茶树叶片抗氧化系统对土壤水分胁迫的响应

Effects of soil water stress on the antioxidant system in leaves of tea plants(Camellia sinensis)

采用盆栽试验研究了土壤水分胁迫下茶树铁观音和福鼎大白茶2年生幼苗抗氧化系统的响应.结果表明,在土壤水分胁迫下,茶树叶片O2.-的产生速率加快,细胞膜透性增大,MDA含量上升;铁观音SOD、POD、CAT、APX和GR的活性以及AsA和GSH的含量在轻度、中度水分胁迫下上升,在重度水分胁迫下下降;而福鼎大白茶的保护酶活性和抗氧化剂含量在轻度水分胁迫下上升,在中度、重度水分胁迫下下降.在正常供水或水分胁迫下,铁观音均表现出更强的抗氧化能力,表明生长在同一生境中的铁观音对土壤水分的生态适应能力高于福鼎大白茶.

The two-year-old seedlings of tea plants （ Camellia sinensis cv. Tieguanyin and C. sinensis cv. Fudingdabaicha） were grown in pots to study the effects of soil water stress on the antioxidant system. There were four soil water stress treatments ： 75% （ normal water supply）, 55% （ slightly water stress）, 35% （ mild water stress） and 20% （ severe water stress） of field water-holding capacity. The results showed that the producing velocity of O2^-, cell membrane permeability and content of malondialdehyde （MDA） increased in both of cuhivars＇ leaves under soil water stress; and the activities of superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT）, ascorbate peroxidase （APX） and glutathione reductase （GR） increased in the leaves of Tieguanyin under slightly stress and mild stress, but decreased under severe stress. The content of ascorbic acid （AsA） and glutathione （GSH） in leaves had the same profiles as the enzyme activities. But in leaves of Fudingdabaicha, the enzyme activities, the content of ascorbic acid （AsA） and glutathione （GSH） increased under slightly stress, while decreased under mild stress and severe stress. Compared with Fudingdabaicha, Tieguanyin presents higher antioxidant capacity, indicating that Tieguanyin has higher capacity to acclimate to different soil water supply than Fudingdabaicha grown under the same habitat.