Use of plant growth regulators in micropropagation of Kappaphycus alvarezii (Doty) in airlift bioreactors

Abstract

The effects of plant growth regulators on callus induction rate and regeneration of K. alvarezii explants was evaluated. K. alvarezii calluses were induced in vitro with kinetin (K), 6-benzylaminopurine (B), 1-naphtalene acetic acid (N) and spermine (S). After 30 days, K. alvarezii explants produced filamentous calluses and isolated crystalline filaments growing from the medullar region and from cortical cells at the cut edge. The plant growth regulators 1-naphtalene acetic acid (1 mg L −1 ) and 6-benzylaminopurine (1 mg L −1 ) and the 1-naphtalene acetic acid + kinetin + spermine (1, 1, 0.018 mg L −1 respectively) combination produced 85 to 129% more calluses, with significant differences versus the control ( p < 0.05). Spermine at 0.018 mg L −1 produced calluses in the apical, intercalary and basal regions of explants. Spermine also reduced callus induction time to 7 days, which is faster than previously reported induction times with other plant growth regulators. An airlift bioreactor was designed and characterized to micropropagate K. alvarezii calluses. The bioreactor had mixing times ranging from 4.6-10.3 s at T 90 and T 95 , which is shorter than those for the Fernbach (5.2-13.4 s) and balloon flasks (6.3-17.3 s). Mixing time standard deviations were smaller for the bioreactor (1.1-4.6) than for the Fernbach (9.3-13.6) and balloon flasks (5.5-15.8), suggesting an adequate flow regime within the bioreactor. The results are useful for improving callus induction in K. alvarezii and propagating microplantlets in an airlift bioreactor, and provide baseline data for macroalgal bioreactor culture.

Micropropagation as a tool for sustainable utilization and conservation of populations of Rhodophyta

“…Species of Grateloupia showed the highest regeneration potential, which could be increased by the addition of plant growth regulators (auxins and/ or cytokinins), as reported for Grateloupia dichotoma by Yokoya & Handro (1996. For other species of Gigartinales, regeneration from callus was found to be stimulated by PGR in Solieria filiformis (Yokoya & Handro, 2002), Hypnea musciformis (Yokoya et al, 2003) and Kappaphycus alvarezii (Muñoz et al, 2006). However, the presence of PGR was facultative for the last two species, as reported by Bravin et al (2006) and Reddy et al (2003), respectively.…”

Flow of cytokinins through the environment

“…Yokoya and Handro (2002) and Muñoz et al (2006), it has not yet been shown that seaweeds are able to take up cytokinins from the growth medium. However, the numerous examples of the positive effects that applied cytokinins have on seaweeds grown in culture suggest that this is likely and thus cytokinins occurring in seawater may influence the growth of seaweeds.…”

Genetic transformation in Kappaphycus alvarezii using micro-particle bombardment: a potential strategy for germplasm improvement

“…The advantage of Kappaphycus is that techniques for its micro-propagation have long been worked for efficient and rapid plantlet regeneration (Dawes and Koch 1991;Dawes et al 1993;Muñoz et al 2006). Callus formation can be observed after 15 days of culture (Hayashi et al 2008b) and a new plant can be micro-propagated in about 30 days (Hurtado and Biter 2007).…”