Effect of chitosan on germination and enzyme activity of Caragana korshinkii Kom seed from different provenances

C. korshinkii seeds from two regions (Wuqi County, and Yuyang District in Yulin City) of Shaanxi Province were treated with acidic chitosan solution of different concentrations. Then the germination and seedling growth indices were investigated along with the activities of a-amylase, dehydrogenase, POD and CAT. Results show that chitosan improves seed germination and at the same time shortens germination time. With increasing chitosan concentration, germination indices and enzyme activities initially increase before decreasing under higher chitosan concentration. Seeds from different provenances respond differently to chitosan. When chitosan concentration is 0.5%, germination rate of seeds from Yuyang is 1.2 times that of CK, with mean germination time shortened by 0.9 d. Enzyme activities increase significantly compared with CK, producing the best enhancement effect. At 1.0% chitosan concentration, the germination rate of seeds from Wuqi increases by 13% and the mean germination time shortens by 1.7 d. Enzyme activities increase significantly compared with CK, producing the best enhancement effect. However, 1.5% chitosan concentration inhibits germination of seeds from Yuyang, but does not negatively impact germination of seeds from Wuqi. Chitosan generally improves growth of C. korshinkii seedling. Seedling root length, height, dry-weight, fresh-weight and chlorophyll content significantly increase. Optimum chitosan concentrations for seeds from Wuqi and Yuyang are respectively 1.0% and 0.5%.