Preparation of oligoalginate plant growth promoter by γ irradiation of alginate solution containing hydrogen peroxide.

Degraded alginate compounds with molecular weights of 7-26, 40-77, or 11-26 kDa were obtained by γ irradiation, hydrogen peroxide (5% H(2)O(2)) treatment, or a combination treatment involving ionizing radiation and H(2)O(2), respectively. The 14 kDa oligoalginate, prepared by the combined method, promoted the growth of mustard greens and lettuce at an optimal concentration of 75 mg/L. The growth promotion effects of the oligoalginate prepared by γ irradiation in the presence of H(2)O(2) were statistically equivalent to those of the oligoalginate prepared by γ irradiation only.