. Bulletin. Science; Natural history; Natural history. MORPHOLOGY OF SORELLA. Fig. 3. Carpogonial development US #\117i). Life history and reproductive structures.—In culture, discharged carpospores germinated and grew into thalli which bore and shed tetraspores. GermHngs from these tetraspores grew into thalli on which male and female gametangia developed, on separate plants, indicating the presence of a Polysiphoiiia-lype life history. The cycle, under laboratory conditions ambient light and tempera- ture, could be completed within a six to eight week period. All plants were v
. Bulletin. Science; Natural history; Natural history. MORPHOLOGY OF SORELLA. Fig. 3. Carpogonial development US #\117i). Life history and reproductive structures.—In culture, discharged carpospores germinated and grew into thalli which bore and shed tetraspores. GermHngs from these tetraspores grew into thalli on which male and female gametangia developed, on separate plants, indicating the presence of a Polysiphoiiia-lype life history. The cycle, under laboratory conditions ambient light and tempera- ture, could be completed within a six to eight week period. All plants were vegetatively similar. In a clump of presumably young, very small unbranched thalli collected in the field, one blade, mm high, bore a spermatangial sorus which implies that rapid development of a germling to reproductive maturity can occur in the ocean as well as in the laboratory. Most collections made throughout the year included blades with apparently mature totrasporangia. cystocarps, and male sori. Tetrasporangial sori wore me- dian on blades, covering the midline, and were often large and thick, protruding from both surfaces. No sori were positioned in any other way, substantiating the use of this criterion to separate .Scrc/Zr/ from liryihr(>i;lssiini (Hi^llenberg. 1^43). Initially, tetrasporangial mother cells develop from cells close to the apc\ to cither side of the central cell row on both surfaces of the blade. A layer of very small (.3-4 /j,m) cells overlies the enlarging sporangia and small cells appear scattered in the sori from which spoics have been shed. Division into IctrahcdralK arranged spores occurs v\hcn the sporangial mother cell is about 22 /um in iliamcter. As cell walls and cytoplasm enlarge, undivided sporangia come to lie over the central line, the sori appearing eventually single and median (Fig. 1 A. C, D). Shed spores. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabilit
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