【作者】 李震；

【导师】 邹崇顺； 张学昆；

【作者基本信息】 中国农业科学院 ， 作物遗传育种， 2010， 硕士

【摘要】 油菜是我国最重要的油料作物之一,但长江流域季节性干旱对我国的油菜生产造成了严重的威胁,筛选油菜耐旱资源、选育油菜耐旱品种是减少干旱造成损失的有效途径之一。本研究对81个甘蓝型油菜种质资源在PEG胁迫下的种子发芽耐旱性进行了鉴定,测定了发芽率、苗高、鲜重和相对活力指数等指标。继而选择17个甘蓝型油菜品种进行盆栽干旱处理,以萎蔫率为主要指标,通过叶片、光合相关、根系等生理性状的比较,筛选出若干苗期耐旱性强的品种。后期以中双10号为研究材料,开展了不同浓度的赤霉素(GA3)浸种在促进甘蓝型油菜发芽期耐旱性中的作用和机理研究。以10%(w/v)PEG6000做渗透介质模拟干旱条件,对不同来源的甘蓝型油菜(Brassica napus L.)品种(系)进行干旱胁迫下种子发芽鉴定,分析油菜种子发芽耐旱性的遗传多样性。结果表明:干旱胁迫下,部分材料处理与对照的发芽性状有显著性差异,81个甘蓝型油菜材料的平均苗高处理比对照低36.5%,平均鲜重处理比对照低31%,成苗率降低11.1%。甘蓝型油菜品种(系)耐旱性有较大遗传差异,幼苗活力指数的变异幅度为19%-81%,平均活力指数为55%。相关分析表明,活力指数与胁迫下的发芽性状达极显著正相关,可以作为油菜种子发芽耐旱的综合指标。根据活力指数,将81个油菜资源划分为强,中,弱三个耐旱等级,并筛选到30295,30253,中双6号,30703,30296,30290,30704,中油杂9号,德油4号等一批耐旱遗传资源。分析干旱胁迫下17个甘蓝型油菜品种苗期生理生化变异,探讨了不同品种间耐旱性差异及品种耐旱性的鉴定方法。水分胁迫条件下,17个甘蓝型油菜品种间叶片保水能力,光合色素的保护,膜脂过氧化程度以及活性氧清除能力都表现出较大差异。总的趋势是,水分胁迫下品种的叶片萎蔫指数与叶片光合速率,叶绿素、类胡萝卜素含量,SOD、CAT酶活性达正相关,以及与WSD,MDA含量,电泄漏达负相关。叶片萎蔫指数最为直观、综合的反映了油菜苗期耐旱性。以叶片萎蔫指数作为主要指标将17个品种评定为三个耐旱等级,筛选出了B108、H3531、Q2、9548、8056等苗期耐旱性强的种质资源。为提高油菜耐旱性,筛选到具有诱导耐旱性提高的植物生长调节剂—赤霉素,并对赤霉素浸种诱导甘蓝型油菜发芽耐旱性的机理进行了研究。利用15%(w/v)PEG6000做渗透介质模拟干旱条件,将0、100、200、300、400和500 m g·l-1的赤霉素溶液中浸种处理8h的油菜籽(中双10号)发芽并进行发芽耐旱鉴定。结果表明:赤霉素可以显著改善干旱条件下油菜种子发芽性状。与对照相比,200—300 m g·l-1的赤霉素溶液显著提高耐旱指数88%、鲜重42%、苗高72.7%、增加可溶性物质含量(可溶性糖47.2%、可溶性蛋白35.6%、脯氨酸62.9%);同时通过提高包括CAT45.6%、POD46.6%、SOD13%的抗氧化酶系活性,显著降低了子叶细胞膜质过氧化水平(MDA36.6%)。赤霉素作为一种可以促进种子萌发、提高油菜发芽期耐旱性的调节物质,在生产上具有很大的应用潜力。更多还原

【Abstract】 Rapeseed (Brassica napus L.) is one of the most important sources of vegetable oil and protein rich meal in the world. Because of frequent seasonal autumn drought occurring, rapeseed production in China is often disturbed. It is an effective pathway for withdraw drought stress to screen idioplasmic resource and breed variety with drought tolerance. According to germination percentage, hypocotyl length, fresh weight and DTI, present study evaluated drought tolerance of 81 varieties of Rapeseeds (Brassica napus L.) from different genetic resources during germination stage with simulate water stress by 10% (w / v) PEG6000. Wither percentage as the key parameter combined photosynthesis, leaf, root were observed to screen out some varieties with drought tolerance from 17 rapeseeds. And Zhongshuang No.10 was used to explore role of GA3 priming with concentrations in improving drought tolerance of germinating seeds in rapeseed.Drought tolerance of 81 varieties of Rapeseeds from different genetic resources was investigated during germination stage with simulate water stress by 10% (w / v) PEG6000. The results showed that the germinating traits of several treatments were significantly different from control after drought stress. The average seedling height of treatment deceased 36.5%, the average fresh weight decreased 31% and relative germinate rate decrease 11.1%. There was significant difference of drought tolerance among different varieties or lines. The vigor index of seedling ranges from 19% to 81%, the average relative vigor index is 55%. Correlation analyses indicated that the vigor index has significant positive correlation with the seedling traits under drought stress. Some varieties or lines, 30295, 30253, Zhongshuang No.6,30703, 30296, 30290, 30704, Zhuongyouza No.9 and Deyou No.4, could be classed as high drought tolerant germplasm resources with higher vigor index.It is positive to evaluate rapeseeds varieties with high drought tolerance in 17 rapeseeds seedling under water stress, we study the physiological variance and the method to evaluate drought tolerance. It is difference to keep water statue, photosynthesis, antioxidants activity in 17 varieties under drought. As higher LWI as lower decrease of Pn, chorophyll, caroternoid content and increase of WSD, MDA content, electrolyte leakage were in 17 varieties. Moreover, there was significant correlation between antioxidants (SOD) activity and LWI. LWI is an easy and general parameter to reflect drought tolerance in rapeseed seedling. Third degrees of drought tolerance and B108,H3531,Q2,9548,8056 with high drought tolerance were evaluate by LWI in 17 rapeseeds.The role of gibberellic acid-3 (GA3) to improve drought tolerance in rapeseed was evaluated. For priming, seeds of rapeseed (c.v. Zhongshuang No.10) were soaked in 0, 100, 200, 300, 400 and 500 mg·l-1 aerated solution of GA3 for 8 h. The primed seeds were sown to germinate for 7 days under a simulated drought stress by applying 15% PEG6000 solution. The result showed that GA3 can significantly improve seed germination characteristics under drought stress. Compared with controls, priming seed with 300 mg·l-1 GA3 significantly increased drought tolerance index by 88%, fresh weight by 42.9% and hypocotyl length by 72.7%. GA3 treatment also increased soluble sugars significantly by 47.2%, soluble proteins by 35.6%, free proline by 62.9%. The level of oxidative damage was reduced significantly with lower electrolyte leakage (decreased by 36.5%) and malondialdehyde (MDA) content (decreased by 36.6%), possibly due to the enhanced superoxide dismutase (SOD) (increased by 13%), catalase (CAT) (increased by 45.6%) and peroxidase (POD) (increased by 46.6%). The result of this research showed that GA3 is an effective regulator to boost seed germination of rapeseed and improve seedling tolerance to drought stress.更多还原