• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.2
• /
• pp.155-161
• /
• 2011

Induction of regeneration and maturation of the free-living gametophytes of Undariopsis peterseniana (Kjellman) Miyabe et Okamura was studied at four temperatures (5, 10, 15, and $20^{\circ}C$), four levels of irradiance (5, 10, 20, and 40 ${\mu}mol$ $m^{-2}\;s^{-1}$) and three photoperiods (14:10, 12:12, and 10:14 h L:D). Female gametophyte fragments were maintained in active regeneration without reaching sexual maturity under conditions of $15^{\circ}C$, 20 ${\mu}mol\;m^{-2}\;s^{-1}$, 10:14 h (L:D), whereas the conditions for male gametophytes were slightly different at $15^{\circ}C$, 20 ${\mu}mol\;m^{-2}\;s^{-1}$, 14:10 h (L:D). The sexual maturation of female and male gametophytes took place under $15^{\circ}C$, 20 ${\mu}mol\;m^{-2}\;s^{-1}$, 14:10 h (L:D) and $10^{\circ}C$, 10 ${\mu}mol\;m^{-2}\;s^{-1}$, 10:14 h (L:D), respectively. These results provide basic information for controlling the regeneration and maturation of free-living gametophytes for artificial seed production of U. peterseniana.

• Korean Journal of Plant Resources
• /
• v.18 no.2
• /
• pp.302-308
• /
• 2005

This study was carried out to obtain the basic informations on the characteristics of gametophytes formation and embryo developement in Dicentra spectabilis. Microspore mother cells developed from archesporial cells, start meiosis when flower bud length reaches around 1 mm, formed tetrahedral type tetrad. The 4 microspores were separated. They were developed to male gametophytes, respectively. Megaspore mother cells were observed when flower bud length was $4{\sim}5\;mm$. The developemental type of megaspore was polygonum and embryo sac was amphitropous. Three large and distinctive antipodals did not degenerated and remained after embryo sac was developed. When the male and female gametophytes was fully developed, the length of stamen and style was very similar or stamen was shorter about 0.5 mm than that of style. This result indicates that self-fertilization can be occurred in this species. After fertilization, developing zygotic embryos showed various stages of development from globular to cotyledonary embryos, and zygotic embryo in seed scattering time seemed to have an early cotyledonary stage.

• Animal cells and systems
• /
• v.3 no.3
• /
• pp.243-246
• /
• 1999

A type of symbiosis was previously described from nature in which the gametophytes of Laminariales were endophytic in filamentous red algae. Here we reconstruct this symbiosis for the first time in laboratory culture using zoospores of the kelp, Undaria pinnatifida, and the red alga, Aglaothamnion oosumiense. Zoospores of U. pinnatifida readily attached to A. oosumiense. In 48 h these spores germinated and the initial germ tube penetrated into the host cell wall leaving only an empty zoospore wall outside the host. Within ten days, four to five-celled endophytic gametophytes were present. Zoospores of Laminaria religiosa which were also inoculated into cultures of A. oosumiense rarely attached to the red alga and never became endophytic. Within ten days the free-living gametophytes of L. religiosa on cover slips became fertile and produced young sporophytes. These observations demonstrate the ability of U. pinnatifida to become endophytic, and show differences in host specificity among kelp species.

• ALGAE
• /
• v.19 no.1
• /
• pp.31-37
• /
• 2004

Farmed kelp gametophytes were previously observed to be living endophytically in filamentous red algae. The interactions of two farmed kelp species and six red algae were examined in laboratory culture. Undaria pinnatifida (Harvey) Suringar and Laminaria religiosa Miyabe demonstrated the differing abilities of zoospores to become endophytic in four host red algae and neither kelp became endophytic in two non-filamentous red algae. There was a strong seasonal component regarding infectiousness that is associated with the changes in fron erosion in U. pinnatifida from April to June. At the same time, L. religiosa showed no significant changes in frond erosion, and there were no apparent changes in infection levels in the two species they were able infect. This study indicated clear differences between two keip species with regard to their symbiotic relationship to red algae in terms of host specificity and preference of kelp gametophytes.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.40 no.6
• /
• pp.387-393
• /
• 2007

