宁夏枸杞异型绒毡层发育的超微结构特点

Ultrastructural Characteristics of Heterotype Tapetum Development in Lycium barbarum L.

采用半薄和超薄切片技术对宁夏枸杞(Lycium barbarum L.)异型绒毡层的来源、结构及发育特点进行了研究,结果表明:(1)枸杞异型绒毡层由药隔绒毡层和药壁绒毡层组成,两种绒毡层除了来源、形态及分布位置不同外,其分化、成熟和降解时间,以及细胞质组成、分泌物成分等均有差异。(2)小孢子母细胞期间,药隔绒毡层细胞电子密度大,具有很强的脂质性质,光滑内质网和脂质小泡很丰富;而药壁绒毡层细胞中的核糖体和粗糙内质网较多。四分体后期,两种绒毡层细胞均含有很丰富的核糖体、粗糙内质网和分泌团。减数分裂前,两种绒毡层的细胞壁出现松散并呈絮状。之后,由于不同发育时期绒毡层细胞的不同分泌物在絮状细胞壁中的分布,致使二者的细胞壁都出现了一系列变化。(3)从小孢子早期开始,两种绒毡层细胞的质膜都发生了局部解体。分析推测,在母细胞期间药隔绒毡层具有较高的糖和脂类合成率,药壁绒毡层具有较高的蛋白质类合成率;在四分体后期,药隔绒毡层具有加强胼胝质酶合成和分泌的功能;而两种绒毡层絮状松散的细胞壁和局部解体的质膜有利于绒毡层的较大颗粒分泌物大量、顺利地分泌出绒毡层细胞。

To understand the discrepancy of the heterotypic tapetum of Lycium barbarum L.,we investigated the origin,morphology and ultrastructural characteristics using light and electron microscopy.Besides the origin,form,and the location are different,the time of differentiation,mature and degradation,the cytoplasm composition,and secretion components are not the same in the two tapeta.During the microspore mother cell phase the electronic density is higher and having very strong lipid properties,while smooth ER and lipid vesicles are very rich in C-tapeta,but ribosomes and rough ER are very abundant in P-tapeta.At the late of tetrad there are lots of ribosomes,rough ER and secretory groups in the two tapeta.Before Meiosis the wall of two tapeta appears to loose and with the cottony.Following that during the distribution of different secretions at cottony wall in developmental stages,the walls of the both tapeta have gone through a series of special changes.Moreover,from the early stage of microspore the plasma membranes of the both tapeta disaggregate partially.It is presumed that the P-tapeta possess own a higher rate of protein synthesis,and C-tapeta having a higher rate of sugar and lipid synthesis during the microspore mother cell stage.At the late stage of tetrad C-tapeta have strengthening the functions of synthesis and secretion of callose enzyme.The cottony wall and the partial disintegrated plasma membrane of two tapeta facilitate to secrete greater nutrient granules out of the tapetacells with large quantity and smoothly.