施用氮肥对落叶松人工林一级根外生菌根侵染及形态的影响

以落叶松人工林为研究对象,通过施N肥试验,对不同季节、不同土壤深度根系进行取样,研究了1级根外生菌根真菌侵染率和形态,及其与不同季节、土壤深度和土壤N有效性的关系.结果表明:外生菌根真菌对落叶松人工林1级根的侵染率显著受不同季节和土壤深度土壤N有效性的影响.在不同季节和土层之间,施N肥导致菌根真菌侵染率下降.与未侵染菌根真菌相比,菌根真菌侵染导致1级根形态发生明显改变,平均直径增加18.7%,平均根长缩短23.7%,比根长降低16.3%.这种根系形态变化在不同季节、不同土壤深度处理中表现明显.菌根真菌侵染改变了1级根形态,影响根系的生理生态过程.

Effects of nitrogen fertilization on ectomycorrhizal infection of first order roots and root morphology of Larix gmelinii plantation

In this paper, the first order roots of Larix gmelinii plantation under N fertilization were sampled from different soil depths in different seasons to study their morphology under effects of ectomycorrhizal fungi. The results showed that the infection rate of ectomycorrhizal fungi on the first order roots was significantly affected by soil N availability, soil depth, and season. N fertilization induced a decrease of the infection rate, and the decrement varied with soil depth and season. In comparing with the control, the infected first order roots had an obvious variation of their morphology, e.g., averagely, root diameter increased by 18.7%, root length decreased by 23.7%, and specific root length decreased by 16.3%, which differed significantly with N application rate, soil depth, and season. The infection of ectomycorrhizal fungi changed the first order root morphology of L. gmelinii, which might substantially affect the physiological and ecological processes of host plant fine roots.