The potential of using akinetes as seed starters for Cladophora glomerata cultivation: Germination and growth of akinetes under different light intensities and humic concentrations

Abstract

The potential of using akinetes as seed starters for algal cultivation was assessed in Cladophora glomerata. The effects of light intensities and humic acid concentrations on akinete germination, algal growth and biomass production were examined. A C. glomerata akinete that was induced by incubation in 0.1% NaCl under darkness was incubated in Wright's cryptophyte (WC) medium under different light intensities and supplemented humic acid concentrations. Germination and growth were recorded every 24 h for 192 h. Akinetes germinated after 24 h of incubation, and cells started growing after 96 h. Light is required for akinete germination. Light intensity and humic acid concentration significantly affected akinete germination and cell growth (p ≤ 0.001). The incubation of Cladophora akinetes in WC medium with 4 mg L−1 potassium humate under 50 μmol photons m−2 s−1 resulted in high germination and growth. Supplementation with humic acid could extend the growth period and result in an increase in production. In addition, Cladophora germinated from akinetes showed advantages over filaments in terms of attachment to the substratum and expansion of horizontal growth via rhizoid and stolon development. Therefore, akinetes show potential as seed inocula for C. glomerata cultivation, and using akinetes as inocula can be an alternative culture practice for algal production.