珍稀濒危树种─沙冬青体细胞胚胎发生的组织学观察

OBSERVATION OF THE SOMATIC EMBRYO TISSUE SECTIONS OF AMMOPIPTANTHUS MONGOLICUS A KIND OF ENDANGERED PLANTS IN CHINA

采用萌发５天的沙冬青（ＡｍｍｏｐｉｐｔａｎｔｈｎｓｍｏｎｇｏｌｉｃｕｓＭａｘｉｍ）为外植体，ＦｌＭＳ为基本培养基。附加２．４一Ｄ１ｍｇ／Ｌ，６－ＢＡ１ｍｇ／Ｌ，诱导子叶和胚根形成愈伤组织。选生长良好的愈伤组织转人分化培养基中诱导胚状体的发生。切片观察表明；沙冬青的体细胞胚是单个获得胚状体发生能力的胚性细胞发育而来，并且胚性细胞有较高的发生频率，在愈伤组织中常具有—至多个发生层带。体细胞胚的发育过程与双子叶植物的胚胎发育过程基本相似。在切片中可同时观察到球形胚、心形胚及于叶胚，并有连体胚，次生胚等畸形胚，这些胚最终不能发育成苗，都在发育的不同阶段退化或解体。其退化方式有两种类型：一种是胚状体在发育到球形胚和心形胚之后失去发育极性呈花状发展；另一种是在原来的胚上又发生新的胚，吸收其营养使其内部解体。

The callus was initiated from the roots and cotyledons ofthe plantlets of Ammopiptanthus mongolicus Maxim after germinating fivedays. Then the callus were cultured in MS medium with2.4一D0.5mg/L、6一BA 2 mg/L to induce embryos. The embryo initial cells,which wereordenarylly single ones and were happened with high frequentily, wereinitiated from inside or on the surface of the callus. The single cellsthen becomed embryos which genetic stages were like embryogenetic proc-ess of the dicotyls. The sections had shown that ovate, cordate, cotyled-onary and deformed embryos were in the same callus. But theembryoshadn’t developed to normal ones.