ORGANOGENESIS AND HISTOGENESIS IN THE PLANKTOTROPHIC VELIGER OF DORIDELLA-STEINBERGAE (OPISTHOBRANCHIA, NUDIBRANCHIA)
ORGANOGENESIS AND HISTOGENESIS IN THE PLANKTOTROPHIC VELIGER OF DORIDELLA-STEINBERGAE (OPISTHOBRANCHIA, NUDIBRANCHIA)
复制标题
DOI：
10.1007/bf00389071
复制
发表时间：
1979-01-01
期刊：
影响因子：
2.4
通讯作者：
CHIA, FS
中科院分区：
文献类型：
--
作者：
BICKELL, LR;CHIA, FS
裸鳃海蛞蝓营养面盘的发育。通过对4个任意定义的幼虫阶段的组织学检查来研究steinbergae（Lance）。在胚胎期7 1/2至8天（1/2 - 15 ℃）后，C），初孵的面盘幼虫具有功能性消化道、一对肾囊肿、一个次级肾、一对脑神经节、一个由2/3轮组成的幼虫壳和足的后足部分。第一阶段的发育主要包括幼虫壳和内脏器官的生长。第二阶段的特点是外套膜褶从壳孔处缩回，出现眼斑、性腺原基、幼虫心脏、视神经节、足神经节和胸膜神经节。在第三阶段，舌囊的雏形从食管壁向外凸出，颊神经节分化，足柄的雏形开始在后足的腹面发育。第四阶段面盘虫具有6对齿舌齿，左消化腺有脂质沉积，成年肾脏和口唇腺发育不全，肥大的外套膜褶，前足和足腹表面的纤毛密集。在实验室培养条件下，从面盘幼虫孵化到达到变态能力的强制性幼虫期的长度为25-26天，幼虫壳长142-168 μ m。本文还对D. Steinbergae与其他后鳃面盘鱼的比较。D. Steinbergae是地幔褶皱过早收缩的结果。后鳃类的面盘幼虫阶段发育的各种结构的种间差异可能与少年阶段的要求的变化有关。的肠道功能的适应性的lecithotrophic面盘幼虫进行了讨论和比较。
Development of the planktotrophic veliger of the dorid nudibranch D. steinbergae (Lance) was studied by histological examination of 4 arbitrarily defined larval stages. Following an embryonic period of 7 1/2 to 8 days (12-15.degree. C), the newly hatched veligers possess a functional digestive tract, a pair of nephrocysts, a secondary kidney, a pair of cerebral ganglia, a larval shell consisting of a 2/3 whorl and the metapodial component of the foot. Development during stage I mainly involves growth of the larval shell and the visceral organs. Stage II is marked by the retraction of the mantle fold from the shell aperture and the appearance of the eyespots, gonadal rudiment, larval heart and the optic, pedal, and pleural ganglia. At stage III the radular sac rudiment evaginates from the esophageal wall, the buccal ganglia differentiate and the propodial rudiment begins to develop on the ventral surface of the metapodium. Stage IV veligers, which are competent to metamorphose, possess 6 pairs of radular teeth, lipid deposits in the left digestive gland, rudiments of the adult kidney and the oral lip glands, a hypertrophied mantle fold, a propodium and densely packed cilia over the entire ventral surface of the foot. The length of the obligatory larval period, from hatching of the veliger until the attainment of metamorphic competence, is 25-26 days under laboratory culture conditions and the larval shell grows from 142-168 .mu.m in length. The sequence of morphogenetic events and the structure of the competent veliger of D. steinbergae are compared to those of other opisthobranch veligers. The relatively small maximal shell size attained by D. steinbergae results from precocious retraction of the mantle fold. Interspecific differences in the kinds of structures that develop during the veliger phase of opisthobranchs may relate to variations in the requirements of the juvenile phase. The functional adaptations of the gut of planktotrophic veligers are discussed and compared to those of lecithotrophic veligers.