Eucheuma , Orig. name Gigartina isiforme () Endlicher , Variety Eucheuma isiforme var. denudatum , The yield and physicochemical properties of native and alkali treated carrageenan from Eucheuma isiforme harvested from the Nicaraguan. The yield and physicochemical properties of native and alkali treated carrageenan from Eucheuma isiformeharvested from the Nicaraguan coast were .
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The production and use of Eucheuma 1. The three kinds, the annual production of each and their specific carrageenans are, respectively: The principal carrageenan uses are as suspensoids in dairy, luxury human and pet foods and drug products.
In addition to foreign exchange earnings ekcheuma those countries exporting the seaweed and the final use values of its carrageenans, the labor-intensive farming of Eucheuma is of great socio-economic value to the often nearly indigent shore dwelling families who grow it. Only the latter is predominantly from wild crops. The others are almost all farmed. The taxonomy of the Eucheuma section Cottoniformia, which produces the cottonii of commerce, is most difficult due to the wide range of environmentally induced forms.
It proved to be so much more easily grown that it has completely eucheumq the other species, such euchema E. Likewise, many of the former wild crop components of commercial lots of Eucheuma were either never farmed such as E.
They are illustrated in Figures 1, 2, and 3. A common and a scientific binomial name are given for each. The presence and nature of special core tissues usually requires microscopic study. Eucheuma denticulatum branch showing the cylindrical axis with rings of spinous primary initially-determinate branches, some of which have become indeterminate but are yet small.
Eucheuma alvarezii branch showing its cylindrical axis with branches that are commonly enlarged maximally just beyond a basal curvature toward the light. Eucheuma gelatinae showing the flat branches arising from marginal cylindrical teeth.
The scale bars represent 3 centimeters. Burman in and the use of this specific epithet is continued today as E. That Linnaeus in sought to substitute Fucus spinosus for Burman’s name, which has been used as E. Agardh, has no standing Dixon in view of the priority of Burman’s epithet, a priority acknowledged by Linnaeus himself.
Eucheuma was first distinguished as a genus and named by J. Agardhwho included seven species one of which was E. Agardh, in turn based on earlier species including Fucus spinosus Linnaeus and F. The Lectotype is the specimen in the Linnaean Herbarium as and illustrated by Turner as Figure “a” of his Plate There is no question as to the nomenclature of this species, Eucheuma alvarezii Doty The Holotype is in the B.
Bishop Museum in Honolulu, Hawaii, bearing the author’s voucher number Among the species originally included in Eucheuma by J. Agardh was E. Thus today one uses E.
Agardh for this third commercial entity. Basically it is a multiaxial filamentous red algal genus which becomes strongly pseudoparenchymatous. The nature of their triphasic life history results in their relegation to the family Solieriaceae of the order Gigartinales as these taxa are defined by Kylin and more recent authors. The species vary greatly in form as a result of the environments in which they grow.
This is particularly true of those in the section of the genus to which the cottonii forms belong. Commercial spinosum and cottonii are composed of cylindrical branches that are rigid. Mature gelatinae branches are apically flat, somewhat flexible, have marginal teeth and arise from a cushion of strongly compressed branches. None of these authors treats the sections of the genus, Anaxi-ferae, Cottoniformia or Gelatiformia, from which the commercial cottonii and gelatinae crops arise.
Weber-van Bosse and Doty provide some iskforme the structural details of the section Cottoniformia but they are still largely undefined anatomically. A very small amount of the third, gelati-nae, comes from the Philippines and China Hainan Island and Taiwan.
These three species of the genus are isifirme entirely restricted to the same brightly lit waters Figure 4 in which coral reefs form. Eucheuma is now being commercially produced in the far western Pacific.
Sea Temperature Habitat for Commercial Eucheuma. Production both north and south of the equator occurs between the paired winter The anticipated micro-forms persisting during the off-season are not known See Section 3. Possibly the tolerance of spinosum is greater than that of cottonii and gela-tinae is the least tolerant.
Since Eucheuma grows almost entirely in open ocean water in areas of high water motion, light and temperature are not significant factors in local distribution. Water motion is most isiformee. In some cases there may be some influence of run-off from land.
