PEG模拟干旱胁迫下甘蓝型油菜的根系特性与抗旱性

摘要

采用砂培法,利用14％ (m/V)聚乙二醇(PEG-6000)模拟干旱胁迫,研究39份甘蓝型油菜发芽期根系性状的变化及其与抗旱性的关系.结果表明,干旱胁迫对油菜根鲜重和侧根数有明显的抑制作用,而对根长和根冠比的影响较小.相关分析表明,相对侧根数与活力指数之间以及根长与活力指数之间均呈显著正相关,可作为抗旱性鉴定的辅助指标.杂交种和常规种在根系性状上差别不显著,表明其抗旱能力相当.对油菜的抗旱性进行综合评价和聚类分析发现,在欧式距离为60时39份材料可分为5个类群,其中A类抗旱性最强,平均相对侧根数77.9％,相对根长98.9％；E类抗旱性最差,平均相对侧根数69.3％,相对根长84.5％.筛选出发芽期抗旱性较强的3份材料:OR918、OR805和OR2025.%A new method based on sand culture and 14% (m/V) polyethylene glycol -6000 (PEG -6000) was developed to evaluate root traits of 39 rapeseed genotypes at seedling stage and the connections between root traits and drought tolerance. Results showed that root weight and lateral - root number were significantly inhibited by drought, while root length and root -to -shoot ratio were modestly affected. Significant correlations were found between vigor index and both lateral roots number and root length, implying that these two traits can be used as selecting criteria for drought tolerance. Inbred lines and hybrid varieties had no significant difference on root traits for drought tolerance. By clustering analysis, the 39 genotypes were divided into 5 groups at Euclidean distance of 60. Among them, group A was considered as the most tolerant to drought, and group E was the most sensitive. Three drought tolerant genotypes (OR918, OR805 and OR2025) showed potentials for further breeding program.