Effects of Temperature Changce on The Early Embryo Development of Rana chensinensis David

It is very promising to develop Rana chensinensis David breeding in South China.Whether the changeable air temperature of the South has an effect on its embryo development is uncertain.We studied the effects of temperature change on early embryo development by moving fertilized eggs between incubators of different temperatures.The results showed:(1) Rapid temperature increase had a harmful influence on hatching and normal rates of the embryos,and the wider the temperature span was,the more harmful the impact was.Effects of moderate temperature increase on embryos were hinged upon the temperature span and starting point.High starting temperature was more harmful.In commercial production,rapid temperature increase should be within 2℃,moderate increase should be within 4℃.(2) In moderate temperature decrease,a span of 4℃ had no influence,but an 8℃ decrease was detrimental.If rapid temperature decrease span was 4℃,both hatching and normal rates were impaired.In commercial production,moderate temperature decrease should be within 8℃ and rapid decrease should be within 4℃.(3) When the change spans were the same,the quicker the change was,the more harmful the impact was.(4) The Gastrula Stage was the time when embryos were sensitive to temperature increase,and the Neural Canal Stage was not.Embryos were more sensitive to temperature increase than to decrease.(5) No serious harm would be imposed upon Rana chensinensis David embryos in development by the changeable climate of South China.