In vitro somatic embryogenesis and regeneration of somatic embryos to whole plants through micropropagules was successfully demonstrated from pigmented uniseriate filamentous callus of Kappaphycus alvarezii (Doty) Doty in axenic cultures. More than 80% of the explants cultured on 1.5% (w/v) agar‐solidified Provasoli enriched seawater (PES) medium showed callus development. The callus induction rate was consistently higher for laboratory‐adapted plants. The excised callus grew well in subcultures and maintained its growth for prolonged periods if transferred to fresh medium in regular intervals. Some subcultured calli (<10%) did undergo transformation and produced densely pigmented spherical or oval‐shaped micropropagules (1–5 mm in diameter) that subsequently developed into young plantlets in liquid PES medium. The micropropagule production was further improved through somatic embryogenesis by a novel method of culturing thin slices of pigmented callus with naphthaleneacetic acid (NAA) or a mixture of NAA and 6‐benzylaminopurine. Transfer of embryogenic callus along with tiny somatic embryos to liquid medium and swirling on orbital shaker facilitated rapid growth and morphogenesis of somatic embryos into micropropagules that grew into whole plants in subsequent cultivation in the sea. The daily growth rate of one tissue cultured plant was monitored for seven generations in field and found to be as high as 1.5–1.8 times over farmed plants. The prolific somatic embryogenesis together with high germination potential of somatic embryos observed in this study offers a promising tool for rapid and mass clonal production of seed stock of Kappaphycus for commercial farming.

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The effect of two chlor-alkali industry effluents and domestic sewage has been studied, in situ, on tropical seaweeds of the Okhamandal coast. Maximum biomass was observed at a distance of 400 and 5000 m away from the discharge points of the two chlor-alkali industries. Ulva lactuca and Rhizoclonium kochianum were most resistant while Caulerpa scalpelliformis, Halimeda tuna and Codium dwarkense were most sensitive. Species of Sargassum, Cystoseira and Gelidiella were completely eradicated due to the long term effect of the effluent from one chlor-alkali industry. Gracilaria corticata, G.foliifera and species of Hypnea produced good biomass under mildly polluted conditions and they may be cultivated in such areas. Algal species diversity (ASD) was not recorded up to 400 and 4000 m away from chlor-alkali industries outfalls as intensity of pollution was high in this region. The ASD increased as the distance from the outfall increased. In general, brown seaweeds were most sensitive to this type of pollution.Domestic sewage was much less inhibitory to seaweeds. Species of Ulva and Enteromorpha were maximum biomass producers while brown seaweeds were least productive in the near vicinity of the discharge. Species diversity was also high, in this area, as compared to the chlor-alkali industry effluents.Vertical distribution of seaweeds was not evident up to 400-4000 m away from chlor-alkali effluents outfall and up to 10m away from domestic sewage discharge points. Seaweeds showed characteristic vertical distribution after these distances. n ro uc on sewage and industrial effluents on Indian seaweed has Domestic sewage and industrial effluents affect the been published (Subbaramaiah and Parekh 1966, Tegrowth of seaweeds. The response ranges from stim-wari 1972, Sreeramulu et al. 1977, Umamaheswara ulation through indifference to total devastation. Spe-Rao 1977, Joshi et al. 1982, Tewari and Rao 1982, cies may respond uniformly or in diametrically op-Dhargalkar 1986. These studies were confined mostly posite ways (North et al 1972). The effect of such to the laboratory with analytical studies on selected complex effluents on temperate marine algae have species of seaweeds. The present study was underbeen studied in different parts of the world (Golubic taken to find out the effect of such complex wastes 1968, Borowitzka 1972, Littler and Murray 1975, Niel on tropical Indian seaweeds in situ.

Indian seaweed species Enteromorpha linza, Enteromorpha prolifera, Ulva fasciata, Caulerpa taxifolia and Sargassum johnstonii from natural and cultivated populations were evaluated for food safety and nutritional quality. Among the above seaweeds, Enteromorpha prolifera showed the highest caloric value and protein content, while these values were lowest in Sargassum johnstonii species of natural habitat. The lipid content was maximum in cultivated seaweeds of E. linza and U. fasciata species. Crude fiber varied within a narrow range in all the seaweeds analyzed. Protein efficiency ratio (PER) studies conducted with E. linza and U. fasciata showed low PER values compared to control rats fed on casein as source of protein. Acute oral feeding of seaweeds E. linza, U. fasciata, C. taxifolia and S. johnstonii and subacute oral feeding of E. linza for 12 weeks did not produce any toxic effects on male and female rats.