不同土壤水分条件下小麦根系生态生理效应的研究

1988～1990年的研究结果表明,土壤水分不足或过多,均抑制小麦根系的生长。干旱导致土壤表层根量减少,而深层根量所占比例增大。当土壤相对含水量低于60％时,单株次生根数明显减少;低于50％时,单株根量显著下降。根系活性随水分胁迫程度的加强而下降,其中以扬花期的下降幅度为最大。小麦单茎伤流量与土壤含水量呈极显著的正相关,而根冠比与土壤含水量则呈极显著的负相关。此外,研究还指出,40％的土壤相对含水量是小麦生育后期重度干旱的极限指标。

Ecological and Physiological Effects on Root Systems of Wheat under Different Soil Water Conditions

From 1988 to 1990, the ecological and physiological effects on root systems of wheat were studied under different soil water conditions. Results showed that the development of root systems could be inhibited by deficiency and oversupply of soil water. Drought might lead to the reduction of roots in the surface layer and the increase of the ratio of the roots in the deeper layer. When the relative soil water content was below 60%, the number of secondary roots of the individual plant decreased obviously. When it was below 50%,the root system reduced significantly.Less activity of root systems resulted from the higher severity soil water stress, and the least activity wax found in the flowering period. The wound sap flow of the single plant was in extremely significant positive correlation with the content of soil water. However, there existed an extremely significant negative correlation between the root-top ratio and the soil water content. It was found that the 40% relative soil water content was the lower limit index for severe drought in the later growing stage of wheat.