• 한국수산과학회지
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• 제46권6호
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• pp.827-834
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• 2013

The effects of environmental factors, such as irradiance, daylength, salinity, and desiccation, on the growth of Lithophyllum yessoense and Hildenbrandia rubra sporelings were examined. Sporelings of each species were cultured with 10, 50, 80, 120, $150{\mu}mol$ photon $m^{-2}s^{-1}$ for 14 days and their maximum growth occurred under $80{\mu}mol$ photon $m^{-2}s^{-1}$. Germlings of both species survived for 21 days in darkness, and even the L.yessoense germlings grew. In the salinity experiment, sporelings of each species survived for 7 days and died after 14 days under 20 and 25 psu, but the sporelings grew well under 34 psu. Physiological features of each species with respect to the evaluated daylengths (8, 12, 14 and 16 h) were slightly different, and maximal growth occurred at 16 h for L. yessoense and at 14 h for H. rubra sporelings. Mortality of the sporelings increased with the exposure period, but H. rubra was less tolerant to desiccation than L. yessoense. In conclusion, sporelings of the two species showed similar growth responses to various environmental factors with slightly different physiological features with respect to salinity, daylength, and desiccation. However, more ecological and physiological studies on slow-growing crustose algae are required to elucidate the expansion of barren ground around the coastal areas of Korea.

• 한국수산과학회지
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• 제44권3호
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• pp.290-297
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• 2011

The phenology of Campylaephora hypnaeoides J. Agardh and optimal conditions for carpospore release, growth and reproduction were examined in the field and in the laboratory from January to December 2007. In the field population of C. hypnaeoides, approximately 50% of the plants were vegetative during the study period. Additionally, the percentages of carposporophytes and tetrasporophytes were maximal in April (37%) and June (57%), respectively. Maximum growth in plant length, dry weight, and hook number coincided with the tetrasporophyte reproductive peak in the field. In culture, carpospore release, sporeling growth and reproduction were affected by environmental factors such as daylength, temperature, and salinity. The liberation of carpospores was maximum under continuous light and at a combination of $15^{\circ}C$ and $10\;{\mu}mol$ photons $m^{-2}\;s^{-1}$. Maximum growth of tetrasporophyte sporelings occurred at a combination of $20\;{\mu}mol$ photons $m^{-2}\;s^{-1}$ of constant light and $25^{\circ}C$. However, the growth of gametophyte sporelings was maximal under $40\;{\mu}mol$ photons $m^{-2}\;s^{-1}$ of constant light and in a combination of $20^{\circ}C$ and 35 psu. The tetrasporophyte sporelings were grew faster than gametophytes, indicating that gametophyte- and tetrasporophyte-sporelings have different physiological responses to irradiance and temperature. Tetrasporangial branches and cystocarps of C. hypnaeoides were produced from carpospores and tetraspores within 1 month, and they were stimulated at high temperature and irradiance levels. In conclusion, C. hypnaeoides should be seeded using carpospores during early winter (November-December) because cystocarps are easily identified by fishermen, and tetrasporophytes grow faster than gametophytes.

• Ocean and Polar Research
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• 제42권2호
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• pp.133-139
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• 2020

The aim of this study is to examine the physiological characteristics of an agarophyte Agarophyton vermiculophyllum (Ohmi) Gurgel, J.N. Norris et Fredericq in the early life stage of tetrasporophytes (2n) and gametophytes (n) to select appropriate seedlings for mariculture. Growth experiments were carried out at the combinations of four temperatures (20, 25, 30, and 35℃) and three light intensity levels (20, 60, and 100 µmol photons m^-2 s^-1) in the two ontogenetic stages: discoid holdfasts and erect sporelings. Holdfast areas and sporeling lengths of tetrasporophytes and gametophytes were estimated after 14 days in culture. Relative growth rates (RGRs) for holdfast areas were 7.08-28.38% day^-1 for tetrasporophytes and 11.58-23.67% day^-1 for gametophytes. At 35℃, holdfasts of tetrasporophytes survived with RGRs of 7.08-23.28% day^-1 but those of gametophytes died. Maximal holdfast growth of tetrasporophytes occurred at 30℃ and 100 µmol photons m^-2 s^-1, which were different from gametophytes (25℃ and 100 µmol photons m^-2 s^-1). RGRs of tetrasporophytic sporelings were 2.93-11.11% day-1 and were between 0.78-10.82% day-1 for gametophytes. Maximal growth of A. vermiculophyllum sporelings occurred at 25℃ and 60 µmol photons m^-2 s^-1 for tetrasporophytes, and at 20℃ and 100 µmol photons m^-2 s^-1 for gametophytes. In conclusion, the present results indicate that carpospores could be used as resources of spore-seedling methods having genetic diversity for mass field cultivation because tetrasporophytes showed higher-temperature tolerance and faster-growing ability than gametophytes of A. vermiculophyllum in the discoid holdfast and sporeling stages.

