Effect of gibberellic acid and tebuconazole retardant on leaf mesostructure formation and pigment apparatus of scoto- and photomorphic maize seedlings (Zea mays L.)

Abstract

V.G. Kuryata, B.O. Kuts*, I.V. Poprotska, L.А. Golunova, O.O. Khodanitska, O.A. Shevchuk, O.O. Tkachuk, N.V. Baiurko and V.A. Frytsiuk

The influence of gibberellic acid and antigibberellic drug tebuconazole on the peculiarities of leaf mesostructure, photosynthetic pigments accumulation and chlorophyllase activity in the leaves of scoto- and photomorphic seedlings of maize was analyzed. Leaf thickness was significantly reduced under gibberellic acid influence and increased under tebuconazole action compared with control in light and in the dark. These changes were determined by the fluctuations in chlorenchyma thickness and the size of upper and lower epidermis of the leaves. Under tebuconazole action there was a significant increase in stomata quantity per area unit of the abaxial surface of leaf while their linear size was reduced. Under tebuconazole influence, chlorophyll a content increased compared with control. There was a decrease in chlorophyll b content, which, in our opinion, indicates that the drug inhibits chlorophyll conversion process. Gibberellic acid led to a slowdown in chlorophyll a synthesis and decreased the total chlorophyll content. The decrease in chlorophyll content occurred due to increased chlorophyllase activity. The changes indicate the inhibition of formation of light-harvesting complexes of photosystems I and II by gibberellin.