芦荟叶内芦荟素细胞的发育和蒽醌类物质的积累

应用石蜡切片、半薄切片、组织化学和荧光显微镜观察相结合的方法研究了木立芦荟叶内芦荟素细胞的发生、发育以及其蒽醌类物质的积累过程。结果表明，在叶内原形成层束分化成维管束初期，原形成层束外侧的一层细胞发育成维管束鞘。原生韧皮部筛管产生时，其外方尚保留1—2层原形成层细胞，当后生韧皮部和木质部开始分化时，此层细胞分裂。在后生韧皮部和木质部发育成熟过程中，这些细胞体积逐渐增大，并液泡化，发育成为大型薄壁细胞(芦荟素细胞)，位于筛管外侧。据此，芦荟叶维管束内的大型薄壁细胞的来源与韧皮部相同，属于特化的韧皮部薄壁组织细胞。用醋酸铅处理过的上述材料的切片观察表明，芦荟素细胞在细胞体积增大，并液泡化时，在液泡内出现蒽醌类物质沉淀物，在成熟细胞的大液泡中充满沉淀物，此时，在荧光显微镜下芦荟素细胞发出桔黄色荧光。可见，此种芦荟素细胞是芦荟叶内蒽醌类物质的主要储存场所。

Development of aloin cells and accumulation of anthraquinone in aloe leaf]

The development of aloin cells and its relationship with the accumulation of anthraquinone in aloe leaf were investigated with the methods of paraffin section, semi-thin section, histochemistry and fluorescent microscopy. The results showed: cells rounded the procambium bundle differentiated into bundle sheath at the initial stage of procambium bundle developing into vascular bundle. When the sieve tube members appeared in protophloem, there were a lay of procambium bundle cells reserved between the sieve tube members and bundle sheath. These cells began to devise, then developed into aloin cells through enlargement of volume and vacuolization with the differentiation of metaphloem and metaxylem. So the aloin cells were special phloem parenchyma cells because they shared the same origin with the other phloem cells. The investigation of histochemistry reflected that there were aloin precipitate in the central vacuole of aloin cells after the material was soaked in the liquid of 1% lead acetate Pb (CH3COO)2]. In addition, the yellow fluorescence was observed in aloin cells when the section of fresh material was investigated under the fluorescent microscope with blue light, which suggested the aloin cells of vascular bundles were the mainly storage site of anthraquinone.