The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and...The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and early development as well as the morphology, of egg and larva in different ascidian species were compared. Styela canopus is oviparous. Its egg, 230.4 similar to 336.0 mum in diameter, is equipped with extraembryonic cell layers measured 43.2 similar to 63.0 mum thick. The early development of Styela canopus is typical urodele development, including fertilization, cleavage, gastrulation, tadpole in membrane, tadpole, initiating metamorphosis and juvenile. The tadpole of Styela canopus, with a length of 0.6 similar to 0. 9 mm, consists of trunk and tail. There are obvious notochord, ocellus and adhesive papillae in the tadpole. Under the water temperature of (25 +/- 0-5) degreesC and the salinity of 27.0, the larva was hatched after 9.5 similar to 11.0 h since the fertilization.展开更多
The larvae of ascidian Styela canopus Savigny were treated with epinephrine, norepinephrine, L-DOPA, GABA and thyroxin to test the ability of these compounds to induce or inhibit larval settlement and metamorphosis. T...The larvae of ascidian Styela canopus Savigny were treated with epinephrine, norepinephrine, L-DOPA, GABA and thyroxin to test the ability of these compounds to induce or inhibit larval settlement and metamorphosis. The results showed that epinephrine, norepinephrine and L-DOPA at the concentration of 1 μmol/dm^3 induced larval settlement and metamorphosis in S. canopus, with short exposure （ 1 h） to 1 μmol/dm^3 of L-DOPA inducing rapid settlement. In contrast, GABA at the concentrations of 0.1 ～1130.0 μmol/dm^3 significantly inhibited the settlement and metamorphosis of S. canopus larvae. In addition, thyroxin at 1 -50 μg/dm^3 had no effect on larval settlement and metamorphosis in S. canopus. These results suggest the importance of neurotransmitters in the settlement and metamorphosis of S. canopus larvae.展开更多
The larvae of Styela canopus show the highest rates of settlement and metamorphosis when treated with 40 mM KCl-elevated seawater at 25 degreesC in temperature and 27.0 in salinity. Induced by 40 mM KCl-elevated seawa...The larvae of Styela canopus show the highest rates of settlement and metamorphosis when treated with 40 mM KCl-elevated seawater at 25 degreesC in temperature and 27.0 in salinity. Induced by 40 mM KCl-elevated seawater, it took Styela canopus larvae approximately 3 h after hatching to develop competence to settle and metamorphose. The present experiment shows that Styela canopus larvae is an ideal model organism for examining the efficiency of antifouling substance.展开更多
文摘The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and early development as well as the morphology, of egg and larva in different ascidian species were compared. Styela canopus is oviparous. Its egg, 230.4 similar to 336.0 mum in diameter, is equipped with extraembryonic cell layers measured 43.2 similar to 63.0 mum thick. The early development of Styela canopus is typical urodele development, including fertilization, cleavage, gastrulation, tadpole in membrane, tadpole, initiating metamorphosis and juvenile. The tadpole of Styela canopus, with a length of 0.6 similar to 0. 9 mm, consists of trunk and tail. There are obvious notochord, ocellus and adhesive papillae in the tadpole. Under the water temperature of (25 +/- 0-5) degreesC and the salinity of 27.0, the larva was hatched after 9.5 similar to 11.0 h since the fertilization.
基金This research was supported by the National Natural Science Foundation of China under contract Nos 40276041 and 49976034.
文摘The larvae of ascidian Styela canopus Savigny were treated with epinephrine, norepinephrine, L-DOPA, GABA and thyroxin to test the ability of these compounds to induce or inhibit larval settlement and metamorphosis. The results showed that epinephrine, norepinephrine and L-DOPA at the concentration of 1 μmol/dm^3 induced larval settlement and metamorphosis in S. canopus, with short exposure （ 1 h） to 1 μmol/dm^3 of L-DOPA inducing rapid settlement. In contrast, GABA at the concentrations of 0.1 ～1130.0 μmol/dm^3 significantly inhibited the settlement and metamorphosis of S. canopus larvae. In addition, thyroxin at 1 -50 μg/dm^3 had no effect on larval settlement and metamorphosis in S. canopus. These results suggest the importance of neurotransmitters in the settlement and metamorphosis of S. canopus larvae.
基金National Natural Science Foundation of China under contract No. 49976034.
文摘The larvae of Styela canopus show the highest rates of settlement and metamorphosis when treated with 40 mM KCl-elevated seawater at 25 degreesC in temperature and 27.0 in salinity. Induced by 40 mM KCl-elevated seawater, it took Styela canopus larvae approximately 3 h after hatching to develop competence to settle and metamorphose. The present experiment shows that Styela canopus larvae is an ideal model organism for examining the efficiency of antifouling substance.
