Department of Botany and Bessey Microscopy Facility.
Am J Bot. 2002 Mar;89(3):417-26. doi: 10.3732/ajb.89.3.417.
Cytoplasmic male sterility has been found independently in soybean three times since 1995, but no microscopic investigation has been published. The purpose of this microscopic study was to establish the developmental sequence leading to sterility in a cytoplasmic male-sterile soybean line that has been found to be stable under all environmental conditions tested and to demarcate the temporal and spatial parameters that result in degeneration of the microspores and pollen grains. Light microscopy showed an abnormal development and/or premature degeneration of the tapetum after meiosis II, but some pollen grains persisted until after microspore mitosis. The pollen grains never completely filled with reserves. Premature formation of the endothecium also was evident. Histochemical staining for water-insoluble carbohydrates revealed an abnormal pattern of starch deposition in anther walls that coincided with lack of pollen filling. Electron microscopy showed degeneration of the inner mitochondrial membrane in the tapetal cells as the first detectable change leading to cell degeneration. Subsequently, the tapetal endoplasmic reticulum exhibited atypical concentric rings. Pollen grains displayed mitochondria with unusually enlarged inner mitochondrial spaces, degraded plastids, a rudimentary intine, and no starch or lipid reserves. Results link mitochondrial degeneration, premature formation of the endothecium, and energy deprivation to male sterility.
自 1995 年以来，大豆中已独立发现了 3 次细胞质雄性不育，但尚未发表过显微镜研究。本显微镜研究的目的是确定在已发现的在所有测试环境条件下均稳定的细胞质雄性不育大豆品系中导致不育的发育顺序，并确定导致小孢子和花粉粒退化的时空参数。光镜观察显示，减数分裂 II 后绒毡层发育异常和/或过早退化，但有些花粉粒一直持续到小孢子有丝分裂之后。花粉粒从未完全充满储备物质。中内层的过早形成也很明显。水不溶性碳水化合物的组织化学染色显示，花药壁中淀粉沉积的异常模式与花粉填充不足相对应。电子显微镜显示，绒毡层细胞中线粒体的内膜退化是导致细胞退化的第一个可检测到的变化。随后，绒毡层内质网呈现出非典型的同心环。花粉粒显示线粒体具有异常增大的内部线粒体空间、降解的质体、不完整的内皮层，以及没有淀粉或脂质储备。结果将线粒体退化、中内层过早形成和能量剥夺与雄性不育联系起来。
