籽粒建成期高温胁迫影响糯玉米籽粒胚乳发育的生理机制

大气温度升高不可避免，高温（>35℃）在中国南方夏季已成为一种常态。课题组前期阐明了结实期高温胁迫对糯玉米籽粒淀粉结构和品质的影响，并明确了籽粒建成期是影响籽粒产量和淀粉品质形成的关键时期。项目拟在前期研究的基础上，深入分析籽粒建成期高温胁迫类型(昼高温、夜高温、昼夜高温)和高温胁迫程度对糯玉米籽粒胚乳细胞和淀粉体形态、大小、数量和分布的影响，利用同位素相对标记与绝对定量技术进行蛋白质组学鉴定，明确高温胁迫下蛋白表达的差异位点，利用实时荧光定量PCR技术分析与籽粒生长发育、组分代谢、逆境响应等基因的表达差异，并分析籽粒灌浆特征，淀粉、糖和蛋白质合成相关酶活性，籽粒淀粉结构和品质。大田生产中通过播期调整，分析结实期日最高温度、最低温度和平均温度对籽粒胚乳发育的影响，验证盆栽试验结果。明确高温胁迫影响糯玉米籽粒胚乳发育的生理生化机制，为糯玉米在温度升高条件下的抗逆优质栽培提供理论支撑。

Global warming is inevitable, and high temperature (>35°C) is normal phenomenon during summer in Southern China. Our group clarified the effects of heat stress during grain filling on the grain starch structure and property of waxy maize and ascertained that the grain yield and starch quality was seriously affected by grain formation stage in the past 7 years . The projects will analysis the types (day high temperature stress, night temperature stress, and day and night temperature stress) and degrees of heat stress at grain formation stage on morphology, size, quantity and distribution of the grain endosperm cell and amyloplast. The discrepancy locus of protein expression under heat stress was identified by isobaric tags for relative and absolute quantitation technology. The differential expressions of gene involved in grain development, grain component metabolism, adversity response were analyzed by real-time fluorescence quantitative PCR. The grain filling parameters, activities involved in starch, sugar and protein synthesis, starch structure and property were studied. In field production, by adjust sowing dates, the daily maximum, minimum, and average temperature during grain filling on grain endosperm development was clarified and to verify the pots research results. By clarification the physiological and biochemical mechanism of grain endosperm development to heat stress, the results could afford theoretical basis for anti-adversity and improve quality cultivation in the warming conditions for waxy maize production in the future.