Influence of Growth Regulators and Different Spectra of Monochromatic Radiation on the Growth and Biosynthetic Characteristics of Callus Culture of Ipomoea batatas (L.) Lam.

Abstract

The work studied the influence of plant growth regulators as well as the effect of monochromatic radiation of different spectral composition on the growth and accumulation of secondary metabolites in the callus culture of sweet potato (Ipomoea batatas L.). It was found that auxin analogues in low concentrations (0.5 mg/L) significantly stimulated the growth of cell biomass, while the effect of 4-chlorophenoxyacetic acid (4-CPA) was more pronounced (stimulation 16 times) than that of 2,4-dichlorophenoxyacetic acid (2,4-D) (13.5 times stimulation). Both the increase in the concentration of 2,4-D and 4-CPA in the medium and the addition of cytokinin, 6-benzylaminopurine (BAP), led to a significant inhibition of culture growth (up to three times). In contrast to 2,4-D, the addition of 4-CPA led to an eightfold increase in the total content of polyphenolic compounds in cultured cells. Activating effect of 4-CPA on the biosynthetic characteristics of I. batatas cell culture persisted even with the addition of BAP, while an increase in the concentration of 4‑CPA led to the leveling of the activating effect. Monochromatic radiation—white, red (660 and 630 nm), yellow, green, and blue (440 and 460 nm) light—inhibited growth (up to 1.5 times) and the total accumulation of secondary metabolites in I. batatas cells (up to 1.8 times). At the same time, the white, bright blue, and red spectra differentially activated the formation of individual compounds 3,4-dicaffeoylquinic acid and 3-feruloyl-5-caffeoylquinic acid. Thus, the authors have established that both auxin analogues and spectral radiation exhibit different effects on the growth and biosynthetic characteristics of the I. batatas calli.