外源钒胁迫下甜玉米植物可溶性蛋白含量的动态变化

Dynamic changes of soluble protein contents in the sweet corn under exogenous vanadium stress

采用盆栽试验,研究了不同浓度的钒(V)胁迫对甜玉米植株根、茎和叶蛋白含量的影响.结果表明,随着V胁迫浓度增加,玉米植株各器官蛋白含量呈现先上升后下降的变化趋势,当V浓度达200 mg·kg^(-1),根、茎和叶蛋白含量达最大,分别为63.63 mg·g^(-1)、42.74 mg·g^(-1)和120.08 mg·g^(-1),相比于对照增加52.1%、80.1%和165.7%(34 d),随着V浓度继续增加,植物中蛋白含量下降,但始终高于对照.当V浓度为500 mg·kg^(-1),根、茎和叶中蛋白含量分别降低为55.52 mg·g^(-1)、31.08 mg·g^(-1)和102.2 mg·g^(-1)(34 d).V胁迫时间不同,玉米植株各器官蛋白含量变化趋势不同,在相同V浓度胁迫下,随着胁迫时间的增加,叶蛋白含量先降低后增大,玉米茎蛋白含量变化不大,根蛋白含量则显著下降,当V浓度为500 mg·kg^(-1)时,玉米根蛋白含量分别为27.86 mg·g^(-1)(61 d)和20.63 mg·g^(-1)(91 d),比对照下降了31.4%和43.5%.在低浓度V和短时间胁迫下,玉米植物被诱导作出应激反应,使体内一些参与缓解氧化胁迫的酶活性上升,从而产生相关具有解毒作用的蛋白,使植物蛋白含量增加;当V浓度超过了植物耐受限度,打破了植物新陈代谢平衡,对细胞产生毒性,蛋白合成机制受到破坏,表现为随着V浓度和胁迫时间增加植物蛋白含量下降显著.

Effects of vanadium（V） stress on protein contents in the roots,stems and leaves of sweet corn were investigated by pot experiments.The results showed that with increase of V concentration,protein contents in various organs of the sweet corn showed the trend of increasing first and then decreasing.When V concentration was 200 mg·kg^-1,the protein contents in roots,stems and leaves of the sweet corn were 63.63 mg·g^-1,42.74 mg·g^-1 and 120.08 mg·g^-1 respectively（after 34 days）,increased by 52.1%,80.1% and 165.7% compared with the control.As the concentration of V continues to increase,the protein contents decreased,but it was always higher than the control.When V concentration was 500 mg·kg^-1,the protein contents in roots,stems and leaves of the sweet corn was decreased to 55.52 mg·g^-1,31.08 mg·g^-1 and 102.2 mg·g^-1,respectively.The change of protein content in different organs of the sweet corn was different depending on the V stress time.Under the same V concentration,protein contents in the leaves decreased first and then increased with increase of stress time,and protein contents in the stems changed little,but protein contents in the roots decreased significantly.When V concentration was 500 mg·kg^-1,the roots protein content of the sweet corn was 27.86 mg·g^-1（61 d） and 20.63 mg·g^-1（91 d）,respectively,which was 31.4%and 43.5% lower than that of the control.Under V stress with low concentration and short stress time,the sweet corn was induced to respond to stress,so the activities of some enzymes involved in the alleviation of oxidative stress increased,and proteins relateds to detoxification were produced,resulting in the increase of plant protein content.When the V concentration exceeded plant tolerance,it broke the metabolism balance of plants,and become toxic to the cells.The mechanism of protein synthesis was destroyed in the sweet corn,and the plant protein contents decreased significantly with the increase of V concentration and stress time.