Species Of Gracilaria Research Articles

Atypical carotenoids for the Rhodophyceae in the genus Gracilaria (Gigartinales)

Abstract It has been generally accepted that the carotenoids of the rhodophycean algae are α-carotene, β-carotene, lutein, and zeaxanthin. However, one report on a species of Gracilaria indicated that antheraxanthin, an epoxide, was the major carotenoid. We have confirmed this report and have examined twenty-one other samples (mostly unialgal cultures, some field material) representing at least another eight species of Gracilaria. All of these samples contained antheraxanthin, and many also had the diepoxide, violaxanthin. This is the first report of the latter compound for this genus. Our data indicate that carotenoid epoxides are probably more common in the Rhodophyceae than is generally indicated, and phylogenetic schemes based on pigment composition must be modified accordingly to accommodate these compounds in the Rhodophyceae.

Some field and laboratory studies on colloid-producing red algae in central California

Field studies were conducted in central California into various red algae which are potential colloid producers. From an original list of 19 species, 11 were collected seasonally and the colloids extracted. From these, only three had κ-carrageenan of quality suitable for media preparation and one species showed good quality agar for the same purpose. Field observations showed that in many species of carrageenophytes, gametophytes were more common than sporophytes, and that young plants were present throughout the year, though total biomass per unit area of each individual species did not fluctuate significantly with season. The abundance of gametophytes the κ-carrageenan phase) of Rhodoglossum affine (Harv.) Kylin and Gigartina leptorhynchos J. Ag. compared with the sporophytes was noteworthy. All life phases of two species of Gracilaria and Gymnogongrus linearis (C. Ag.) J. Ag. were harvested together. κ-carrageenan was identified in eight species in the family Gigartinaceae, iota carrageenan in Gymnogongrus linearis (Phyllophoraceae) and agar in Gracilaria sjoestedtii Kylin and G. verrucosa (Huds.) Papenf. (Gracilariaceae).

Reproductive phenology and growth rates in two species of Gracilaria from Hawaii

Observations on wild populations of Gracilaria bursapastoris (Gmelin) Silva and G. coronopifolia J. Ag. showed significant differences in gametophyte: tetrasporophyte ratios from the expected 1: 1 ratio. As in many other perennial red algae, the proportion of tetrasporic individuals in a population of these two Gracilaria spp. dominates the combined male and female gametophytc stage. There were significantly more male than female thalli in the G. cornopifolia population whereas the gametophytes of G. bursapastoris occurred in the expected 1: 1 ratio. In addition, there are seasonal changes in the proportions of tetrasporic and gametophytic individuals within the populations. Tetrasporic thalli of G. coronopifolia evinced a biphasic seasonal pattern with high proportions in winter and summer. The tetrasporic phase of G. bursapastoris, on the other hand, showed a low proportion in winter. Maximum biomass does not necessarily correlate with maximum proportion of the tetrasporophyte generation. Seasonal patterns in the proportion of male and female gametophytes differed for each stage as well as for each species. The proportion of male thalli in G. bursapastoris and G. coronopifolia showed high peaks in winter and autumn, respectively. Cystocarpic thalli were most abundant in the former in late winter and summer and in the latter in winter and spring. In both species the female gametophytes grew significantly slower than did the male gametophytic or tetrasporophytic stages. Practical applications regarding seasonal cycles in the various reproductive stages and their differential growth rates are discussed.

Gracilaria abbottiana sp. nov. (Rhodophyta, Gigartinales): a second intertidal species of Gracilaria from the island of Oahu, Hawaii

Abstract A new erect, compressed species of Gracilaria (G. abbottiana sp. nov.) is described from the island of Oahu Hawaii. It is the first compressed, and the second truly intertidal, species of the genus to be reported from that Island. In some respects the new species resembles three other compressed, generally nonproliferous species (G. Incurvata Okamura, G. textorii (Sur.) J. Ag. and G. sublittoralis Yamada et Segawa) from the Pacific, and differs from them primarily by its smaller habit, morphology, anatomy or habitat.

STUDIES ON GRACILARIA (GIGARTINALES, RHODOPHYTA): REPRODUCTIVE STRUCTURES1,2,3

ABSTRACTThe reproductive structures of Gracilaria foliifera (Forsk.) Børg. from England and an unnamed species of Gracilaria from Nova Scotia were studied by light microscopy. These two entities are distinguishable on the basis of the type of gonimoblast tissue in their mature cystocarps. This, together with other evidence, suggests that these are separate taxa.

Agar Studies in Two Gracilaria Species (G. bursapastoris (Gmelin) Silva and G. coronopifolia J. Ag.) from Hawaii. II. Seasonal Aspects

Article Agar Studies in Two Gracilaria Species (G. bursapastoris (Gmelin) Silva and G. coronopifolia J. Ag.) from Hawaii. II. Seasonal Aspects was published on January 1, 1978 in the journal Botanica Marina (volume 21, issue 6).

