试论麦类作物非水力根信号与生活史对策

A discussion on the non-hydraulic root-sourced signals and life history strategy of wheat crops

从植物非水力根信号的生理调节作用和生活史进化角度看 ,在水分亏缺条件下 ,自然选择会导致植物产生大量根系以增加对水分的竞争能力 ,而浅根系则可在干旱来临时 ,以快速反应的根信号来调节和平衡植株水分状况 ,度过干旱时期。但是 ,自然选择压力下的植物特征往往不利于作物籽粒产量这一种群水平上的属性的改善。作物产量的提高过程是一个不断加强的人工选择过程。在作物生产中 ,作物水环境得到了改善 ,强大的多年生竞争者基本消失 ,为强化人工选择力度 ,提高作物产量 ,麦类作物的根信号作用应当有所消弱。据此提出了在黄土高原农田环境下 ,麦类作物根系的理想分布应当是深而窄幅的形式。

From the point of view of physiological regulation of root sourced signals and life history strategy,natural selection in water deficit environment would result in a large root system in which many lateral roots would play a very important role in the relation of plant water balance.The rapid response of root sourced signals would occure based on the larger root systems for the coming drought.The natural selection,however,is not a favorable mecharism to improve the characteristics of grain yield.The increase in crop grain yield is a continual process of artificial selection.In wheat production process,the soil water can be improved and the strong competitors may be disappeared.In order to strengthen artificial selection and to increase grain yield,the roles of root signals in wheat crops should be reduced.As a result,the paper suggested that under the condition of Loess Plateau field,the ideal type of root system in wheat crops should be smaller in upper soil and deeper in lower soil.