天山北坡前山带12种植物对干旱胁迫和复水的响应及抗旱性评价

【目的】探讨12种植物对干旱胁迫的动态生理适应性及抗旱能力，筛选适宜在天山北坡前山带进行植被恢复的灌木树种。【方法】以新疆天山北坡前山带种植的刺蔷薇、柠条锦鸡儿、文冠果、山杏、柽柳、梭梭、中亚沙棘、蒙古沙棘（‘新棘1号’、‘新棘2号’、‘新棘3号’、‘新棘4号’、‘新棘5号’）共12种植物为研究对象，观测灌水之后土壤水分的时空分布变化，分析干旱胁迫和复水处理对植物光合气体交换参数、抗逆生理生化指标、叶绿素荧光参数的影响，利用主成分分析法评价12种植物的抗旱能力。【结果】（1）在干旱胁迫发生前后，各植物立地土壤表层（0—20 cm）水分散失最快，中层（20—40 cm）次之，底层（40—60cm）水分散失最慢，而不同植物因其生长策略不同，通过改变其生长情况来适应干旱；（2）随着干旱胁迫的加剧，植物叶片光合生理指标净光合速率、气孔导度、蒸腾速率、胞间二氧化碳浓度、PSⅡ潜在活性、 PSⅡ最大光化学效率、电子传递速率和叶绿素含量降低，而抗逆生理指标超氧化物歧化酶活性、脯氨酸含量、丙二醛含量及非光化学猝灭系数升高，复水之后各指标都有一定程度的恢复，但均未达到初始水平；（3）主成分分析结果显示，净光合速率、叶绿素含量、电子传递效率和丙二醛含量等指标贡献率较大，梭梭、柽柳、刺蔷薇和柠条锦鸡儿抗旱性较强，中亚沙棘、‘新棘5号’、‘新棘1号’和山杏抗旱性次之，而‘新棘4号’、‘新棘3号’、文冠果和‘新棘2号’较弱。【结论】净光合速率、叶绿素含量、电子传递效率和丙二醛含量可作为评价各植物适应干旱胁迫的重要指标；新疆天山北坡前山带区域植被生态恢复过程中应优先考虑梭梭、柽柳、刺蔷薇及柠条锦鸡儿进行建植。

Responses and drought resistance evaluation of 12 species of plants to drought stress and rehydration in the Northern Piedmont, Tianshan Mountains

【Objective】Investigating the dynamic physiological adaptability and drought resistance of 12 plant species to arid stress, this study aims to select suitable shrub and tree species for vegetation restoration in the piedmont belt of the northern slope of the Tianshan Mountains.In this study, by discussing the dynamic physiological adaptability and drought resistance of 12 shrubs and screened out the shrubs suitable for vegetation restoration in the Northern Piedmont of Tianshan Mountains. 【Methods】In this study, 12 plant species planted in the piedmont belt of the northern slope of the Tianshan Mountains in Xinjiang, including Rosa acicularis, Caragana korshinskii, Xanthoceras sorbifolium, Prunus sibirica, Tamarix chinensis, Haloxylon ammodendron, Hippophae rhamnoides, Hippophae rhamnoides (‘Xinji 1#’ to ‘Xinji 5#’), were selected as the subjects. The study observed the spatiotemporal distribution of soil moisture following irrigation and analyzed the impact of drought stress and rewatering treatment on plant photosynthetic gas exchange parameters, anti-stress physiological and biochemical indicators, and chlorophyll fluorescence parameters. The drought resistance of these twelve plant species was evaluated using principal component analysis.【Results】(I) Both before and after the onset of drought stress, the surface layer (0-20 cm) of the soil at each plant''s location exhibited the most rapid moisture loss. This trend diminished with depth, with the middle layer (20-40 cm) experiencing a lesser rate of loss and the bottom layer (40-60 cm) showing the slowest rate of water depletion. To cope with the drought conditions, different plant species adapted by altering their growth strategies, as evidenced by changes in their growth patterns. (II) As drought stress intensified, key photosynthetic physiological parameters in plant leaves, such as the net photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO2 concentration, potential activity of PSII, maximum photochemical efficiency of PSII, electron transport rate, and chlorophyll content, all declined. In contrast, physiological indicators of stress resistance, including the activity of superoxide dismutase, proline content, malondialdehyde content, and non-photochemical quenching coefficient, increased. Following rewatering, a recovery was observed in these parameters, yet they did not fully return to their initial levels. (III) The results of principal component analysis highlighted that factors like net photosynthetic rate, chlorophyll content, electron transport efficiency, and malondialdehyde content were major contributors. Species such as Haloxylon ammodendron, Tamarix chinensis, Rosa acicularis, and Caragana korshinskii demonstrated significant drought resilience. Hippophae rhamnoides, H. rhamnoides ‘Xinji 5’, H. rhamnoides ‘Xinji 1’ and Prunus sibirica showed moderate levels of drought resistance, while H. rhamnoides ‘Xinji 4’, H. rhamnoides ‘Xinji 3’, Xanthoceras sorbifolium and H. rhamnoides ‘Xinji 2’ exhibited relatively lower drought tolerance.【Conclusion】Net photosynthetic rate, chlorophyll content, electron transfer efficiency, and malondialdehyde content are crucial indicators for evaluating the adaptability of various plant species to drought stress. In the context of ecological restoration efforts in the piedmont belt of the Tianshan Mountains'' northern slope in Xinjiang, prioritizing the cultivation of Haloxylon ammodendron, Tamarix chinensis, Rosa acicularis, and Caragana korshinskii is recommended.