羧甲基壳聚糖对黄瓜幼苗抗冷性的影响

 试验分别采用0(对照CK)、1/1 500、1/1 000、1/500和1/100(w/v)5个浓度的羧甲基壳聚糖处理二叶一心的黄瓜幼苗，再于(6±1)℃下低温胁迫5 d，以研究羧甲基壳聚糖对黄瓜幼苗抗冷性的影响。结果表明，适当浓度的羧甲基壳聚糖处理与对照相比，在低温胁迫下黄瓜幼苗冷害指数较小，叶片保护酶（SOD、CAT和POD）活性和Vc、可溶性糖、脯氨酸及叶绿素含量均较高，根系活力也维持了较高的水平， MDA含量较低；胁迫后于温室自然条件下恢复5 d，羧甲基壳聚糖处理幼苗的干物质增加量、光合速率和羧化效率均较高。表明羧甲基壳聚糖能够明显提高黄瓜幼苗的抗冷性。

Effect of Carboxymethyl Chitosan on Chilling Tolerance in Cucumber Seedlings

Carboxymethyl chitosan at 0 (CK), 1/1500, 1/1000, 1/500 and 1/100 (w/v) was sprayed on cucumber seedlings on two leaves stage respectively, and then the cucumber seedlings were stressed under low temperature at 6±1℃ for 5 days, in order to study influence of carboxymethyl chitosan on chilling tolerance of the cucumber seedlings. The main results were as follows: Under low temperature stress, the cucumber seedlings sprayed with carboxymethy chitosan of favorable concentration obtained lower chilling injury index and MDA content, higher activities of protein enzyme (SOD, CAT and POD), root activity and content of Vc, soluble sugar, proline and chlorophyll compared with control. After low temperature stress, the cucumber seedlings were transferred to greenhouse for 5 days. Increase of dry matter , photosynthetic intensity and carboxlyation efficiency of the cucumber seedlings treated with favorable concentration of carboxymethyl chitosan were much higher than that of control. This fully explained that carboxymethyl chitosan in favorable concentration evidently improved chilling tolerance in cucumber seedlings.