甜荞pin型花与thrum型花雌雄蕊发育的比较研究

为从形态上研究甜荞(Fagopyrum esculentum)二型花发育的差异性,该文运用石蜡切片技术对甜荞pin型花和thrum型花大、小孢子发生和雌、雄配子体的发育过程进行观察比较.结果表明:(1)甜荞2种花的雌蕊、雄蕊发育的细胞学特征有很高的相似性,具直生胚珠、双珠被、厚珠心;大孢子四分体直线型排列,合点端为功能...

Development of stamens and carpels on pin typeand thrum type flowers of common buckwheat

In order to reveal the morphological differences between pin type and thrum type flowers development of common buckwheat. The megasporogenesis, microsporogenesis and development of female and male gametophytes in pin type and thrum type flowers of Fagopyrum esculentum were investigated by using the paraffin section method. The results were as follows:(1)The cytological characteristics of pistil and stamen development of pin type and thrum type flowers had highly similar. Both type flowers had orthotropous ovule, inner and outer integument, and thickly nucellus. Moreover, the megaspore mother cells underwent meiosis and divided into linear type tetrads, and the one in the chalazal end was functional, which suggested that their development of embryo sac belonged to Polygonum type. The anther had four chambers and the anther wall was composed of epidermis, endothecium, one layer of middle layer and glandular tapetum. In addition, meiosis of microspore mother cell was followed by simultaneous cytokinesis and results in common tetrahedral tetrads. Furthermore, most of tetrads were tetrahedral, but a small number of decussate tetrads were also observed in thrum flower. Most of mature pollen grains were 2-cell type, and 3-cell type pollen grains were also observed in pin type and thrum type flowers.(2)Comparing the pistil and stamen developmental progress between the pin type and thrum type flowers, the development of microspores in thrum type flower was more slowly than that of the pin type flower, but the male gametophytes in thrum type flower grew faster. However, mature embryo sac and pollen grains were observed when pin type and thrum type flowers bloomed.(3)According to the reproduction development process of two type flowers, many relatively primitive embryological characteristics, and some relatively evolutionary embryological characteristics, such as orthotropous ovule and 3-cell type pollen grains, coexisted in common buckwheat. This study not only accumulated the morphological data of the distylous flower reproductive development in common buckwheat, but also provided embryological evidence for understanding the genetic relationships among the species of Caryophyllales.