Abstract:A chimeric gene TA29-Bamase/bxn was transformed into tobacco (Nicotiana tabacum L. ) plants. This gene confers on transgenic plants male sterility feature and resistance to the herbi- cide--bromoxynil. The resistance to the herbicide was used as a dominant marker for the male sterility trait in agricultural application. Seven of the sixteen transgenic bromoxynil-resistant plants were partially male sterile at the greenhouse temperature of 27 ℃/23 ℃,and the others were male fertile. However twelve of the seventeen transgenic bromoxynil-resistant plants were male sterile at 20 ℃/15 ℃ in the greenhouse, and the other five bearing male sterile flowers and fertile flowers were partially male sterile. As the temperature reached 27 ℃ or higher, four of the twelve male sterile plants restored their fertility in respect to their morphology and cytology of the new flowers in about one month, and 5 transgenic plants showed partially male sterile and the other 3 transgenic
plants remained male sterile. The most prominent morphological change in the male sterile plants was a noticeable shortening of their stamen-filaments and absence of pollen. Cytological abnormality exhibited destruction of tapetal cell layer as early as from the stage of tetrad to the free uninuclear microspore during which the noimal tapetum was not observed. The male sterile anthers contained no pollen grains, and the male sterile flowers failed to self-pollinate, then fell off.