外源柠檬酸对水稻铜毒害的缓解效应

Alleviative Effect of Exogenous Citric Acid on Rice under Copper Toxicity

以水稻(宜香4106,Oryza sativa L.cv.Yixiang4106)种子为实验材料,研究铜(Cu)对水稻种子萌发和生长的影响,以及外施柠檬酸对铜毒害的缓解效应.结果表明,在不同浓度Cu2+(20、50、80μmol/L)胁迫下,水稻幼苗的芽长、胚根长、须根数和活力指数均明显下降.当Cu2+浓度达到80μmol/L时,与未胁迫处理相比,幼苗芽长和胚根长度抑制率分别高达23.6%和96.7%.2mmol/L的外源柠檬酸可缓解Cu2+的抑制作用,水稻种子萌发的活力指数提高,根系长度增长近7倍,幼苗平均每株根数增加约8.8倍,水稻幼苗叶片中丙二醛(MDA)含量降低,叶绿素含量提高41.9%,可溶性蛋白质的含量为铜胁迫处理的2.9倍,超氧化物歧化酶(SOD)、过氧化物酶(POD)的活性均显著提高.

Using rice seed （Oryza sativa L.cv.Yixiang 4106） as material to study the toxicity of Cu 2＋ to the seed germination and the alleviative effect of exogenous citric acid.The result showed that different Cu 2＋ concentrations could restrain seedling length,radicle length,amount of hair roots and vigor index.Under 80 μmol/L of Cu 2＋,seedling length and radicle length were inhibited by 23.6% and 96.7%,respectively.The toxicity of Cu 2＋ was relieved to some extent after adding 2.0 mmol/L citric acid,increasing the vigor index.The radicle length and hair roots were increased by 7 times and 8.8 times,respectively.Physiological and biochemical changes occurred,and chlorophyll and soluble protein contents increased by 41.9% and 2.9 times,superoxide dismutase （SOD） and peroxidase （POD） activities increase by 12.3% and 88.6%,malondialdehyde （MDA） content declined by 47.3%.