Physiological and Biochemical Response of Corn (Zea mays L.) and Soybean (Glycine max L.) to Cadmium in Mixed Culture

This experiment in order to investigate the effect of cadmium on physiological characteristics and biochemical activities of corn (Zea mays L.) and soybean (Glycine max L.) in mono and mixed cultivation. An experiment in the greenhouse of Sari University of Agricultural Sciences and Natural Resources in a completely randomized design with four repeats. Cadmium concentrations included 0, 50, 100, 150 and 200 mg of cadmium per kg of soil. Planting ratios included mono cultivation of corn and soybean and mixed cultivation of corn and soybean with a ratio of 50: 50. The results showed that chlorophyll a and b, decreased with increasing the level of cadmium in both mono and mixed cultures. The relative water content of corn and soybeans in mixed culture was higher than mono culture and corn plants in mono and mixed culture had higher relative leaf water content than soybeans. Corn plants in mono and mixed culture had higher relative leaf water content compared to soybean; while mixed cultivation increased the sugar content of corn and soybean leaves compared to mono cultivation. Also with increasing the concentration of cadmium in the soil increased the amount of proline in all planting ratios of both corn and soybean plants. In general, corn and soybeans by physiological and biochemical mechanisms, responded positively to reduce stress; especially in mixed culture.