The ultrastructure of oogenesis in the fern Osmunda cinnamomea L. var. asiatica Fernald has been studied by electron microscopy. During oogenesis, numerous vesicles not only moved towards the periphery, but also were ...The ultrastructure of oogenesis in the fern Osmunda cinnamomea L. var. asiatica Fernald has been studied by electron microscopy. During oogenesis, numerous vesicles not only moved towards the periphery, but also were arranged in line along the inside of plasmalemma, and in addition aggregated outside the plasmalemma by exocytosis. They released or excreted osmiophilic material. It was observed that a few vesicles containing lamellar osmiophilic material situated closely along the plasmalemma, seemed to break open. Simultaneously, a separation cavity between egg cell and archegonium wall formed. Its width was broader than the other advanced ferns reported previously, and an extra egg membrane occurred outside around the plasmalemma of the egg, its thickness being greater than in Pteridium and Dryopteris. Amyloplasts around the nucleus were filled with large triangular semicircular or subelliptical starch grains, but as the egg matured they progressively decreased. Nucleus was large and flattened, and paired membrane in two to three couples laid within the nucleus, close and parallel to the nuclear membrane. No nuclear evagination was observed. Mitochondria seemed to have been undeveloped, but finally recovered normally.展开更多
The ultrastructure of the X organ sinus gland complex in sexually immature Chinese mitten crab Eriocheir sinensis was examined under the electron microscope. The sinus gland (SG) is composed primarily of nerve te...The ultrastructure of the X organ sinus gland complex in sexually immature Chinese mitten crab Eriocheir sinensis was examined under the electron microscope. The sinus gland (SG) is composed primarily of nerve terminals and glial cells. The terminal contains a great number of membrane bound granules, mitochondria, rough endoplasmic reticulum and electron lucent vesicles. The profiles of the terminals are sometimes exhibited finger like projections. The X organ (XO) locates at the ventral surface of the medulla terminalis ganglion in the eyestalk, oppositing to SG. According to the features of granule size, shape, electron density and cytoplasm, 6 types of terminals in SG and 7 types of neurosecretory (NS) cells in XO were identified. The release process by exocytosis of the granules in SG was observed and a tentative comparison was made for the granules between different types of terminals and NS cells. It seemed that they had a good correspondence since no change in electron density and just a slight increase of sizes was shown.展开更多
文摘The ultrastructure of oogenesis in the fern Osmunda cinnamomea L. var. asiatica Fernald has been studied by electron microscopy. During oogenesis, numerous vesicles not only moved towards the periphery, but also were arranged in line along the inside of plasmalemma, and in addition aggregated outside the plasmalemma by exocytosis. They released or excreted osmiophilic material. It was observed that a few vesicles containing lamellar osmiophilic material situated closely along the plasmalemma, seemed to break open. Simultaneously, a separation cavity between egg cell and archegonium wall formed. Its width was broader than the other advanced ferns reported previously, and an extra egg membrane occurred outside around the plasmalemma of the egg, its thickness being greater than in Pteridium and Dryopteris. Amyloplasts around the nucleus were filled with large triangular semicircular or subelliptical starch grains, but as the egg matured they progressively decreased. Nucleus was large and flattened, and paired membrane in two to three couples laid within the nucleus, close and parallel to the nuclear membrane. No nuclear evagination was observed. Mitochondria seemed to have been undeveloped, but finally recovered normally.
文摘The ultrastructure of the X organ sinus gland complex in sexually immature Chinese mitten crab Eriocheir sinensis was examined under the electron microscope. The sinus gland (SG) is composed primarily of nerve terminals and glial cells. The terminal contains a great number of membrane bound granules, mitochondria, rough endoplasmic reticulum and electron lucent vesicles. The profiles of the terminals are sometimes exhibited finger like projections. The X organ (XO) locates at the ventral surface of the medulla terminalis ganglion in the eyestalk, oppositing to SG. According to the features of granule size, shape, electron density and cytoplasm, 6 types of terminals in SG and 7 types of neurosecretory (NS) cells in XO were identified. The release process by exocytosis of the granules in SG was observed and a tentative comparison was made for the granules between different types of terminals and NS cells. It seemed that they had a good correspondence since no change in electron density and just a slight increase of sizes was shown.
