单瓣与重瓣樱花雌雄蕊发育的比较研究

Development of stamens and carpels in single and double flowers of Cerasus serrulata

对单瓣和重瓣樱花雌雄蕊的发育进行了系统观察。结果表明:单瓣樱花‘大岛樱’雌蕊1心皮1室,胚珠发育后心皮开始愈合,2倒生胚珠,通常仅有1个能发育为成熟胚囊,双珠被,厚珠心,大孢子四分体线型排列,胚囊发育方式属蓼型;雄蕊小孢子四分体为四面体型,成熟花粉为二细胞型。重瓣樱花‘普贤像’和‘一叶’雄蕊数量显著少于‘大岛樱’,花药瓣化,花粉败育,雌蕊叶化。‘普贤象’少数花萼筒上着生异位子房和败育胚珠,‘一叶’少数花未完全叶化的子房内壁着生败育胚珠;‘普贤象’和‘一叶’均存在同株花异型现象。并对樱花重瓣花形态建成的分子机制展开了探讨。

Morphogenesis of stamens and carpels in single and double flowers of Cerasus serrulata var.lannesiana as well as the development of their male and female gametophytes were investigated.First,the ‘Makino’ovules are borne on unsealed carpels.During their development,carpels close with the ovules hidden inside.The ovule is anatropous,bitegmic and crassinucellate.Megaspore mother cells undergo meiosis and develop into linear tetrad.Subsequently,the larger one at the chalazal end becomes functional megaspore and develops into an embryo sac of a polygonum type after the third mitotic division.The ‘Makino’ microspore tetrads belong to the tetrahedral type,with two-celled mature pollen.In contrast,the ‘Albo-rosea’and ‘Hisakura’double flowers have petaloid anthers and leaflike carpels,with fewer numbers of stamens compared with ‘Makino’.The petaloid anther houses a large number of sterile pollen grains.Flowers on the same tree show different final floral architectures,where some flowers contain ectopic unsealed carpels housing abortion ovules.The molecular mechanisms of double flower morphogenesis in cherry are discussed.