THE EFFECT OF SOIL WATER DEFICIENCY ON THE ACCUMULATION AND ALLOCATION OF ROOT BIOMASS OF SPRING WHEAT
土壤水分亏缺对春小麦根系干物质累积和分配的影响

An experiment was conducted in a plant growth chamber,in which light and temperature were controlled automatically. The soil water content was controlled to 30% (SD),60%(LD) and 90%(CT) of the field watercapacity.This experiment indicated that from the seedling stage to the heading and flowering stage,stomatal resistance in all treatments decreased,but the rate of photosynthesis and transpiration increased gradually.The rate of photosynthesis in LD treatment was similar to or significantly higher than that in CT,but the rate of transpiration in the former was significantly lower than that in the later.From heading stage to flowering stage,root length and root weight in the deeper soil layer in LD treatment were significantly higher than those in the other two treatments, although root length in the upper layer was no significantly different among three treatments, but root weight in the upper layer was higher in the treatment with higher soil water content.All these results show that LD treatment is favorable to a deeper root system.It will be helpful to use soil water in the deeper layer,tap productivity and yield potential.