Endogenous Levels of Cytokinins, Indoleacetic Acid, Abscisic Acid, and Pigments in Variegated Somaclones of Micropropagated Banana Leaves

Abstract.

The banana (Musa spp. AAA) micropropagation shows a high incidence of off-types, among whose variegated plants are very common. Endogenous levels of growth regulators and pigment content were measured in normal and variegated leaves of the micropropagated banana plants growing in a greenhouse. Growth regulators were separated by high pressure liquid chromatography and submitted to enzyme-linked immunosorbent assay for quantification. Pigment content was measured using the colorimetric method. Green leaves contained 1.9 and 10 times more cytokinins compared with green and yellow sectors of variegated leaves, respectively. The levels of indoleacetic acid in normal leaves were significantly higher than those found in green and yellow sectors of variegated leaves; however, the levels of abscisic acid were lower in normal leaves. The lower content of chlorophylls in variegated leaves coincided with decreased endogenous levels of cytokinins, which indicated that variegation in banana leaves may be associated with alterations in the metabolism of this growth regulator.