玉米苗期干旱复水过程中叶片膜脂响应与干旱适应能力的关系

ISWC OpenIR > 水保所2018--2022届毕业生论文(学位论文、期刊论文)

	玉米苗期干旱复水过程中叶片膜脂响应与干旱适应能力的关系
	刘婷婷
学位类型	硕士
导师	王仕稳
	2018-05-24
学位授予单位	中国科学院研究生院
学位授予地点	北京
关键词	玉米膜脂干旱复水干旱适应性
摘要	随着全球气候变化的影响，旱灾发生频率逐渐增加，其对作物生产的影响越来越大,与此同时，不断增加的人口对粮食的需求也持续增加。因此提高作物抗旱能力，减轻未来干旱胁迫对作物生产的影响，对保障未来粮食安全具有重要的意义。植物生产主要来源于光合作用，而光合作用在叶绿体中类囊体膜上发生。前人的研究表明包含干旱在内的多种逆境胁迫可以影响含类囊体膜在内的生物膜系统膜脂脂肪酸的饱和度、脂肪酸种类及分布比例。然而，干旱过程中膜脂响应及其与抗旱能力的关系并不清楚，同时，膜脂响应与作物复水后恢复能力的关系的研究也尚属空白。因此，本试验随机选取18个玉米品种进行盆栽模拟干旱复水过程，通过研究干旱、复水过程中膜脂脂肪酸的含量、叶绿素含量、MDA含量等的变化及其与植物抗旱能力的关系，以此探究膜脂脂肪酸如何响应干旱再复水过程，以及在干旱适应过程中的作用。结果如下：（1）不同玉米品种的抗旱能力、复水恢复能力、干旱适应能力及其之间的关系干旱胁迫条件下，不同玉米品种的生物量都有所下降，但下降程度不同，复水后恢复的程度也不同。较高的干旱适应能力可能是由于抗旱能力较强导致的，例如利民33母本和先玉335品种，也可能是由于较强的复水恢复能力造成的，例如良玉99父本，同时也可能是因为抗旱能力和复水后恢复能力两者都比较强，例如P3、B3-1和良玉66父本。抗旱能力、复水恢复能力与干旱适应能力的相关分析结果表明，抗旱能力和复水恢复能力均与干旱适应能力呈显著正相关，复水恢复能力与干旱适应能力的相关系数大于抗旱能力与干旱适应能力的相关系数。（2）干旱及复水对不同玉米品种主要生理指标的影响及其和植物抗旱能力、复水恢复能力以及干旱适应能力的关系干旱胁迫导致玉米的相对含水量、叶绿素含量、Fv/Fm和总脂含量降低，过氧化产物MDA、H₂O₂积累增多。复水后，这些指标均开始恢复，但恢复程度因品种不同而有所不同。干旱胁迫时期，叶片相对含水量、叶绿素含量、Fv/Fm和总脂含量的变化与抗旱能力均呈显著正相关，MDA、H₂O₂含量的变化与抗旱能力呈显著负相关，总脂含量在胁迫时期的变化与复水后的恢复能力显著正相关，叶片相对含水量、叶绿素含量、Fv/Fm、总脂含量、MDA和H₂O₂的变化与干旱适应能力具有显著性相关关系。复水恢复时期叶片相对含水量和C16:3含量的恢复与玉米复水恢复能力具有显著性正相关关系。（3）干旱复水过程中膜脂响应与干旱适应能力的关系干旱胁迫条件下，玉米饱和脂肪酸（C16:0和C18:0）含量增加，增加程度具有品种差异性。C16:1、C16:2和C18:3含量呈下降趋势，C18:1、C18:2含量整体呈增加趋势，而C16:3的变化趋势与品种有关。干旱胁迫条件下玉米总脂含量下降，膜脂不饱和度降低，主要是由于C18:3、C16:2、C16:1含量下降所致。由膜脂脂肪酸组分在干旱复水过程中的变化得出，C18:3与玉米抗旱能力密切相关。干旱胁迫期间玉米的抗旱性越强，C18:3含量下降的程度越低。由主成分分析结果得出，在复水修复过程中，相对于其他生理指标，C18:1、C18:2、C18:3对于玉米的旱后恢复起着较为突出的作用。在所检测出的脂肪酸组分中，C18:3含量的变化对玉米的抗旱能力、复水恢复能力贡献性比较大。综上所述，提高玉米在干旱胁迫期间的抗旱能力，或者提高玉米在干旱复水后的恢复能力均能增强玉米对干旱-复水环境的适应能力。膜脂组分及含量与植物的抗旱能力、复水恢复能力以及干旱适应能力均密切相关，膜脂含量及组分的调节不仅是干旱胁迫期间适应环境胁迫的一个有效调节方式，而且在复水后恢复期间也是作物自身的一种积极性调节机制，在植物干旱适应过程和复水后修复过程中起着不可替代的重要作用。因此，调控脂肪酸的合成能力有望成为增强作物抗旱能力的一条有效途径。
其他摘要	With the global climate changing, the occurrence frequency of drought has increased, also the impact on crop production of drought is growing more and more severe. On the other hand, the increasing population demands more food production. Therefore, it is of great important to improve drought resistance ability of crops to enhance crop production, and reduce the effect of drought stress on crop production to ensure food security. Plant production arises mainly from photosynthesis, while photosynthesis occurs in the thylakoid membranes in chloroplasts. Previous studies have shown that multiple environment stresses, including drought, can affect the saturation degree and the varieties of membrane lipid fatty acids, and their distribution on bio-membranes, especially on thylakoid membranes. However, it still remains unclear that what the relationship is between membrane lipid alteration and drought resistance, drought recovery during drought period and subsequent re-watering of crops. Therefore, we randomly selected 18 maize cultivars to simulate the process of drought and re-watering, and measured the changes of membrane lipid fatty acid content, relative permeability of membranes, chlorophyll content, chlorophyll fluorescence, MDA content and H₂O₂ content. Through analyzing these physiological traits, we explored their relationship with drought adaptation ability in the process of drought and re-watering, how membrane lipid fatty acids response to drought and re-watering, also to explore its role in drought adaptation. The results are as follows: （1）The drought resistance, drought recovery and drought adaptability of different maize varieties. The biomass of maize decreased under drought stress condition and started to recover after re-watering, however, the degree of decrease and recovery was different among different maize cultivars. Higher drought adaptability of maize may be caused by strong drought resistance, such as Limin33 of the female parent and Xianyu 335 varieties, or may also be due to strong recovery capacity caused by re-watering, such as Liangyu 99 male parent, or may be caused by both strong drought resistance and re-waterring, such as P3, B3-1 and Liangyu 66 male parent. Correlation analysis of drought resistance, drought