金乌贼(Sepia esculenta)早期发育阶段内壳形态学指标的主成分分析

Principal Component Analysis of the Morphometric Traits of the Cuttlebone of Sepia esculenta at Early Developmental Stages

为揭示金乌贼(Sepia esculenta)早期发育阶段内壳生长发育规律和形态学特征,本研究采集其红珠与黑珠期、心跳期、出膜期、初孵化幼体、5日龄、10日龄6个时期的金乌贼,分别测量其胴腹长(DML)、胴宽(MB)、体重(BW)、壳长(CL)、壳宽(CB),壳重(CW)、生长纹数(LN)7项指标,进行内壳形态学的主成分分析。结果显示,红珠与黑珠期、出膜期和10日龄时期各生长指标间均呈显著性正相关,心跳期、初孵化幼体期和5日龄时期部分生长指标间相关性不显著。主成分分析显示,红珠与黑珠期、心跳期的第1主成分为质量因子(体重和壳重),出膜期、初孵化幼体、5日龄、10日龄等4个时期的第1主成分为长度因子(胴腹长和壳长),这表明金乌贼不同时期内壳形态学各性状的生长速率存在一定差异,出膜前(红珠与黑珠期和心跳期)质量因子的增长优于长度因子的增长,而出膜后(出膜期至10日龄时期)长度因子的增长优于质量因子的增长。

To characterize the traits of the cuttlebone of Sepia esculenta at the early developmental stages, we collected data at different stages including the red-bead and black-bead stage, the heart-beating stage, the hatching stage, the newly-hatched larvae stage, the 5-day-old stage and the 10-day-old stage. The principal component analysis was performed to evaluate seven growth traits including the dorsal mantle length, the mantle breadth, the body weight, the cuttlebone length, the cuttlebone breadth, the cuttlebone weight and the lamella number. The results showed that there were significant correlations between any two traits at the red-bead and black-bead stage, the hatching stage and the 10-day-old stage. However, some traits showed no correlation at the heart-beating stage, the newly-hatched larvae stage and the 5-day-old stage. The first principal component was the weight factor at the first two stages, and it became the length factor at other four stages. The second principal component was the length factor and width factor. The third principal component was mostly the width factor. At only two stages there was the fourth principal component that was the lamella factor and the width factor. The growth rate of these traits varied at different stages. From the red-bead and black-bead stage to the heart-beating stage, the morphometric traits outgrew the body weight, and this pattern was reversed from the hatching stage to the 10-day-old stage.