地方稻资源D43的开花期耐热特性研究

水稻在抽穗开花期对高温胁迫非常敏感,通过挖掘耐热资源,培育耐热水稻品种是应对高温热害最有效的方式。前期研究发现,地方稻资源D43在花期连续高温条件下能保持较高的结实率。本研究在大田和人工气候室不同高温处理下,分析了D43的开花时间与耐热性之间的相互关系。结果表明,高温能够使水稻的开花时间提前,D43表现出稳定的早花时特性,高温胁迫下的开花时间集中在8∶30~10∶00;在开花时间段恒定高温胁迫下,D43的结实率较低;但在大田高温和人工气候室模拟高温胁迫下,D43的开花时间避开了日高温段,从而表现出较高的结实率;花器官形态性状包括花药开裂率、柱头上的花粉附着数、花粉萌发数与结实率之间呈显著正相关,因此可用于评价水稻的花期耐热性。

Heat resistance analysis of an early-morning-flowering landrace D43 at anthesis

Rice is extremely sensitive to high temperature,especially at the flowering stage.Identifying new germplasm and breeding heat-resistant rice varieties are therefore essential.After multi-year evaluations,a heat-resistant rice landrace D43 have been identified in our previous research.In this study,the relationship between heat resistance and flowering opening time(FOT) was analyzed both in the field and in phytotron.The results showed that high temperature could accelerate flowering opening of different rice varieties.The landrace D43 showed early morning flowering(EMF) habit in different conditions,and the FOT of which was mainly concentrated in a period of 8:30 ～ 10:00 AM under high temperature.The spikelet fertility of D43 was relative low after exposure to invariable high temperature during flowering opening.However,the EMF habit of D43 was conductive to avoid mid-day high temperature,and therefore increased the spikelet fertility under rising high temperature conditions in the field and in phytotron.In addition,morphological traits including the anther adhesion rate,the total number and germinated number of pollens on the stigma were significantly correlated with the spikelet fertility,and therefore they could be used to evaluate rice heat resistant at anthesis.