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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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Effective extraction of Hg(2+) and Cr(3+) ions from aqueous media by novel rhodamine-alginate polymer-based highly fluorogenic, as well as colorimetric, chemosensor beads.

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The sap expelled from the fresh harvest of Kappaphycus alvarezii , a red seaweed growing in tropical waters, has been reported to be a potent foliar spray. Tandem mass spectrometry of various organic extracts of the sap confirmed the presence of the plant growth regulators (PGRs) indole 3-acetic acid, gibberellin GA(3), kinetin, and zeatin. These PGRs were quantified in fresh state and after 1 year of storage by ESI-MS without recourse to chromatographic separation. Quantification was validated against HPLC data. The results may be useful in correlating with the efficacy of the sap. The methodology was extended to two other seaweeds. The method developed is convenient and precise and may find application in other agricultural formulations containing these growth hormones.

Grafting of agar and k-carrageenan with polyvinylpyrrolidone (PVP, average molecular weight 10,000 D) in an aqueous medium at a pH of about 7 produced agargraft-PVP and k-carrageenan-graft-PVP blends capable of forming hydrogels. The reaction was carried out with microwave irradiation in the presence of a water-soluble initiator, potassium persulfate. Optimum microwave irradiation conditions for obtaining hydrogels of the grafted products were achieved. The structural characteristics and thermal stability of the grafted blends were studied by Fourier transform infrared, 13 C-NMR, and thermogravimetric analyses. Appearance of new IR bands at 1661, 1465, and 1426 cm À1 in the grafted products indicated the insertion of PVP into the polysaccharide structure. Powder X-ray diffraction studies revealed the enhanced crystallinity in the products compared to in the control polysaccharides as well as PVP. Agar and k-carrageenan were grafted to a considerable degree, with 62.5 E % and 125 G % for agar-graft-PVP and 65.5 E % and 131 G % for k-carrageenan-graft-PVP. Optical micrographs of the grafted blends indicated considerable changes in the morphology of the agar and the k-carrageenan, substantiating the X-ray diffraction data. A plausible mechanism for the crosslinking of PVP to agar and k-carrageenan is proposed. These hydrogels exhibited enhanced water-holding capacity despite weaker gel strength than that in the respective control polysaccharides.