3种类型油菜对干旱胁迫的生理响应

为了解芸薹属亚种间抗旱差异,选育抗旱材料,以3种类型油菜（甘蓝型油菜Q2、芥菜型油菜新油9号、白菜型油菜L14）为实验材料,采用盆栽控水法,测定干旱胁迫下油菜叶片光合参数、叶绿素荧光参数、水分等生理生化指标,研究3种类型油菜对干旱胁迫的生理响应和抗旱机制。结果表明：随着干旱胁迫的加重,三个不同油菜品种抗旱指标存在差异,其叶片的总生物量、离体叶片失水速率（RWL）、叶片相对含水量(RWC),叶绿素荧光参数及气体交换参数呈降低趋势,其中新油9号的光合系统受到的影响最小,Q2的光合系统受损最严重;根冠比、丙二醛（MDA）、超氧化物歧化酶（SOD）、过氧化物酶（POD）呈升高趋势,其中L14的SOD、POD活性在所有植物中升幅最大,干旱下分别为胁迫前的2.92、4.14倍。此外,3种类型油菜各有机溶质的积累量存在较大的差异,Q2和新油9号积累最多的是脯氨酸（Pro）,分别增至原来的12.37、6.60倍,L14则积累较多的可溶性蛋白（SP）,增至原来的6.55倍。隶属函数法分析得出抗旱性强弱顺序为：芥菜型油菜新油9号>白菜型油菜L14>甘蓝型油菜Q2。综上表明：油菜可以通过生长调节、光合抑制调节、活性氧代谢调节和渗透调节4种途径共同作用来响应干旱胁迫。

Physiological response of 3 Brassica species to drought stress

 For better understand the differences of drought tolerance among Brassica species, 3 materials fromBrassica napus (Q2), B. juncea (Xinyou 9) and B. rapa (L14) were used to investigated the physiological and bio⁃chemical changes. Photosynthesis parameters, chlorophyll fluorescence parameters and water content of their leavesunder drought stress were measured by pot experiments. Results showed that with the aggravation of drought stress,drought resistance indexes of 3 materials were different. Total biomass, water loss rate of leaf, leaf relative water con⁃tent, chlorophyll fluorescence parameters and gas exchange parameters had decreasing trend, among which photo⁃synthetic system of Xinyou 9 was the least affected, Q2 was the most severely damaged. All the root-shoot ratio andmalondialdehyde content increased, and their superoxide dismutase and peroxidase activities increased also. Butthe superoxide dismutase and peroxidase activities increased the most, which were 2.92 and 4.14 times respectivelythan normal control. In addition, more differences were found in organic solutes accumulation. Proline was the mostaccumulated protein in Q2 and Xinyou 9, which increased to 12.37 and 6.60 times of the originals, while solubleprotein in L14 increased to 6.55 times of the original. By subordinate function values analysis, capability of droughtresistant was in the order of B. juncea Xinyou 9 > B. rapa L14 > B. napus Q2. In conclusion, 3 Brassica species asB. juncea, B napus and B. rapa could respond to drought by 4 main strategies: growth regulation, photosynthesis inhi⁃bition aadjustment, active oxygen metabolism system and osmotic adjustment.