• 한국수산과학회지
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• 제43권3호
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• pp.239-245
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• 2010

The effects of sediment and water movement on the survival and growth of Campylaephora hypnaeoides J. Agardh were examined in culture to elucidate why this species grows as an epiphytic alga. The survival and growth rates of Campylaephora tetraspores declined as the sediment concentration increased under both water-movement and no-water-movement treatments. After 5-day cultures under various sediment treatments, the respective survival and growth rates ranged from 27.32 to 78.63% and 0.22 to 0.29 $day^{-1}$ under the no-water-movement and from 15.66 to 82.69% and 0.19 to 0.31 $day^{-1}$ under the water-movement treatments. The maximum survival and growth of C. hypnaeoides tetraspores occurred at 20 and 40 ${\mu}mol$ photons $m^{-2}s^{-1}$, respectively. The survival of Campylaephora tetraspores and germlings declined with increasing dark period, but the tolerance of total darkness based on the survival rates was two-times greater for 5-day old sporelings than for tetraspores after 12 days. In conclusion, Campylaephora hypnaeoides grows as an epiphytic alga because its survivorship and growth decline rapidly with greater water movement and sedimentation and with lower light intensities.

• ALGAE
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• 제30권3호
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• pp.207-216
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• 2015

Caloglossa species occurs in freshwater streams around Southest Asia. We report it from 2 different riverine sites in Kerala, India. Tetrasporangiate plants were observed in field collections from the Periyar River and Chalakkudy River. The Chalakkudy isolate did not reproduce in culture but the Periyar isolate developed abundant tetrasporangial sori in culture. Many spores were discharged and most were abortive, but some germinated normally, sporelings forming male gametophytes with numerous spermatangial sori and females with many procarps, viable carposporophytes and some nonfunctional (no carpospores) pseudocystocarps. Some carpospores germinated forming new tetrasporophytes. Molecular evidence (28S rDNA and rbcL) placed the Indian specimens close to C. beccarii and C. fluviatilis. Considering the freshwater habitat and morphology of vegetative thalli (blade shape, rhizoid arrangement, and number of rhizoid filament per cell), the Indian specimens should be assigned to C. beccarii.

• 한국수산과학회지
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• 제46권3호
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• pp.296-302
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• 2013

The effects of temperature on spore release, growth and photosynthetic efficiency of Lithophyllum yessoense and Hildenbrandia rubra were examined. L. yessoense was collected at Galnam and H. rubra was collected at Gyeokpo, Korea. The experimental temperatures were different for spore release (10, 15, $20^{\circ}C$), sporeling growth (10, 15, 20, 25, $30^{\circ}C$) and photosynthetic efficiency (10, 15, 20, $25^{\circ}C$). All other culture conditions were the same: 34 psu, 12:12 LD and $50{\mu}mol$ photon $m^{-2}s^{-1}$. Spore liberation was maximal at $10^{\circ}C$ for L. yessoense and at $20^{\circ}C$ for H. rubra. After 14 days, the surface area of L. yessoense was 0.031 $mm^2$ at $25^{\circ}C$ and for H. rubra was 0.032 $mm^2$ at $20^{\circ}C$. Sporelings of L. yessoense were a dark-red color and grew in a round shape. In contrast, H. rubra was bright pink and changed from a round shape in the early growth stage to later become flabelliform. Photosynthetic efficiency was highest between $20-25^{\circ}C$ in both species. In conclusion, L. yessoense and H. rubra display different physiological features based on the optimal temperatures for spore release and sporling growth.