生长前期三疣梭子蟹(Portunus trituberculatus)附肢再生系统解析及阶段划分

摘要

以三疣梭子蟹(Portunus trituberculatus)第Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ期幼蟹为材料,采用组织切片等方法研究其大螯断肢后再生生长规律.结果表明,第Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ期幼蟹大螯一次蜕壳再生率分别为59.9％,75.3％,74.2％,80.4％,69.5％;断肢组存活率分别为89.4％,84.9％,85.2％,89.4％和74.2％,均低于对照组的98.2％,90.3％,95.1％,90.2％和80.3％,但差异不显著(P＞0.05);第Ⅰ、Ⅱ、Ⅲ期断肢组在去大螯后平均蜕壳周期分别为3.33d、4.47d和6.27d,显著长于正常组的2.13d、3.89d和5.63d) (P＜0.05),而第Ⅳ、Ⅴ期断肢组平均蜕壳周期分别为7.12d和10.86d,极显著长于对照组的6.11d和8.09d (P＜0.01),且断肢个体的生长期越往后,断肢再生所需时间越长.本研究依据再生附肢发育特点将三疣梭子蟹大螯断肢再生划分为6个标志性发育阶段:再生芽基期、肢芽趾缝期、肢芽分化期、肢芽斑点期、肢芽成熟期、肢体出膜期;第1、Ⅱ、Ⅲ、Ⅳ、Ⅴ期蟹再生肢芽横纵比平均值分别达到0.32、0.318、0.398、0.518、0.538时,断肢幼蟹可以达到附肢出膜的临界点.综上所述,三疣梭子蟹断肢后能在1个蜕壳周期内完成大螯再生,第Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ期断肢幼蟹蜕壳周期时间显著高于正常幼蟹;断肢组成活率低于对照组,但差异不显著,第Ⅳ期幼蟹的再生率和存活率均最高;各期幼蟹断肢再生附肢均经过6个具有标志性事件的发育阶段;各期再生肢芽横纵比值具有一定临界值(0.32,0.318,0.398,0.518,0.538).本研究首次对三疣梭子蟹断肢再生过程及再生能力进行了探究,结果将有助于甲壳类断肢再生机理的阐明.%Limb regeneration mechanism ofPortunus trituberculatus in different growth stages (Ⅰ to Ⅴ) was studied with histological sections.The results indicate that the limb regeneration rate after the first molt for stages Ⅰ to Ⅴ was 59.9％,75.3％,74.2％,80.4％,69.5％,respectively.The survival rate of limb (89.4％,84.9％,85.2％,89.4％,and 74.2％,respectively) was lower than that of the control group (98.2％,90.3％,95.1％,90.2％,and 80.3％,respectively),insignificantly.The average molting days of limb regeneration group for stages Ⅰ,to Ⅲ was 3.33,4.47,and 6.27d,respectively,which is significantly longer than the control group's (P＜0.05).However,the average molting days of stages Ⅳ and Ⅴ was 7.12 and 10.86d,which is significantly longer than the control group's (P＜0.01).For crabs in stage Ⅳ,six landmark developmental stages can be divided,i.e.,regeneration of bud base,limb bud toe seam,limb bud differentiation stage,limb bud spots,limb bud maturity,and molt regeneration.The regeneration could succeed when average ratio of spine buds for these five stages reached 0.32,0.38,0.39,0.518,and 0.538.Totally,large chelating regeneration could be completed in a molting cycle.The molting cycle of the larvae in stages Ⅰ to Ⅴ were significantly longer than those of normal crabs.Both the regeneration rate and survival rate of the first-stage crab were the highest.The regeneration could be completed after all the six landmark developmental stages and the average ratio of spine buds must reach a certain critical value.Therefore,the limb regeneration mechanism of P.trituberculatus may enrich our knowledge for crustacean aquaculture industries.