水稻叶热间距随叶位变化的生理机制及其对叶面积形成的影响

叶热间距（Phyllochron）是指相邻两片叶子出现的热时间（Thermal time）间隔，是定量化衡量作物生长发育对温度响应的重要指标。研究表明水稻叶热间距随叶位的提高呈阶段性递增变化，然而叶热间距随叶位变化的关键生理机制及其对叶面积形成的影响并不明确。本项目以具有不同叶片数和叶片形态的水稻品系作为主要研究对象，以强感光型的水稻品系作为补充，运用分段函数模型对水稻在自然变温和人工控温环境下的叶热间距进行计算，明确叶热间距随叶位变化的定量特征；在此基础上，对决定叶热间距的两个重要因素﹝叶片分化热间距（Plastochron）和单叶出伸速率﹞及其关键调控因子和形态基础进行研究，探明叶热间距随叶位变化的关键生理过程和调控机制；通过分析叶热间距变化和单叶、单茎、单株、群体叶面积变化的关系，明确叶热间距的变化对水稻叶面积形成的影响。本项目旨在为揭示水稻发育过程对温度变化的响应机制提供理论参考。

Phyllochron is defined as the thermal time elapsing between the visual appearances of two successive leaf tips. It is an important indicator to quantitatively estimate the response of crop growth and development to temperature. Researches have showed that phyllochron of rice presented a phased increase depending on the leaf position. However, the main physiological mechanism of change in phyllochron depending on leaf position and its effect on formation of leaf area are not clear. Rice lines with different leaf number and leaf morphology will be included in this study, and a photosensitive rice line acted as supplement. Piecewise function will be selected to precisely describe and calculate the change in phyllochron depending on leaf position on the main stem of the rice plant under nature condition and in phytotron. And on this basis, we will explore the key physiological process and regulatory mechanism through investigating leaf plastochron, leaf elongation rate, key regulatory factor and leaf morphological basis. The effect of change in phyllochron on formation of leaf area will be estimated by analyzing the relationship between change in phyllochron and changes in leaf area, leaf area of stem, leaf area of plant and leaf area of population. This study aims to provide theory reference for revealing the mechanism of rice development response to temperature.