小麦旗叶衰老过程不同数学模型拟合比较及衰老特征分析

Comparison of different mathematical models describing flag leaf senescence process of wheat and characteristics of leaf senescence process

为了准确了解小麦叶片的衰老特征,筛选适合描述小麦叶片衰老过程的数学模型, 2011年和2012年分别以91个和105个小麦品种(系)为材料,用"S"型曲线中的Logistic、Gompertz和Richards模型拟合了试验品种叶片的衰老过程,解析了其叶片衰老特征。结果表明,试验品种可分为延绿、中等延绿、中等早衰和早衰4种类型。其旗叶衰老过程可分为衰老起始期、快速衰老期和衰老结束期3个阶段,3个阶段旗叶的衰老速度表现为"慢–快–慢",不同延绿类型品种开花后旗叶的绿色叶面积百分比下降主要在衰老过程的中后期。3种模型对不同延绿类型品种旗叶衰老过程均可以拟合,Gompertz和Richards模型拟合度接近,高于Logistic模型。Gompertz模型的拟合度以早衰>中等早衰>中等延绿>延绿类型。不同延绿类型品种旗叶衰老曲线特征参数达到最大衰老速度时间(TMRS)、平均衰老速度(ARS)和绿色叶面积持续期(GLAD)存在显著差异, TMRS和GLAD以延绿>中等延绿>中等早衰>早衰, ARS以早衰>中等早衰>中等延绿>延绿。Gompertz模型对小麦叶片衰老过程的拟合度优于Logistic模型。叶片衰老过程特征参数可以用于品种延绿性差异评价。

To clarity leaf senescence patterns and characteristics of wheat,we used91and105varieties or advanced lines in2011and2012respectively,to fit the leaf senescence process by Logistic,Gompertz,and Richards models.The varieties tested were classified into stay green(SG),moderately stay green(MSG),moderately non-stay green(MNSG)and non-stay green(NSG)types.Development of the flag leaf senescence was divided into initial senescence stage,rapid senescence stage and terminal senescence stage in all variety types.The senescence rates of the three stages showed a slow–fast–slow changing pattern.The decrease of green leaf area(%GLA)after anthesis occurred mainly in the middle and late senescence stages.Logistic,Gompertz and Richards models were able to simulate the leaf senescence process of all variety types and the fitness of Richards and Gompertz models was better than that of Logistic model.The fitting goodness of Gompertz model ranked as NSG type>MNSG type>MSG type>SG type.There was a significant difference in time of maximum rate of senescence,green leaf area duration and average rate of senescence derived from Gompertz equation in all varieties.The average rate of senescence showed a trend of NSG type>MNSG type>MSG type>SG type,while the remaining two parameters showed a trend of SG type>MSG type>MNSG type>NSG type.Our results indicate that Gompertz model is more suitable than Logistic model to describe the leaf senescence process of wheat and the characteristic parameters for leaf senescence process can be used to evaluate stay green difference between wheat varieties.