文冠果体细胞胚发生中钙的超微细胞化学定位

Ultracytochemical Localization of Ca^(2+) in the Somatic Embryogenesis of Xanthocera sorbifolia

用电镜细胞化学定位的方法,对文冠果种胚诱导体细胞胚发生过程中非胚性愈伤组织、胚性愈伤组织及球形胚、鱼雷胚发育期间Ca2+的分布动态进行超微结构水平上的定位比较研究。结果表明:非胚性细胞Ca2+的含量最少,集中分布在细胞壁和细胞间隙中;胚性愈伤组织的细胞Ca2+的含量明显增加,集中分布在液泡膜、质膜和细胞质中;球形胚时,质膜上Ca2+积累的颗粒较大,但量相对较少;鱼雷胚期Ca2+的含量明显增多,集中分布在胚芽端和胚根端,胚根最外层细胞的外侧的细胞壁明显增厚,其细胞壁的外侧Ca2+分布多。推测Ca2+与文冠果体细胞胚发生过程中细胞的发育时期密切相关。

This study was targeted to investigate, by means of ultracytochemical localization, the distribution of Ca^2＋ during different developmental stages of seed embryo-induced somatic embryogenesis of Xanthocera sorbifolia, i, e, , of non-embryogenic calli （NEC）, embryogenic calli, globular and torpedo embryoids, The results showed that the NEC had the lowest deposit of Ca^2＋ , which was largely distributed in cell walls and intercellular spaces, A marked increase in the level of Ca^2＋ was observed in embryogenic cells, which were mainly localized in plasma membranes, vacuole membranes and cytoplasm. The Ca^2＋ grains, deposited in plasma membranes during the globular embryoid stage, were large but with little substance, During the torpedo embryold period, deposits of Ca^2＋ increased significantly and were concentrated largely in the radicle and embryo tips, A clear thickening of the outside cell walls, where more Ca^2＋ was deposited, could be found in the outermost layer of radicle cells. We speculate thatCa^2＋ might be closely related to different developmental stages of cells in the somatic embryogenesis of X, sorbifolia ,