‘正午’牡丹有性生殖败育的形态学观察

Morphological Observation of Sexual Reproduction Abortion in‘High Noon’Tree Peony

采用光镜和杂交等方法对牡丹远缘杂交一代品种‘正午’有性生殖败育进行系统形态学观察发现：（1）雄蕊较雌蕊先成熟,初花期即散粉,正常2-细胞花粉仅占2.41%,且花粉在多种培养液中、在自身和其它两种柱头上均不萌发;柱头在谢花期大量分泌粘液,进入最佳授粉状态;（2）同一胚珠中多个大孢子母细胞减数分裂高度不同步,胚囊发育与受精延迟,部分胚乳游离核在细胞化时期分裂异常;（3）自花及品种内异花授粉不结实,天然授粉结实率为0.053‰～0.130‰.认为‘正午’牡丹有性生殖败育的主要原因是不能形成足够多的有生活力的配子和缺乏有效授粉.

Morphology of sexual reproduction abortion in ‘High Noon＇ , a distant hybridization cultivar of tree peonies （P. delavayi var. lutea × P. suffruticasa）, was systematically investigated with light microscopy and cross. The results indicated that： （ 1 ） The stamens matured earlier than the gynoecia and pollens dispersed at the early stage of anthesis but the rate of normal 2-celled pollens were merely 2. 41%. No pollens germinated not only in liquid nutrition but also on its own stigmas and on other two female parents＇ stigmas. When flower withered, stigmas excreted a great deal of exudation and became in the best for pollination; （2） The meiosis of muhi-megasporocytes were highly asynchronous in one ovule, the development of embryo sac and fertilization were retarded, and the mitosis of some free endosperm nuclei were abnormal during the cellularization stage; （3） No seeds were produced by self- and cross-pollination in the same cultivar group, but natural pollination seeds were produced with the rate of 0. 053‰ - 0. 130‰. It was suggested that the main reasons for the sexual reproduction abortion in ‘High Noon＇ were that it can not form enough viable gametes and lack valid pollination.