摘要
玉米(Zea mays)根尖的氧化还原活性随介质环境氧的浓度增高而升高,当氧分压达17.262 kPa时,氧化还原活性趋于平稳。有氧与缺氧的根尖各种辅酶的含量有显著差异,其中NADPH和NAPP^+的含量与氧化还原活性的变化呈正相关,但与NADH和NAD^+的含量关系不大。缺氧根再供氧,其NADPH和NADP^+含量随加氧的时间而升高,而NADH和NAD^+的含量则相应减少。供氧根比缺氧根NAD激酶活性提高约20％,表明NAD激酶在有氧条件下与辅酶Ⅰ转换为辅酶Ⅱ有关。
The redox activity of root tips increases with the gradual increasingconcentration of O_2 level in the medium. The activity reaches saturation at17.622 KPa of O_2 partial pressure. Under condition of having O_2 and beingshort of content of O_2, the coenzyme Ⅰ and coenzyme Ⅱ are markedlydifferent. The variation of redox activity of the root tip is consistent withthe variation of coenzyme Ⅱ content but not of coenzyme Ⅰ. When O_2 isintroduced into the medium with anoxic root tips, the concentration ofNADPH and NADP^+ increases rapidly, but NADH and NAD^+ correspondinglydecrease, and the actitivity of NADKinase raises about 20.1%. These resultssuggest that the increase of NADPH and NADP^+ content possibly involvesthe increase of activity of NADKinase, which catalyzes the coversion ofcoenzyme Ⅰ into coenzyme Ⅱ.
基金
国家自然科学基金
关键词
玉米
根尖
细胞质膜
氧化还原活性
corn root tip
redox activity
pyridine nucleotide
NADKinase
