Effects of soil thickness on the senescence of root system after anthesis in dry land wheat

With the increase of soil thickness,the root system vigor,the activity of superoxide dismatase (SOD) and catalase (CAT),and the soluble protein content in wheat root system increase,and the content of malondiadehyde (MDA) in wheat root system decrease,the thinner soil is,the rapider senescence of root system is.From the total soil layer,because of insignificant difference between treatment 3 (160 cm) and control (200 cm),and significant difference between treatment 1 (80 cm),treatment 2 (120 cm) and control,the 160 cm of soil thickness can be as index for delaying senescence,and the basis for taking administration programme,and gainning high yield and high efficiency.