Abstract:

Thin section technique was applied in the study of the initiation and development of the ovulate strobilus in Pinus tabulaeformis Carr. In the early August, as the primordium of ovulate strobilus occurred, cytohistological zonation of cone apex was similar to those of the vegetative shoot apex, but the cone apex appeared different from the vegetative shoot apex morphologically. In mid-October, the first bract primordium was formed in the axil scale at the cone base, then bract initiation had occurred in an acropetal direction. At this phase, cytohistological zonation of the cone apex has changed into two zones, the outer mantle of small cells was derived from the apical initial zone, central mother cell zone and peripheral zone, the inner pith of larger cells originated from the activity of the rib meristem. In the middle of March, ovuliferous scale primordia were acropetally formed in the axils of the developing bracts. In the middle of April, the bract attained approximately their full size, and a pair of anatropous ovules with single integument was initiated on the adaxial surface at the base of the fertile ovuliferous scale. Ovulate strobilus continued to grow during the fall and winter, while the vegetative shoot apex entered a dormancy. No basic structural difference was observed in the vegetative and reproductive apices, but apparent difference was present in the growth characteristics.

油松雌球果的发生和发育研究
吴鸿¹ 崔大方¹ 胡正海²

（1. 华南农业大学生物技术学院，广州510642；2. 西北大学生物系，西安710069）

摘要：运用薄切片技术对油松 (Pinustabulaeformis Carr.)雌球果的发生和发育进行了研究。结果表明 :8月初 ,雌球果原基发生 ,其外部形态发生明显变化 ,但内部细胞组织学分区结构与营养茎端结构相似 ;10月中旬 ,雌球果原基的鳞片叶腋处产生最初的苞片原基 ,以后苞片原基由基部向顶端连续发生。此时球果原基的顶端结构发生变化 ,顶端分生组织区、中央母细胞区和周围分生组织区衍化为套层 ,肋状分生组织衍化为髓区 ;翌年 3月中旬 ,在苞片原基的叶腋处 ,珠鳞原基发生 ,其发生方向同样呈向顶发育 ;4月中旬 ,苞片体积已达到最终大小 ,此时 ,在珠鳞基部的近轴面分化出 2个具单珠被的倒生胚珠。油松雌球果原基在秋冬季依然保持生长 ,其营养茎端则进入休眠状态。尽管营养茎端和生殖端两类原基在结构上并无本质的区别 ,但在生长特性方面具有显著的差异。

关键词： 油松；雌球果；发生和发育

Key words: Pinus tabulaeformis, ovulate strobilus, initiation and development