广西板栗胚珠形成与胚胎发育

The Ovule Formation and Embryonic Development of Castanea mollissima in Guangxi

以广西10年生地方板栗品种东兰油栗为研究对象,通过石蜡切片技术对板栗胚胎发育过程进行观察。结果表明:5月31日—6月7日,板栗雌花发育进入胚珠形成期,胚珠为倒生。到6月12日和6月21日时,大孢子母细胞经过减数分裂,发育成为具有4个成熟细胞核的胚囊和8个核的成熟胚囊。6月23日观察到板栗处于受精卵形成或分裂时期,同时伴有8~10胚乳核细胞围绕在受精卵周围,中央为大液泡。6月30日采集的样品中,胚体成球形均匀增长,其细胞分裂方式以平周、垂周分裂为主。7月8日为心形胚形成期到子叶发育期,已经能观察到形成完全的胚,有子叶细胞形成。胚乳细胞体积大,细胞壁薄,有明显的大液泡;7月15日可以观察到子叶细胞充满到整个子房内,胚乳细胞逐渐退化消失。

Using the 10-year-old Chinese chestnut as object, the development of embryo of chestnut was ob- served by Paraffin section. Results showed that the female flower of chestnut developed into the ovule formation stage from May 31 to June 7, and the ovule was inverted. On June 12 and June 21, after the meiosis of mega- sporocyte, it became an embryo sac with four mature nuclei and a mature embryo sac with eight nuclei. The fertilized eggs were observed in the stage of formation or division on June 23, and there were 8 - 10 endo- sperm nucleus cells around the fertilized eggs and a large vacuole was in the center. In the samples collected on June 30, the embryo grew uniformly in a spherical shape, and periclinal division and anticlinal division were the major cell division modes. On July 8, from heart-shaped embryo formation stage to cotyledon development period, the complete embryos and cotyledon cells could be observed. The endosperm cells were bulky with thin cell wall and obvious large vacuoles. It could be observed that the cotyledon cells were filled into the whole ovary and the endosperm cells gradually degenerated and disappeared on July 15.