灌浆结实期高温对杂交稻两优培九籽粒形成生理的影响

探讨灌浆结实期高温对杂交稻两优培九籽粒形成生理的影响.利用人工气候室在灌浆结实期进行高温(昼/夜温度为36.5℃/27.5℃)和适温(昼/夜温度为29.5℃/23.5℃)处理,对两优培九灌浆结实期籽粒质量、籽粒中直链淀粉和蛋白质质量分数及ADPG焦磷酸化酶(ADPGPase)、颗粒结合型淀粉合成酶(GB-SS)、谷草转氨酶(GOT)和谷丙转氨酶(GPT)活性进行分析.结果表明,在高温条件下,籽粒直链淀粉积累快,粒质量增长快,成熟后籽粒质量和直链淀粉质量分数较适温条件下低,而蛋白质质量分数较适温条件下高.在高温条件下,籽粒中ADPGPase和GBSS活性在始花后前10d活性较适温条件下高,始花10d后迅速下降；GOT和GPT活性先升后降,均在始花后10 d出现峰值.在适温条件下,籽粒中ADPGPase和GBSS活性在始花后13d达到其活性高峰值,GOT和GPT活性均呈缓慢下降趋势,但始花13d后ADPGPase、GBSS、GOT和GPT活性均不同程度地高于高温处理.可见,在灌浆中后期,相对低的日均温度有助于提高两优培九籽粒中ADPGPase、GBSS、GOT和GPT活性和改善稻米品质.

Effect of High Temperature at Grain Filling Stage on Grain Formation Physiology of Hybrid Rice "Liangyou-peijiu"

In order to investigate the effect of high temperature during the grain filling on grain formation physiology of hybrid rice Liangyou-peijiu.Liangyou-peijiu was treated under high temperature and proper temperature conditions in phytotrone,and the following indexes were analyzed,such as grain mass,protein and amylose mass fraction,ADPG pyrophosphorylase(ADPGPase),granule-bound starch synthase(GBSS),glutamic-oxalacetic transaminase(GOT) and glutamic-pyruvic transaminase(GPT) activities.The results showed that,under the high temperature condition,the grain mass and amylose mass fraction increased quickly but continued for a few days,and the grain mass and amylose mass fraction were lower than those under the proper temperature condition,and the soluble protein mass fraction in grains was higher than that under the proper temperature condition.Under the high temperature condition,the activities of enzymes such as ADPGPase,GBSS,GOT and GPT in grains were improved immediately at 7-10 d after flowering and reached the peaks at 10 d,then decreased.Under the proper temperature condition,the activities of ADPGPase and GBSS changed slowly,and the peak time of the two enzyme activities was 13 d after flowering,and the activities of GOT and GPT decreased slowly in grains after flowering,and at 13-25 d after flowering,the activities of enzymes such as ADPGPase,GBSS,GOT and GPT in grains under the proper temperature condition were higher than that under the high temperature.To sum up,at the middle and late stage of grain filling,the comparatively low mean daily temperature during filling favored the rising of the enzyme activities such as ADPGPase,GBSS,GOT and GPT in grains and improved the rice grain quality.