棉花在不同生育期响应淹水胁迫的生理学机制研究

Waterlogging is a major hazardous abiotic stress which has become increasingly frequent due to global warming during the last few decades. Cotton is poorly adapted to waterlogging stress and usually suffers from waterlogging stress at boll-setting stage. However, in recent years, waterlogging events has been greatly exacerbated by climate change, which may occur at growth stage of cotton. The effects of waterlogging at boll-setting on cotton growth and yield are well documented, but it is not clear how cotton plants deferentially respond to waterlogging at different growth stages. The objective of this study is to determine the possible differential response of cotton to waterlogging at different growth stages and the underlying mechanisms. Cotton will be grown in a rain-shelter and subjected to 10~20 day-waterlogging at seedling, squaring, flowering and full-boll stage, respectively. The effects of waterlogging at each growth stage on plant growth, yield and yield components will be studied. On this basis, the physiological mechanism will be investigated by examining plant biomass and partitioning, photosynthsis, activity of anaerobic enzymes, levels of endogenous hormones and nutrient uptake in cotton plants. The roots and leaves of each waterlogging treatment and non-waterlogged control will be used for gene expression analysis through solexa sequencing method. Waterlogging stress related genes such as ADH, PDC, NCED, ACS, ACO, CSD and ERF and all gene expression differences in roots and leaves under different treatments will be determined by analyzing cotton genome data using bioinformatics methods. Thus the mechanism of waterlogging at different growth stages in cotton will be further documented at the molecular level.

淹水胁迫影响棉花生长发育，持续淹水引起棉花减产甚至绝产。随着全球气候变暖，棉花遭受淹涝灾害的频率和程度增加，各个生育阶段都可能遭受淹涝灾害，但现有对棉花淹涝灾害的研究集中在花铃期，迄今关于棉花响应不同生育期淹水胁迫的差异及其机制尚不清楚。鉴于此，拟在田间遮雨棚内，对苗期、蕾期、花期和铃期棉花淹水处理10~20 d，比较研究同等时长淹水胁迫对不同生育期棉花生长发育、产量和品质的影响；测定受淹棉花干物质积累与分配、养分吸收、厌氧代谢酶活性、内源激素含量等的变化，揭示棉花响应不同生育期淹水胁迫差异的生理学机制；在此基础上，通过基因表达谱分析，并根据棉花基因组数据，采用生物信息学方法寻找棉花淹水相关基因，实时定量PCR检测ADH、PDC、NCED、ACS、ACO、CSD和ERF等关键基因在棉株体内的表达，在分子水平上进一步揭示棉花响应不同生育期淹水胁迫差异的机制，为抗灾补救和选育耐涝品种提供支持。

本项目以棉花（Gossypium hirsutum L.）品种K638为材料，在山东棉花研究中心试验站（山东临清）的田间电动遮雨棚内，对蕾期、花期和铃期棉花淹水处理0（未淹水对照）、10、15和20 d，研究了淹水胁迫对不同生育期棉花生长发育、产量和品质的影响，旨在探明棉花响应不同生育期淹水胁迫的差异；测定了受淹棉花干物质积累与分配、养分吸收、厌氧代谢酶活性、内源激素含量等的变化，旨在揭示棉花响应不同生育期淹水胁迫差异的生理学机制；通过基因表达谱分析，实时定量PCR检测ADH、PDC、NCED、ACS、ACO、CSD和ERF等关键基因在棉株体内的表达，揭示棉花响应不同生育期淹水胁迫差异的分子机制。我们发现，淹水持续时间越长不利影响越大、减产越严重，淹水胁迫发生的时期越早，对棉花造成的不利影响越大；棉花对淹水胁迫的响应是一个多基因参与、多个生理生化过程协同调控的结果，基因表达量的变化是其最早响应胁迫的方式之一，随后引起了相应生理指标的变化，继而导致了最终农艺性状和产量的改变。在此基础上，本研究总结提出了棉花适应淹水胁迫的3条途径，为耐涝品种选育和抗涝栽培提供了重要指导和参考。