不同温度条件下土壤水分对羊草幼苗生长特性的影响

Effects of soil moisture on growth characteristics of Leymus chinensis seedlings under different temperature conditions

采用生长箱控制方法 ,研究了羊草幼苗生长对 5个温度和 5个水分梯度的响应。结果表明 ,不同温度改变了羊草生物量对土壤水分变化的响应类型。在 2 0～ 2 6℃下羊草植株生物量对土壤水分的响应曲线呈三次多项式或抛物线变化规律 ,而在 2 9～ 32℃下为指数方程。在温度较低或适度时 ,轻度乃至中度干旱有促进生长的作用 ,但在温度较高时轻度干旱及比其程度更高的干旱显著地影响羊草的生长 ,表明羊草在较高温度下对水分更加敏感。在适当的温度下 (2 6℃ ) ,羊草根的贡献率或根冠比与土壤水分呈直线关系。高温加强了干旱对羊草幼苗生长的抑制作用 ,表明高温降低了羊草对干旱的适应能力。

The experiment was conducted to stimulate the responses of growth characteristics of L.chinensis seedlings to 5 soil moisture and 5 temperature levels in the control growth chambers.The responses of biomass to soil moisture were altered with different temperatures.The curve equations of response of plant biomass to soil moisture were cubic or quadratic at 20～26 ℃,but were exponential at 29～32 ℃.Light and moderate soil droughts slightly promoted the growth at lower or moderate temperatures,while light and moderate drought significantly limited its growth at higher temperatures,indicating the higher sensitivity of Leymus chinensis seedling to soil water stress at higher temperature.Under moderate temperature (26 ℃) condition,there was a linear relationship between the contribution or ratio of root and shoot,and soil moisture.It was suggested that elevated temperature may strengthen the effects of soil drought on the seedling growth,resulting in a decline of adaptability to soil drought for L.chinensis.