木麻黄二代更新“困难”的原因调查研究

An Investigation on the Reason of "Difficulties" in the Regeneration of Casuarina

不同的木麻黄种,对青枯病(Pseudomonas solanacearum)的抗性有所不同。木麻黄(Casuarina equisetifolia)是感病种;细枝木麻黄(C.cunninghamiana)和粗枝木麻黄(C.glauca)的抗病性较强。我省“崇武”以北地区木麻黄林木枯死率高,气候不是主要限制因子,与树种的抗病性和所占面积比例有关。沿海沙地有粘土间层的林地,其保水、保肥力较好,二代更新的林木生长良好。不同种的木麻黄其结瘤特性有明显的差异。于8年生的幼林中,木麻黄的根瘤固氮酶活性低于其他二个种。不论是木麻黄或细枝木麻黄,施肥区林木的生长均超过对照不施肥区。

The resistance of Casuarina to Pseudomonas solanacearum varies with the species of Casuarina. C. equisetifolia is a susceptible species while the disease resistance of C. cunninghamiana and C. glauca is stronger. Thehigh dry mortality of forest trees of Casuarina in the region to the north ofChongwu, Fujian Province is related to the resistance of species and their areaproportion and the climate is not the main limiting fastor. The forest trees of regeneration of Casuarina grow well in the coastalsand land with clay layer having a relatively good capacity to preserve mois-ture and fertility. The characteristics of nodule formation are evidently dif-ferent among the diifferent species of Casuarina..The nitrogenase activity inthe nodules of C.equisetifolia in the young stand at the age of eighi years islower than that of the other two species. Whether the forest trees of C.equi-setifolia or C.cunninghamiana in the fertilized plots grow better than those inthe unfertilized plots.