Browsing by Author "MCLACHLAN, J"

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    PHOTOPERIOD AND TEMPERATURE REGULATION OF THE LIFE-HISTORY OF PORPHYRA-COLUMBINA (RHODOPHYTA, BANGIALES) FROM CENTRAL CHILE
    (1986) AVILA, M; SANTELICES, B; MCLACHLAN, J
    The effects of temperature (10, 15, 20.degree. C) and photoperiod (8:16, 12:12. 16:8 (hours of light:hours of dark)) on the growth and reproduction of different stages in the life history of Porphyra columbina Montagne were assessed. The conchocelis phase had higher growth rates at 12 h light: 12 h dark, 45 .mu.mol m-2s-1, and 15.degree. C. Under all the temperatures and photoperiods tested, the conchocelis phase could propagate either by monospores or vegetative fragmentation. Conchosporangia were formed only at 10.degree. C and 8 h light: 16 h dark or at 15.degree. C and either 8 h light:16 h dark or 12 h light: 12 h dark. Long photoperiods inhibited conchosporangia formation at all temperatures tested with the exception of 20.degree. C and 16 h light: 8 h dark, where sporangia was formed once. Conchospores were released when the temperature was decreased (15 to 10.degree. C) maintaining the photoperiod, Conchospore germination occurred under the three photoperiods and temperatures tested. Growth of juvenile fronds was maximum at 15.degree. C and either 12 h light: 12 h dark of 16 h light: 8 h dark. Fronds formed carpospores and spermatia at 15.degree. C and 16 h light: 8 h dark only. With optimum conditions the life history was completed in 60 days. Spermatia had three chromosomes (n = 3).