美国紫树属树种引种研究

从美国引进4种紫树属树种在长江中下游平原地区试种,重点对水紫树、沼地紫树与国产蓝果树的形态特征、生长特性、适应性和耐涝性等进行比较研究.3～4 a引种结果表明:水紫树和沼地紫树生长良好,未出现冻害、病虫害和其它不适应表征.水紫树幼年高生长和耐涝性超过沼地紫树和蓝果树.水紫树和沼地紫树对水分需求高,适宜在平原水网地区防护林建设中推广应用.种子播种前须经层积沙藏,选择低湿地育苗造林,在培育管理过程中保持土壤的湿润环境,切忌干旱,是保障成活率和促进快速生长的关键.

Prelim inary Study on Nyssa Spec ies Introduction in Ea stern Pla in of China

Four tree species of the genus Nyssa from southern America were introduced. Of them,N, aquatica and sylvatica var. biflora had been planted in plain sites of Zhejiang, Jiangsu ,Jiangxi, and Shanghai for 3 -4 years. Their morphological characters, growth, adaptability, and waterlogging tolerance were emphatically investigated in comparison with N. sinensis, which ranges in mountain area of southern China. The saplings of the two exotic tree species had good growth in most places and had not freeze damage, diseases and insect pests. N. aquatica had better height growth than N. sylvatica var. biflora and N. sinensis. The two foreign species showed high water demand and waterlogging tolerance, so could be popularized in low, wet plain. The key for their successful culture is to maintain enough water supply, such as to make seeds stratification by sowing, to choose low and wet site for seedling-raising and planting, and to keep from soil aridity.