. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 266 K. YAMASHITA ET AL. Developmental Stage Figure 8. Changes in nematocyle composition of the ahoral tentacles during larval development: • atrichous isorhizas, &3 stenoteles, D des- monemes, D microbasic mastigophores. SE. star-shaped embryos: PA, preaetinulae; YL, young (2-4-h-old) larvae; IDL. 1-day (24-28 h)-old larvae; NP, nematocyte-printing larvae; S. newly settled individuals; JP. juvenile polyps 2 days after settlement. Vertical bars = standard deviation of total numbers of nematocysts in a tentacle. polyps. In
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 266 K. YAMASHITA ET AL. Developmental Stage Figure 8. Changes in nematocyle composition of the ahoral tentacles during larval development: • atrichous isorhizas, &3 stenoteles, D des- monemes, D microbasic mastigophores. SE. star-shaped embryos: PA, preaetinulae; YL, young (2-4-h-old) larvae; IDL. 1-day (24-28 h)-old larvae; NP, nematocyte-printing larvae; S. newly settled individuals; JP. juvenile polyps 2 days after settlement. Vertical bars = standard deviation of total numbers of nematocysts in a tentacle. polyps. In contrast, our observations revealed that the lib- erated actinula larvae underwent marked behavioral changes that could be divided into the following phases: floating (or sinking), temporary attachment, nematocyte- printing, and settlement followed by stolon elongation. In parallel with these behavioral changes, we observed func- tional changes in the aboral tentacles (from floating or temporary attachment to feeding or defense) and physiolog- ical changes in the body (disappearance of the cushion-like tissues of the aboral endoderm and development of diges- tive gland cells of the oral endoderm). In addition to these settlement processes, larvae whose settlement was delayed retained many atrichous isorhizas (AIs), and larvae whose tentacle tips had been cut off showed no settling behavior until the tips and the AI nematocytes regenerated. These results show that the settlement of actinulae occurs through coordination of the aboral tentacles and the basal protrusion, and that nematocyte-printing behavior is both peculiar to and indispensable for settlement and morphogenesis of the actinula larvae of T. mesembryanthemum. The settlement process of the actinula larvae thus proved to involve radical 100. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may
Size: 1981px × 1261px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
