Allelopathy of water extract of Alnus nepalensis on the seedling growth of Pinus yunnanensis

Effect of water extract of different concentrations(20、10、5 g/L)from Alnus nepalensis on the seedling growth and its physiology and biochemistry characteristics of Pinus yunnanensis was studied.Results showed that compared with the contrast,after treated with 20 g/L and 10 g/L water extract,the seedling growth was inhibited especially the root length,the activities of protective enzymes,SOD,POD and CAT decreased,the contents of O-2 and malondialdehyde both increased,the root activity decreased and chlorophyll content decreased too.While treated with 5 g/L water extract,seedling growth was promoted,the activity of protective enzymes,SOD,POD and CAT increased,the contents of O-2 and malondialdehyde decreased,the root activity and chlorophyll content increased.Through the analysis of variance and multiple comparisons,the seedling growth and physiological indexes between high concentration water extract treatments and control were significant or extremely significant different.Among all growth indexs,the root length was the most sensitive on allelopathy.Root activity and SOD enzyme activity were more sensitive on allelopathy among physiological indexs.