中文摘要：

【目的】探讨花后高温和外源脱落酸（ABA）对不同持绿型小麦籽粒胚乳细胞增殖、籽粒灌浆和内源激素的影响，为高温逆境下采用激素调控措施提高粒重提供理论依据。【方法】选用持绿型汶农6号和非持绿型济麦20，花后1-5 d，用透明聚乙烯塑料膜搭设增温棚进行高温处理，同时花后1-3 d喷施10 mg·m^-1的ABA于穗部，用量100 mL·m^-2，3次重复。定期取籽粒样，用高效液相色谱法测定4种内源激素，用简易胚乳细胞计数法测定胚乳细胞数目，Richard方程对籽粒增重及胚乳细胞增殖动态模拟并计算相关参数。【结果】高温处理显著降低了两品种强弱势籽粒的胚乳细胞数目，降低胚乳细胞增殖速率，但延长了籽粒胚乳细胞活跃分裂期和实际分裂终期；显著降低两品种弱势籽粒的灌浆速率，缩短了两品种弱势粒的生长活跃期及实际灌浆终期。高温处理显著降低两品种千粒重和穗粒数，其中汶农6号强、弱势粒分别减少3.7和8.2粒/穗，济麦20强、弱势粒分别减少1.3和4.3粒/穗；显著降低两品种产量，汶农6号和济麦20产量分别降低19.65%和26.22%。常温及高温下喷施ABA均显著提高了两品种灌浆速率，提高了籽粒胚乳细胞增殖速率，扩大胚乳细胞数目。高温处理降低了强弱势籽粒ZR含量，显著提高了济麦20强、弱势粒花后3-27 d的GA3含量，显著提高汶农6号花后12-27 d的GA3含量；但降低了弱势粒花后15-27 d的IAA含量。高温处理下喷施ABA，降低了济麦20强势粒花后3-9 d ZR含量，但显著提高济麦20强势粒花后3-28 d内源ABA含量，显著提高汶农6号强势粒花后3-18 d ABA含量。常温下喷施ABA显著降低了济麦20和汶农6号强、弱势粒的GA 3含量；高温下喷施ABA，显著降低了汶农6号强弱势粒的GA 3含量，降低济麦20强势粒花后3-12 d的GA3含量，显著降低弱势粒花后6-15 d的GA3含量。常温下喷施ABA?

英文摘要：

Objective The purpose of this study was to test the effects of high temperature stress and spraying exogenous absisic acid （ABA） post-anthesis on endosperm cell division, grain filling and changes of endogenous hormones in different types of stay-green wheat cultivars, and provide a theoretical basis for enhancing grain weight and minimizing the loss of grain yield result from high temperature. [Method] Both Wennong 6 （a stay-green cultivar） and Jimai 20（a non-stay-green cultivar） were grown in the experimental plots covered with transparent plastic sheds at 1 to 5 days after anthesis （DAA）, which were mimicked the high temperature that occurs during the natural heat event in this region, whilst exogenous ABA （10 mg·m^-1） to the spikes was sprayed at the rate of 100 mL·m^-2 between 5 pm and 6 pm from 1 to 3 DAA. High performance liquid chromatography method （HPLC） and a simple method of endosperm cell number determination were used to determine endogenous hormones contents and endosperm cell number, respectively. Both grain filling process and endosperm cell division process were simulated by Richard equation, and then the related parameters were calculated. [Result] The endosperm cell number of superior and inferior grains in both cultivars were significantly decreased by high temperature stress, and the endosperm cell division rate was markedly decreased. However, high temperature extended the active endosperm cell division period and the division duration. The grain filling rate of inferior grains in both cultivars was decreased in the high temperature treatment. Grain-filling duration and the active growth phase were also reduced in the high temperature treatment. High temperature after anthesis significantly decreased the number of grains per spike and thousand-grain weight. In contrast, Wennong 6 showed 3.7 and 8.2 grain/spike reduction in superior and inferior grains, respectively. Similarly, Jimai 20 was reduced by 1.3 and 4.3 grain/spike in superior and inferior grains, respecti