黑鲷视网膜结构与视觉特性研究

黑绸Ｓｐａｒｕｓｍａｃｒｏｃｅｐｈａｌｕｓ（Ｂａｓｉｌｅｗｓｋｙ）视网膜中存在视杆、单锥和孪生双锥三种光感受细胞，视杆与视锥的比例较大，为６７：１。每一双极细胞接受约５—８个视杆的输入，每一神经节细胞接受约１７—２５个双极细胞输入，表明神经节细胞有较大的感受野。视网膜细胞这种形态组合有利于提高视网膜对光的敏感性，与黑鲷生存的浅海底层弱光环境相适应。黑鲷的视杆色素经测定为视紫红质ＶＰ４８５１（吸收光谱峰值为４８５ｎｍ），其吸收光谱与黑鲷栖息水层中日光能量分布相对应，也与该水层中的生物光场相适应。黑鲷暗视光谱敏感曲线峰值与视紫红质吸收光谱曲线相一致，均在４８５ｎｍ处。此外，黑鲷光谱敏感曲线存在普氏位移，表明黑鲷具有辩色力。

A STUDY ON THE STRUCTURE OF THE RETINA AND VISUAL CHARACTERISTICS OF SPARUS MACROCEPHALUS BASILEWSKY

here are three kinds of photoreceptors in the retins of Sparus macrocephalus (Basilewsky), rods,single cones and twin cones. The ratio of rod to cone is higher,about 76: 1, each bipolar cell receives about 5-8 rods, and each ganglion cell receives about 17-25 bipolar cells. That is to say each ganglion cell has a bigger receptive field. This kind of communication of the retina cells can improve the sensitivity of the retina, and adapt to the dim light environment at the bottom of a shallow sea. The rod photo-sensitivity pigment is rhodopsin VP4851, which absorption spectra correspond to the distribution of solar light in the bioluminescence as well. The peak of scotopia spectral sensitivity curve corresponds to that of the absorption spectra curve, which for both are at 485um. The spectral sensitivity curve shifts when logI=2.1 i. e. The retina has the ability of colour discrimination.