摘要:我国油菜生产经常遭受干旱胁迫而影响产量和品质，综合评价油菜种质资源的耐旱性，筛选耐旱种质，确定耐旱性鉴定指标，是耐旱新品种培育和耐旱机理研究的基础性工作。本研究利用229份甘蓝型油菜种质资源，在苗期设置干旱胁迫组和正常灌溉（对照）组，测定地上和地下部鲜重和干重及叶片过氧化物酶活性、丙二醛含量、脯氨酸含量、可溶性蛋白含量、可溶性糖含量和相对含水量10个性状，采用耐旱系数、聚类分析、隶属函数、主成分分析和灰色关联度分析等方法对其耐旱性进行综合评价。结果显示，苗期干旱胁迫使甘蓝型油菜幼苗地上和地下部干重和鲜重及叶片相对含水量和可溶性蛋白含量显著降低，使叶片过氧化物酶活性、丙二醛含量、可溶性糖含量和脯氨酸含量显著升高，而地下部干重在正常灌溉组与干旱胁迫组之间差异不显著。229份种质资源划分为8个类群，各类群表现出不同的耐旱特性。RR002、9801C、炎81-2、07037、浙油758和09-P64-1为耐旱材料，11-P30、CY16PXW-35、08-P35、09-P36、甲972和A148为干旱敏感材料。地上部鲜重、叶片脯氨酸含量和可溶性糖含量可作为甘蓝型油菜苗期综合耐旱性快速、简便、准确的鉴定指标。
关键词:甘蓝型油菜/
耐旱性/
种质筛选/
鉴定指标/
苗期
Abstract:The yield and quality of Brassica napus L. are often affected by drought stress in China. To identify drought-tolerant and drought-sensitive germplasms, screen for indices of drought tolerance to reduce cost and improve efficiency, provide a basis for breeding drought-tolerant varieties, and investigate the mechanisms of drought tolerance, 229 B. napus accessions were subjected to two water treatments (drought stress and well watering) at the seedling stage. The shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, leaf peroxidase activity, malonaldehyde content, proline content, soluble protein content, soluble sugar content, and leaf relative water content were measured. The drought resistance index, clustering analysis, subordinative function, principal component analysis, and gray correlation analysis were used to comprehensively evaluate drought tolerance. The correlation coefficients between the drought resistance index of each trait and the average value of the subordinative function, composite value of the principal component factors, and comprehensive relation degree and those among the drought resistance indexes of the ten traits were calculated to determine the drought tolerance index. The results showed significant differences between the drought-stressed and well-watered plants at the seedling stage. During drought stress, the leaves of drought-stressed plants gradually wilted and curled to different degrees, and the leaves were born slowly and became smaller, while the old leaves turned yellow. After 30 days of stress, the drought-stressed plants were shorter, weaker, and had lower biomass than the well-watered plants. The shoot fresh weight, shoot dry weight, root fresh weight, leaf relative water content and soluble protein content were lower, and the leaf peroxidase activity, malonaldehyde content, proline content, and soluble sugar content increased under drought stress. The root dry weight did not differ between drought stress and well watering. The 229 B. napus accessions were divided into eight groups, and the accessions of each group showed different drought tolerance characteristics. The significant correlation between the average value of the subordinative function, composite value of the principal component factors, and the comprehensive relation degree indicated that the comprehensive evaluation was reliable. Therefore, by means of the subordinative function, principal component analysis, and gray correlation analysis, accessions RR002, 9801C, Yan81-2, 07037, Zheyou758, and 09-P64-1 were identified as drought tolerant. Accessions 11-P30, CY16PXW-35, 08-P35, 09-P36, Jia972, and A148 were drought sensitive. The correlations of shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, leaf proline content, soluble sugar content with the average value of the subordinative function, composite value of the principal component factors, and the comprehensive relation degree were significant with high correlation coefficients, as did those among shoot fresh weight, shoot dry weight, root fresh weight, and root dry weight. The shoot fresh weight, leaf proline content and soluble sugar content can serve as rapid, simple, and accurate traits to identify comprehensive drought tolerance at the seedling stage in B. napus.
Key words:Brassica napus L./
Drought tolerance/
Germplasm screening/
Identification index/
Seedling stage
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