Variação da fotossíntese e dos teores de carboidratos induzidos por etefom e déficit hídrico na fase de maturação da cana-de-açúcar

Abstract

An important index for the ethanol industry is the sucrose yield in sugarcane, which is affected by plant ability to accumulate sucrose during ripening. Despite the known efficiency of treatments such as water restriction and the application of regulators to stimulate the sucrose storage in culms, little is known about the physiological responses of the plant that lead to ripening. In this context, the aim of this study was to evaluate the physiological responses of sugarcane to different ripening treatments. Two varieties, IACSP95-5000, with high yield, and IACSP94-2094, with moderate yield were subjected to water deficit or application of chemical regulator (ethephon 480 g ha -1) and both treatments associated. Growth, accumulation of carbohydrates in leaves and culms were measured. It can be concluded that the effects of ethephon on sugarcane are genotype-dependent. Ethephon stimulates sucrose accumulation in the culm and the photosynthate supply by the source in the responsive variety (IACSP95-5000). Such effects are not associated with growth restriction. In relation to the drought combined with the application of ethephon, the responsive variety shows increased sucrose content in culm at the same level as when ethephon is applied alone, hence treatments have no additive effects on sugarcane ripening.

Aplicação de maturador e fertilizante foliar em cana-de-açúcar

“…Tais mudanças na planta podem explicar o aumento do teor de sacarose na variedade RB855536, apresentando ganho máximo de 18% aos 28,5 DAA; semelhante ao observado por Meschede et al (2010) que obtiveram ganhos de 16% com a aplicação de Sulfometuron methyl. Trabalhos de pesquisa constataram que a aplicação de maturadores em cana-deaçúcar favorece o acúmulo de sacarose nos colmos (VIANA et al, 2007;LEITE et al, 2010;INOUE et al, 2015;Roberto et al, 2015) e a melhoria na qualidade tecnológica da matériaprima (MESCHEDE et al, 2010;INOUE et al, 2015).…”

“…As características tecnológicas para a cana-de-açúcar apresentam incremento significativo com a aplicação de maturadores, o que permite melhor expressão do potencial genético quanto ao acúmulo de sacarose nos colmos (VIANA et al, 2007;LEITE et al, 2009a;LEITE et al, 2010;MESCHEDE et al, 2012;ROBERTO et al, 2015) e aumento de ATR, POL e Brix (INOUE et al 2015). No entanto, esses atributos dependem da responsividade da variedade (ROBERTO et al, 2015) e das condições climáticas, que, além de relacionar-se ao modo de ação destes produtos (FARIA et al, 2014), influenciam o crescimento dos colmos e a produtividade da cultura (ABREU et al, 2013).…”

Productivity and Biochemical Characteristics of Sugarcane When Submitted to the Action of Chemical Ripeners

“…The increase in Reducing Sugar content favors plant growth and directly affects juice purity, resulting in lower efficiency recovery of sucrose by the industry. On the other hand, the reduction of these carbohydrates enhances the technological quality of the juice, favoring sugarcane ripening (LEITE et al, 2009a;ROBERTO et al, 2015).…”

Biochemical modulations in açaí palm (Euterpe oleracea Mart.) under vegetative stages in an agroforestry system of the Amazon

“…Under normal conditions of light intensity, CO 2 and water, photoassimilates synthesized in the biochemical stage of photosynthesis are stored as starch in the chloroplast or sucrose in vacuoles ( Roberto et al., 2015; Oliveira et al., 2016). However, according to Oliveira et al.…”