硝酸盐胁迫对不同抗性菠菜抗氧化物酶活性和甾醇含量的影响

Effects of Nitrate Stress on the Antioxidant Enzyme Activities and Sterol Content in Two Spinach Varieties with Different Resistance

以"大叶菠菜"和"超级菠菜"为试验材料,分析不同浓度硝酸盐(NO3-)对两种菠菜品种种子萌发、幼苗膜脂过氧化、抗氧化物酶活性、渗透调节物质和甾醇含量的影响.结果表明,160 mmol/L NO3-显著抑制菠菜种子萌发,且"超级菠菜"的相对发芽率高于"大叶菠菜",说明"超级菠菜"的抗性高于"大叶菠菜".160 mmol/L NO3-胁迫处理菠菜幼苗发现MDA(malondialdehyde)和H2O2(hydrogen peroxide)含量在处理24、48 h时显著高于对照,且"大叶菠菜"中含量高于"超级菠菜";SOD(superoxide dismutase)、POD(perioxidase)和CAT(catalase)三种抗氧化物酶活性及可溶性糖、可溶性蛋白含量增加,且"超级菠菜"含量高于"大叶菠菜";两品种中豆甾醇和谷甾醇含量在NO3-胁迫处理48 h后升高,"超级菠菜"中豆甾醇/谷甾醇的比值与"大叶菠菜"相比变化较小.以上结果表明,"超级菠菜"的抗性高于"大叶菠菜"可能与其胁迫后具有较高的抗氧化物酶活性、渗透调节物质和甾醇含量有关.

The effects of nitrate stress on the germination and seedling lipid peroxidation, antioxidant enzyme activities, osmotic regulation substances and sterol contents were investigated in two spinach cuhivars （＂Chaoji＂ and ＂Daye＂）. The results showed that 160 mmol/L nitrate inhibited the germination of spinach and the germination rate of ＂Chaoji＂ was higher than ＂Daye＂, indicated that the stress tolerance of ＂Chaoji＂ was higher than ＂Daye＂. When the spinach seedlings were treated with 160 mmol/L nitrate for 0, 8, 24, and 48 h, as compared to the control, the MDA （Malondialdehyde） and H202 （Hydrogen peroxide） content increased after 24 and 48 h treatment and the content of ＂Chaoji＂ was higher than ＂Daye＂. The antioxidant enzyme activities of SOD （superoxide dismutase）, POD （Perioxidase）, CAT （Catalase） and soluble protein and soluble sugar content increased with the increasing treatment time and the increase in ＂Chaoji＂ was higher than ＂Daye＂. Besides, the stigmasterol and sitosterol content in the two cultivars increased after 48 h nitrate stress treatment and the ratio of stigmasterol to sitosterol changed smaller in ＂Chaoji＂. The results suggested that the higher tolerance in ＂Chaoji＂ might be related with the higher antioxidant enzyme activities, osmotic regulation substances and sterol content.