Physiological responses of a young Gansu elm (Ulmus glaucescens) to soil water loss and rehydration

Subjects: Biology >> Botany submitted time 2022-12-20 Cooperative journals: 《干旱区研究》

赵子涵 王树森 罗于洋 刘瑞香 韩 峰 马迎梅

Abstract：

The physiological responses of young trees to soil water after afforestation in arid areas are important factors in water management and their survival. To provide a theoretical basis for water management in the cultivation of Gansu elm trees (Ulmus glaucescens), we analyzed the responses of morphology, physiology, and photosynthetic characteristics of young Gansu elm trees to different degrees of soil water loss and rehydration by using the potted method under mimicking natural water loss and rehydration conditions. The results showed that relative water content, chlorophyll content, and water use efficiency of Gansu elm leaves increased slightly by 14.8% , 1.2% , and 43.2% , respectively when the soil water loss was less (15% ). The net photosynthetic rate, stomatal conductance, and transpiration rate of leaves decreased significantly by 26.5% , 27.1% , and 48.7% , respectively. When soil water content was at its lowest point (0%), the relative water content, chlorophyll content, and water use efficiency of Gansu elm leaves decreased significantly that the relative water content decreased by 78.4%, 65.4%, and 47.3%, respectively. There was a gradual decrease in the net photosynthetic rate, stomatal conductance, and transpiration, by the values of 89.9% , 83.3% , and 79.9% which were lower than the corresponding rates before soil water loss. One of the main reasons for the decline in the photosynthetic rate was the change in stomatal conductance. Rehydration can alleviate the adverse effects caused by soil water loss in Gansu elm. Therefore, in the environment of continuous soil water loss, Gansu elm adapts to the decline of soil water content through a series of changes in morphology, physiology, and photosynthetic characteristics by showing strong drought tolerance. In the case of severe soil water loss after planting, rehydration can alleviate the damage to Gansu elm trees.

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希拉穆仁草原近自然恢复状态下植被-土壤响应特征

Subjects: Biology >> Ecology submitted time 2017-03-08 Cooperative journals: 《生态学报》

王琴,蒙仲举,汪季,党晓宏,张晓娜,王则宇,赵青,张吉祥

Abstract：通过对内蒙古阴山北麓围封区域草原近自然状态下植被群落特征及其土壤颗粒物理特性的研究，探讨草地群落与土壤颗粒物理特性在自然风蚀条件下的特征。结果表明：（1）草地全覆盖时以羊草、赖草为优势种，当草地盖度下降为40%以下时以指示草地退化的冷蒿为优势种；且随着植被盖度的降低，草地植物群落生物量呈降低趋势，Shannon-Wiener指数、Simpson指数均呈现出先升高后降低的趋势；（2）草地植被覆盖度对地表土壤颗粒分形维数有显著影响（P< 0.05），随着盖度的降低，其地表土壤颗粒分形维数呈显著降低趋势，地表土壤颗粒粗化明显；（3）在近自然状态下，草地植被覆盖较低时，地表0-1 cm土壤颗粒粗粒化现象尤为显著，粒度累计差异达到1 mm，垂直结构上表现为由3-5 cm、1-3 cm土层至0-1 cm土层，土壤颗粒粗粒化程度加重，粗颗粒粒度累积差异分别出现在0.1、0.25、1 mm；（4）在近自然状态下，随着草地植被盖度增加，表层土壤受植物遮蔽，得到有效保护，土壤颗粒逐渐细化，容重也缓慢下降。在近自然状态下，草地及土壤环境发生有层次且多样性的变化，草地植被的斑块状变化使得希拉穆仁围封区草原在近原始状态下出现自然风蚀现象成为可能。

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