PEG模拟水分胁迫对白菜型冬油菜幼苗生长及生长特性的影响

摘要

采用不同质量分数的聚乙二醇6000(Polyethylene glycol 6000,PEG6000)溶液模拟水分胁迫,研究4种白菜型冬油菜幼苗形态特征及生理生化特性,评判不同品种的抗旱性强弱.结果表明,PEG对4种白菜型冬油菜的成苗率、主根长、苗高、单株鲜质量、相对活力指数有显著的抑制效应;PEG质量分数为5％～15％时,超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性与胁迫质量分数呈正相关关系,在质量分数15％～20％时酶活性出现峰值,达显著性水平(P＜0.05),随之下降.可溶性糖(SS)含量、可溶性蛋白(SPr)含量、脯氨酸(Proline)含量、相对电导率、丙二醛(MDA)含量与胁迫质量分数呈显著正相关关系.线性回归分析得到白菜型冬油菜PEG胁迫的半致死质量分数(LC50)为18.2％、半致死相对电导率(EC of LC50)为15.73％.4个品种的抗旱性顺序依次为:陇油6号＞陇油7号＞天油7号≥天油5号.%Different mass fractions of polyethylene glycol 6000(PEG6000)solution were used to simulate the water stress.The morphological characteristics and physiological and biochemical characteristics of four B.campestris were studied and the drought resistance of different varieties was evaluated.The results showed that PEG had a significant inhibitory effect on seedling rate,main root length,seedling height,fresh weight per plant,and relative vigor index of four kinds of winter campestris.At 5％to 15％PEG mass fraction,there was a positive correlation between superoxide dismutase(SOD)activity,peroxidase(POD)activity,catalase(CAT)activity and stress mass fraction,while at a mass fraction of 15％to 20％,the enzyme activity peaked,reaching a significant level(P≤0.05),followed by a decrease.There was a significant positive correlation between soluble sugar(SS)content,soluble protein(SPr)content,proline content,relative conductivity,malondialdehyde(MDA)content and stress mass fraction.Linear regression analysis showed that the semi-lethal mass fraction(LC50)of PEG stress was 18.2％and the EC of LC50 was 15.73％.The order of drought resistance of the four varieties was as follows: Longyou 6＞ Longyou 7 ＞Tianyou 7≥Tianyou 5.