Very slow embryonic and larval development in the Antarctic limpet Nacella polaris
Very slow embryonic and larval development in the Antarctic limpet Nacella polaris
复制标题
南极帽贝的胚胎和幼虫发育非常缓慢
作者：
L. Peck;S. Heiser;M. Clark
寒冷的极地海洋物种的胚胎和幼体发育速度非常慢。南极棘球类、双壳软体动物和孵化腹足类的发育速度比温带和热带物种慢12倍，这与Arrhenius关系背道而驰，也超出了与生化反应速率降低10℃相关的正常Q10(2-3)。此前有报道称，在0摄氏度左右的温度下，发育放缓的程度比全球海洋温度范围的其他部分要大得多。在这里，我们在0.6摄氏度到扭转后的绒毛阶段产卵和饲养了南极极地眼镜蛇的胚胎和幼虫。产卵卵直径221微米。盘状星形足类的发育速度比之前报道的任何一种都要慢三倍，第一次分裂在受精后2.5小时，原肠胚期在55小时后，孵化在70-75小时后，担轮孢子阶段在大约100小时后。在0摄氏度左右，发育明显放缓，与之前报道的其他极地类群的发育速度相匹配。这支持了这样一种假设，即在0°C附近有一个冷的海洋生理转变到明显较慢的生理速率。这种转变在发育过程中尤其明显，但也有报道表明生长过程中，这两个过程都涉及大量的蛋白质合成。
Cold polar marine species have very slow embryonic and larval development rates. Antarctic echinoids, bivalve molluscs and brooding gastropods develop up to 12 times slower than temperate and tropical species, departing from Arrhenius relationships and outside the normal Q10 of 2–3 associated with 10 °C reductions in biochemical reaction rates. The slowing of development at temperatures around 0 °C has been reported previously to be much greater than for other parts of the global marine temperature range. Here we spawned and reared embryos and larvae of the Antarctic limpet Nacella polaris at 0.6 °C to the post-torsional veliger stage. Spawned eggs were 221 µm in diameter. Development rates were three times slower than any previously reported for patellogastropod limpets, with first division at 2.5 h post-fertilisation, the gastrula stage being reached after 55 h, hatching occurring after 70–75 h and the trochophore stage being reached after around 100 h. The marked slowing of development around 0 °C matches that previously reported for other polar taxa. This supports the hypothesis that there is a cold marine physiological transition to markedly slower physiological rates at temperatures near 0 °C. The transition is especially apparent here for development, but has also been reported for growth, both of which involve significant protein synthesis.