琯溪蜜柚汁囊分化和粒化过程的解剖学观察

用徒手切片、石蜡切片、细胞化学等方法观察了琯溪蜜柚（Ｃｉｔｒｕｓ　ｇｒａｎｄｉｓ（Ｌ．）Ｏｓｂｅｃｋ）汁囊的分化和粒化过程。结果表明，心皮内表皮细胞和表皮下细胞分裂共同形成汁囊原基。由汁囊原基发展成柱状结构。柱状结构顶端有类似分生组织的细胞群，中心有类似分生组织的细胞柱。它们的细胞呈多角形，细胞核大，原生质浓厚。类似分生组织的细胞柱纵贯柱状结构中心（除柄部外）。开花后７周近柄端明显分化。开花后约两个半月，汁囊雏形形成。汁囊的粒化分为４个阶段：（１）正常汁囊阶段，汁囊透明，切开溢出果汁。表皮下细胞为角隅加厚的厚角组织，个别薄壁组织细胞原生质体已死亡。（２）凝胶化阶段，汁囊透明、坚挺，切开为凝胶状，表皮下细胞区的厚角组织细胞壁全面加厚。有的汁囊中已有部分细胞的细胞壁木质化。（３）粒化阶段，汁囊乳白色或部分乳白色。表皮、表皮下细胞区、长细胞区和汁细胞区等四个细胞区均有较多细胞的细胞壁木质化加厚。（４）粒化后期，汁囊黄白色，部分硬化，部分萎缩，汁囊变形，硬化部分大部细胞木质化，萎缩部分死亡的细胞被挤压，随果实贮存时间延长，正常汁囊减少，汁囊中淀粉量减少，油滴增多。

Anatomical Observation on Differentiation and Granulation Processes of Juice Sacs in Citrus grandis

in Citrus grandis (L. ) Osbeck, cells in the inner epidermis and subepidermal layers of carpels divided and formed the primoldium of the juice sac which grew into columnar structure. There were meristem-likecell clusters at the apex and meristem-like cell columns at the centre of the columnar structure. These cellswere polygonal, each with a big nucleus surrounded by dense cytoplasm. The meristem-like cell column,which was absent in the stalk, ran longitudinaly through the centre of the columnar structure. It differentiatednear the stalk 7 weeks after anthesis. Two and a hall months after anthesis, miniature of juice sac was formed.Juice sac consisted of 4 zones, viz, epidermis, subepidermal cell zone, elongated cell zone and juice cellzone. The granulation process of juice sac included four stages. 1. The stage of healthy juice sac: At thisstage the juice sac was fulfilled with juice and the sac appeared transparent. The subepidermal cells were collenchymatous with thichened corners. Death of protoplasts occurred in individual parenchyma cells. 2. Stage Ofgelatination. The juice sac was transparent and filled with gelatinous juice. The collenchyma cell wall of thesubepidermal cell were completely thickened. Some cell walls in some juice sacs were lignified. 3. Stage ofgranulation. A portion of , if not the whole, juice sac is milky white. Walls of more cells in four zones arethickened and lignified. The walls of more cells in the four zones were thickened and lignified. 4. Late granu- lation stage: The juice sac was yellowish white in color, partly hardened and partly atrophied giving the sac inan irrgular contour. Most cells of the hardened portion were lignified and most cells of the atrophied portionwere dead and became oppressed. Eventually, healthy juice sac reduced, starch in the juice sac reduced andoil drops increased with the prolongation of stoop time of fruits.