中国鲎幼鲎形态性状与体重的通径分析及异速生长研究

为了探究不同龄期中国鲎幼鲎生长特性，实验测定了2～4龄幼鲎头胸部长(X₁)、头胸部宽(X₂)、腹部长(X₃)、腹部宽(X₄)、剑尾长(X₅)、全长(X₆)和体重(Y)等参数，运用相关分析和通径分析方法，探讨形态性状对体重的作用效果。结果显示，2～4龄幼鲎体重相关系数最高的形态性状均为头胸部宽(X₂)；通径分析发现，头胸部宽(X₂)对2龄和3龄幼鲎体重直接影响最大，腹部宽(X₄)对4龄幼鲎体重直接影响最大；各形态性状对体重决定程度分析与通径分析变化趋势一致。对2～4龄幼鲎头胸部宽和体重进行对数处理，获得异速生长方程回归系数(b)为2.746，表明此阶段幼鲎体重增长率大于头胸部宽增长率，处于正生长期。实验表明，不同龄期阶段中国鲎苗种筛选所依据的形态性状有所差异，中国鲎幼鲎阶段种质评价应考虑其异速生长规律，同时也为探究鲎的生长与性状、结构与生理之间的关系奠定基础。

Path analysis and allometric growth of morphological characters and body mass of juvenile Tachypleus tridentatus

IThe blood of the horseshoe crab, an ancient marine arthropod, is widely used in the production of tachypleus amebocyte lysate (TAL) for medical testing. The number of horseshoe crab resources in China has declined significantly in the last 30 years, the study of the relationship between morphological traits and body mass of Tachypleus tridentatus and the analysis of anisotropic growth will not only help to understand the growth characteristics of juvenile horseshoe crabs, but also reflect the resource allocation strategy and help to conserve horseshoe crab resources. In this study, the cephalothorax length (X1), cephalothorax width (X2), opisthosoma length (X3), opisthosoma width (X4), telson length(X5), total length (X6) and body mass (Y) of 2- 4 instars juvenile horseshoe crabs were measured, correlation analysis and path analysis were used to explore the effect of morphological traits on body weight. The results showed that the morphological traits with the highest correlation coefficient (r) of body weight of 2-4 instars juvenile horseshoe crabs were cephalothorax width (X2). Path analysis showed that the cephalothorax width (X2) had the most immediate impact on the body weight of 2 and 3 instars juvenile horseshoe crabs, and the opisthosoma width (X4) had the greatest direct impact on the body weight of 4 instars juvenile horseshoe crabs. The analysis of the degree of determination of various morphological traits on body mass is consistent with the path analysis. The cephalothorax width and body weight of 2-4 instars horseshoe crabs are processed logarithmically, and the regression coefficient (b) of the allometric growth equation is 2.746, it shows that the growth rate of juvenile horseshoe crab body mass is greater than the growth rate of cephalothorax width at this stage, and it is at the stage of positive growth. The present study shows that the morphological traits of seedling screening of T. tridentatus at different age stages are distinct, and the evaluation of the germplasm of the juvenile T. tridentatus should take into account its allometric growth pattern. The current study also provides a basis for exploring the relationship between growth and traits, structure and physiology of the horseshoe crab.