Comparative Studies on the Changes of Microtubule Distribution and Reorganization During the Meiotic Stages of Development in Normal (IR36) and a Temperature/photoperiod Sensitive Male Sterile Line (Peiai 64S) of Rice (Oryza sativa)

Abstract

Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sensitive male sterile line (Peiai 64S) of rice were studied using immunofluorescence confocal microscopy. In IR36, from pre-meiotic interphase to metaphase I , the pattern of microtubule distribution in the meiocytes underwent a series of changes. Some new organizational patterns of microtubules (that have not been described before) were observed during microsporogenesis, including the existence of a broad band of perinuclear microtubules at the diakinesis stage of development. The pattern of microtubule distribution in the meiocytes of the male sterile line, Peiai 64S, was quite different from that seen in IR36. In Peiai 64S, the microtubules showed abnormal patterns of distribution from pre-meiotic interphase to metaphase I . For example the broad band of perinuclear microtubules seen at diakinesis in IR36 was much disorganized and loosened in Peiai 64S. The spindles formed were also very abnormal and different from the normal spindle. The appearance of abnormal microtubule distribution in the early stages of microsporogenesis may contribute to the malformation and ultimate abortion of pollen in Peiai 64S.

對水稻(Oryzasativa L.)IR36及光溫敏核雄性不育系培矮64S小孢子母細胞減數分裂期間微管骨架的變化的研究顯示,微管在小孢子母細胞正常發育的情況下,每一個發育階段(即造孢細胞時期、細線期、偶線期、粗線期、雙線期、終變期、中期Ⅰ、後期Ⅰ)都出現不同的組織結構形態和分佈。在IR36中，還發現了一些新的和特殊的微管組織結構和分佈。主要包括：(1)在細線期，從核膜向胞質衍射的微管呈螺旋狀，顯示核具旋轉功能；(2)在偶線期，微管的分佈呈極性分佈現象；( 3)在終變期，核被一組微管形成的寬帶圍繞著（perinuclearbroadband）。而培矮64S小孢子母細胞減數分裂期間，各發育階段的細胞內的微管骨架結構呈現許多不正常現象。如：(1)在偶線期具極性分佈的微管分佈不存在；(2)在小孢子母細胞減數分裂期間的細胞內出現許多特別粗的微管束；(3)在終變期圍繞核的微管寬帶結構鬆散及內含微管密度低。由於微管骨架的分佈變化可以使人們較早地在雄性不育細胞內看到敗育現象，故此微管的分佈和構型變化應可作為一個早期確立雄性不育現象的視覺標記（visualmarker）或形態指標予以利用。