮分配的权衡变化，尤其是P_R与P_B的下降。水分限制条件下大豆叶片PNUE下降主要归因于光合系统氮分配比例降低、叶片CO₂扩散能力减弱及P_R与P_B降低。

英文摘要:

Photosynthetic nitrogen use efficiency（PNUE）, a key parameter in leaf economic spectrum theory, is a critical indicator for understanding the trade-off strategies between nutrient utilization and stress adaptation in crops under resource-limited environments. To investigate the mechanistic links between PNUE and nitrogen allocation in soybean leaves under progressive water deficit, we implemented a field experiment with five water regimes：full irrigation throughout growth cycle（CK）; mild drought during entire growth period（W1T1）; moderate drought during entire growth period（W2T1）; adequate irrigation at seedling stage + moderate drought from flowering to maturity （W2T2）; adequate irrigation at seedling and flowering stages + moderate drought at maturity（W2T3）. Key photosynthetic parameters including light-saturated net photosynthetic rate（A_max′）, nitrogen content per unit leaf area（N_area）, CO₂ diffusion conductance（stomatal conductance, g_s; mesophyll conductance, g_m）, and nitrogen allocation proportions（Rubisco-associated nitrogen proportion, P_R; bioenergetics components nitrogen allocation proportion, P_B; light-harvesting complex nitrogen proportion, P_L） were systematically quantified. Significantly, the W2T1 treatment showed reductions of 32.2% in PNUE, 42.6% in A_max′, and 11.9% in N_area compared to CK（P<0.05）. Water deficit significantly impaired stomatal functionality, with g_s in W2T1 and W2T3 decreasing to 56.0% and 52.0% of CK values, respectively. Concurrent reductions in g_m were observed（60.9% and 78.3% of CK for W2T1 and W2T3）, while a robust positive correlation emerged between g_s and PNUE（P<0.01）. Chlorophyll content（c_chl）demonstrated progressive depletion under water stress, peaking at 25.6% reduction in W2T1（P<0.05）. Nitrogen allocation to photosynthetic machinery showed systematic declines, with P_R and P_B significantly decreasing across drought treatments（P<0.05）; all moisture treatments（W1T1, W2T1, W2T2, W2T3）exhibited significantly reduced P_L compared to CK（P<0.05）, though no significant inter-treatment differences in P_L were observed. P_R and P_B showed significant positive correlations with PNUE（P<0.05）, indicating their crucial roles in mediating moisture-induced variations in soybean PNUE. The investigation revealed that water stress significantly decreased A_max′, N_area, and PNUE in soybean leaves. Furthermore, water deficit not only impaired leaf CO₂ transport capacity but also reduced chlorophyll content, while simultaneously altering nitrogen allocation patterns between photosynthetic and non-photosynthetic systems-particularly manifesting as decreased P_R and P_B. These findings collectively demonstrate that the observed PNUE reduction under water-limited conditions primarily stems from three interrelated factors：diminished nitrogen allocation to photosynthetic components, compromised leaf CO₂ diffusion capacity, and reductions in both P_R and P_B.

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