不同季節生長下母株菸草花葯培養植物體之形成

Abstract

利用Hoagland 液體培養配合不同氮素濃度栽培菸草，以為花葯培養植物體形成的材料，發現盛夏季節所栽培之菸草，其花葯培養植物體形成能力極差，若再配合過量或不足的氮素量則情形更嚴重；將夏日生長下的菸草花物以石蠟切片法觀察其內部詼育，發現此時期所形成的花葯，有許多是發育不正常的，其花粉囊均為不正常細胞所佔滿，以至無法形成正常的小胞子，部份花葯雖有小胞子形成，但小胞子數少或許多均屬無功能者，這種情形可能是夏季生長的菸草花葯，培養後植物體形成低下的主要原因。此外，夏日配合過量氮素肥有剌敵產生一花多葯的情形，反之缺氮則有形成一花少葯的趨勢。 The anthers of N. tabacum cv. Wisconsin 38 which were grown in Hoagland nutrient solution with different nitrogen levels were collected during the period of May-November. The collected anthers were cultured in Murashige and Skoog medium (1962) to produce haploid plants. It was found that the embryogenic ability of anthers collected from the plants grown under the high temperature and long photoperiod condition (August-September) was extremely lower than those collected from the plants grown under the lower temperature and shorter photoperiod condition. In the hot summer season, the abnormal cells instead of functional microspores in pollen sacs as it was observed by the cytological study. The effects of high temperature and long photoperiod on the abnormal formation of microspore were considered to be the main reason why the embryogenic ability is so poor when this kinds of anthers were cultured in vitro. Further, it was observed that the rate of abnormal anther was promoted when tobacco plants were cultured under either excess or deficient nitrogen supply condition. The low nitrogen supply resulted in fewer anther formation per flower bud and more anther formation per flower bud under the high nitrogen supply condition as compared with controls.