Scanning Electron Microscopic Observations on Morphogenesis of the Panicle and Spikelet in Rice Plants

[摘要] Morphogenesis of panicle and spikelet in paddy rice, cultivars Yuhkara and Fujihikari was studied by SEM. Germinated seeds planted in containers with submerged soil were cultured under natural conditions. The young panicle and spikelet were dissected and fixed every day until heading with modified Karnovsky's solution with 5% aclorein, dehydrated with acetone, and were dried at critical point, and then coated with gold for investigation. At the panicle primordium differentiation stage (PDS), the ratio of height to width (H/W) in the apical meristem (AM) decreased from one to 0.4 and 0.2 at the palea and stamen PDS respectively. Before the lemma and palea completely covered the inside floral organs, the stamen primordium differentiated to the anther and filament, and pistil primordium to ovule and ovary wall. A central stamen in the lemma side was located at the lowest position among all stamens. This indicated that the three stamens located in the lemma side may be situated at lower positions than the palea-sided organs. When the ridged cuticle (RC) in the anther epidermis began to develop at the meiotic stage of pollen mother cell (PMC), stigma cell started to differentiate, forming stigma hairs when RC covered the anther epidermis. RC changed to a more complicated structure almost at the same time as xylem vessel differentiated in stigma vascular bundles. Therefore, this structural change was considered to have some correlation with sclerification or shrinking of inner anther wall cells. Development of orbicules on the surface of pollen and tapetum cells was discussed.

[学科分类] 农业科学（综合）

[关键词] Anther cuticle;イネ;Apical meristem;形態形成;Morphogenesis;小穂;Panicle;走査電子顕微鏡;Rice plant;頂端分裂組織;Scanning electron microscope;表面構造;Spikelet;ç©‚;Surface structure;葯クチクラ