'京白梨'结实与雌雄配子体发育的解剖学研究

以‘京白梨’、‘鸭梨’、‘雪花梨’为材料,用石蜡切片技术对其雌雄配子体发育过程进行了观察研究,并对其花粉育性、自然授粉结实率进行统计分析。结果表明:(1)‘京白梨’自然授粉结实率和花粉发芽率明显低于‘鸭梨’和‘雪花梨’;(2)京白梨从小孢子母细胞形成到成熟花粉的各个发育阶段观察到未形成小孢子或形成后很快退化、花粉囊中的花粉极少、花粉发育阶段细胞发生退化等不同类型的雄性败育个体,而且在花粉成熟阶段有部分花药中的绒毡层细胞不发生退化,花粉难以散出造成雄性败育;(3)雌配子体在大孢子母细胞发育阶段发现不能形成大孢子和大孢子形成后退化或发育不良等多种发育异常的雌配子体败育类型,而且败育频率高达36.7%。研究表明,‘京白梨’雌、雄配子体在其形成发育过程中的各种异常使其不能正常受精,最终导致坐果低下。

Anatomical Study of Fruit Setting and Male and Female Gametophytes in Pyrus ussuriensis

In 'Jingbaili' pear(Pyrus ussuriensis Maxim.),'Yali' pear and 'Xuehua' pear(Pyrus bretschneideri) the developments of male and female gametophytes were observed by paraffin sectioning and the pollen fertilities and the fruit-setting rates through natural pollination were statistically analyzed.It was shown that(1) the fruit-setting rate through natural pollination and the pollen-germination rates of 'Jingbaili' pear were obviously lower than those of 'Yali' pear and 'Xuehuali' pear;(2) In 'Jingbaili' pear,different types of aborted male gametophytes such as microspores that did not completely formed or formed and then degenerated,very few pollens in the pollen sacs,and degenerated cells in pollen development were observed at all the stages from microsporocyte formation to pollen maturity and the tapetum cells did not degenerate in some anthers at the stage of pollen maturity,which resulted in the pollens difficult to disperse and male gametophyte abortion;(3) At the stage of megaspore mother cell development female gametophytes were observed to form no megaspores or to form such aborted female types as megaspores which formed and then degenerated soon or developed poorly and their abortion rate was as high as 36.7%.The study indicated that there were many abnormalities occurring to male and female gametophytes of 'Jingbaili' pear in their formation and developments,which led to the low fruit-setting rate of the pear.