欧洲垂枝桦对PEG诱导干旱胁迫的响应机制
Response mechanism of European birch to PEG-induced drought stress
[目的]干旱是限制植物生长发育的重要非生物因素之一,欧洲垂枝桦(Betula pendula Roth)原产欧洲,1981年引种到辽东山区,为探讨欧洲垂枝桦在干旱胁迫下的生理响应机制,明确欧洲垂枝桦幼苗在干旱胁迫下各生长生理参数与光合特性的变化,以综合评价欧洲垂枝桦幼苗对干旱胁迫的响应。[方法]本研究采用不同浓度的PEG-6000处理模拟干旱胁迫,对胁迫后与复水后欧洲垂枝桦幼苗进行生长生理指标的测定和叶片解剖结构、气孔结构以及细胞器超微结构观察,探寻欧洲垂枝桦对PEG浓度的最大阀值和抗旱能力。[结果]PEG浓度和胁迫时间的增加,对欧洲垂枝桦幼苗的生长特性具有极显著影响(p<0.01);抗氧化酶活性、膜脂过氧化与渗透调节物质浓度随胁迫浓度增加和胁迫时间的延长而增加且具极显著差异(p<0.01);光合参数与光合色素随胁迫浓度增加和胁迫时间的延长而极显著降低(p<0.01);不同PEG浓度处理下幼苗叶片解剖结构变化较为明显,并且幼苗叶片平均气孔长度变化具有显著影响(p<0.05),对气孔平均结构变化具有极显著影响(p<0.01)。[结论]欧洲垂枝桦从生长生理响应到解剖结构,气孔结构以及细胞器超微结构的变化中不难体现其对干旱环境做出的积极响应,具有极高的可塑性,也预示着欧洲垂枝桦在干旱环境下具有良好的训化能力,未来对于欧洲垂枝桦的抗性研究与造林技术推广,都可以使其更好的适应极大部分地区,为当地带来更大的经济价值和发展可持续林业奠定基础。
[Objective]Drought is one of the important abiotic factors limiting plant growth and development,Betula pendula Roth is native to Europe and introduced to the mountains of eastern Liaoning in 1981,in order to explore the physiological response mechanism of European weeping birch under drought stress,to clarify the changes of growth physiological parameters and photosynthetic characteristics of European weeping birch seedlings under drought stress,so as to comprehensively evaluate the response of European weeping birch seedlings to drought stress.[Methods]In this study,different concentrations of PEG-6000 were used to simulate drought stress,and the growth physiological indexes and leaf anatomy,stomatal structure and organelle ultrastructure of European weeping birch seedlings after stress and rehydration were determined,and the maximum threshold value and drought resistance of European weeping birch on PEG concentration were explored.[Results]The increase of PEG concentration and stress time had a significant effect on the growth characteristics of European weeping birch seedlings(p<0.01).The activity of antioxidant enzymes,membrane lipid peroxidation and osmomodulator concentrations increased with the increase of stress concentration and the prolongation of stress time,and there were significant differences(P<0.01).The photosynthetic parameters and photosynthetic pigments decreased significantly with the increase of stress concentration and the extension of stress time(P<0.01).The changes in leaf anatomy were obvious under different PEG concentration treatments,and the change of average stomatal length of seedling leaves had a significant effect(p<0.05)and a significant effect on the average stomatal structure change(p<0.01).[Conclusion]It is not difficult to reflect its positive response to arid environment from the physiological response of growth to the changes of anatomical structure,stomatal structure and organelle ultrastructure,with extremely high plasticity,and also indicates that European birch has good training ability in arid environment,and the future research on resistance and afforestation technology promotion of European weeping birch can make it better adapt to most areas,and lay the foundation for the local area to bring greater economic value and develop sustainable forestry.
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