歐洲松（Pinus sylvestris）的小花子形成──VII.花粉外壁的膨脹和營養層的發育

Microsporogenesis in Pinus sylvestris - VII. Exine Expansion and Tapetal Development

本文研究歐洲松（Pinus sylvestris）由小孢子四分體末期和胼脂質壁喪失一直到花粉氣囊膨脹這階段之發育，此發育階段約相當於花粉粒之液胞期。在發育中，花粉帽（近心部分）和氣囊的小泡皆大大的膨脹，但無任何放射狀成分的分離。氣囊小泡的遠心部分延長。在花粉帽和氣囊小泡進行加厚之同時，在小泡的壁上或附近有許多臘梅糖。營養層的粗糙內質網有多次的膨脹，囊胞忽少忽多，產生烏氏體。在小孢子的液胞期一開始，營養層細胞即行有絲分裂。在小孢子的液胞期的全盛時期。營養層細胞伸入花粉腔，並圍繞在小孢子周圍。此時氣囊膨脹，花粉外壁亦加厚。

This paper deals with stages from the terminal portion of the microspore tetrad period and loss of the callose envelope through to extensive expansion of sacci (= ca. vacuolate stage of pollen grain cytoplasm). The alveoli of both cap and sacci expand greatly, circumferentially, without any separation of radial components. It is the distal portion of alveoli which elongates. Thickening of alveoli in cap and sacci is accompanied by many glycocalyx elements on, around or within the ''walls'' of alveoli. Tapetal cells go through many cycles with respect to dilation of rER, few or many vesicles and production of Ubisch bodies. They undergo mitosis at the beginning of vacuolation of microspores. Tapetal cells extend into locules surrounding many microspores during a stage of great vacuolation of microspore cytoplasm, expansion of sacci, and thickness increase of the exine.