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在人工气候室和温室条件下,控制不同土壤水势梯度,从苗木水分生理生态特点研究了1～3年生的油松、侧柏、栓皮栎、元宝枫、刺槐、白蜡、紫穗槐、沙棘和黄栌的耐旱特性.测定指标主要包括,叶水势及水分饱和亏缺、叶失水速率、叶肉质化程度及比叶面积、水分释放曲线以及束缚水含量等.结果表明,苗木叶水势与土壤水势呈紧密的指数关系(Y=A·eBX),与土壤含水量呈双曲线关系(Y=A+B/x),而与水分饱和亏缺(即水分释放曲线)则呈明显的线性关系(Y=A+BX).在维持水分平衡方面,无论从叶水势变化趋势和水分释放曲线的斜率,还是从叶失水速率、叶肉质化程度、比叶面积以及束缚水含量等指标看,都表明针叶树的吸持水能力强于阔叶树,其中油松在持水能力方面占优势,而侧柏在吸水能力方面占优势,其它阔叶树种也各有特点.
Under the conditions of artificial climate chamber and greenhouse, the gradient of different soil water potentials was controlled. According to the water eco-physiological characteristics of seedlings, Pinus tabulaeformis, Platycladus orientalis, Quercus variabilis, Acer negundo, Robinia pseudoacacia, Ash, Amorpha fruticosa, The results showed that the leaf water potential of seedlings and the soil water content of soil were higher than those of soil water, (Y = A · eBX) and a hyperbolic relationship with soil water content (Y = A + B / x), but a clear linear relationship with water saturation deficit (ie, water release curve) (Y = A + BX) .In the aspect of maintaining water balance, no matter from the trend of leaf water potential and the slope of water release curve or from the index of leaf water loss rate, leaf quality, specific leaf area and irreducible water content, All showed that coniferous trees had stronger water holding capacity than broadleaf trees, of which Pinus tabulaeformis was dominant in water holding capacity, while Arborvitae had the most superior water absorption capacity and other broadleaf species had their own characteristics.