Callus and Organ Formation in Tissue Cultures of Spinach (Spinacia oleracea L.)

Abstract

When hypocotyl segments of the spinach plant were cultured on medium containing IAA (15mg/l) in the presence of GA, those cultivars in which the callus growth was profuse in terms of the concentrations of GA (10^-7-10^-4M), e.g. ‘HOYO’, ‘TOKAI’ and ‘WAKAKUSA’, showed generally low bud-forming activity. Furthermore, in the cultivars which had relatively high bud-forming capacity on the medium containing IAA plus GA, e.g. ‘NIPPON’ and ‘TOKO’, callus proliferation of their hypocotyl tissue segments were low overall. Root formation derived from hypocotyl segments of ‘TOKO’ and ‘NIPPON’ were markedly enhanced by the simultaneous application of GA to the medium with IAA. While the effective concentrations of GA on bud formation of spinach hypocotyl segments were different among these cultivars, the bud formation was enhanced by the addition of GA at the concentrations ranging from 10^-7 to 10^-4M, except in the case of ‘TOKAI’. Optimal concentrations of GA on the bud formation of ‘NIPPON’, ‘TOKO’ and ‘HOMO’ were 10^-5, 10^-6 and 10^-4M, respectively. The induction of bud formation of hypocotyl segments in the spinach plant may take place during a relatively early stage of the incubation.