Sheldon J M, Dickinson H G
J Cell Sci. 1983 Sep;63:191-208. doi: 10.1242/jcs.63.1.191.
Centrifugation of living pollen mother cells of Lilium henryi has permitted the modifications of complex walls developed on the four daughter microspores. This experimental approach has not only provided an insight into the mechanism by which patterning is established, but has also identified the stages in cell development when wall determinants are present. These determinants can be first detected late in the meiotic prophase, but are not necessarily active at the cell surface at this early stage. The fact that treatment during cytokinesis may affect subsequent wall formation, combined with the obvious interference of the colpus with the spore patterning, indicates pattern determination to be a lengthy process, commencing during late prophase and reaching completion in the young tetrad. The study of walls formed on enucleate cell fragments suggests that neither the spindle nor the cytoskeleton is intimately involved in formation of the basic reticulate patterning. It is proposed that material is inserted into the mosaic of the plasma membrane and is reorganized biophysically to form contiguous 'plates', which then modify the properties of the membrane in such a way that the cytoplasmic protrusions that constitute the first stages of wall formation only develop in the interstices between them. Changes in the plasma membrane have been detected over this period and it seems that a population of coated vesicles is closely involved in these events. Examination of the cytoskeleton of the young spore suggests that microtubules play a critical rôle in the positioning of the colpus, and reveals ways by which only small changes in this skeleton could give rise to multicolporate grains.
对川百合的活花粉母细胞进行离心处理，使得四个子小孢子上形成的复杂细胞壁发生了改变。这种实验方法不仅让我们深入了解了细胞壁图案形成的机制，还确定了细胞壁决定因素存在时细胞发育的阶段。这些决定因素最早可在减数分裂前期后期被检测到，但在这个早期阶段它们不一定在细胞表面起作用。胞质分裂期间的处理可能会影响后续细胞壁形成这一事实，再加上萌发沟对孢子图案形成的明显干扰，表明图案确定是一个漫长的过程，始于前期后期并在年轻的四分体中完成。对无核细胞碎片上形成的细胞壁的研究表明，纺锤体和细胞骨架都没有密切参与基本网状图案的形成。有人提出，物质被插入到质膜的镶嵌结构中，并通过生物物理方式重新组织形成连续的“板块”，然后这些“板块”以这样一种方式改变膜的特性，即构成细胞壁形成第一阶段的细胞质突起只在它们之间的间隙中发育。在此期间已检测到质膜的变化，似乎一群被膜小泡密切参与了这些事件。对年轻孢子细胞骨架的检查表明，微管在萌发沟的定位中起关键作用，并揭示了仅通过该骨架的微小变化就能产生多萌发沟花粉粒的方式。
