Sugarcane growth, sucrose accumulation and invertase activities under trinexapac-ethyl treatment

Abstract

Since the 980's Brazilian sugarcane growers and mills have used chemical ripeners to reach higher industrial yield, increase profits and broaden the harvesting season of sugarcane. Trinexapac-ethyl (TE), one of the main ripeners used in Brazil, suppresses vegetative growth and favors sucrose accumulation in sugarcane stems by inhibiting the biosynthesis of GA (Gibberelic acid isoform ) from GA20. So far, little research has been done on the physiological effects of this ripener. The present research was undertaken to determine the effects of the chemical ripener trinexapac-ethyl upon sugarcane growth, sucrose accumulation and soluble and wall bound invertase activities. The experiment was installed in a second ratoon area of the sugarcane variety SP8-3250 in Pradópolis, state of São Paulo, Brazil, and arranged in randomized blocks (split-plots). Trinexapac-ethyl was applied at a rate of 0.2 L of active ingredient per hectare. The results suggest that this ripener can be used to increase sugar yield and its repressive effect on vegetative growth does not affect stalk productivity. The activity of soluble acid invertase in young stem tissues can be used as a reliable biochemical parameter to determine the response of sugarcane to the trinexapac-ethyl.Additional keywords: Saccharum; gibberellin inhibition; sugar metabolism; sucrose yield; chemical ripener.