水稻細胞質-基因雄不稔性之研究(四)雄蕊不稔之花葯組織與形態解剖

Abstract

本實驗係就水稻細胞質雄不稔(Reimei CMS)及其花粉親本(Reimei)之花葯形態與解剖上作備一比較，以期對於細胞質雄不稔性機構能進一步的瞭解。 雄不稔與其花粉親本之花葯，在花粉囊構造分化時即呈現結構上之差異；正常花葯是由兩個花葯瓣組成（每個花葯瓣再由兩個花粉囊組成），亦即每個花葯是由四個花粉囊組成，但雄不稔花葯形成三個花粉囊或甚至兩個花粉囊，其間可能由於同一花葯瓣之花粉囊之表皮層與內殼層分化不完全所致。 營養層細胞結構上之差異，在小孢子早期即開始出現；雄不稔花葯之營養層細胞呈現肥大液胞狀（可能為細胞質退化，細胞質物質之突出或產生原生質塊等異常現象），小孢子之退化則大多延遲到單核中期以後才出現，很少有進行小孢子第一有絲分裂，花葯葯壁之中間層細胞及內殼層細胞亦呈衰退狀況，內殼層細胞亦無桿狀細胞壁之形成。有些中間層細胞膨脹而無組織化。 在正常成熟花葯之表面，具有縱橫交錯之脊狀角質凸起，而雄不稔花葯則不具有是項凸起或僅有發育不完全之小凸起。 Cyto-bistological and morphological obser-vations on the male sterile anthers of Reimeihaving O. rufipogon cytoplasm were made incomparison with its maintainer in order toclarify the cause of pollen abortion. The most outstanding morphological alter-nation in anther of CMS plants was the locularfusion. Anthers of maintainer varieties differ-entiated into tetralocular structure without ex-ception, while the anthers of CMS lines werefrequently trilocular or dilocular due to thefusion of loculi of the same anther lob ordifferent anther lobes. The fusion alreadyoccurred at pre-meiotic stage. Most of degeneration and disintegration ofmicrospore in the CMS plants centered at thestages after meiosis. Histological observationson anthers during microsporogenesis indicatedthat the main characteristics associated withmicrospore abortion were abnormalities oftapetal cells. Those abnormalities were tapetalhypertrophy, hill and ballon types; vacuolationof tapetal cells, formation of intratapetal syn-cytium or tapetal periplasmodium. In allexamination made in this study, the abnormalbehavior of tapetum was found to associatedwith male sterility. On the maturing anther of maintainer,epidermal cells were covered with ridges whichdeveloped at late yound pollen stage and formeda highly ridged epidermal surface rapidly.However, there were no recognizable ridge onthe surface of epidermal cells of male sterileanther.