| Meretrix meritrix is an important economic shellfish in China. The shell colorpolymorphism of M. meritrix is very rich. In this paper, comparison of cultured effect;traits at early developmental stage and digestive enzyme activities of different shellcolors M. meritrix were studied.The main experimental contents and results were as follows:1. Types of shell color and their distribution frequency in individuals from redshell color M. meritrix were analyzed, traits of different shell colors M. meritrix werequantified such as shell length, s hell width and s hell height. Also, morpHological traitsand growth rate were studied. The results showed that the frequency of shell colorsincluding red, yellow, double-white, double-yellow and ripple were75.58%,8.55%,0.53%,14.83%and0.50%, which indicating that the shell color of M.meretrix is ofpolymorpHism. The cluster analysis and Euclidian matrix showed that ripple had theclosest relationship with yellow, double-white had the closer relationship withdouble-yellow, and the furthest relationship between red and other colors. Results ofprinciple component analysis revealed the spatial distribution of different shell colors,which further explained the relationship of five shell colors. In the same pond, thedaily growth rate of red shell color was0.20%while the one of other shell colors was0.18%. The growth rate of red shell color was10.41%higher than other shell colors.The shell length had the regression with shell width, shell height and individual weight.The regression equations of red shell color spectively were:y=0.5024x-0.556(R2=0.992), y=0.8103x+0.62(R2=0.9956), y=0.0003x2.9029(R2=0.9919).The regression equations of other shell color were: y=0.4953x-0.4192(R2=0.9909),y=0.7985x+0.7935(R2=0.9956), y=0.0004x2.8458(R2=0.9934). 2. The study of breeding about shell color of M.meretrix was carried out in July2011. Family with red shell color (RR), family with yellow shell color (YY) andfamily with F1of red shell color (F1RR) were established respectively. The diameterof fertilized eggs, hatching rate and the growth during different stages as well as theshell color of individuals from established family were analysed respectively. Theresults showed that:(1) the diameter of fertilized eggs and hatching rate among threefamilies existed no significant difference（P>0.05）. At the planktonic stage and earlyattachment stage, the difference of individuals about growth traits was not significant.After15d, the growth rate of RR,F1RR was more faster than that of YY（P<0.05）.(2)During15d-35d F1RR grew faster significantly than RR. However after42d, F1RRgrew slower significantly than RR, which may be related to the size of individuals ofparents.(3) the result of statistical analysis about shell color showed that the proportionof individuals about red shell color among F1RR,RR,YY was97.93±0.31%,75.65±0.73%,2.05±0.29%respectively.3. With two shell color groups breeding from red M.meretrix as experimentalmaterial, traits of different shell color groups were quantified such as shell length, s hellwidth and s hell height. These different shell color M.meretrix were divided into fivegroups N1, N2, N3, N4, N5, according to shell length. Under the same experimentalconditions, compare the amylase and cellulase activity of different shell colors ofM.meretrix.The results showed that: the average shell length, shell height, shell widthand weight of the red s hell color groups were25.83±3.05mm,12.41±1.66mm,21.58±2.56mm,4.20±1.70g. Yet the average shell length, s hell height, s hell width andweight of the yellow shell color groups were24.65±2.82mm,11.87±1.46mm,20.42±2.27mm,3.61±1.38g. Univariate analysis showed that the red shell colorM.meretrix grow faster significantly than the shell color yellow M.meretrix(P <0.05).The amylase activity of red shell color M.meretrix changed in the range was1.90~3.30U/mg, while the yellow shell color M.meretrix was1.38~3.00U/mg. Thecellulose activity in the red shell color M.meretrix changed in the range was 36.81~72.41U/mg,but the yellow shell color M.meretrix was29.50~57.18U/mg.Amylase and cellulase activity of the red shell color M.meretrix was significantlyhigher than the yellow shell color M.meretrix (P <0.05). These results show thatgrowth rate, amylase and cellulase activity of M.meretrix may relate to shell color. |
