Effects of Chitosan Treatment on Physiological and Biochemical Characteristics in Cucumber Seedlings Under Low Temperature

Chitosan 50 mg/L treatment alle- viated the low temperature injury of cucumber seedling membrane. The chitosan treatment re- duced electrolyte leakage and the MDA content of cucumber leaves and alleviated the decreases in photosynthetic rate, the photochemical effi- ciency of photosystem Ⅱ(ΦPSⅡ), the photo- chemical quenching of fluorescence (qP) and the efficiency of excitation energy captured by the open photosystemⅡ reaction centers (Fv’ ) /Fm’un- der low temperature(6℃) (Figs.1-4).At the same time, the chitosan treatment enhanced the anti- oxidant enzymatic activities and increased the proline and soluble protein contents in cucum- ber leaves under low temperature (Figs.5, 6). The results indicated that chitosan treatment im- proved cold resistance of cucumber seedlings, which protected the membrane system, improved the capability of eliminating active oxygen spe- cies and alleviated the damage to photosynthetic organization under low temperature.