Long-term and diurnal carpospore discharge patterns in the Ceramiaceae, Rhodomelaceae and Delesseriaceae (Rhodophyta)

Abstract

In laboratory culture, controlled fertilization resulted in mature carposporophytes of the Ceramiales indicated below. Carpospore discharge was observed daily. In the Ceramiaceae Spyridia filamentosa cystocarp-pairs released spores twice in succession (range: 32-537 total spores/carposporophyte). Discharge by all cystocarp-pairs occurred during the dark period of the daily light:dark cycle (12:12 LD) and was completed in 12 d. In reverse cycle (12:12 and 16:8 DL) spore release reversed in 3d. In the Rhodomelaceae Bostrychia moritziana, Pterosiphonia pennata and Murrayella periclados discharged spores from isolated cystocarps over periods up 58 d (ranges: 318-4112, 1051-2271 and 451-3162 total spores/carposporophyte respectively) without any diurnal or long-term rhythmicity. In the Delesseriaceae cystocarps of Caloglossa leprieurii and Caloglossa ogasawaraensis released spores for up to 31 d (ranges: 271-3050 and 565-1286 total spores/carposporophyte respectively). Discharge peaks occurred at 5-7 d intervals with viable cystocarps and spore numbers gradually declining. Thus, in the plants studied, there are at least three patterns of carpospore release from individual mature carposporophytes: a relatively short-term dual release pattern, a long-term non-rhythmic release pattern and a long-term rhythmic release pattern. Results also indicated that excised cystocarps without associated vegetative branches showed a much reduced spore production.