文章摘要
单环刺螠的繁殖生物学
Reproductive Biology of Urechis unicinctus
投稿时间:2019-06-24  修订日期:2019-09-01
DOI:
中文关键词: 单环刺螠  繁殖生物学  环境条件
英文关键词: Urechis unicinctus  reproductive biology  environmental factors
基金项目:江苏省科技厅苏北科技专项(LYG-SZ201814);江苏省优势学科建设工程资助项目(CXKT20180102);连云港市科技局现代农业项目(CN1411);连云港521高层次人才培养工程项目(KK18027);江苏省研究生和大学生科研与实践创新计划项目(SJCX18-0928)
作者单位E-mail
许星鸿 江苏海洋大学 xhxu119@163.com 
孟霄 江苏海洋大学  
甘宏涛 江苏海洋大学  
刘统昊 江苏海洋大学  
姚海洋 江苏海洋大学  
徐国成 江苏海洋大学  
丁姗 江苏海洋大学  
傅子玥 江苏海洋大学  
陈伟 江苏海洋大学  
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中文摘要:
      运用实验生态学和组织学方法研究了单环刺螠的性比、性腺指数、繁殖力、胚胎与胚后发育等繁殖生物学特征,并采用正交实验法分析了单环刺螠受精率和孵化率的最佳环境条件,为单环刺螠的人工增养殖提供科学依据。结果显示,单环刺螠雌雄比例为1∶1.17,雄性略多于雌性。成熟卵径为(145.16±1.70)×(141.27±1.94)μm,处于第1次成熟分裂前期。绝对繁殖力为111 800~720 488(449 684±265 905)粒,相对繁殖力为2 214~12 702(6 849±4 854)粒,怀卵量与体质量呈显著正相关(R=0.683,P<0.05)。生物学最小型体长约7 cm,体质量为11.21 g。精子密度为(5.88±0.52)×109/mL,雄体平均精子数为(2.41±0.73)×1010。雌性性腺指数在繁殖季节4—5月份呈现2个峰值,表明为分批产卵类型。在盐度25、水温15℃的条件下,胚胎发育经20~24 h孵化。组织学研究表明,单环刺螠为间黄卵,进行不等全裂,且有螺旋卵裂的特征,形成偏极囊胚,原肠作用方式为外包和内陷。胚后发育经担轮幼虫(孵化后1~10 d)、体节幼虫(11~20 d)、蠕虫状幼虫(21~30 d)发育为幼螠。正交实验结果表明,单环刺螠受精率的最佳环境条件为:温度25℃、盐度35、pH 8~9;孵化率的最佳环境条件为:温度15℃、盐度25、pH 8~9。
英文摘要:
      The reproductive biology of Urechis unicinctus was studied by the method of experimental ecology and histology, including the sex ratio, gonadosomatic index (GSI), fecundity, embryonic and postembryonal development. The optimal environmental conditions for fertility and hatching rate of U. unicinctus were also assessed by orthogonal experiments in order to provide reliable protocols for the artificial culture of U. unicinctus. The sexual ratio between the female and male was 1:1.17 and the males were slightly more than females. The mature oocyte remained at the prophase of the first maturation division with the diameter of (145.16±1.70) μm × (141.27±1.94) μm. The absolute fecundity ranging from 111 800 to 720 488 (449 684±265 905), while the relative fecundity ranging from 2 214 to 12 702 (6 849±4 854), and positive correlation between fecundity and weight were recorded. The biological minimum was about 7 cm of length and 11.21 g of weight. The sperm density was (5.88±0.52) × 109/mL, and the average number of sperm produced by each male was (2.41±0.73) × 1010. Two peaks of female GSI were observed in the breeding season from April to May, which suggested the type of spawn of U. unicinctus was in batches. The trochophore was hatched after 20-24 h of embryo development under the condition of salinity 25 and temperature 15 °C. According the histological observation, the oocyte of U. unicinctus was a type of mesopodium that developed into hemipolar blastocyst by unequal cleavage and spiral cleavage, and then the gastrulation was formed via outsourcing and invagination of cell migration. The postembryonal development after hatching included three stages: trochophore (1-10 d), somatic larva (11-20 d) and worm larva (21-30 d). The results of orthogonal experiments showed that the highest fertility and hatching rate was obtained under the conditions of temperature of 25 °C, the salinity of 35, and pH 8~9, and temperature of 15 °C, the salinity of 25, and pH 8~9, respectively.
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