水分胁迫下氮素增加对玉米生长的抑制作用  

Inhibition of Nitrogen Increasing on Maize Growth under Water Stress

作　　者：邢换丽 周文彬 郝卫平[1] 李丽[1] 王超 马海洋 王耀生[1] XING Huan-li;ZHOU Wen-bin;HAO Wei-ping;LI Li;WANG Chao;MA Hai-yang;WANG Yao-sheng(State Engineering Laboratory of Efficient Water Use of Crops and Disaster Loss Mitigation/Key Laboratory of Dryland Agriculture,Ministry of Agriculture and Rural Affairs of China/Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,Beijing 100081,China;Institute of Crop Sciences,Chinese Academy of Agricultural Sciences,Beijing 100081;South Subtropical Crops Research Institute,Chinese Academy of Tropical Agricultural Sciences,Zhanjiang 524091)

机构地区：[1]作物高效用水与抗灾减损国家工程实验室/农业农村部旱作节水农业重点实验室/中国农业科学院农业环境与可持续发展研究所,北京100081 [2]中国农业科学院作物科学研究所,北京100081 [3]中国热带农业科学院南亚热带作物研究所,广东湛江524091

出　　处：《中国农业气象》2020年第4期240-252,共13页Chinese Journal of Agrometeorology

基　　金：政府间国际科技创新合作重点专项(2018YFE0107000);国家自然科学基金(51509250);中央级公益性科研院所基本科研业务费专项(BSRF201710)。

摘　　要：水分和氮素是影响玉米生长发育的重要因子。在干旱和土壤贫瘠条件下,作物的生长和生理过程受到水分和氮素的交互作用。因此,研究水分胁迫下不同施氮水平对玉米叶片光合生理及根系形态的影响可以为玉米栽培中水氮的高效管理提供科学理论依据。利用温室盆栽试验,在中度水分胁迫(W1,40%~50%田间持水量)、轻度水分胁迫(W2,60%~70%田间持水量)和充足供水(W3,75%~90%田间持水量)三个水分处理下设置低氮(N1,1.0g·盆^(-1))、中氮(N2.5,2.5g·盆^(-1))和高氮(N5,5.0g·盆^(-1))三个施氮水平,研究玉米的生长状况、叶片气体交换参数、光和二氧化碳响应曲线和根系形态等。结果表明:在不同水分条件下玉米对氮素的生理响应过程不同。水分胁迫下根长和根系比表面积较充足供水处理显著增加,增幅分别为106.39%~208.82%和45.81%~105.85%,根干重在中度水分胁迫下降低23.94%~36.61%;此时增加施氮量尤其是高氮处理,玉米的根长和根系比表面积比水分胁迫下低氮处理显著降低41.85%~54.10%和18.68%,根干重比中度水分胁迫下低氮处理显著降低33.75%。因此,水分胁迫下施氮加剧了根际的水分胁迫,造成根水势下降,进而影响地上部分叶片的气孔导度(G_s)及二氧化碳和光的利用效率。水分胁迫和施氮处理均影响玉米叶片的光和CO_2响应曲线,水分处理的影响更显著。相同施氮水平下,随着水分胁迫程度的加剧,光响应曲线参数暗呼吸速率(R_d)、最大净光合速率(A_(max))和饱和光强(Q_(sat))以及CO_2响应曲线参数初始羧化效率(a)、光呼吸速率(R_p)、光合能力(A_(max))和高氮条件下的饱和胞间CO_2浓度(C_(isat))均呈下降趋势,前者参数变化显著,而且中度水分胁迫下,增加施氮量进一步降低了这些参数,即水分胁迫下氮素进一步抑制了植株的光合性能;同时,中度水分胁迫下叶片G_s和光合速率(A_n)分别显著降低32.37%~51.Water and nitrogen (N) are two important factors affecting crop growth and development. The growth and physiological processes of crops are affected by interactions between water and N under drought and poor soil conditions. Therefore, the study on effect of different N fertilization on leaf photosynthetic physiology and root morphology of maize under water stress can provide a scientific theoretical basis for the effective water and N management of maize cultivation. The experiment was carried out in a glasshouse. The soil water treatments included three levels: moderate drought (W1, 40% 50% soil water holding capacity (SWHC)), mild drought (W2, 60% 70% SWHC) and well-watered (W3, 75% 90% SWHC). The N fertilization included three levels: low N (N1, 1.0g pot 1), middle N (N2.5, 2.5g pot 1) and high N (N5, 5.0g pot 1) levels. The maize growth, leaf gas exchange, the photosynthetic CO2 response curve (An/Ci) and light response curve (An/Q), and the root morphology were investigated. The results showed that the physiological responses of maize to N fertilization were different under varied soil water regimes. Compared with well-watered treatment, the root length and root specific surface area increased by 106.39% 208.82% and 45.81% 105.85%, respectively, under water stress condition, and the root dry weight decreased by 23.94% 36.61% under the moderate drought condition. Increasing N dose, especially the high N treatment, significantly decreased the root length and root specific surface area by 41.85% 54.10% and 18.68%, respectively, and the root dry weight decreased by 33.75% significantly under low N treatment with soil water stress. Thus, N fertilization aggravated plant water stress in the root zone, leading to reduced root water potential. Consequently, the stomatal conductance (Gs), CO2 and light use efficiency of maize leaf were affected. Both water and N treatments affected CO2 and light response curves, and water treatments showed a more prominent effect. Under the same N treatments, the dark respiration ra

关 键 词：干旱 气孔导度 水势 响应曲线 直角双曲线修正模型 根系形态 

分 类 号：S513[农业科学—作物学]