配子浓度、年龄和接触时间对热带物种杜氏白星海胆（Salmaciella dussumieri）受精成功率的影响。

Impacts of gamete concentration, age and contact time on the fertilization success in the tropical species of white sea urchin, Salmaciella dussumieri.

作者信息

Rahman M A, Yusoff F M, Arshad A, Amin S M Nurul

出版信息

J Environ Biol. 2016 Jul;37(4 Spec No):647-56.

Abstract

The globoid sea urchin (Salmaciella dussumieri) occurs abundantly in the Indo-West Pacific from the Island of the West Indian Ocean, East Africa, Magdagascar, Red Sea, South-East Arabia, Ceylon, Bay of Bengal, North Australia, Philippine, China and South Japan and Australia, and also has significant biological, ecological, aquaculture, conservational and medicinal importance. An experiment was carried out to assess the influence of sperm dilution, egg concentration, sperm-egg exposure time, and gamete aging on fertilization success of S. dussumieri in a captive laboratory condition. It has been found that dilution, age and contact time of sperm to egg were successively the most dominant factors effecting the success of fertilization, but concentration of eggs did not significantly so over the range investigated. The sperms retained their competency for more than two hours only in relatively dense sperm concentrations (≥ 10-(4) dilution of 'dry' sperm), although they exhibited lower capability and potency with increasing dilutions and age. In the trials of the egg-sperm exposure time, >80% eggs were fertilized within 10 sec of contact time at lower dilutions (10(-3)-10(-2)) of concentrated sperm, while some longer times were required to get the higher rates of fertilization. On the contrary, eggs remained in good quality for up to a period of 3 h and no abnormality or any adverse effects in fertilization were observed. The findings obtained from the present experiment reveal that limited longevity of diluted sperm have an important effect on fertilization rate of sea urchin eggs during natural spawning seasons in the field. Hence, the globoid sea urchin (S. dussumieri) is under extensive selective pressures to breed synchronously with the purpose of producing high sperm concentrations and higher sperm-egg interactions to maximize the success of fertilization in the water column.

摘要

球形海胆（Salmaciella dussumieri）大量分布于印度洋 - 西太平洋地区，范围包括西印度洋岛屿、东非、马达加斯加、红海、阿拉伯半岛东南部、锡兰、孟加拉湾、北澳大利亚、菲律宾、中国、日本南部以及澳大利亚，并且具有重要的生物学、生态学、水产养殖、保护及药用价值。在实验室圈养条件下开展了一项实验，以评估精子稀释度、卵子浓度、精卵接触时间以及配子老化对球形海胆受精成功率的影响。研究发现，精子的稀释度、老化程度以及与卵子的接触时间依次是影响受精成功的最主要因素，但在所研究的卵子浓度范围内，卵子浓度对受精成功率并无显著影响。精子仅在相对较高的精子浓度（“干”精子稀释度≥10⁻⁴）下能保持两小时以上的受精能力，不过随着稀释度增加和老化，其受精能力和活力会降低。在精卵接触时间试验中，在较低浓度精子稀释度（10⁻³ - 10⁻²）下，超过80%的卵子在接触10秒内受精，而要达到更高的受精率则需要更长时间。相反，卵子在长达3小时内质量良好，未观察到受精异常或任何不利影响。本实验结果表明，稀释精子的有限寿命对野外自然产卵季节海胆卵子的受精率有重要影响。因此，球形海胆（S. dussumieri）面临着巨大的选择压力，需要同步繁殖，以产生高精子浓度和更强的精卵相互作用，从而在水柱中最大限度地提高受精成功率。