四种转基因苜蓿抗旱生理比较研究

发布时间：2018-05-06 04:15

本文选题：多抗基因 + 紫花苜蓿　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：以新疆大叶苜蓿与其四种转基因苜蓿[转codA基因苜蓿(SC)、转AtNDPK2基因苜蓿(SN)、转IbOr基因苜蓿(SOR)和转AtABF3基因苜蓿(SAF)]为材料,通过盆栽控制实验,比较研究了土壤水分持续下降过程中(土壤含水量从80%FC逐渐下降至40%FC),始花期各株系形态特征与生理生态对干旱胁迫的响应及其相互间差异。主要取得如下结果:(1)充足供水条件下,4种转基因苜蓿形态表现不同:SC株高显著最高,根长较短;SN株高、根长居中,叶面积显著最大;SOR和SAF株高显著最低,根长显著最长,且SAF叶面积显著最小,说明不同抗逆基因的表达对苜蓿表现型影响不同。(2)阶段干旱胁迫后,4种转基因苜蓿总生物量变化不明显,以SAF和SN较高;除SAF外,根冠比均显著增加;水分利用效率显著提高85.84%-142.70%;非转基因苜蓿总生物量显著降低47.44%,水分利用效率未发生明显变化,说明转基因苜蓿通过改变根冠分配、提高水分利用效率以适应水分亏缺。(3)在逐渐干旱过程中,各株系苜蓿叶片相对含水量、叶绿素总量、净光合速率、Fv/Fm值均不同程度下降;丙二醛含量和非光化学淬灭值上升。土壤含水量为40±5%FC时,4种转基因苜蓿叶片相对含水量、叶绿素总量、净光合速率、Fv/Fm值均显著高于非转基因苜蓿,而丙二醛含量和非光化学淬灭值(SN除外)显著低于非转基因苜蓿,表明多抗基因在苜蓿中的表达提高了其在干旱胁迫下的叶片保水能力、改善其光合性能并降低热耗散、降低膜脂过氧化的程度,提高了其膜结构的稳定性。(4)综合分析干旱胁迫下各株系形态与生理生态特征及差异,本研究认为,SC可维持较高光合活性和光能转化速率,SN具有较强抗氧化能力,SOR能够维持光合性能的稳定性,SAF具有较高的生物量。
[Abstract]:Xinjiang large leaf alfalfa and its four kinds of transgenic alfalfa [transgenic alfalfa with codA gene, AtNDPK2 gene, IbOr gene sod] and AtABF3 gene alfalfa were used as materials, and the pot control experiment was carried out. In the process of soil water continuous decline (soil water content decreased gradually from 80 to 40), the morphological characteristics and physiological and ecological responses to drought stress of each strain at the beginning of flowering and their differences were studied. The main results were as follows: (1) under the condition of sufficient water supply, the plant height of four transgenic alfalfa varieties was significantly highest, the root length was shorter than that of SN plant, the root length was in the middle, the significant maximum leaf area was the highest, the plant height was the lowest, the root length was the longest, and the leaf area was the largest, and the root length was the longest. The leaf area of SAF was the smallest, which indicated that the total biomass of four transgenic alfalfa varieties changed little after drought stress, especially SAF and SN, except for SAF, the ratio of root to shoot increased significantly, except for SAF, the effect of different stress resistance genes on phenotype of alfalfa was different. Water use efficiency (Wue) increased 85.84-142.70, total biomass of non-transgenic alfalfa decreased significantly (47.44), water use efficiency (Wue) did not change significantly, which indicated that transgenic alfalfa changed root and crown distribution. In the process of drought, the relative water content, total chlorophyll content and net photosynthetic rate (FV / FM) of alfalfa leaves decreased, and the content of malondialdehyde (MDA) and non-photochemical quenching value increased. The relative water content, total chlorophyll content, net photosynthetic rate and FV / FM value of four transgenic alfalfa varieties were significantly higher than that of non-transgenic alfalfa. The content of malondialdehyde (MDA) and non-photochemical quenching value (SN) were significantly lower than that of non-transgenic alfalfa, indicating that the expression of polyresistance gene in alfalfa increased the water retention ability of leaves under drought stress, improved its photosynthetic performance and reduced heat dissipation. The degree of membrane lipid peroxidation was reduced, and the stability of membrane structure was improved. (4) the morphological, physiological and ecological characteristics and differences of different strains under drought stress were analyzed. The results showed that SC could maintain high photoactivity and light energy conversion rate (SN) with strong antioxidant capacity and stability of photosynthesis.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S541.9

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