花后高温干旱下乙烯与脱落酸对小麦胚乳细胞程序性死亡的调控研究

The development of wheat endosperm was companied by the progression of programmed cell death (PCD).Abiotic stress had an importmant impact on the PCD of endosperm.The high temperature and drought condition may accelerate the progression of endosperm PCD, which shorten the period of grain filling and lead to the low quality and yield of wheat in most of XinJiang.In this study,two winter wheat cultuvars were employed to explore the progression of endosperm PCD by inhibiting ETH and ABA respectively under hight temperature and drought condition.The progeression of endosperm cell death was investigated by Evans blue staining and transmission electron microscopy.DNA-fragmentation of endosperm cell was analyzed by gel.The genes involved in endosperm PCD and biosynthesis of ETH and ABA were revealed by using real-time PCR.The content of hormone and the pattern of grain filling were tested during the grain development.The characteristic and mechanism of endosperm PCD induced by ETH and ABA under high temperature and drought stress was elucidated.The objective of this study is to provide more information for using cultural practice to delay the occurrence of endosperm PCD and further improve the yield and quality .

小麦胚乳细胞发育伴随着胚乳细胞程序性死亡（PCD）的过程。环境胁迫对胚乳PCD发生具有重要的影响。新疆大部分小麦产区灌浆期高温干旱频发，可加速小麦胚乳PCD进程，缩短籽粒灌浆期，严重影响小麦产量和品质。本研究设想通过探明高温干旱共胁迫下胚乳PCD变化特征及乙烯和脱落酸调控胚乳PCD 机理，来延长籽粒灌浆期，增加粒重，减少损失。因此，本项目以新疆两个冬小麦主栽品种为供试材料，从胚乳细胞超微结构、核DNA降解方式等方面研究阐明高温干旱危害下小麦胚乳PCD的变化特征；通过花后抑制乙烯和脱落酸合成，利用组织化学染色、透射电镜观察、凝胶电泳检测、Real-time PCR检测PCD相关基因表达等技术，研究揭示高温干旱胁迫下乙烯和脱落酸对胚乳PCD的调控机理；并进一步验证胚乳PCD调控减缓小麦花后高温干旱胁迫危害。结果可以为高温干旱危害下采取相应措施延缓小麦胚乳PCD进程，提高籽粒产量和品质提供依据。

小麦籽粒胚乳细胞发育经历由活细胞到死营养贮存库转变是典型PCD过程。受全球气候暖化影响，新疆麦区花后高温干旱频发，加速小麦胚乳PCD进程，造成小麦籽粒减产和品质下降。本项目以新疆主栽两个冬小麦品种新冬18号和新冬22号为研究材料，设置田间小区试验，采用小麦花后停止灌水（阴雨天搭遮雨棚，阻止大气降水）及灌浆期高温形成高温干旱共胁迫条件，研究高温干旱胁迫下胚乳PCD变化特征及乙烯和脱落酸调控胚乳PCD机理，为延缓胚乳PCD进程，增加粒重减轻危害提供依据。取得以下重要和新颖结果：.1、探明小麦花后高温干旱胁迫下胚乳PCD变化特征.（1）花后高温干旱胁迫下胚乳PCD发生部位随机且不固定，发生时期提前；.（2）高温干旱加速胚乳细胞核衰退和解体，并造成细胞器中线粒体內嵴消失和中空化；.（3）高温干旱籽粒ABA和ETH前体（ACC）含量升高，胚乳核酸酶活性升高，DNA片段化程度加深。.2、揭示小麦花后ETH和ABA动态平衡对胚乳PCD调控机理.（1）花后高温干旱胁迫下抑制ETH处理，胚乳细胞着色程度减轻，延缓细胞核衰退和解体，推迟和减弱DNA片段化程度，降低核酸酶活性，增加胚乳细胞数量，延缓胚乳PCD进程；抑制ABA处理结果与之相反；.（2）抑制ETH处理籽粒灌浆中后期ETH受体基因和ABA合成基因表达量上调，降低籽粒中ACC含量，延缓胚乳PCD进程；抑制ABA处理结果与之相反。.3、验证ETH和ABA动态平衡调控胚乳PCD减缓小麦花后高温干旱胁迫危害.花后高温干旱胁迫下抑制ETH处理，籽粒灌浆中后期灌浆速率提高，粒重增加，减缓小麦花后高温干旱胁迫危害，抑制ABA处理结果与之相反。.4、提出一种快速检测小麦籽粒中ABA和IAA的方法.上述结果揭示ETH和ABA调控小麦胚乳PCD机制，为高温干旱危害下采取相应措施延缓小麦胚乳PCD进程，提高籽粒产量和品质提供依据。.本项目按照计划内容实施，超额完成预期目标和任务。共发表学术论文14篇，其中被SCI收录论文5篇，申请专利2项，审定冬小麦新品种1个，培养毕业博士生1人，硕士生2人。