干旱胁迫下壳聚糖对苹果幼苗抗旱性生理指标的影响

以"红富士"苹果幼苗为材料,采用盆栽控水的方法研究了干旱胁迫条件下低分子质量的壳聚糖(Chitosan,CTS)对提高苹果幼苗抗旱性的效应。结果表明,在一定浓度范围内(20、50、100、150、200 mg/L)苹果幼苗的抗旱性效果随壳聚糖浓度的增加而增强。壳聚糖浓度为100 mg/L时苹果苗抗旱性达到最佳,与干旱对照(CK2)相比,质膜透性和MDA分别下降29.89%和75.56%(p<0.05),SOD、CAT活性和可溶性糖含量分别提高79.31%、63.88%和73.85%(p<0.05),壳聚糖浓度再增大其作用效果不再提高。由此可知,在干旱胁迫条件下适宜浓度的壳聚糖可提高苹果幼苗的抗旱性机制可能是能够清除活性氧、保护质膜稳定性、维持或提高SOD和CAT保护酶活性、促进有机渗透调节物质的增加。

Effects of chitosan on some physiological indices of apple seedlings under drought stress

Effects of low molecular weight chitosan(CTS) on drought resistance of the Red Fuji apple seedlings under water stress were studied using pot-culture experiments.The results showed that the treatment with CTS(20,50,100,150,200 mg/L) could improve membrane stability,maintain or enhance the activities of SOD and CAT,and increase the content of soluble sugar under moderate water stress.The effects of CTS on drought resistance of apple seedlings may be related to concentration.The effect would be improved when the CTS concentration increased within a certain range.The best concentration was 100 mg/L,compared with CK2.The permeability of membrane and MDA content decreased by 29.89% and 75.56%(p<0.05).The activities of SOD and CAT and content of soluble sugar increased by 79.31%,63.88% and 73.85%(p<0.05).If CTS concentration continued to increase,the effect of CTS on drought resistance would not enhance.Therefore,the mechanism of low molecular weight CTS of appropriate concentration that enhanced drought resistance may scavenge active oxygen species,protect membrane stability,maintain or increase the activities of SOD and CAT,increase accumulation of organic substance.Thus this mechanism might be the theoretical basis for application and research of CTS in adverse resistance.