水稻光合能力的高温稳定性评价指标与遗传分析

Genetic analysis and evaluation indexes for high temperature stability of photosynthesis in rice

为了探讨一种简单适用的可用于水稻品种资源的光合速率高温稳定性评价指标,以指导水稻高温适应性研究和高光效生理育种,利用CIRAS-Ⅰ型便携式光合测定系统,对不同类型水稻品种在武汉夏日高温和人工控制温度条件下的光合作用日变化进行了多年测定,并用光合高温稳定性较好的品种蜀恢527和稳定性较差的品种特籼占杂交F2群体对光合作用高温稳定性进行了遗传分析。结果表明:在自然高温条件下,09:00与13:00的叶片净光合速率之差值能较好反映品种间光合高温稳定性差异,同时气孔导度、光合下降起点温度值也可作为参考指标;蜀恢527/特籼占的F2群体各单株高温下光合速率下降值特性呈连续分布,但偏向高温稳定性好的亲本分布,表现为数量性状遗传特征。高温光合速率下降值、气孔导度和光合下降起点温度值可作为水稻光合高温稳定性的评价指标,在光合作用生理育种中,选用光合速率高温稳定性好的亲本,对后代在较高世代进行选择较为有效。

Simple and useful evaluation indexes for the high temperature stability of photosynthesis （HTSP） in different rice varieties was studied for screening and identifying germplasm resources and new variety breeding.The diurnal changes of photosynthesis were tested under high temperature both in natural and illuminating incubator conditions using CIRAS-I portable photosynthesis system.Meanwhile,the genetic characters of HTSP were analyzed using F2 population derived from Texianzhan,a worse HTSP variety,and Shuhui 527,a better HTSP variety,respectively.The results showed that the difference value （D-value） of net photosynthetic rate （Pn） at 09：00 a.m and 13：00 p.m,as well as stomatal conductance （Sc）,in flag leaf could be regarded as the evaluation indexes for high temperature stability of photosynthesis （HTSP） in the natural condition.The D-value of Pn of individual plant from F2 population of Shuhui 527/Texianzhan showed a continuous distribution at 09：00 a.m and 13：00 p.m under high temperature.Based on the proportion of D-value of individual plant to population,10%～30% accounted for the maximum part.In addition,the aptness test of D-value distribution curve and theoretic normal distribution of Pn in F2 generation indicated that,the trait of midday depression in photosynthesis was inherited as quantitative character controlled by polygene,other than a simple qualitative character.It was suggested that the identification of and screening HTSP should be carried out in advanced generation populations.