<正>采用石蜡切片法观察了‘晚籽银桂’、‘多芽金桂’花芽形态分化过程。结果表明：‘晚籽银桂’花芽分化从6月下旬苞片原基分化至9月初雌蕊原基形成历时近3个月，其过程可分为苞片分化期、花序原基分化期、小花原基分化期、顶花花萼分化期、花瓣分化期、雄蕊分化期和雌蕊分化期7个时期。其中雄蕊分化期历时长，分化较慢，其他6个时期历时较短。聚伞花序的中间顶花先分化，侧花后分化，各小花几乎同时完成花芽分化进程。‘多芽金桂’的花芽分化除雌蕊发育与‘晚籽银桂’不同外，其余基本一致。

The resistance of 27 wilt-resistant Pinus densiflora families induced from Japan to 3 isolates of Bursaphelenchus xylophilus was determinated. The result indicated that all 27 Pinus densiflora families had resistance to the 3 isolates, and there were significant differences from each other. It was found by bark inoculation that 13 families (No. 1, 4, 5, 6, 7, 8, 13, 14, 15, 17, 20, 23 and 25) were more resistant than others. The histopathological observation of No. 5 family sampled at 4, 8, 12, 24, 36, 48, 72, 96, 120h after inoculation showed that B. xylophilus migrated much slower in the induced pine seedlings than in the control. Pathological changes in parenchyma radial cell and the parenchymatous cells around resinosis cells occured later in wilt-resistant pine seedlings than in the control. In addition, the pathological changes occured more gently in the induced pine seedlings than in the control.