外源抗坏血酸对酸雨胁迫油菜幼苗的缓解效应

为探讨抗坏血酸（AsA）对酸雨胁迫油菜毒害效应的缓解效果,以苏油1号为供试材料,采用盆栽土培的方法研究了不同浓度的外源AsA处理对pH2.5酸雨胁迫下油菜幼苗生长的影响。结果表明,pH2.5酸雨显著抑制了油菜幼苗的生长,喷施外源AsA后,一定浓度范围的AsA可明显缓解油菜的酸雨胁迫,生物量、叶片色素含量、抗氧化酶活性等显著高于酸雨胁迫的油菜,丙二醛（MDA）含量和相对电导率显著低于酸雨处理油菜。但随着AsA喷施浓度的增加,缓解效应下降,生物量、叶绿素含量等下降,而MDA和电导率上升。可见适宜浓度的外源AsA对酸雨胁迫下的油菜幼苗具有一定的缓解效应,但浓度过高则产生促氧化作用,在试验中以4.0 mmol.L-1的效果最佳。

Alleviative Effects of Exogenous ASA on Acid Rain Stressed Oilrape Seedlings

Acid rain is considered the top ten environment concerns in the world.In a pot experiment,oilrape（B.napus var.）cultivar Suyou No.1 was subjected to simulated acid rain（AR,pH2.5）,followed by foliar application of different concentrations of ascorbic acid（AsA）.The alleviative effect of AsA on AR stress in oilrape seedling was then investigated.AR obviously depressed growth and reduced biomass of seedlings.Chlorophyll content,antioxidant content,antioxidative enzyme activities in AR stressed seedlings were enhanced,while malonyl-dialdehyde（MDA）content and relative conductivity（RC）were repressed by application of 4 mmol.L-1 AsA.However,biomass and chloro-phyll content in leaf reduced while MDA and RC increased when concentration of AsA was higher than 4 mmol.L-1,compared with plants treated with 4 mmol.L-1 AsA.Thus,AR stress on oilrape plants was effectively alleviated by foliar application of mild concentration of AsA,and the alleviation effect could be depressed under excessively high concentration of AsA.Here,the optimum concentration of AsA was 4.0 mmol.L-1 for the best alleviation of AR stressed plants.