NaCl胁迫对不同柑橘砧木品种抗氧化系统的影响

采用土培的方式,研究了不同浓度的NaC(l0,50,100,150,250,350mmol·L-1)对岑溪酸橘Citrus reticulata Blanco、龙州土柠檬Citrus limonia Osbeck和临桂砧板柚Citrus grandis Osbeck叶片抗氧化酶(SOD、POD、CAT、APX)活性以及谷胱甘肽(GSH)、丙二醛(MDA)、超氧自由基(O2·-)含量的影响。结果表明,随着NaCl处理浓度的增加,岑溪酸橘、龙州土柠檬和临桂砧板柚3种柑橘叶片中O2·-均有不同程度的增加,表明在NaCl处理下3种柑橘均受到了不同程度的O2·-胁迫。NaCl处理对岑溪酸橘和龙州土柠檬SOD、POD活性,临桂砧板柚MDA含量的影响不显著(P0.05),但引起临桂砧板柚SOD活性、岑溪酸橘和龙州土柠檬APX活性显著增加(P0.05)。在不同浓度的NaCl处理下,3种柑橘叶片的CAT活性均有不同程度的下降,但GSH的含量随着NaCl浓度的增加而增加,在NaCl处理浓度为350mmol·L-1时,岑溪酸橘、龙州土柠檬、临桂砧板柚GSH含量分别比对照提高了137%、59.1%、90.8%,表明GSH在解毒NaCl胁迫时起重要作用。

Antioxidative responses to NaCl stress in the leaves of different cultivar of citrus rootstocks

Effects of NaCl on various enzymatic antioxidants in citrus Cenxisuanju(Citrus reticulata Blanco), Longzhoutuning-meng(Citrus limonia Osbeck) and Linguizhenbanyou(Citrus grandis Osbeck) were studied. Which were grown in soils added with various NaCl concentrations (0, 50, 100, 150, 250, and 350 mmol·L~(-1)) for 21 days. Plant leaves were analyzed for contents of glu-tathione (GSH), malondialdehyde (MDA) and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). Results showed that the contents of O_2~(·-) were higher than control. The activities of SOD, POD in the leaf of Cenxisuanju and Longzhoutuningmeng show no significant difference with control, and the same result found to the content of MDA in Linguizhenbanyou. But the activities of SOD in the leaf of Linguizhenbanyou show significant difference with control, and the same results found to the activities of APX in the leaf of Cenxisuanju, Longzhoutuningmeng. The activities of CAT were decreased with the increasing of NaCl. Compared to the control, the contents of GSH increased by 137%, 59.1%, and 90.8%, respec-tively with the soil NaCl concentration at 350 mmol·L~(-1). The results indicated that both enzymatic antioxidants and GSH played significant roles in NaCl detoxification in these plants.