背角无齿蚌稚蚌的生长和发育研究

Growth and Development of the Early Juvenile Anodonta woodiana

背角无齿蚌(Anodonta woodiana)为具有食用、育珠、净水及生物监测等重要经济和生态价值的淡水双壳贝类。为把握其早期生活史过程中形态变化、器官发育和生长速率的特征,本研究对从脱落后第1~30天稚蚌期的个体开展了连续性、系统性的研究。结果显示,在稚蚌1~30 d的生长过程中,铰合部的前缘和后缘向上突起,壳顶相对向内收缩,前端生长迅速、向外侧扩展,后端向腹缘方向生长,而腹缘相对向后端生长。第1天,稚蚌出现了斧足;第4天,内脏团较为明显;第10天,鳃清晰可见,前、后闭壳肌已经形成;第15天,肠道和心脏清晰可见;第20天,进水管和出水管形成;第25天以后,稚蚌的器官已经全部发育完成。壳长、壳高和年龄之间呈指数型相关关系,壳长与壳高之间呈正异速生长关系。上述结果可为背角无齿蚌的人工繁育、种质资源保护和种群恢复以及有效开发、利用其为水污染监测专用指示生物等工作提供理论指导。

The freshwater mussel Anodonta woodiana is a freshwater bivalve with important economic and ecological values, e.g., as a food source or for pearl cultivation, water purification, and aquatic biological monitoring. In order to understand the morphological change, organ development, and growth rate characteristics of A. woodiana during its early life stages, relevant studies were conducted on 1~30-day-old juveniles. From the 1 to 30-day stages, the leading and trailing edges of the hinge for the juveniles were raised upward. The umbo was contracted relatively inward. The anterior grew rapidly and extended outwards, but the posterior grew toward the ventral edge. The ventral edge grew toward the ventral edge. The most obvious feature in the one-day-old juveniles was the appearance of a mobile foot. The visceral mass was more obvious in 4-day-old juveniles. At 10 days old, the gills were clearly visible, and the anterior and posterior adductors were formed. The intestine and heart were obviously visible in 15-day-old juveniles. The incurrent and excurrent siphons had been formed in 20-day-old juveniles. For the 25-day-old juveniles, the organs were fully developed. The shell length, height, and age grew exponentially, and the shell length and height grew at a positive allometry. These results can provide theoretical guidance for the artificial breeding of A. woodiana, its germplasm resource protection and population restoration, and the effective development and utilization of this bivalve as a special indicator for aquatic pollution biomonitoring.