We examined the conditions for separating and preserving the male and female gametophytes of Kjellmaniella crassifolia. The highest percentage of zygote germination (85%) was on semi-solid medium composed of 1.0% transfer gel agar at $15\;^{\circ}C$ and $20\;{\mu}mol/m^2/s$ after a 4-week culture. Zygote germination in PESI liquid medium was 93.5% at $20\;^{\circ}C$ and $20\;{\mu}mol/m^2/s$. The maximum zygote growth was $252{\pm}19.7\;{\mu}m$ on 1.0% transfer gel agar at $15\;^{\circ}C$ and $40\;{\mu}mol/m^2/s$ after 5-week culture, and was $76.7{\pm}2.8\;{\mu}m$ in PESI liquid medium at $20\;^{\circ}C$ and $40\;{\mu}mol/m^2/s$. The respective numbers of separated male and female gametophytes from germinated zygotes were 157 and 93 on 1.0% transfer gel agar and 14 and 28 in PESI liquid medium. The maximum growth of separated male and female gametophytes was $575{\pm}28.3\;{\mu}m$ at $5\;^{\circ}C$ and $60\;{\mu}mol/m^2/s$ and $686{\pm}35.4\;{\mu}m$ at $20\;^{\circ}C$ and $20\;{\mu}mol/m^2/s$ in PESI liquid medium after 3 weeks, respectively. The highest percentage fertilized was $93.3{\pm}5.8%$ at $15\;^{\circ}C$ and $20\;{\mu}mol/m^2/s$ in PESI liquid medium. These results show that the best conditions for the separation and preservation of gametophytes (male and female) consisted of culturing on 1.0% transfer gel agar at $15\;^{\circ}C$ and $20\;{\mu}mol/m^2/s$.

• Korean Journal of Environmental Biology
• /
• v.36 no.4
• /
• pp.576-583
• /
• 2018

Investigation of optimal temperature, irradiance and photoperiod conditions for free-living gametophytes of Saccharina sculpera for natural resources conservation and mass cultivation of endangered species in the eastern coast of Korea. Induction of regeneration and maturation of the free-living gametophytes of S. sculpera were cultured at temperatures (5, 10, 15, 20 and $25^{\circ}C$), irradiance (10, 20, 40, 60 and $80{\mu}mol\;photons\;m^{-2}\;s^{-1}$ and photoperiods (14:10, 12:12 and 10:14 h L:D). The female gametophyte were actively regenerated without reaching sexual maturity under $10^{\circ}C$, $20{\mu}mol\;photons\;m^{-2}\;s^{-1}$ and 12:12 h (L:D) conditions. In contrast, the conditions for male gametophytes were slightly different at $15^{\circ}C$, $10{\mu}mol\;photons\;m^{-2}\;s^{-1}$ and 12:12 h (L:D). The sexual maturation of female and male gametophytes took place under $15^{\circ}C$, $40{\mu}mol\;photons\;m^{-2}\;s^{-1}$, 14:10 h (L:D) and $10^{\circ}C$, $20{\mu}mol\;photons\;m^{-2}\;s^{-1}$, 10:14 h (L:D), respectively. These results provide basic information for controlling the regeneration and maturation of free-living gametophytes for conservation and utilization of S. sculpera.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.5
• /
• pp.381-388
• /
• 2008

