气候变化背景下玉米地上部和地下根系对关键发育期干旱胁迫响应研究

With the climate warming and shortage of water resources, the less precipitation and the frequent drought often occur in the main maize production of Northeast China, drought stress is the predominant limiting factor to corn growth and output increased. Strengthening research on influence mechanism of spring maize key development period drought stress is expected to play an important role in steady grain-production, at present, the observation less of spring maize key development period of gradual drought based on root observation in field. The research taking spring maize in Northeast China as research object, based on Jinzhou Maize Agricultural Ecosystem Observation Station, the large soil moisture control experimental field and root observational system, integrating minirhizotron and gradual drought method, overground part and underground root at spring maize key development period under different soil water contents will be dynamically observed, and synchronous observe soil moisture, soil temperature and background meteorological conditions. Firstly, the influence mechanism of overground and underground parts of spring maize to drought stress is expected to be revealed with a deep analysis of observation data. Secondly, through evaluating quantitatively the effects on yield under different drought stress conditions of spring maize key development period based on quantitative relationship of overground part and underground root under different drought stress conditions. The study will be provided the root module data for the crop growth model, provided basis and methods for the spring drought prediction and evaluation, and provided scientific basis for drought-resistant sowing pattern and water-saving irrigation, better service to the Liao northwest agricultural production.

随着气候变暖和水资源匮缺，东北地区春玉米主产区降水减少，干旱灾害频繁发生，干旱胁迫已成为限制作物生产的重要因子。加强玉米关键发育期干旱胁迫响应机制研究对稳定粮食生产具有重要意义，目前基于大田根系观测进行玉米关键发育期渐进干旱的研究较少。本项目以春玉米为研究对象，基于锦州玉米农田生态试验站、大型土壤水分控制试验场、大型根系观测系统，结合微根管和渐进干旱方法，对不同干旱胁迫条件下春玉米关键发育期地上部与地下根系进行动态观测，同步观测土壤湿度、土壤温度和背景气象条件，通过对试验资料的深入分析揭示春玉米地上部与地下根系对干旱胁迫的响应机制；基于不同干旱胁迫条件下春玉米地上部与地下根系的定量关系，分析春玉米关键发育期不同干旱胁迫程度对产量的定量影响，为作物生长模型提供地下根系模块观测数据，为干旱灾害预测和影响评估提供依据与方法，为抗旱播种与节水灌溉提供科学参考，以更好地为干旱地区的农业生产服务。

本项目对不同干旱胁迫条件下东北地区春玉米关键发育期地上部分和地下根系对干旱的响应进行了研究，以春玉米为研究对象，基于锦州玉米农田生态试验站、大型土壤水分控制试验场、大型根系观测系统，结合微根管和渐进干旱方法，对不同干旱胁迫条件下春玉米地上部和地下根系进行动态观测，利用2018—2019年观测数据，分析春玉米关键发育期不同程度干旱胁迫对玉米地上部和地下根系及产量的定量影响。得到以下结论：（1）2010—2019年锦州站玉米发育期长度呈减少的气候变化趋势，气候倾向率为-19.27/10 a，其中播种—出苗期、出苗—三叶期、三叶—七叶期和乳熟—成熟期长度显著减少。（2）2018年和2019年玉米地上部指标和地下根系相关不显著，但是根系和光合对干旱响应敏感，可以作为干旱指示因子。（3）在干旱胁迫条件下，深层土壤根系对玉米产量的影响较大，而土壤水分条件较好时，表层土壤根系对玉米产量的影响较大。（4）轻度和中度干旱可以促进根系发展，有利于玉米吸收营养和水分，可以提高产量，但重度干旱则抑制根系的发展，造成玉米减产。（5）土壤表层0—10cm土壤湿度变化幅度最大，而随着土层加深湿度变化幅度减小，出现降水时，土壤相对湿度最大值出现日期随着土壤深度加深延后。