荔枝果皮发育细胞学研究

Cytological Studies of Litchi Pericarp during Development

以‘淮枝’荔枝为试材 ,对花前子房和花后果皮发育的解剖学特点进行了观察。荔枝果皮可划分为内、中、外 3层 ,外果皮由单层表皮细胞、龟裂片峰处表皮细胞上的角质、裂纹处表皮细胞上的薄壁细胞构成 ;中果皮是构建果皮的主体 ,由龟裂片峰下的厚壁组织、上中果皮和下中果皮构成 ;内果皮由薄壁未木栓化的皮层细胞构成。果皮的细胞分裂主要发生在开花前 ,花后不同部位的果皮细胞还有一定的分裂行为 ,但分裂的旺盛程度和停止时间有所不同 ,下中果皮停止早 ,约在花后 19d ,上中果皮其次 ,约在花后 32d ,内果皮和裂纹处外果皮最晚 ,约在花后 4 7d。细胞膨大规律总体呈“慢 -快 -慢”的S型。

Microscopic research has been made with cv. Huaizhi of litchi( Litchi chineasis Sonn.),using 7022LH(Leica 7022 histeresin embedding kit) plastic embedding and half thin slice up techniques. Ovary and pericarp collected before and after anthesis served as materials. The exocarp was the outermost layer consisting of uniseriate epidermis, cuticle on the epidermis and in the tubercles, and parenchyma cells in the epidermis of the crackles. The mesocarp, being the main body of a pericarp, contained sclerenchyma, upper mesocarp and lower mesocarp. The endocarp was composed of unsuberized small and thin walled epidermal cells. Cell division in the pericarp proceeded mainly during the period prior to anthesis, and continued after anthesis while the dates of cessation were different in endocarp, mesocarp and exocarp; the cell division in the lower mesocarp ceased as early as about 19 days, that in the upper mesocarp ceased about 32 days, and that in the endocarp and the epicarp in the crackles ceased about 47 days after anthesis. Cell expansion in the pericarp exhibited roughly a single sigmoid pattern, with some differences for different parts of tissues and different types of cells.