recovery and drought adaptability showed that both drought resistance and drought recovery were positively correlated with drought adaptability, and the correlation coefficient between drought recovery and drought adaptability was greater than that between drought resistance and drought adaptation ability. （2） Effects of drought and re-watering on main physiological traits of different maize cultivars and the relationship between these physiological traits changes and drought resistance, drought recovery and drought adaptation. Drought stress resulted in the decrease of relative water content, chlorophyll content, Fv/Fm and total lipid content of maize, and the increase of H₂O₂ content and MDA accumulation. After the re-watering, these indexes all began to recover, but the degree of recovery varied with the different cultivars. During the drought stress period, the relative water content of leaves, the chlorophyll content, Fv/Fm and total lipid content were positively correlated with drought resistance, MDA and H₂O₂ contents were negatively correlated with drought resistance, while the change of total lipid content in stress period was positively correlated with drought recovery after re-watering, and the relative water content of leaves, the chlorophyll content, Fv/Fm, total lipid content, MDA and H₂O₂ content all had significant correlations with drought adaptability. The recovery degree of the relative water content and C16:3 content of the leaves of maize has significant positive correlation with the recovery ability after re-watering of the maize. （3）Relationship between membrane lipid responses and drought adaptability in the process of drought and re-watering. Under the condition of drought stress, the content of saturated fatty acids (C16:0 and C18:0) in maize leaves increased, and the degree of increase was different for different cultivars. The content of C16:1, C16:2 and C18:3 showed a downward trend, the C18:1 and C18:2 contents increased, while the trend of C16:3 was related to the variety. Under drought stress, the total lipid content of maize decreased, and the membrane lipid saturation decreased, mainly due to the decrease of C18:3, C16:2 and C16:1 content. It can be concluded that C18:3 was closely related to drought resistance of maize through the alteration of membrane lipid fatty acid composition in the process of drought and re-watering. Drought resistance of maize was more stronger, the decrease degree of C18:3 content was more lower during drought stress. The results of principal component analysis showed that C18:1, C18:2 and C18:3 had a prominent effect on the recovery of maize after drought, compared with other physiological indexes in the process of re-watering. The change of C18:3 content in the fatty acid composition has a more significant effect on the drought resistance and drought recovery during drought and subsequent re-watering condition. To sum up, improving the drought resistance of maize during drought stress, or improving the drought recovery ability of maize after re-watering can both enhance the drought adaptability of maize to drought-rehydration environment. The composition and content of membrane lipids are closely related to the drought resistance, recovery ability and adaptability of drought, and the regulation of membrane lipid content and components is not only an effective regulation way to adapt to environmental stress during drought stress, but also a kind of active regulation mechanism of crop itself during recovery period after re-water. It plays an irreplaceable role in the process of plant drought adaptation and repair after re-waterring. Therefore, the ability to control the synthesis of fatty acids is expected to be an effective way to enhance crop drought resistance.
语种	中文
文献类型	学位论文
条目标识符	sbir.nwafu.edu.cn/handle/361005/8165
专题	水保所2018--2022届毕业生论文(学位论文、期刊论文)
作者单位	中科学院大学水土保持与生态环境研究中心
推荐引用方式 GB/T 7714	刘婷婷. 玉米苗期干旱复水过程中叶片膜脂响应与干旱适应能力的关系[D]. 北京. 中国科学院研究生院,2018.

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