化肥减量配施茉莉酸甲酯对连作草莓NO合成和AsA-GSH循环的影响

Effects of chemical fertilizer reduction with methyl jasmonate on NO synthesis and AsA-GSH cycle in continuous cropping strawberry

关键词:  连作障碍, 抗坏血酸-谷胱甘肽循环, 抗坏血酸过氧化物酶, 谷胱甘肽还原酶, 硝酸还原酶

Key words:  continuous cropping obstacles, ascorbic acid-glutathione cycle, ascorbic acid peroxidase, glutathione reductase, nitrate reductase

摘要:

为从植株抗坏血酸-谷胱甘肽(ascorbic acid-glutathione,AsA-GSH)循环等抗氧化系统角度理解外源茉莉酸甲酯(methyl jasmonate,MeJA)和化肥减施消减草莓连作障碍机制,该研究将‘红颜'草莓种植于4年连作土壤,测定了草莓叶片硝酸还原酶(nitrate reductase,NR)活性、一氧化氮(nitric oxide,NO)含量和AsA-GSH循环系统非酶类抗氧化剂含量和相关酶活性。结果表明:(1)化肥常规用量条件下,外源MeJA使连作草莓NO含量显著提高35.31%,AsA含量显著降低19.70%,抗坏血酸过氧化物酶(ascorbic acid peroxidase,APX)活性显著降低6.60%,经济产量显著提高6.41%,生物量显著提高7.71%,但是并未显著影响NR活性、GSH含量和谷胱甘肽还原酶(glutathione reductase,GR)活性。(2)化肥用量减半条件下,外源MeJA使连作草莓NO含量显著提高53.31%,AsA含量显著降低45.45%,APX活性显著降低9.23%,经济产量显著提高6.66%,生物量显著提高8.17%,但是并未显著影响NR活性、GSH含量和GR活性。(3)喷施清水条件下,化肥减施使连作草莓NO含量、AsA含量和APX活性分别显著提高27.34%、86.11%和6.88%,但是并未显著影响NR活性、GSH含量和GR活性,以及经济产量和生物量。(4)喷施MeJA条件下,化肥减施使连作草莓NO含量显著提高44.27%,AsA含量显著提高26.42%,但是并未显著影响NR活性、GSH含量、APX活性和GR活性,以及经济产量和生物量。综上认为,外源MeJA和化肥减施均对连作草莓GSH含量和GR活性无显著影响,但外源MeJA可以缓解草莓植株对连作和高盐胁迫的应激反应,因此降低了连作草莓AsA含量和APX活性,化肥减施则显著提高了AsA含量和APX活性,这说明连作草莓可能主要依赖AsA路径应对连作障碍和化肥过量的胁迫。

Abstract:

In order to understand the mechanism of exogenous methyl jasmonate(MeJA)and chemical fertilizer reduction in reducing continuous cropping strawberry obstacles from the perspective of antioxidant systems such as ascorbic acid-glutathione(AsA-GSH)cycle, this study planted ‘Hongyan' strawberry in soil where strawberry have been grown continuously for 4 years, and measured the nitrate reductase(NR)activity, nitric oxide(NO)content, the non-enzymatic antioxidant content and related enzyme activity of the AsA-GSH cycle. The results were as follows:(1)Under the condition of conventional chemical fertilizer application, exogenous MeJA significantly increased the NO content of continuous cropping strawberry by 35.31%, significantly reduced the AsA content by 19.70%, significantly reduced the ascorbic acid peroxidase(APX)activity by 6.60%, significantly increased economic yield by 6.41%, and significantly increased biomass by 7.71%. However, it did not significantly affect NR activity, GSH content, and glutathione reductase(GR)activity.(2)Under the condition of halving the amount of chemical fertilizer, exogenous MeJA significantly increased the NO content of continuous cropping strawberry by 53.31%, significantly reduced the AsA content by 45.45%, significantly reduced APX activity by 9.23%, significantly increased economic yield by 6.66%, and significantly increased biomass by 8.17%. However, it did not significantly affect NR activity, GSH content, and GR activity.(3)Under the condition of spraying water, chemical fertilizer reduction significantly increased the NO content, AsA content, and APX activity of continuous cropping strawberry by 27.34%, 86.11%, and 6.88%, respectively. However, it did not significantly affect NR activity, GSH content, and GR activity, as well as the economic yield and biomass.(4)Under the condition of spraying MeJA, chemical fertilizer reduction significantly increased the NO content and AsA content of continuous cropping strawberry by 44.27% and 26.42%, respectively. However, it did not significantly affect NR activity, GSH content, APX activity, and GR activity, as well as the economic yield and biomass. In summary, both exogenous MeJA and chemical fertilizer reduction have no significant effect on the GSH content and GR activity of continuous cropping strawberry. However, exogenous MeJA can alleviate the stress response of strawberry plants to continuous cropping and high salt stress, thus reducing the AsA content and APX activity. Chemical fertilizer reduction significantly increases the AsA content and APX activity, indicating that continuous cropping strawberry may mainly rely on the AsA pathway to cope with continuous cropping obstacles and excessive fertilizer stress.