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A STUDY OF LIGHT INTENSITY, PERIODICITY, AND WAVELENGTH ON ZOOSPORE PRODUCTION BY PROTOSIPHON BOTRYOIDES KLEBS 1 2
Author(s) -
Durant Jennie P.,
Spratling Larry,
O'Kelley Joseph C.
Publication year - 1968
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1968.tb04708.x
Subject(s) - darkness , zoospore , biology , irradiation , white light , biophysics , botany , spore , optics , physics , nuclear physics
SUMMARY When mature Protosiphon cells were placed in darkness, zoospore production was more extensive and was completed in a shorter time at a temperature of 27 C than at 22 or 15 C. Cool‐white fluorescent (Sylvania) light inhibited the process measurably at a radiation intensity of 0.6 ± 10 3 ergsjcm 2 ‐sec; inhibition was 96% complete at 14 ± 10 3 ergs/cm 2 ‐sec. For mature cells previously grown under repeated 12‐12 hr light‐dark cycles, a dark period of approximately 2 hr at 22 C allowed cell division to proceed to a stage such that reillumination did not inhibit continued development of zoospores. Monochromatic light from 402 to approximately ‐494 nm, as compared to darkness, inhibited zoospore formation; maximal inhibition was at 432‐461 nm. In contrast, monochromatic light from 522 to 726 nm stimulated zoospore formation relative to darkness. Synchronous zoospore production was obtained using the following regimes: (A) 12 hr cool‐white alternated with 12 hr yellow, (B) 12 hr cool‐white alternated with 12 hr blue. Under regime A synchronous zoospore release (following synchronous production) occurred near the end of the yellow irradiation period, while under regime B it occurred near the end of the cool‐white irradiation period. The significance of this in terms of photoprocesses and possible photoreceptors is discussed.