盐度对沙蜇有性繁殖阶段早期发育的影响  

Effects of salinity on early development in sexual reproduction stage of the scyphozoan Nemopilema nomurai Scyphozoa Rhizostomeae

作　　者：柴雨[1] 董婧[1] 段妍[1] 孙明[1] 王彬[1] 李玉龙[1] 刘修泽[1] 王爱勇[1] 王小林[1] 于旭光[1] 郭栋[1] CHAI Yu;DONG Jing;DUAN Yan;SUN Ming;WANG Bin;LI Yulong;LIU Xiuze;WANG Aiyong;WANG Xiaolin;YU Xuguang;GUO Dong(Liaoning Ocean and Fisheries Science Research Institute,Key Laboratory of Marine Biological Resources and Ecology,Liaoning Province,Dalian 116023,China)

机构地区：[1]辽宁省海洋水产科学研究院,辽宁省海洋生物资源与生态学重点实验室,大连116023

出　　处：《生态学报》2020年第13期4383-4391,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(31770458,41906138);国家重点研发计划项目(2017YFC1404400);辽宁省科学事业公益研究基金项目(20180053)。

摘　　要：近几十年来,沙蜇的频繁暴发给东亚海域的海洋生态系统带来了广泛影响。在秋季,沙蜇成熟的雌雄水母体在沿岸水域聚集产卵,有性繁殖产生的受精卵发育成新的底栖螅状体,为螅状体种群数量进行补充。河口浅滩海域为沙蜇的繁育地,沿岸盐度较低,在秋季降雨期盐度多变,较低、多变的盐度可能对沙蜇有性繁殖阶段的早期发育产生重要作用,从而影响螅状体种群数量的补充。实验设置了4种不同盐度(15、20、25、30)试验组,在不同盐度下对沙蜇受精卵进行培养,探讨盐度对沙蜇早期发育过程中受精卵、浮浪幼虫发育以及早期螅状体生长及存活的影响。试验结果:沙蜇受精卵胚胎发育的适宜盐度为20,发育基本与盐度25、30同步,盐度15受精卵细胞发育迟缓,发育率显著降低;浮浪幼虫发育适宜盐度为20和25,两组浮浪幼虫附着变态率高于盐度15、30,盐度15时浮浪幼虫活力明显降低、发育迟缓,浮浪幼虫在盐度15时水中存活时间较长可达8 d,但附着时间集中在培养后的3、4天,与其他组相同;早期螅状体幼体适宜盐度为20、25、30,早期螅状体存活率、相对增长率及特定生长率均显著高于盐度15,三组间差异不显著。结果表明,盐度显著影响沙蜇有性繁殖阶段的早期发育,随着受精卵至螅状体的发育生长,其对盐度的适应范围逐步扩大。In the past few decades, Nemopilema nomurai underwent blooms over many years that have affected ecosystems in East Asian waters. In the fall, male and female N. nomurai medusa gather to spawn in coastal seawaters. The egg develops into a tiny larva known as planula that swims to the seabed and transforms into the polyp stage. New polyps formed by sexual reproduction replenish the polyp population, and after sexual reproduction, the mature medusa die during the autumn season. The polyps survive in the winter to produce the following year′s progeny. Therefore, the number of polyps serves as the basis for medusoid stage(free-swimming) blooms. The Yangtze river′s offshore area is a principal breeding location of N. nomurai, where its pelagic stages appear earliest in the Yellow Sea and East China Sea. Additionally, the northern inner coast of the Liaodong Bay(LDB) is another breeding place, and as the season progresses, N. nomurai in this area grow and mature, expanding their area of distribution to the whole LDB or are advected to the southern Liaodong peninsula. In these coastal waters, the spawning of N. nomurai coincides in August-September with the summer monsoon season, where extreme rainfall subject fertilized egg embryo development, planula survival and settlement, new polyp survival and growth. In this study, laboratory experiments were conducted to determine how prolonged exposure to salinity(15, 25, 20, and 30) affected the development of the fertilized egg, settlement of planula, and the development of metamorphosed new polyps. During the embryonic development stage, salinity 20 fertilized eggs developed the highest percentage of planula, where the time to develop planula was synchronized with salinities of 25 and 30. Salinity 15 fertilized eggs were stunted, and their embryo development rate decreased significantly. In the planula settlement stage, planulae showed the highest settlement rates in environments with salinities of 20 and 25. At salinity 15, the larvae′s swimming ability in water was si

关 键 词：沙蜇 盐度 有性繁殖 受精卵 浮浪幼虫 螅状体 

分 类 号：S917.4[农业科学—水产科学]