Silla Aimee J
Institute for Conservation Biology and Environmental Management, School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia. Email:
Reprod Fertil Dev. 2013;25(8):1134-41. doi: 10.1071/RD12223.
Anurans exhibit a greater reproductive diversity than any other vertebrate order. However, studies investigating the effects of the external fertilisation environment on fertilisation success are limited to aquatic-breeding species. This study investigated the effects of fertilisation medium osmolality, sperm concentration and short-term oocyte storage on fertilisation success in a terrestrial-breeding anuran, Pseudophryne guentheri. Split-clutch experimental designs were used to determine optimal fertilisation conditions. To determine the effect of short-term sperm storage, sperm viability was assessed using fluorescence microscopy and percentage sperm motility and velocity quantified with a computer-assisted sperm analysis system. Fertilisation success was highest in media ranging in osmolality from 25 mOsm kg⁻¹ to 100 mOsm kg⁻¹, representing a broader range and higher optimal osmolality than previously reported for aquatic breeders. High rates of fertilisation (>75%) were achieved in relatively low sperm concentrations (2.5×10⁴ mL⁻¹). Oocytes stored in isotonic solutions (200 mOsm kg⁻¹) retained fertilisation capacity (32%) after 8h of storage, while sperm suspensions maintained motility (≥26%) for 13 days. Additional studies on terrestrial-breeding anurans will be required to ascertain whether the optimal fertilisation conditions reported reflect adaptations to achieve fertilisation in a terrestrial environment.
无尾目动物展现出了比其他任何脊椎动物目都更为丰富的繁殖多样性。然而，研究外部受精环境对受精成功率影响的研究仅限于水生繁殖物种。本研究调查了受精介质渗透压、精子浓度和短期卵母细胞储存对一种陆生繁殖无尾目动物——冈氏伪蛙受精成功率的影响。采用分窝实验设计来确定最佳受精条件。为了确定短期精子储存的影响，使用荧光显微镜评估精子活力，并通过计算机辅助精子分析系统对精子活力百分比和速度进行量化。在渗透压范围为25 mOsm kg⁻¹至100 mOsm kg⁻¹的介质中，受精成功率最高，这表明与先前报道的水生繁殖者相比，其渗透压范围更广且最佳渗透压更高。在相对较低的精子浓度（2.5×10⁴ mL⁻¹）下也能实现较高的受精率（>75%）。储存在等渗溶液（200 mOsm kg⁻¹）中的卵母细胞在储存8小时后仍保留受精能力（32%），而精子悬液在13天内保持活力（≥26%）。还需要对陆生繁殖无尾目动物进行更多研究，以确定所报道的最佳受精条件是否反映了在陆地环境中实现受精的适应性。
