北京地区油松胚珠发育时期的确定

采用显微观察法对北京地区不同发育时期的油松胚珠进行解剖结构观察,以确定北京地区油松胚珠的发育时期。结果表明,北京地区油松胚珠的发育历时13个月(从2003年4月~2004年5月),具体时期为:2003年4月12日为胚珠分化期,4月21日左右为大孢子母细胞时期,5月至8月为游离核时期,2003年8月至2004年2月为胚珠休眠期,2004年4月15日左右进入雌配子体细胞化时期,4月21日左右为颈卵器原始细胞活动期,5月8日左右为中央细胞分裂期,5月14日左右为成熟颈卵器时期。本研究结果中油松胚珠经历的发育阶段与前人的研究基本一致,但在时间上存在差异,而且北京地区比辽宁兴城地区油松胚珠发育时期平均提前了大约20~30 d。

Determination of Ovule Development of Pinus tabulaeformis in Beijing,China

The anatomical structure of the ovules at different developmental stages of Pinus tabulaeforrnis in Beijing was observed by microscopy to determina the ovule development of P. tabulaeformis in Beijing. It is shown that the ovule development lasted for thirteen months from April 2003 to May 2004 in P. tabulaeformis in Beijing,ovule differentiation stage occurring on April 12,2003, megasporocyte stage occurring on April 22,2003 or so, free nucleus stage occurring from May to August, 2003, ovule dormancy stage spanning from August 2003 to February 2004 and cell-wall formation stage of male and female gametophytes occurring on April 15,2004, archegonium primitive cell stage occurring on April 22 or so, central cell division stage occurring on May 8,2004 or so and mature archegonium stage occurring on May 14,2004 or so. The stages of ovule development in P. tabulaeformis revealed by this study agrees with those in previous studies but differ from them in temporal demarcation,and they occurs 20-30 days earlier than those in P. tabulaeformis in Xingcheng of Liaoning.