【作者】 李聪；

【导师】 张显；

【作者基本信息】 西北农林科技大学 ， 蔬菜学， 2012， 硕士

【摘要】 在我国干旱与半干旱地区约占国土面积的1/2，在这些地区（在约占我国国土面积1/2的干旱与半干旱地区），干旱不但对农业生产有着极为严重的影响，也严重制约着其经济发展、社会进步和生态环境的保护。因此，鉴定、改良和提高植物的抗旱性、选育抗旱种质资源就显得尤其重要和迫切。西瓜作为一种抗旱性较强的重要经济作物，鉴定其抗旱性、选育抗旱品种就有着重大的现实意义。在本课题研究中，主要进行了种子萌发期PEG胁迫试验、苗期反复干旱试验、苗期持续干旱试验、苗期水分梯度试验。其中苗期试验主要采用盆栽称重控制水分模拟干旱胁迫法，统计测定了多项形态生理生化指标，通过抗旱指数分析、主成分分析、聚类分析等方法，评价了不同西瓜品种抗旱性，筛选出了部分抗旱鉴定指标及抗旱品种，建立了比较系统的西瓜抗旱性鉴定与评价方法。主要结果如下：1.苗期反复干旱胁迫试验：以红冠龙、148、M08、京5、中10幅3、F09为材料，每隔2d记录了各品种的生长状况以及反复干旱2次后的存活率。所测定的生长指标包括株高、叶片卷曲情况、植株挺拔情况等。并根据植株生长状况将植株生长形态划分了5个级别，统计各时期各级别的植株数。对株高胁迫指数、叶片伤害率、各级别植株比率与存活率进行相关分析、灰色关联度分析。结果表明，株高胁迫指数、叶片伤害率、各级别植株比率均可作为鉴定西瓜品种抗旱性的鉴定指标。植物生长形态观察的方法可以初步判定品种间抗旱性的强弱，若准确的对品种抗旱性进行评价需要结合多项指标综合量化分析。2.苗期持续干旱试验：选用11份参试材料，对其多项生物学抗旱指标进行了统计分析，主要包括形态伤害指标和生长发育指标，结合各指标的抗旱指数对单项指标的抗旱性进行分级，用分级评价法确定了西瓜品种抗旱性的5个等级，即极抗旱、较抗旱、中等抗旱、抗旱较弱、抗旱极弱。最终确定了11个参试品种的抗旱级别，初步建立了鉴定和评价西瓜抗旱性的生物学指标鉴定法。3.萌芽期干旱胁迫与苗期干旱胁迫试验：对11份参试材料进行了种子萌发期PEG胁迫处理以及苗期干旱胁迫。对种子发芽率、发芽势、萌发抗旱指数、MDA、SOD、Proline、POD、Chl、Carotinoid进行了统计测定。利用系统聚类分析、抗旱系数分析、相关分析、主成份分析筛选出了MDA、SOD、Pro、萌发抗旱指数这4个指标来鉴定西瓜品种的抗旱性。4.苗期水分梯度试验：根据苗期持续干旱试验中利用生物学指标鉴定法确立的5个抗旱级别，从中选取抗旱性不同的6个品种为参试材料，设置5个水分梯度处理，在干旱处理后测定分析了MDA、SOD、Pro在不同的5个水分梯度下的变化规律。结果表明，MDA含量、SOD活性、Pro含量在不同的水分处理条件下，表现出不同程度的差异，在第4个水分胁迫处理水平(最大持水量的20%)时各指标差异最显著。结合抗旱系数用聚类分析法确定了6个品种的抗旱性。5.运用前期试验确定的生物学指标鉴定与评价方法对20个西瓜品种进行了抗旱性鉴定。筛选出了Ky-1、Ky-2、M05、Ky-3、148、黑牡丹等比较抗旱性的品种。更多还原

【Abstract】 In the arid and semi-arid regions which account for1/2of land area in China, thedrought not only has a very serious effect on the agricultural production, but also severelyrestricts their economic development， social progress and the protection of ecological.Therefore, it is particularly important and urgent to breeding the drought-resistant germplasmresources by identifying, modifying and improving the drought of plant. Watermelon acts as aimportant economic crop and it is particularly important to identity drought resistance andbreeding drought resistant variety. This research project mainly contained the PEG stressexperiment at germinate stage, recurrent drought experiment at seedling stage, continuousdrought experiment at seedling stage, moisture gradient experiment at seedling stage. Amongthem, the experiment at seedling stage got the statistics of multiterm morphology physiologybiochemistry indexes by simulation drought stress method of potting and evaluated droughtresistance of different watermelon variety, screened severel drought resistance indexes andvarieties, established a system of watermelon drought resistance appraisal and evaluationmethod by drought resisting exponent analysis,(PCA) Principal Component Analysis, Clusteranalysis and so on. The main results were as follows:1．Recurrent drought stress experiment at seedling stage: Hongguanlong,148, M08,Jing5, Zhong10Fu3, and F09were used as materials, and the growth condition and thesurvival rate after repeated two drought of the varieties was recorded at2day intervals. Thedeterminated growth indexes include plant height, leaf curl and plant straight, etc. And theplant growth morphology is divided into5levels according to the plant growth situation, andrecording the all levels of plant number at every period. The plant high stress index, leavesdamage rate, all levels of plant ratio and survival rates are done related analysis and grayrelational analysis. The results show that plant high stress index, leaf damage rate, all levelsof plant ratio can be used as the appraisal index of identifying watermelon variety droughtresistance. The observation method of plant growth morphology can do a preliminaryjudgment for varieties of drought resistance. The comprehensive analysis of more indexes is done to evaluate accurately the varieties drought resistance.2．Sustainable drought experiment at seedling stage:11materials were chosen to make astatistical analysis of the many biological drought resistance indexes, which mainly includedthe morphology damage index and growth index, and graded for single index according toeach drought resistance index,5levels of the watermelon varieties drought resistance wereset through grading method, namely the extremely drought resistance, a drought resistance,medium drought resistance, weak drought resistance, very weak drought. Finally, droughtresistance levels of11test varieties were determined; a biological index verification methodwas preliminary established for identification and evaluation of watermelon droughtresistance.3．Bud state drought stress and seedling stage drought stress test:11materials weremade PEG stress processing of seeding germination and drought stress seedling state. Doingstatistics and measurement on seed germination rate, sprout potential, germination droughtindex, MDA, SOD, Proline, POD, Chl and Carotinoid. Screening out the MDA, SOD, Pro,germination drought resistance index these four indexes to identify the drought resistance ofthe watermelon variety by using system clustering analysis, drought resistance coefficientanalysis, correlation analysis, the principal component analysis.4．Water gradient experiment at seedling stage: according to5drought resistance levelsestablished using the biological index in the seeding stage continuous drought experiment,choosing six different drought resistance varieties as tested material, setting five moisturegradient and analyzing the change rules of MDA, SOD and Pro in different five moisturegradient after dry treatment. The results show tha the difference level of each index indifferent moisture treatment level is different, and difference of each index is the mostsignificant in the fourth moisture stress processing level(moisture content20%). The sixvarieties drought resistances are determined by using cluster analysis combining droughtresistance coefficient.5. Drought resistances of20varieties were identified using the biological index appraisaland evaluation method determined in the earlier experiments.更多还原