Browsing by Author "MALBRAN, ME"

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    SEASONAL CYCLES OF GROWTH AND TETRASPORE FORMATION IN GLOSSOPHORA-KUNTHII (PHAEOPHYTA, DICTYOTALES) FROM PACIFIC SOUTH-AMERICA - FIELD AND LABORATORY STUDIES
    (1990) MALBRAN, ME; HOFFMANN, AJ
    The seasonal patterns of growth and tetraspore formation in Glossophora kunthii (C. Agardh) J. Agardh were determined in plants collected in central Chile (32.degree.57'' to 33.degree.15''S) and compared with results obtained from cultures under laboratory conditions. The prostate phase of G. kunthii is apparently perennial. Erect fronds grow during winter. In some locations fronds are persistent, in others they disappear in summer, probably due to local environmental factors. Plants collected in the field showed two peaks of maximal tetraspore formation, in August-October and in January. Ligulae cultured under controlled experimental conditions showed seasonal variations in fertility similar to plants in the field, through the peaks appeared earlier.
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    TEMPERATURE, PHOTOPERIOD AND LIGHT INTERACTIONS ON GROWTH AND FERTILITY OF GLOSSOPHORA-KUNTHII (PHAEOPHYTA, DICTYOTALES) FROM CENTRAL CHILE
    (1989) HOFFMANN, AJ; MALBRAN, ME
    Excised ligulae of Glossophora kunthii from central Chile were cultured at temperatures of 5-25.degree. C, photoperiods of 16:8 and 8:16 h LD cycles, with photon irradiances of 10 and 50 .mu.mol .cntdot. m-2 .cntdot. s-1. Growth of the ligulae, number of fertile ligulae and number of tetrasporangia forming on the ligulae were assessed. Ligulae tolerated temperatures between 10 and 23.degree. C. Temperature interacted with daylength and photon dose, determining quantitative responses in the growth and fertility of ligulae. Growth was least at 8:16 h LD and was not affected significantly by temperature. It was greatest at 16:8 h LD, 50 .mu.mol .cntdot. m-2 .cntdot. s-1 and increased with temperature up to 20.degree. C. Percentage of fertile ligulae and number of tetrasporangia increased with temperature at the 8:16 h LD cycle, reaching a maximum at 20.degree. C. Fertility was low at 16:8 h LD, except at 20.degree. C (and low photon dose) suggesting that reproduction at 20.degree. C is independent of daylength in this species. Ligulae grew larger at the lung-day photoperiods and the proportions of fertile ligulae were higher at the short-day photoperiods, irrespective of the total photon dose received. These results suggest that some aspects of growth and fertility are controlled by photoperiod.