Key Laboratory of Freshwater Fishery Germplasm Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, China.
Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai, China.
J Fish Biol. 2019 Sep;95(3):903-917. doi: 10.1111/jfb.14088. Epub 2019 Aug 1.
We describe the process of retinal development in mandarinfish Siniperca chuatsi from larvae to young fish. The developmental characteristics of the retinal structure and related cells were identified. Siniperca chuatsi were found to exhibit an altricial mode of retinal development that required considerable time to be completed after hatching. The retina was classed as a pure cone type during the early developmental stage. In the subsequent developmental stages, however, double cones gradually occupied the majority of the cone cells, while rod cells represented the majority of the photoreceptor cells. The outer segment (OS) of the rod cells were significantly longer compared with other morphological features, the OS of the two kinds of cone cells were significantly elongated and the diameters of the inner segment (IS) and OS of the double cone cells were significantly narrower in the later developmental stages. Combined with the scattered arrangement of cone cells at the different stages, the retina was found to have sacrificed a considerable part of visual acuity in the developmental process. The distribution of cone cells was observed to have gradually become regionalised during development. The findings of the present study also indicated that S. chuatsi have a high photosensitivity under dim light conditions as a result of specialised structures of the OS of photoreceptor cells and an increased number of rod cells. The loose arrangement of the cone mosaic presumably resulted in a poor imaging quality and, to some extent, the regionalisation of the cone-cell distribution compensated for the above shortcomings, which would enhance the ability of S. chuatsi to perceive targets in important directions for effective predation behaviour.
我们描述了从幼鱼到仔鱼阶段的中国团头鲂（Siniperca chuatsi）视网膜的发育过程。确定了视网膜结构和相关细胞的发育特征。中国团头鲂表现出晚成型的视网膜发育模式，孵化后需要相当长的时间才能完成。在早期发育阶段，视网膜被归类为纯锥细胞类型。然而，在随后的发育阶段，双锥细胞逐渐占据了大多数锥细胞，而杆细胞则代表了大多数感光细胞。杆细胞的外节（OS）比其他形态特征长得多，两种锥细胞的 OS 显著延长，双锥细胞的内节（IS）和 OS 的直径在后期发育阶段明显变窄。结合不同阶段锥细胞的分散排列，发现视网膜在发育过程中牺牲了相当一部分视力。在发育过程中，观察到锥细胞的分布逐渐区域化。本研究的结果还表明，由于感光细胞 OS 的特殊结构和杆细胞数量的增加，中国团头鲂在暗光条件下具有较高的光敏性。锥细胞镶嵌的松散排列可能导致成像质量较差，而锥细胞分布的区域化在一定程度上弥补了上述缺点，这将增强中国团头鲂感知重要方向目标的能力，从而有效地进行捕食行为。
