Kuang A, Musgrave M E, Matthews S W, Cummins D B, Tucker S C
Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge 70803, USA.
Am J Bot. 1995 May;82(5):585-95.
The development of pollen and ovules in Arabidopsis thaliana on the space shuttle 'Endeavour' (STS-54) was investigated. Plants were grown on nutrient agar for 14 days prior to loading into closed plant growth chambers that received light and temperature control inside the Plant Growth Unit flight hardware on the shuttle middeck. After 6 days in spaceflight the plants were retrieved and immediately dissected and processed for light and electron microscope observation. Reproductive development aborted at an early stage. Pistils were collapsed and ovules inside were seen to he empty. No viable pollen was observed from STS-54 plants; young microspores were deformed and empty. At a late stage, the cytoplasm of the pollen contracted and became disorganized, but the pollen wall developed and the exine appeared normal. The tapetum in the flight flowers degenerated at early stages. Ovules from STS-54 flight plants stopped growing and the integuments and nucellus collapsed and degenerated. The megasporocytes appeared abnormal and rarely underwent meiosis. Apparently they enlarged, or occasionally produced a dyad or tetrad, to assume the form of a female gametophyte with the single nucleus located in an egglike cell that lacks a cell wall. Synergids, polar nuclei, and antipodals were not observed. The results demonstrate the types of lesions occurring in plant reproductive material under spaceflight conditions.
对搭载在航天飞机“奋进号”（STS - 54）上的拟南芥花粉和胚珠的发育情况进行了研究。植株在营养琼脂上生长14天后，被装入封闭的植物生长室，该生长室在航天飞机中甲板的植物生长单元飞行硬件内接受光照和温度控制。在太空飞行6天后，将植株取回并立即解剖，进行光学显微镜和电子显微镜观察处理。生殖发育在早期就中止了。雌蕊萎陷，内部的胚珠为空。未从STS - 54植株中观察到有活力的花粉；幼嫩小孢子变形且为空。在后期，花粉细胞质收缩并变得紊乱，但花粉壁发育，外壁看起来正常。飞行花朵中的绒毡层在早期退化。来自STS - 54飞行植株的胚珠停止生长，珠被和珠心萎陷并退化。大孢子母细胞出现异常，很少进行减数分裂。显然它们增大，或偶尔产生二分体或四分体，形成具有位于类似卵细胞中且无细胞壁的单核的雌配子体形式。未观察到助细胞、极核和反足细胞。结果表明了在太空飞行条件下植物生殖材料中出现的损伤类型。