Spinosum especially appears to be sensitive to water quality. Both the commercial wild and farmed kinds of Eucheuma are mostly found in water less than a half meter deep at extreme low isjforme level.
The greatest depth recorded is that of Weber-van Bosse26 fathoms.
For Eucheuma, deep water habitats are of no commercial importance. Also tides may exert an influence on productivity through light intensity and water motion control. Thus generally commercial production is in areas with low tide ranges.
Pigmentation is characteristically more or less dense at brighter light levels. Thalli may be black in intense light and relatively redder in the shade or in deeper water due to relative abundance of phycoerythrin. Pale yellower thalli are found in some bright light conditions. Some cottonii forms may become negatively phototropic in intense light, and the spininess of some spinosum forms may be reduced to bilaterality, and the axial segments may then suffer some dorsiventral compression.
Cottonii thalli exposed to air tend to form “heads,” or become prostrate and dorsiventrally flattened. Bushy thalli are formed in turbulent water, and trailing cottonii forms are found Doty where current dominates. Cottonii may form erect cane-like forms seasonally in pools or deeper water. At greater depths the species may change in morphology as though etiolated in a phycological sense. See DawesChapter 14 for the basic physiological nature of the responses expected of such a seaweed as Eucheuma as its extremes of vertical distribution are approached.
The rigid and bush-like thallus form enhances thinning of the boundary layers wherever they are subjected to water motion. Thus, since materials move into and out of algae such as Eucheuma by diffusion, their growth increases as water motion increases, up to the point where drag or force produces excessive physical damage.
Only gelatinae tolerates direct wave action. It is Figure 3 the smallest of the three, and the fronds are apically flat and pliable. Commercial production is from level sedimentary bottoms that are under water except during the lowest of tides. Level sedimentary bottoms are desirable for they are uniform and easily workable whereas sloping or irregular areas are not.
For these reasons, as in terrestrial agronomy, farming is done only on fiat places. Local horizontal and vertical distribution are correlated with the variations in the above factors. The chemical nature of the substratum is of little importance. The physical nature of the substratum is important as a stable anchorage for wild crop thalli.
Its stability correlates with water movement, which, in turn, is essential See Section 2. In the Hawaiian experiment See Section 2. For the commercial forms of Eucheumabeyond the results in Section 5.
Temperature and light are felt to be relatively independent of water motion and its quality. It is not economic for farmers to provide control of these factors directly, so in selecting sites it is essential all be within tolerable limits. Water motion especially is a factor that must be taken into account in selecting sites.
It often affects sediment in the water, which, in turn, affects light. Mineral nutrition is surely important in view of the high mineral content of the species. Table 2 provides various cation as well as nitrogen and phosphorus, values for the commercial species. They are similar among other Eucheuma species.
Eucheuma isiforme () :: Algaebase
Unfortunately, the variation in these elements in different commercial lots is not publicly known. Arsenic is below the U.
Federal Drug Administration limits. The cation determinations were eycheuma by atomic adsorption methods in replicate. Phosphorus and nitrogen are in terms of percent dry weight. The values for Fe were from thalli ground in porcelain. In an unpublished study the fixed nitrogen and dissolved phosphorus eucheua of the water, as well as other factors, were determined weekly as the water passed through about 15 meters of usually dense Eucheuma planting. The Hawaiian Eucheuma Experimental Habitat.
The values are mean microgram atoms isifkrme liter from all weekly measurements made over the 55 weeks of a study period. It affects growth in such ways as change in mass growth ratedifferentiation formreproduction and production of the hydro-colloid materials for which Eucheuma is prized.
These topics are discussed above and in Section 5.
Eucheuma – Wikipedia
Yet these relationships are important for farm production. For example, in regard to the space occupied and diffusion as a whole, the Eucheuma thallus is analogous in isiforrme relationships to the sea water in the same way the root system of a terrestrial flowering plant is related to the soil water.
Unpublished results indicate that, in a desirable commercial Eucheuma habitat, the water in a one-liter thallus space may be laterally changed over a half million times a day.
A diploid vegetative phase Phase 1 produces haploid non-motile spores called tetra-spores. The tetraspores produce haploid gametophytes Phase 2 that in turn produce diploid carposporophytes parasitic in the female thalli.