| The gourmets like to eat Capitulum mitella which is a natural resource that can’t artificially cultivate,and there is less research on the cirripedia.The paper determined the optimum temperature and salt range of juvenile,young in Capitulum mitella,proved that juvenile hormone and ecdysone were related with the process of molt and metamorphosis.Respectively,salinity and temperature experiments were conducted on Capitulum mitella juvenile,recorded the number of deaths,rostro-carina length and capitulum length regularly.The results showed that the juveniles could survive at the salinity from 16 to 48,the highest survival rate was 63.33±4.71%at the salinity of 28,and the lowest survival rate was 21.67±5.14%when the salinity was 16.When the salinity was 32,the growth rates of rostro-carina length and capitulum length both were highest,which were 4.57±0.24 μm/d,6.28±0.44 μm/d,and the lowest growth rates both at the salinity of 48,which were 1.04±0.37 μm/d,0.89±0.55 μm/d.At the temperature of 10℃ to 40℃ with a gradient of 5℃,seven groups of temperature were set for 30 days of experiment to find the optimum temperature range of Capitulum mitella juvenils growth.The juveniles could survive at temperature range from 10℃ to 35℃ and have a maximum survival rate of 93.02%at 20℃ and all dead at 40℃.The growth rates of rostro-carina length and capitulum length both were highest at the temperature of 25℃,which were 23.61±0.20μm/d and 37.02±0.51 μm/d,respectively,the lowest growth rates were at the temperature of 10℃,which were 0.45±0.11 μm/d,1.19±0.44 μm/d.So the best cultivation conditions for Capitulum mitella juvenile were salinity range from 28 to 32 and temperature range from 20℃ to 25℃.The experiment was conducted to study the combined effects of salinity and temperature on the growth of Capitulum mitella young,recorded the growth date regularly.The results showed that salinity and temperature both had significant differences on growth of rostro-carina lengths and capitulum lengths,but there was no difference in interaction,and only the temperature had significant difference on weight gain of individual.The combinations of temperature and salinity which rostro-carina length and capitulum length grow fastest both were 25℃+30 ‰,the rates both were 0.027±0.002 mm/d,the combinations which grew slowest both were 25℃+30‰,the rates were 0.002±0.001 mm/d,0.004±0.003 mm/d respectively;The combination of individual weight gain rate maximum was 25℃+30‰,the rate was 0.449±0.116 mg/d,the smallest combination was 35℃+34‰,it was 0.098±0.036 mg/d.So the optimum incubation temperature for Capitulum mitella young is 25℃+30‰.The contents of juvenile hormone and ecdysone were measured in the different stages of Capitulum mitella embryo and larval development,the three stages of metamorphsis from cyprid to juvenile which were treated by MF or NF,and the soft part and the handle muscle of Capitulum mitella young and adult.The results showed that the changes of juvenile hormone were significant during larval development,and the changes of ecdysone was not obvious.NF could increase the level of juvenile hormone and reduce ecdysone content in juveniles.There were no differences in the contents of juvenile hormone between the soft part and the handle muscle of young and adult,but there was significant difference between young and adult on ecdysone.It shows that there are juvenile hormone and ecdysone in Capitulum mitella,juvenile hormone plays a dominant role in the larvae stage,ecdysone promote the cirrus molting on larvae. |
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