| Abstrakt: |
This experiment was conducted 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 in the greenhouse of Sari University of Agricultural Sciences and Natural Resources as a factorial experiment in a completely randomized design with four replications. 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. In the concentration of 200 mg of cadmium per kg of soil, chlorophyll a in corn and soybean plants in mixed culture showed a decrease of 25.33 and 10.31%, respectively, compared to the no cadmium contamination. Also, the results showed that the main effects of cadmium and planting ratios on the relative water content of leaf and the amount of sugar content were significant at the probability level of 1%. However, the interaction of cadmium and planting ratios did not show any significant effect on these two mentioned traits. The relative water content of corn and soybean in mixed culture was higher than mono culture, so that the relative water content of corn and soybean leaves in mixed cultivation showed an increase of 5.26% and 7.31%, respectively, compared to pure cultivation. Corn plants in mono and mixed culture had higher relative leaf water content than soybeans. Corn and soybean leaves in mixed culture had less starch than pure culture. The reduction of leaf starch in corn and soybean mixed culture at the highest level of cadmium investigated was 54.58% and 78.73%, respectively. Compared to pure cultivation, mixed cultivation increased the amount of sugar content in corn and soybean leaves, which was 8.54% in corn and 7.91% in soybean. Also, increasing the concentration of cadmium in the soil increased the amount of proline in all planting ratios of both corn and soybean plants, so that the highest corn proline (0.961 μmol/g fresh weight) was observed at the highest cadmium level and the lowest corn proline (0.034 μmol/g fresh weight) was observed in the absence of cadmium contamination in the mixed culture. According to the results of this research, the mixed cultivation of corn and soybean using physiological and biochemical mechanisms can modify the negative effects caused by the stress of cadmium heavy metal. [ABSTRACT FROM AUTHOR] |
