番茄低温寡照灾变过程的临界气象条件及灾害分级定量研究

Low temperature and weak light hazard is the main meteorological disaster affecting facility agriculture in winter and spring. It severely affects the production of facility crops. At present, the disaster-inducing process of low temperature and weak light is still unclear, and research on scientific identification and quantitative evaluation of the occurrence and development process of low temperature and weak light hazard on facility crops is far from sufficient, which restricts the comprehensive understanding of the disaster inducing mechanism of low temperature and weak light stress as well as the breakthrough of key technologies of disaster prevention and reduction. This project intends to carry out experiments on the solar greenhouse tomato in North China during its flowering stage. Based on the experiment, we want to explore the variations of multi-level growth characteristics of tomato and correlations among them, in order to clarify the changing process of tomato undergoing low temperature and weak light stress, and reveal how the stress affecting the growth of tomato dynamically and systematically. Besides, we will determine the critical points and the corresponding meteorological thresholds of multi-level growth characteristics of tomato in response to low temperature and weak light stress. Then, we will construct a model to reflect the stress intense of low temperature and weak light stress, and classified it according to the responses of multi-level growth characteristics of tomato, and come up with the classification index system of low temperature and weak light hazard on tomato. The research results would contribute to better understanding the mechanism of low temperature and weak light hazard and provide references for its monitoring and early warning as well as its evaluation and classification.

低温寡照是设施农业冬春季面临的最主要气象灾害，严重威胁着设施作物的安全、优质生产。然而，目前对低温寡照的致灾过程认识不足，针对设施作物低温寡照灾害发生发展过程的科学辨识及定量评估研究较为欠缺，制约着低温寡照致灾机理的全面揭示以及防灾减灾关键技术的突破。本项目拟以华北地区日光温室番茄为研究对象，通过在开花坐果期开展低温寡照模拟试验，研究不同类型低温寡照影响下，番茄不同层次生长指标的响应规律及指标间相互作用关系，阐明番茄低温寡照灾变过程，动态、系统地揭示其致灾机理；找出番茄各生长层次对低温寡照响应最为敏感的指标，分别从灾害强度和灾害持续时间两个方向确定其灾变临界点及临界气象条件；提出低温寡照致灾程度的评估模型，基于番茄多层次生长指标对致灾程度的响应规律，进行低温寡照灾害定量分级。项目研究成果可望补充和完善番茄低温寡照致灾机理，为番茄低温寡照灾害监测预警和评估提供依据。

低温寡照是设施农业冬春季面临的最主要气象灾害，严重威胁着设施作物的安全、优质生产。然而，目前对低温寡照的致灾过程认识不足，针对设施作物低温寡照灾害发生发展过程的科学辨识及定量评估研究较为欠缺，制约着低温寡照致灾机理的揭示和防灾减灾关键技术的突破。本项目以华北地区日光温室番茄为研究对象，开展了幼苗期低温寡照模拟试验，分析了不同强度低温寡照对番茄不同层次生长指标变化规律及产量和果实品质的影响，确定了番茄生长指标对低温寡照的敏感程度；采用结构方程模型并结合机理分析初步明晰了低温寡照条件下番茄的灾变过程及其影响机制；利用容忍限法找到了番茄不同层次生长指标灾变临界点，确定了其灾变临界气象条件；提出了低温寡照致灾程度的评估模型，基于番茄多层次生长指标对致灾程度的响应规律，实现了低温寡照灾害的定量分级。研究结果表明：（1）番茄不同生长指标响应低温寡照的敏感程度排序为：叶片光合＞叶面积＞叶生物量＞茎生物量＞根生物量＞株高。光照和温度对番茄不同生长指标的影响程度不同，温度对叶面积、器官鲜重的影响较光照更显著，而光照对器官干重的影响较温度更显著，并且光照和温度对地上生物量的影响均大于地下生物量。（2）低温寡照对番茄生长发育的影响途径可能为：温度直接影响叶面积的生长，光照直接影响叶片生物量的积累，进而间接影响番茄叶面积的扩展，导致番茄干物质积累减少，最终导致产量下降。此外，温度和光照还会直接影响番茄果实的增长。（3）番茄不同生长指标低温寡照的灾变临界温度条件不同，叶面积、叶干重、总干重和株高的临界最高/最低气温分别为17.2/10.2℃、20.5/13.7℃、15.1/8.2℃和14.6/7.6℃。（4）以低温寡照致灾程度等于0、0.32和0.79为转折点，将番茄低温寡照受灾程度划分为4级。项目研究成果有助于深入理解番茄低温寡照致灾机理，为番茄低温寡照灾害监测预警和评估提供指标和依据。