退化草原羊草种群根系形态特征对水分梯度的响应

Response of Root System of Leymus chinensis Population to Water Gradient in Degraded Grassland

分别于内蒙古锡林郭勒典型草原选取轻度退化和重度退化的草地,进行了水分梯度控制试验,研究羊草(Leymus chinensis)种群在不同退化状况下根系特征对水分资源梯度的响应。结果表明:随着水分梯度的下降,不同退化程度的草地均表现为羊草地上高度逐渐下降,而主根系长度和根系体积逐渐增加;根系面积也呈增加趋势,但只在重度退化样地与水分梯度显著负相关;根系直径呈减少趋势,但只在轻度退化样地与水分梯度显著相关。不同退化程度的草地比较,在大部分水分梯度下羊草根系特征没有显著差异,除了湿润条件下(600mm),根系面积和根系体积轻度退化草地显著高于重度退化草地(P<0.05)。干旱条件下(150mm),羊草主根系长度在重度退化草地显著高于轻度退化草地(P<0.05)。

degraded grassland communities were selected in Xilinguole typical steppe region of Inner Mongolia. A water gradient experiment was designed to research the response of root system characteristics of Leyrnus chinensis population to water gradient in degraded grassland in different degree. The results showed that with the decrease of water gradient, the height of Leymus chinensis gradually decreased while main root length and root volume increased gradually in both types of grasslands, the root surface area had an increasing trend, but only significant correlated to water gradient in heavily degraded grassland, root diameter had a decreasing trend, but only significant correlated to water gradient in lightly degraded grass land. Comparing degraded grasslands in different degree, most of root characters of Leymus chinensis had no significant difference under most water gradient, except that, under moist condition （600 mm）, the root surface area and root volume in lightly degraded grassland were much higher than those in heavily degraded grassland. Under drought condition （150mm）, the main root length in heavily degraded grassland was much higher than those in lightly degraded grassland.