Studies On The Impact Of Coumarin On MDA, Proline And Catalase In Rice Seedlings

Preliminary studies showed that allelochemicals coumarin inhibited seed germination, seedling growth, root tip cells mitosis of rice. The experiment set up 0.001 mmol/L, 0.01 mmol/L, 0.1 mmol/L and 1 mmol / L concentrations of coumarin, We carried on rice seedling growth experiment by using sand culture method. Lipid peroxidation indicator MDA, proline content and catalase activity in rice seedlings treated with different concentrations of coumarin were measured on the third day,the sixth day, the ninth day.The results showed that:1, MDA had no significant changes in 0.001 mmol/L, 0.01mmol/L and 0.1 mmol/L coumarin-treated groups on the third day, On the sixth day,in the three coumarin-treated group MDA was significantly higher than the blank, respectively, 23.8 percent, 23.9 percent, 25.7 percent higher than the blank, but there was no significant difference among the three. On the ninth day, MDA in the the three coumarin treated groups fell to be close to the blank, the difference was not significant. MDA treated with 1 mmol/L coumarin was significantly lower than the blank on the third day, while was slightly lower than the blank on the sixth day and on the ninth day, but there was not significant differences with the blank.All the concentrations of coumarin-treated groups over time showed a substantial increase in 3-6 days,6-9 day downward trend.2, proline content was not significantly different with the blank in 0.001 mmol / L, 0.01mmol / L and 0.1 mmol/L coumarin treated groups on the third day,.1mmol / L coumarin treatment was significantly lower than the blank and other concentrations, on the sixth day, proline content was significantly higher than that blank by 29.9% with 0.1 mmol/L coumarin teated, 0.001 mmol/L and 0.01 mmol/L coumarin-treated groups are lower than the blank,but there was not significant differences . 1 mmol/L coumarin treatment is slightly lower than the blank, but was significantly lower than 0.001 mmol / L and 0.1 mmol / L coumarin-treated groups.On the ninth day, All the coumarin treated groups are significantly different, but were all significantly lower than the blank. proline content of rice seedlings in the whole show 3-6 day up, 6-9 day downward trend over time.3, catalase activity were not significantly different with the blank in 0.001 mmol/L, 0.01mmol/L and 0.1 mmol/L coumarin treated groups on the third day. catalase activity treated with 1 mmol/L coumarin was significantly lower than the blank and others.On the sixth day, 0.001 mmol/L and 0.01 mmol/L coumarin treated groups were similar to the blank, 0.1 mmol/L coumarin treatment is higher than the blank, 1 mmol/L coumarin treatment was significantly lower than the blank. On the ninth day, 0.1 mmol / L coumarin treatment was significantly higher than the blank and other concentrations. 1mmol/L treatment was significantly lower than blank and other concentrations.4, MDA and proline in the third day and the sixth day showed the significant and highly significant correlation. Correlation coefficient is 0.952 and 0.963 respectively.In low concentrations coumarin treated groups, MDA and proline content were increased first and then decreaced. a certain concentrations of coumarin stress can cause lipid peroxidation and proline accumulation, and then could be restored through rice own internal mechanism Proline content can be a sensitive indicator to reflect the coumarin stress level. Low concentrations of coumarin treated groups have not a significant impact on catalase in rice seedlings, catalase activity with 0.1 mmol / L coumarin treated increased as the exposure time gradually increased. 1mmol / L coumarin concentration has reached or exceeded the threshold that rice can withstand the stress reling on physical mechanism.