低温下壳聚糖处理对黄瓜幼苗生理生化特性的影响

50 mg/L的壳聚糖处理减轻了低温对黄瓜幼苗膜的伤害,低温(6℃)处理4 d后,幼苗膜透性和MDA含量明显低于对照,并且显著减缓了低温导致的光合速率、实际光化学效率(ФPS Ⅱ)、光化学猝灭系数(qP)和1光系数(F’v /Em’)的下降;同时,处理使抗氧化酶SOD、POD、CAT和APX活性提高,可溶性蛋白和脯胺酸含量增加.因此,壳聚糖处理增强了黄瓜幼苗的抗冷性,保护了膜系统,提高了活性氧清除能力,减轻了低温对光合机构的破坏.

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

Chitosan 50 mg/L treatment alleviated the low temperature injury of cucumber seedling membrane. The chitosan treatment reduced electrolyte leakage and the MDA content of cucumber leaves and alleviated the decreases in photosynthetic rate, the photochemical efficiency of photosystem II (PhiPSII), the photochemical quenching of fluorescence (q(P)) and the efficiency of excitation energy captured by the open photosystem II reaction centers (F(v)'/F(m)') under low temperature (6 degrees C). At the same time, the chitosan treatment enhanced the antioxidant enzymatic activities and increased the proline and soluble protein contents in cucumber leaves under low temperature. The results indicated that chitosan treatment improved cold resistance of cucumber seedlings,which protected the membrane system, improved the capability of eliminating active oxygen species and alleviated the damage to photosynthetic organization under low temperature.