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采用盆栽试验的方法 ,研究了不同土壤干旱条件下渭北主要造林树种苗木根系活力的变化。结果表明 :在一定的土壤干旱范围内 ,苗木可以通过提高根系活力来适应逆境。当土壤干旱超过一定的阈值后 ,树木根系将逐步丧失其活力和功能 ,最终导致地上部分的枯死。各树种中 ,山杏根系的抗旱性最强 ,其次是侧柏、刺槐和油松。苗木根系活力除了受土壤干旱胁迫程度的影响之外 ,还受到干旱持续时间的影响。当土壤含水量降至 40 %的田间持水量时 ,土壤干旱已经对油松的生长构成了威胁 ,但对山杏、侧柏及刺槐的影响不大。
A pot experiment was conducted to study the changes of root activity of seedlings of main afforestation trees in different soil conditions in Weibei. The results showed that seedlings could adapt to stress by increasing root activity within a certain range of soil drought. When the soil drought exceeds a certain threshold, the tree roots will gradually lose their vitality and function, eventually leading to the death of the aboveground parts. Among all tree species, the root system of the apricot has the strongest drought resistance, followed by Platycladus orientalis, Robinia pseudoacacia and Pinus tabulaeformis. In addition to the root activity of seedlings under the influence of soil drought stress, but also by the duration of the drought. Soil drought has posed a threat to the growth of Pinus tabulaeformis when the soil water content is reduced to 40% of the field capacity, but it has little effect on Armeniaca sibirica, Oriental arborvitae and Robinia pseudoacacia.