The Changes in Anti-oxidant Activity of Roots in Wintering Period under Single Sowing of Alfalfa and Mixed Sowing of Alfalfa and Bromus inermis Leyss

This paper aimed to study the change in MDA content and antioxidant enzyme activity of roots in wintering period under single sowing of alfalfa and mixed sowing of alfalfa and Bromus inermis Leyss. By the single sowing of 4 alfalfa varieties with different cold resistance and mixed sowing of alfalfa varieties and Bromus inermis Leyss, the changes in MDA content, SOD, POD and CAT activity of alfalfa roots throughout the wintering period were measured. Results indicated that after single sowing of alfalfa and mixed sowing of alfalfa and Bromus inermis Leyss, the MDA content of roots showed an up-down-up trend with temperature; the CAT activity increased with the decreasing temperature but decreased when the temperature rose in the spring of the following year; the SOD and POD activity showed an increasing trend with sharp decline in temperature, and decreased when the temperature continued to decline, but increased with alfalfa reviving in the following year. The enzymic activity of the same variety under mixed sowing was higher than under single sowing. The membership function was used for comprehensive evaluation of cold resistance, and the cold resistance under different treatments was in the order of Wega7F+Bromus inermis Leyss>Wega7F>Xunlu+Bromus inermis Leyss>Xunlu>Aohan+Bromus inermis Leyss>Aohan>WL319HQ+ Bromus inermis Leyss>WL319HQ. This was of great significance to the study on cold resistant alfalfa breeding and cultivation in cold areas of northern China.