| In order to provide basic information and reference for the selection of improved varieties of Pinctada martensii and the response mechanism of air exposure stress.This paper systematically compares the differences between male and female in four shell color(golden,red,black and white)breeding lines of P.martensii,and explores the correlation between their shell color and total carotenoid contents(TCC)and physiological changes under air exposure conditions.The main results are as follows:To reveal the production performance of male and female populations of P.martensii with different shell colors(golden shell color,red shell color,black shell color and white shell color),quantitative traits(wet weight,shell weight,tissue weight,adductor muscle weight,shell height,shell width,shell length,hinge length and adductor muscle tension)and the infection status of Polydora ciliata in male and female were measured for comparative analyses.What’s more,we comprehensive assessment the advantages and disadvantages of the four different shell colors strains of P.martensii.The results showed that the females were bigger than the males in P.martensii,and the gender had little effect on the adductor muscle tension and the infection of P.ciliata.The growth performance of the red-shell color breeding line was the best.The adductor muscle tension of the white-shell color breeding line was 58.9±11.4 N,which was significantly larger than the black-shell color breeding line,golden-shell color breeding line and red-shell color breeding line of P.martensii(P<0.05).The total P.ciliata Infection rate of the red-shell color breeding line was highest as 85 %,so it’s ability of resistance to P.ciliate was the worst.There was a significant difference in gender differentiation between four different shell color strains of P.martensii(P<0.01),among which that the white-shell color breeding line and golden-shell color breeding line was male-most strains,and the red-shell color breeding line was female-most breeding line.In order to exploring the difference of TCC in tissues and its correlation with shell colors between four shell color strains of P.martensii.A total of 120 individuals(30 golden shells,30 red shells,30 black shells and 30 white shells)of P.martensii with a similar size were evaluated.In this study,the determination of TCC was measured at stomach,gill,adductor and mantle.The color measurements were taken at both the nacre shells and cuticle shells.The results showed that,the TCC significantly varies among four different tissues and the four different shell color strains(P<0.05).Significant difference between the cuticle shell colors of the four different shell color strains of P.martensii was observed(P<0.05),while the nacre shell colors of four shell strains were similar(P>0.05).In the present study,the results indicated that the TCC of P.martensii was significantly related to tissues and cuticle shell colors(P<0.001),but not related to nacre shell colors(P>0.05).The TCC related to the cuticle shell color suggesting that increasing or decreasing TCC in P.martensii through selective breeding of cuticle shell color was feasible,and it can be can be of significance and promising for the food for human and the cultivation of high-quality pearls.In order to investigate the effect of air exposure at different temperatures on the physiological indexes of four shell color strains of P.martensii,four shell color strains of P.martensii were measured at 19 ℃,26 ℃,and 31 ℃ for 12 hours,and re-watering for 72 hours.The survival rate at 72 h after re-watering and the 13 physiological indexes of stomach at 0,6,24,and 72 h during re-watering were measured.The results showed that 12 hours of air exposure at 31 ℃ significantly reduced the survival rate of P.martensii.In the 12 hours air exposure at 31 ℃,the black-shell color breeding line had the highest survival rate(80 %),and the golden-shell color breeding line had the lowest survival rate(44 %).The results showed that adipose is more important than cellulose and starch as the main energy source for anti-air exposure stress of P.martensii.The recovery of P.martensii after air exposure stress may not depend on NO,but mainly protects itself through the cooperation of SOD,CAT,GSH-PX of the antioxidant system and the hydrolytic enzymes ACP and ALP,and GSH-Px can be used as a detection index of anti-air exposure stress ability of P.martensii.In addition,air exposure at different temperatures had significant effects on LPS,ASAFR,SOD,NO,and ALP of P.martensii(P<0.05),different recovery times had significant effects on AMS,CL,ASAFR,SOD,T-AOC,POD,NO,ACP,and ALP(P<0.05),and there were significant differences in LPS,ASAFR,T-AOC,GSH-Px,MDA,ACP,and ALP in four shell-color strains of P.martensii(P<0.05).The results of three-way ANOVA showed that the effects of 2 or 3 factors in air exposure temperature,recovery time,and shell color on LPS,AMS,CL,ASAFR,SOD,T-AOC,POD,GSH-Px,CAT,MDA,NO,ACP and ALP of P.martensii had a significant interaction(P<0.001). |
