Leaf Boron application in eucalypt under water stress

Abstract

Mineral fertilization is a common practice to increase crop productivity; in regions with occurrence of water stress foliar application of boron has become more important in the last years. The objectives of our study were to evaluate the effects of foliar application of two boron fertilizers in two level of soil water availability on: growth, nutritional levels, boron accumulation in leaves, and physiological characteristics of two clones of eucalypt. The experiment was conducted in a greenhouse. The plants were in containers with 7 I of sand. The experiment was comprised of a 6x2x2 factorial (six boron fertilizations; two clones; and two water regimes -stressed and non-stressed), totaling 24 treatments, set up with five replications per treatment. The plant characteristics evaluated, 90 days of planting, were: growth (leaf area and biomass production), foliar concentrations of B, boron foliar mineral mass, stomata conductance, transpiration and photosynthesis. The foliar applications of boron improve tree nutrition, even under conditions of drought stress, regardless of genotype and boron source. The boron source affects the assimilation of the nutrient uptake and the assimilation was higher when applied with sorbitol.