玉米和小麦对伴生杂草识别与防御能力的温度敏感性

The impact of global warming on crops is the hot issue of agricultural studies. Rising temperatures will affect the interspecific competition relationship between crop and their associated weeds. Researching on the impact the temperature changes on the competition between crops and associated weed would help to predicting their growth and preventing and controlling of weeds. This project intends to adopt technical route of combining literature and simulation experiments: taking the Meta-analysis which can evaluate the influence of the temperature changes on crop growth and secondary metabolism; illustrating the response of C4 maize-crabgrass and C3 wheet-wild oats to temperature variations which can analysis the influence of ambient temperature on their relationships; utilizing related techniques of plant metabolic substances detection and carbon isotope analysis which is important to evaluate the environmental temperature stress on maize and wheat of 13C in-take and investigate the influence of their response to weed resistance strength; clarifying the competitive chemical interactions relationships of maize, wheat and their associated weeds with the temperature changes by using allelopathic identification and interference technology. Therefore we clarify the response of maize, wheat and their associated weeds growth, allelochemicals detection and interference capabilities to the temperature changes from morphology, physiological metabolism and allelopathic mechanism, and provide more reliable theoretical basis of taking appropriate measures of weed management agro-meteorological services for future climate changes.

气候变暖对作物的影响是当今农学研究的热点问题。温度升高将影响作物与伴生杂草的种间竞争关系。研究温度变化对农作物与伴生杂草竞争规律的影响，有助于提早对二者的生长进行预测，防止草害发生。本项目拟采用文献研究与模拟实验相结合的技术路线，利用Meta-分析法评估温度变化对作物的生长代谢及化感物质影响；通过以C4玉米—马唐和C3小麦—野燕麦为例考察作物和伴生杂草的生长对温度条件的响应，分析环境温度对二者竞争关系的影响；利用植物相关代谢物质检测技术和碳同位素分析等方法，研究温度对玉米和小麦13C的胁迫作用和它们对杂草抗性反应强弱的影响；采用化感识别与防御技术，明确温度变化对玉米和小麦与伴生杂草的竞争性化学互作关系。从而分别从形态、生理代谢和化感机制角度阐明玉米和小麦抗伴生杂草的生长、化感物质识别及防御能力对温度变化的响应，为未来气候变化后农田杂草管理等农业气象服务提供可靠的理论依据。

气候变化对作物与伴生杂草种间竞争关系的影响是目前全球变化农业研究的核心问题之一。作物通过调控自身的生长代谢以应对环境的变化。本研究以玉米和小麦为主要研究对象，采用文献研究和模拟实验两种技术方案，探讨温度变化对玉米、小麦抑草代谢防御、“识别”和“反抗”杂草能力的影响，进而为揭示温度-伴生杂草-作物三者之间的关系，提高农业气象服务水平，实现农业可持续发展提供新的思路和理论依据。.主要结果如下：.1.气象要素中温度对作物气候产量影响最为明显，气候产量同七叶-拔节和播种-出苗两个玉米生育期关系最为紧密。.2.温度升高或降低会显著降低植物的生长代谢。植物的地下的温度敏感性高于地上。经济作物比大宗作物更易受温度变化影响，玉米和小麦的生长代谢对低温胁迫敏感性更高。温度变化通常会降低同化作用，提高异化作用，通常不利于植物的自身有机物质合成，利于自身有机物质分解，进而阻碍其生长代谢。.3.在玉米、马唐、小麦、野燕麦耐受的极端温度以下，随温度的升高苗高、根长、苗重和根重会明显提高。杂草的温度敏感性更大，而且杂草在温度过高的环境中很难萌发生长。虽然这种极端温度对作物的生长影响也会有影响，但作物比杂草适应极端温度能力生长的能力更强。C4作物玉米和杂草马唐在出苗后对环境温度的变化比C3作物小麦和杂草野燕麦更为敏感。.4.玉米和小麦代谢合成脯氨酸、可溶性蛋白、酶活、多酚、总黄酮和代谢利用13C的能力会随温度的升高先升高后降低；可溶性糖的合成将会逐渐减少。.5.温度升高或降低有利于玉米、小麦代谢合成化感物质，因此能够增强其识别杂草的作用。非挥发性提取物和Maltol比挥发性提取物和Methyl jasmonate作物诱导物对玉米和小麦的化感作用更为明显。.综上所述，文献研究与模拟实验得到相互认证：杂草对温度变化的敏感度高于作物，且杂草的抗高温范围小于作物。