A protective foliar complex boosts sugarcane quality and energy yield by reducing oxidative stress under drought

Abstract

Water stress negatively impacts plant morphology and physiology by inducing metabolic oxidative stress, which leads to cellular damage. Applying nutrients and/or organic molecules, such as amino acids, may mitigate the effects of drought stress. In the present study, the effects of a protective foliar complex (PFC) on late-harvest sugarcane (Saccharum spp L.) (dry season) were evaluated. Four field experiments were carried out in commercial areas of sugarcane production in the central-south region of Brazil using sugarcane variety CTC4: in the fourth and second ratoons in 2019 and in the fifth and third ratoons in 2020. The treatments consisted of foliar application or no application of the PFC at the beginning of the dry period in June. The PFC was applied at a dose of 10 L ha−1 in a water volume of 100 L ha−1. PFC application increased the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) in sugarcane leaves. PFC application also reduced leaf levels of malondialdehyde and hydrogen peroxide (H2O2). On average, PFC application increased sucrose accumulation by 2.26 and 1.74 Mg ha−1 in 2019 and 2020, respectively, indicating improved raw material quality. In addition, PFC application mitigated damage caused by drought, with average increases in stalk productivity of 10.7 and 7.6 Mg ha−1 in 2019 and 2020, respectively. The positive effects of PFC application on plant antioxidant enzymes enabled greater biomass accumulation and, in turn, higher energy cogeneration.