河川沙塘鳢视觉器官的发育及其与摄食的关系

利用光学显微镜观察了河川沙塘鳢(Odontobutis potamophila)视觉器官的发育,并对其发育与摄食的关系进行了研究。河川沙塘鳢的眼囊起源于神经外胚层。当胚胎发育至心跳期时,眼囊内陷形成视杯;之后,视杯内表面的外胚层形成晶状体而与视杯分离,视杯进一步发育形成视网膜。随着胚胎的进一步发育,晶状体的直径增加,结构逐步发育完善。胚胎发育至眼黑色素出现期时,视网膜分化为6层,其中,外核层、内核层和神经节细胞层3个核层明显;胚胎发育至孵化前期时,视网膜已分化为10层。孵出后1d的仔鱼,其视网膜已能行使功能,仔鱼逐渐开口摄食。随着稚、幼鱼的发育,视网膜厚度进一步增加,结构发育完善。视网膜的结构和视觉特性显示河川沙塘鳢是要求光照条件好、白昼活动并具有较好视觉功能的鱼类。

Visual Organ Development and Its Relationship with Feeding of Odontobutis potamophila

The visual organ development of Odontobutis potamophila was examined with microscopy,the relationship between visual development and feeding was also studied.The main results are listed as follows:The optic vesicle was of neuroectodermal origin.At the heart-beating stage,the optic vesicle folded and formed the optic cup.Soon afterwards,optic cup induced the overlying surface ectoderm to form the lens,and it proliferated into the retina.During the development,the lens diameter increased,and the lens gradually developed to be perfect.At the eye pigmentation stage,the retina differentiated into six layers.Outer nuclear layer,inner nuclear layer and ganglion cell layer were observed.At the prehatching stage,the retina was composed of ten layers.One day after the hatching,the retina had become functional and larvae gradually began to feed.The thickness of the retina increased and the structure developed to be perfect with the development.The structural and visual characters of the retina indicated that O.potamophila was diurnal species with good vision.