烟草与蓝猪耳胚胎发生中细胞表面三种凝集素受体的动态分布

以异硫氰酸甲酯(FITC)标记的三种凝集素(伴刀豆凝集素, 麦芽凝集素和大豆凝集素)为荧光探针,对烟草及蓝猪耳各发育时期胚细胞表面的凝集素受体进行了定位.结果显示胚柄基部荧光信号最强,沿胚柄单列细胞向胚体方向渐次减弱.以后随着胚柄功能的逐渐丧失而改变.同时,三种凝集素受体集中分布于胚柄细胞间的分裂面;凝集素受体在原胚中分布的另一个特点是聚集于新形成的细胞壁上.随着胚胎发育至分化阶段,凝集素受体则主要分布在胚体细胞的外切向壁上;三种凝集素受体的动态分布显示了凝集素受体的分布与细胞分裂之间的密切关系及其调控胚胎发育的作用.

Dynamic Distribution of Three Lectin Receptors on Cell Surface During Embryogenesis in Nicotiana tabacum and Torenia fournieri

The dynamic distribution of lectin receptors during development of embryos in animal has been well studied and it is known that these dynamic changes are functionally involved in cell differentiation. However, no report is known so far about lectin receptor distribution on cell surface during embryogenesis in higher plants. In present work, fluorescein isothiocyanate (FITC) conjugated lectins,concanavalin agglutinin (Con A),soybean agglutinin (SBA) and wheat germ agglutinin (WGA),were used as probes to localize the lectin receptors on the cell surface of embryos of Nicotiana tabacum and Torenia fournieri . The results revealed several interesting characteristics of lectin receptor distribution. At the early proembryo stage, polar distribution of lectin receptors was observed on suspensor in tobacco, with stronger fluorescence of FITC Con A and FITC SBA on the basal end and weaker fluorescence on the apical end (Figs.1,3,4, 14). The walls between suspensor cells were strongly labeled by all three lectins(Figs.3,7,14). Such feature was kept as long as the suspensor functioned during embryogenesis. It was also found that lectin receptors were preferentially located on the newly formed cell wall in early proembryos (Figs.3,4), but once the embryos began to differentiate the lectin receptors were mainly located on outer tangential wall of epidermis cell (Figs.5,6); The results also revealed that the same lectin receptors in different species showed different distribution pattern, whereas on the same embryo different lectin receptors showed different distribution characteristics.