. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 302 WM. P. JACOBS results are not unequivocal. There were no replications, no measures of varia- bility; almost half of the lAA-treated samples disintegrated during the 16-day ex- perimental period, and the largest wet-weight increase reported was only 18 per cent over the controls. It appears, then, that while auxin is widely present in the algae, there is little evidence as to its role—if any—in algal morphogenesis. It is reasonable to expect auxin to have somewhat similar roles in the various plant groups in which it occu
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 302 WM. P. JACOBS results are not unequivocal. There were no replications, no measures of varia- bility; almost half of the lAA-treated samples disintegrated during the 16-day ex- perimental period, and the largest wet-weight increase reported was only 18 per cent over the controls. It appears, then, that while auxin is widely present in the algae, there is little evidence as to its role—if any—in algal morphogenesis. It is reasonable to expect auxin to have somewhat similar roles in the various plant groups in which it occurs. Now, one of the most striking effects of auxin in flowering plants is the stimulation of root formation by high concentrations of auxin. The structure in algae which most closely corresponds to the root of a flowering plant is the rhizoid. Although the rhizoid is a mere protuberance from a single cell (instead of a multicellular organ with a very high degree of cellular differentiation and diversity like the root) yet the rhizoid is usually negatively phototropic, forms a close anchoring connection with the substratum, and is formed typically at the basal end of stem-like structures. These are characteristics which rhizoids share with roots. Hence, the following experiments were designed to determine if rhizoid- formation in algae is stimulated by auxin. MATERIALS AND METHODS Bryopsis plitmosa (Hudson) C. Agardh was used as experimental material. Bryopsis was chosen because its normal life cycle is well known, some aspects of its developmental physiology and morphology have been studied (Noll, 1888; Winkler, 1900; Steinecke, 1925; Darsie, 1939), it has already been shown to contain rela- tively large amounts of ether-extractable auxin (Darsie, 1939; van Overbeek,. CAPILLARY CORK IAA SEA WATER BRYOPSIS SAND 1. Diagram to show method of establishing a gradient of IAA along the long axis of Bryopsis Please note that these images are extracted from scanned page ima
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
