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    • Article

      Clonal production of Kappaphycus alvarezii (Doty) Doty in vitro 

      MRJ Luhan & JP Mateo - Journal of Applied Phycology, 2017 - Springer Verlag
      Micropropagation has proven to be a reliable method to mass produce certain crops. This method also has been applied in macroalgae to produce clones for seaweed farming. Protocols for callus production and shoot regeneration from protoplasts have been established for some seaweed species like Kappaphycus alvarezii. Cells and larger tissues, whether in solid or suspension medium, have been used to propagate clones which were later tested for suitability for farming. Although clonal production was successful, the long duration of culture in vitro limits the production process making the growing of Kappaphycus in vitro an expensive technique to produce clones. In this study, K. alvarezii was grown in vitro to develop a more efficient protocol for the production of clones. Small sections of Kappaphycus were grown in suspension for 1 month under the same temperature, light, and salinity. The type of media, source of explants, length of explants, and stocking density that resulted in the highest growth rate and survival rate were determined. Growth rate of K. alvarezii is significantly higher in media with inorganic nitrogen added than in Grund medium or Ascophyllum nodosum medium only. The appearance of shoot primordia as early as 5 days was observed in media with higher nitrogen concentration. Growth rates of explants approximately 3 and 5 mm are significantly higher than 10 mm sections. Shoots develop significantly faster in explants from tips than sections from older branches. Growth rate of K. alvarezii grown at 0.5, 0.75, 1, 1.25 s 10 mL−1 of medium is not significantly different. This protocol could significantly reduce the (1) time of culture and (2) cost of plantlets production by not using plant growth regulators and formulated media in vitro. Nursery reared plantlets/propagules for farming would be affordable to the stakeholders for sustainability of seaweed production.
    • Article

      Effect of short-term immersion of Kappaphycus alvarezii (Doty) Doty in high nitrogen on the growth, nitrogen assimilation, carrageenan quality, and occurrence of “ice-ice” disease 

      MRJ Luhan, SS Avañcena & JP Mateo - Journal of Applied Phycology, 2015 - Springer Verlag
      Short-term immersion of Kappaphycus alvarezii (Doty) Doty in a high-nitrogen-containing medium was tested to increase growth, improve the quality of carrageenan, and decrease “ice-ice” disease occurrence. Tank-reared Kappaphycus were used as explants. Growth, nitrogen assimilation, carrageenan quality, and occurrence of ice-ice disease of enriched (E/N) K. alvarezii were determined. E/N and un-enriched (control) K. alvarezii were planted inside net cages in the sea. Nitrogen assimilation was monitored to determine if nitrogen was incorporated in the tissues after 12 h. Total thallus nitrogen of K. alvarezii doubled after immersion in high nitrogen. Growth rate and carrageenan yield of E/N K. alvarezii were significantly higher than those of the control. Gel strengths of E/N and the control were not significantly different. Ice-ice disease occurrence was significantly higher in the control than the enriched seaweeds. Short-term immersion of K. alvarezii in a high-nitrogen medium before outplanting increased growth rate and decreased the occurrence of “ice-ice”.