| 低氮胁迫下玉米幼苗氮素和蔗糖分配特性 |
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| 引用本文： | 赵泽群,师赵康,王雯,张远航,徐世英,王宁,王伟杰,程皓,冯万军.低氮胁迫下玉米幼苗氮素和蔗糖分配特性[J].植物营养与肥料学报,2020,26(4):783-796. |
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| 作者姓名： | 赵泽群 师赵康 王雯 张远航 徐世英 王宁 王伟杰 程皓 冯万军 |
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| 作者单位： | 1.山西农业大学农学院，山西太谷 030801 |
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| 基金项目： | 国家公益性行业（农业）科研专项（201503121-07）；山西省重点研发计划重点项目（201703D211001-02）；山西省自然科学基金（201701D221186）；山西省科技创新基金（2014020）。 |
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| 摘 要： | 【目的】 明确玉米自交系幼苗氮素吸收、转运与利用特性，探究低氮胁迫下其不同表型和生理性状的变化规律。 【方法】 以玉米自交系XY4和PH4CV为供试材料，进行了水培试验。设置正常氮 (N 2 mmol/L，NN) 和低氮 (N 0.04 mmol/L，LN) 两个氮水平，从培养3 h起，每3天测定一次幼苗生物量、光合特性、根系性状及氮素和蔗糖含量，直至第12天。 【结果】 玉米幼苗根系对低氮胁迫的反应早于地上部，与NN处理相比，LN处理PH4CV和XY4的根干重分别在培养第3和第6天时增加了65.15%和84.63%，而从培养第9天开始，LN处理下两自交系幼苗地上部干重显著低于NN处理，由此导致根冠比增加；与NN处理相比，LN处理下除了胞间CO2浓度 (Ci) 和水分利用效率 (WUE) 外，两自交系幼苗叶片的SPAD值、净光合速率 (Pn)、蒸腾速率 (Tr) 和气孔导度 (Gs) 等光合特性均显著降低，且XY4下降幅度均大于PH4CV；LN处理下两自交系幼苗根干重的变异来源并不一致，XY4根干重的增加与总根长、根表面积、根体积、侧根数和初生根长增加有关，而PH4CV主要与侧根数目增加有关；与NN处理相比，LN处理两自交系幼苗地上部的氮素积累量和蔗糖含量显著降低，且XY4老叶的氮素含量下降速率明显快于PH4CV，而根系的氮素积累量、单株氮素生理利用效率和根中蔗糖含量均显著增加，且XY4增加的幅度均大于PH4CV。 【结论】 低氮胁迫促使玉米幼苗分配给地上部的氮素和蔗糖相对较少，因此限制地上部生物量积累及叶片光合能力的发挥，而分配给根系的氮素和蔗糖相对较多，从而促进根系形态建成，以利于吸收更多的氮素。
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| 关 键 词： | 玉米 低氮胁迫 生物量 光合特性 根系形态 蔗糖分配 |
| 收稿时间： | 2019-06-05 |
Allocation of nitrogen and sucrose in maize seedling under low nitrogen stress |
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| ZHAO Ze-qun,SHI Zhao-kang,WANG Wen,ZHANG Yuan-hang,XU Shi-ying,WANG Ning,WANG Wei-jie,CHENG Hao,FENG Wan-jun.Allocation of nitrogen and sucrose in maize seedling under low nitrogen stress[J].Plant Nutrition and Fertilizer Science,2020,26(4):783-796. |
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| Authors: | ZHAO Ze-qun SHI Zhao-kang WANG Wen ZHANG Yuan-hang XU Shi-ying WANG Ning WANG Wei-jie CHENG Hao FENG Wan-jun |
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| Institution: | 1.College of Agronomy, Shanxi Agricultural University, Taigu, Shanxi 030801, China |
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| Abstract: | 【Objectives】 The study aimed to explore the characteristics of nitrogen (N) uptake, transport and utilization in seedlings of maize inbred lines, in order to reveal the changing patterns of phenotypic and physiological characteristics under low nitrogen stress. 【Methods】 A hydroponic experiment was conducted using two maize inbred lines XY4 and PH4CV as experimental materials. Nutrient solution of normal N (2 mmol/L, NN) and low nitrogen stress (0.04 mmol/L. LN) was prepared. Since 3 h of culturing, the biomass, photosynthetic characteristics, root traits, nitrogen and sucrose contents of maize seedlings were measured, the measurement was done in 3 days interval and the last one was at the 12th day. 【Results】 Root responses to low nitrogen stress were earlier than those of shoot. The root dry weights of PH4CV and XY4 treated with LN for 3 and 6 days increased significantly compared with NN treatment, increased by 65.15% and 84.63%, respectively. However, after 9 days treatment in low nitrogen level, the shoot dry weights of XY4 and PH4CV decreased significantly compared with NN treatment, resulting in the root to shoot ratio increasing. In LN treatment, except for intercellular CO2 concentration (Ci) and water use efficiency (WUE), the SPAD values, net photosynthetic rate (Pn), stomatal conductance (Tr) and transpiration rate (Gs) in seedling leaves of both inbred lines were lower than those of NN treatment, and XY4 decreased more than PH4CV. Under LN treatment, the sources of variation of root dry weight in two inbred lines were different, the increase of XY4 in root dry weight was related to the increase of total root length, root surface area, root volume, lateral root number and primary root length, while that of PH4CV was mainly related to the increase of lateral root number. Compared with NN treatment, the nitrogen and sucrose contents in seedling shoots of two inbred lines decreased significantly, and nitrogen contents in the old leaves of XY4 decreased faster than that of PH4CV, while nitrogen contents in roots, physiological nitrogen use efficiency of individual plants and sucrose contents in roots increased significantly under LN treatment, and XY4 increased more than those of PH4CV. 【Conclusions】 Low nitrogen stress promotes maize seedlings to assign less nitrogen and sucrose to the shoot, results in limiting the accumulation of shoot biomass and the photosynthetic capacity of leaves, while more nitrogen and sucrose are allocated to the roots, thus promoting the formation of root morphology and facilitating their absorption of more nitrogen. |
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