天女木兰小孢子发生及雄配子体发育的观察

天女木兰是珍稀濒危植物,为给其有效保护措施的制定提供参考,从小孢子发生和雄配子体的发育角度探讨天女木兰濒危原因。研究结果表明,天女木兰花药具有4个小孢子囊,花药壁5～8层。四分体排列方式为平面对称型、四面体型和直线型,其中直线型较少;成熟花粉粒为二细胞型花粉粒;能育花粉率最高达84.9%。通过对天女木兰小孢子发育过程的研究发现,四分体时期有2种不正常类型,说明天女木兰小孢子发育过程中存在异常现象,这是导致天女木兰濒危的原因之一,但不是主要原因。

Observation of Microsporogenesis and Male Gametophyte Development in Magnolia sieboldii K.

Magnolia sieboldii K. is a kind of endangered plant. In order to provide reference for making effective protection measures,endangered reasons of M. sieboldii K. were studied from the aspect of microsporogenesis and male gametophyte development. The results showed that there were four microsporangia in each young anther of M. sieboldii K.,and anther wall was composed of 5-8 layers. Microspore tetrads had three arrangement patterns of decussate,isobilateral and linear types,in which linear type was rare. Mature pollen grain was two-cell type. The highest rate of pollen germination was up to 84.9%. Through observing microsporogenesis in M. sieboldii K.,two abnormal types of tetrads were found. It was suggested that endangerment of the species was related to the abnormal phenomenon during microsporogenesis and male gametophyte development,but it was not considered as an important factor responsible for low seeding rate.