不同土壤水分条件下冬小麦根、冠平衡与生长稳定性研究

Winter Wheat Root and Shoot:Equilibrium and Growth StabilityUnder Different Soil and Water Conditions

目的研究不同土壤供水条件下冬小麦不同生育阶段的根、冠平衡与生长稳定性。方法利用管栽试验对供试冬小麦设置11种供水处理。即充分供水、中度缺水、重度缺水、前期中度和重度缺水后分别在分蘖期、拔节期、开花期和灌浆期复水。测定作物根、冠干重。根据已经建立的根、冠关系模型,运用动力系统理论,研究根、冠生长过程中的平衡与稳定性。结果作物根、冠在一生中只有一个随时间而变化的平衡点。水分胁迫使根、冠稳定生长的时间延长,胁迫愈重,延长愈多。复水后作物的稳定生长时间缩短,不稳定生长时间延长。中度水分亏缺条件下开花期复水后,作物的生长由稳定变为不稳定,直到其生育期结束。结论根、冠平衡的本质是,在作物的一生中,根和冠一直在追求生长过程中的相互平衡,但又永远达不到平衡,根、冠始终处于不平衡状态。水分胁迫抑制根、冠功能的发挥,使根、冠之间的影响减小,生长趋于稳定。复水使根、冠之间的相互影响增大,不稳定生长时间延长。开花期复水可以打破作物所固有的从开花始到灌浆止的较长时间的稳定生长,引起作物的不稳定生长,提高干物质积累速度。

[Objective] The root and shoot equilibrium and growth stability under different soil water conditions were investigated in a tube experiment of winter wheat [Method] The water supplying treatments included： sufficient irrigation at full growth phase; moderately insufficient irrigation at full growth phase; seriously deficient irrigation at full growth phase; sufficient irrigation at jointing stage, tilling stage, flowering stage and filling stage （all after moderate and serious water deficit during their previous growth stage）. Root and shoot biomass were measured. Based on the competing and reciprocal relation models for the root and shoot, the equilibrium and growth stability were studied on the basis of a kinetics system theory. [Result] In the whole growth cycle of winter wheat, there was only one time-change equilibrium point between the root and shoot. Water stress prolonged stable growth＇s time period. The more serious the water deficit was, the longer the period of stable growth. The time period of stable growth was shortened and instable growth was prolonged by water recovery. The growth behavior of the plants exposed to moderate water deficit was changed from stable to instable until the end of the growth cycle after water recovery at the flowering stage. [ Conclusion ] In the crop growth cycle, root and shoots pursued mutual equilibrium, but they could not achieve a equilibrium state forever. They were in a disequilibrium state from beginning to end of the growth cycle, which was the essence of root- shoot equilibrium. Water stress inhibited the function of root and shoot and diminished the mutual influence of the root and shoot. As a result, crop growth gradually became stable. Rewatering augmented the mutual influence of root and shoot and prolonged the time period of instable growth. Rewatering during flowering stage can change the inherent growth trends of a relativity long period of stable growth from the flowering stage to the filing stage, and it lead to the instable growth and promoted the dry matter acumulation rate of whole plant.