Induction of regeneration and maturation for the free-living gametophytes of Ecklonia cava Kjellman was conducted under various temperature, irradiance and photoperiod conditions. Culture conditions for female or male gametophyte fragments were 4 temperature (5, 10, 15 and $20^{\circ}C$), 4 irradiance (5, 10, 20 and $40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and 3 photoperiod (14:10, 12:12 and 10:14 h L:D). Female and male gametophyte fragments were maintained in active regeneration without reaching sexual maturity under $5{\sim}10^{\circ}C$, $5{\sim}10{\mu}mol{\cdot}m-2{\cdot}s-1$, 12:12h or 10:14h (L:D) and $15-20^{\circ}C$, $20-40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 14:10h (L:D), respectively. Sexual maturation of female and male gametophytes facilitated under $15^{\circ}C$, $20-40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 14:10h (L:D) and $5-10^{\circ}C$, $5-10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 10:14h (L:D), respectively. These results provide basic informations to control the regeneration or maturation of the free-living gametophytes for artificial seed production of E. cava.

• ALGAE
• /
• v.26 no.1
• /
• pp.51-60
• /
• 2011

Similar to other species of Gigartinaceae Chondrus crispus has an alternation of perennial, isomorphic gametophytic and sporophytic generations. As these two generations co-exist independently within populations and obtain their resources in a similar manner, intraspecific competition is expected. In populations within the southern Gulf of St. Lawrence, fronds of both generations of C. crispus occur in similar numbers. This equivalency can be related to substratum instability, where the population is dynamic with a high turn-over rate of genets. These observations support a stochastic hypothesis to account for distribution of gametophytes and sporophytes in this area. Along the Atlantic coast of Nova Scotia, where the substratum is stable, gametophytes are overwhelmingly predominant. Gametophytic predominance is greatest in the lower littoral zone where C. crispus is abundant and space is limited. Under the fucoid canopy where "free-space" exists, the gametophyte to sporophyte ratio is lower. Gametophytic and sporophytic fronds are distributed equally among different size-classes and size-distribution is not considered a competitive factor. Previous studies have shown that sporophytic fronds of C. crispus are more susceptible to infections by endophytic algae and other pathogens, and are more heavily grazed by herbivores than are gametophytic fronds. Thus, mechanistic factors are strongly implied in the selection of gametophytes in the Atlantic population.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.36 no.5
• /
• pp.474-479
• /
• 2003

The effect of season, life stages and harvesting sites on the yield and properties of agars extracted from Gracilaria verrucosa were determined. G. verrucosa were collected seasonally from November 2001 to August 2002 at Cheongsapo and Boryong, Korea. The plants were sorted Into the different life stages (tetrasporophytes and gametophytes) and dried at $60^{\circ}C.$ The yield, sulfate, protein, uronic acid and 3,6-anhydrogalactose of the agar were determined, and standard parameters of physical quality were measured. No differences were found in yield and properties of agars from the two different harvesting sites and from lift history phases. The yield of agar was maximum in summer $(17.3-20.0\%)$ and minimum in winter $(11.9-13.1\%).$ Maximum gel strength occurred in winter when the agar yield and sulfate content were low. Gel strength was negatively correlated with agar yleld. Seasonal variations in agar yield and its quality were discussed in a view to managing the exploitation of this resource.

• Journal of Plant Biology
• /
• v.28 no.1
• /
• pp.45-55
• /
• 1985

Observations on reproduction of Rhodochorton purpureum (Lightfoot) Rosenvinge (Acrochaetiaceae, Rhodophyta) was carried out with plants from Hokkaido, Japan. This species produces no monosporangia both in nature and culture, even though it does tetrasporangia commonly. The plants from Nemuro produce neither sporangia nor gametangia, and thus vegetative reproduction is the only known way to propagate themselves. It is suggested that the vegetative reproduction occurs in nature by fragmentation of vegetative filaments after development of a rhizoid. Several different modes of rhizoid production are described. The plants from Akkeshi and Oshoro (I) produce tetrasporangia that develop into plants producing only tetrasporangia. The plants from Muroran and Oshoro (II) produce tetrasporangia that develop into gametophytes. Gametophytes of R. purpureum from Muroran produce tetrasporangia as well as spermatangia or carpogonia. Such tetrasporangia on gametophytes are presumed to be mitotic.