Beneficial Effect of Silicon Applied Through Fertigation Attenuates Damage Caused by Water Deficit in Sugarcane

Abstract

Water deficit limits the establishment of sugarcane that uses Pre-sprouted seedlings (PSS). Silicon (Si) can mitigate the effects of water deficiency, but it is not known if the Si applied through fertigation is efficient to mitigate damage caused by water deficit at 60 days after transplantation of PSS to the field, nor what physiological and biochemical mechanisms are involved. For this purpose, the objective of this study was to evaluate whether Si applied through fertigation in the PSS production phase of Saccharum officinarum L. (sugarcane) and S. spontaneum L. (energy cane) is efficient in mitigating the effects caused by severe water deficit at 60 days after transplantation. Another objective was to determine the physiological and biochemical mechanisms involved. Two experiments were developed using PSS from sugarcane and energy cane. The treatments consisted of a 2 × 2 factorial scheme, with absence (−Si) and presence of Si (+Si) applied through fertigation (2.5 mmol L−1); combined with water regime: 70% (without deficit) and 30% (severe water deficit) of soil water holding capacity, arranged in randomized blocks with six repetitions. Severe water deficit at 60 days after transplanting decreased the water content and the water potential of the plants, inducing oxidative stress and impairing photosynthetic efficiency, with a consequent decrease in plant growth. Fertigation was shown to be efficient to supply Si in the PSS of sugarcane and energy cane. The residual effect of Si attenuated the damage caused by water deficit at 60 days after transplanting in both species; the mechanisms involved were related to the antioxidant defense system with increased activity of enzymes catalase, superoxide dismutase, ascorbate peroxidase, and proline content. In addition, water status remained stable and, consequently, there was increased plant growth. This study showed that the strategy based on Si supply enables the use of PSS in sugarcane and energy cane, increasing the viability and sustainability of this production system.