Einfluß von Tageslänge und Beleuchtungsstärke auf den Generationswechsel bei <i>Batrachospermum moniliforme</i>1

Spatial distribution and abundance of Batrachospermum boryanum gametophytes within a headwater stream in Rhode Island, USA varied considerably over a period of two years due to significant changes in dominant substrata. However, periodicity of these plants was similar each year. Juvenile gametophytes were produced by the aseasonal annual 'chantransia' stage most abundantly in September and October. Macroscopic gametophytes appeared in November and attained a peak in development during late winter and spring, correlating with relative light penetration through the surrounding tree canopy. The ratio of female to male plants increased from 1: 1 in January to 4: 1 at the end of the growing season in June during both years. Spermatangia production was continuous throughout the growth period, averaging 26 000 mm -2; mean carpogonial density was 60 mm-2. Approximately 500 spermatia were released for each carpogonium present and the mean proportion of fertilized carpogonia was 22 % . Carposporophytes typically became detached and acted as dispersal agents, settling at 0.075 cm s-'. Current velocities in the stream varied from 10 to 50 cm s-and were calculated to carry the carposporophytes 5-35 m downstream. Monospores released by 'chantransia' upright filaments also added to population spread.

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Morphogenetic effects of daylength in Schottera nicaeensis

Perrone

Felicini

1993

Hydrobiologia

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The S. nicaeensis thallus exhibits a typical secondary heterotrichy: terete perennant creeping axes and flattened annual erect fronds. The prostrate system produces new uprights in autumn, while in late spring the old blades produce marginal terete proliferations, which usually attach themselves to the substratum becoming new creeping axes. The present study demonstrates that the changes in morphogenetic trends are controlled by daylength, regardless of temperature. Both the upright formation and the flattened growth are short day responses, whereas both the terete proliferation outgrowth and the rhizoid production are long day responses. This seems to be the first report on two vegetative photoperiodic responses to different daylengths within a single algal species.

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Einfluß von Tageslänge und Beleuchtungsstärke auf den Generationswechsel bei Batrachospermum moniliforme1

Cited by 8 publications

References 6 publications

Morphogenetic effects of daylength in Schottera nicaeensis

Morphogenetic effects of daylength in Schottera nicaeensis

Reproductive ecology of the freshwater red alga Batrachospermum boryanum Sirodot in a temperature headwater stream

Morphogenetic effects of daylength in Schottera nicaeensis

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