Effect of Illite on Growth Characteristic and Antioxidant Enzyme System of Rice under Cadmium Stress

Nine combinations of illite (0,5,10 g.L-1) and cadmium (0,2.5,5mg.L-1) were set, and the hydroponics was adopted in this experiment to explore the effect of illite on the rice growth characteristics under Cd stress, including chlorophyll content, net photosynthetic rate, plant biomass, and the antioxidant enzyme (SOD, POD and CAT) activities. The results showed that: (1) without adding illite, under severe cadmium stress (5mg.L-1), the activity of antioxidant enzymes (SOD, POD, CAT) increased, chlorophyll content, net photosynthetic rate and the biomass decreased significantly (P< 0.05), but no significant effect on rice growth and antioxidant enzyme system was observed under mild cadmium stress (2.5mg.L-1). (2) without cadmium stress, leaf chlorophyll content, net photosynthetic rate and seedling biomass showed no significant difference between the treatment of adding illite of 5mg.L-1 and 10mg.L-1, implying that illite had no obvious influence on the growth of rice; (3) Under severe cadmium stress, adding illite obviously reduced the cadmium toxicity to chlorophyll, improved the photosynthetic rate and increased the biomass.