. The algae. Algae. EUPHYCOPHYTA 45 sents optimum light conditions for growth of//, reticulatum, whilst the actual growing period depends upon Hght intensity, it is 3 weeks at 600-700 lux, 5J weeks at 250 lux. Under normal condi- tions growth is periodic, increasing by day and decreasing at night. This is reflected in the oxygen balance between photosynthesis and. Fig. 20 Hydrodictyon. A-F, development of young net of H. patenaeforme from the zygote. A, young polyhedron. B, older polyhedron with four nuclei. C, protoplasm granular just before zoospore formation. D, 'pavement' stage. E, zo
. The algae. Algae. EUPHYCOPHYTA 45 sents optimum light conditions for growth of//, reticulatum, whilst the actual growing period depends upon Hght intensity, it is 3 weeks at 600-700 lux, 5J weeks at 250 lux. Under normal condi- tions growth is periodic, increasing by day and decreasing at night. This is reflected in the oxygen balance between photosynthesis and. Fig. 20 Hydrodictyon. A-F, development of young net of H. patenaeforme from the zygote. A, young polyhedron. B, older polyhedron with four nuclei. C, protoplasm granular just before zoospore formation. D, 'pavement' stage. E, zoospores rounding off and wall of polyhedron expanding to form vesicle. F, fully formed net still enclosed in vesicle. (A-E x 250, F x 175.) G, portion of mature net of H. reticulatum. H, polyhedron and young net of H. reticulatum. J, H. reticulatum, formation of net in parent cell from zoospores. (A-F, after Pocock; G, H, after Oltmanns; J, after Fritsch.) respiration. Altering the length of the light period merely alters the degree of growth in the time. Under conditions of continuous Hght the periodicity is much reduced, though the effect is more marked with old cells. Light is essential for growth, as in continuous darkness the oxygen balance falls below the compensation 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 not perfectly resemble the original Chapman, V. J. (Valentine Jackson), 1910-. London, Macmillan; New York, St. Martin's Press
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Keywords: ., bo, bookcentury1900, bookcollectionbiodiversity, booksubjectalgae