Chromosome numbers of Gracilaria foliifera and Gracilaria sp. (Rhodophyta) and attempted hybridizations

Two species of Gracilaria, G. foliifera (Forsk.) Børg. and G. verrucosa (Huds.) Papenf., have been recorded from the Maritime provinces of Canada (South & Cardinal, 1970), although in recent years only G. foliifera var. foliifera is listed (South, 1976). These species are also known from the British Isles (Parke & Dixon, 1976). Chromosome counts of G. foliifera (Greig-Smith, 1954: as G. multipartita) and of G. verrucosa (Magne, 1964) from the European flora suggest these are distinct species.

Gracilaria epihippisora sp. nov. (Rhodophyta, Gigartinales, Gracilariaceae): a new species from the island of Hawaii

Abstract A new species of Gracilaria (G. epihippisora sp. nov.) is described from the island of Hawaii. It is a very polymorphic species with fertile thalli generally more robust than sterile individuals. The male gametophyte bears unique saddle-shaped spermatangial sori.

Life-history and culture of Gracilaria foliifera (Rhodophyta) from South Devon

Three species of Gracilaria, G. foliifera (Forsk.) Børg., G. verrucosa (Huds.) Papenf., and G. bursa-pastoris (S. M. Gmel.) Silva are recognized from the British flora (Parke & Dixon, 1976). In Britain G. verrucosa is widely distributed, although not common, whereas the other two species are rare and their distribution restricted (Newton, 1931). G. foliifera was described from the Red Sea as Fucus foliifer Forsk. (Børgesen, 1932). Plants referable to this species are now reported from various parts of the world, including both the eastern and western coasts of the north Atlantic (South & Cardinal, 1970; Taylor, 1957, 1960). However, considerable variation exists within species of Gracilaria (e.g. May, 1948), thus delimitation of species is often extremely difficult. Gracilaria foliifera from Britain (Fig. 1 A) is similar morphologically to the original material of Fucus foliifer as illustrated by Børgesen (1932, fig. 1), and therefore, we have limited our consideration to G. foliifera as it occurs in Britain (also see Harvey, 1846, pl. 15). However, little information is available on G. foliifera from the British Isles, and in the present instance we have investigated the life history of this alga in culture together with preliminary results on growth in small-scale tanks with running sea water.

Red Seaweed Gracilaria Arcuata in Cage Culture Area of Lawas, Sarawak

Red seaweed Gracilaria sp. is known as ‘Janggut Duyong’ by the local people of Sarawak. This macroalgae iswell-distributed in both temperate and tropical seawaters. Gracilaria sp. could be processed to produce agar forindustrial purposes whereas some people consumed it directly and become part of their daily diet. In terms ofecology, Gracilaria sp. is one of primary producer in the seawater and its presence can form habitats to supportother aquatic organisms. Despite its socio-economic and ecological importance, little is known about Gracilariasp. in Sarawak. Hence, this study is designed to: (i) determine the diversity and abundance of Gracilaria in cageculture of Lawas, Sarawak (ii) assess the water quality of the cage culture area where Gracilaria is found and(iii) determine other aquatic organisms that found within Gracilaria population. Three field samplings had beenconducted from October 2013 to November 2014 at cage culture areas of Awat-Awat Village, Lawas, Sarawak.Only single species of Gracilaria was found namely Gracilaria arcuata. Besides G. arcuata, Acanthophora sp.and Padina sp. were also found but in small patches. In addition, five different groups of aquatic invertebrateswere observed namely tunicates, bivalves, polychaetes, small crabs and brittle stars. The selected water qualityparameters namely temperature, pH, dissolved oxygen, salinity, turbidity, total suspended solid, orthophosphate,silicate and chlorophyll a were significantly different (p= 0.000) during all the three field samplings except fornitrite (p= 0.588). However, the values recorded were within normal range of standard water quality for tropicalestuarine area. Since healthy population of Gracilaria could be easily found here, therefore this area has thepotential for future seaweed aquaculture.

Use of Polyphosphates in Agar Processing

To obtain informations on the interaction between the added polyphosphates and agar, the ash composition of agar which was reproduced from the agar gel containing polyphosphate through the repetition of usual manufacturing process was analyzed. The contents of total and HCl-soluble ash, and soluble P2O5 were closely correlated with the amount of added H-polyphosphate*1, respectively. The highest value of ash increase was equal to 11% of the added polyphosphate for h-agar*2, and 17% for m-agar*3. The additives less than 200ppm did not always increase ash contents of the products. Soluble Fe3+ was reversely proportional to P2O5 in the product. Magnesium showed similar tendencies to ionic iron. Total ash and soluble SO3 decreased with the prolongation of cooking the agar solution.*1 H polyphosphate: Commercial sodium polyphosphate consisted of 85% of metaphosphate and 15% of pyrophosphate.*2 h-agar: Powdered agar of h brand which was processed from the alkali treated seaweeds, Gracilaria species.*3 m-agar: Mixed agar in powder which was experimentally processed from several kind of seaweeds, Gelidium and Gracilaria species.