Efeitos do suprimento potássico no crescimento de clones de eucalipto em déficit hídrico

Abstract

The plantations of Eucalyptus are increasingly establishing themselves in regions with low rainfall. However, the annual growth average of trees is strongly influenced by soil water availability. To mitigate the water deficit in these environments, potassium (K) and tolerant clones can be used as an additional strategy to ensure better productivity. Thus, the objective was to investigate the physiological and initial growth responses of eucalyptus clones, regarding water deficit and K supply. An experiment was carried out in a greenhouse in a 3 x 2 factorial scheme (3 water regimes and 2 K rates) with 5 replications and in two eucalyptus clones (AEC 0144 and VM 01). This study evaluated changes in biomass production, leaf gas exchange, nutritional status and the efficiency of absorption, translocation and use of K. The supply of K helped to mitigate the negative effect of water deficit, plants supplied with K showed significant gains in nutritional status and provided positive physiological responses. In addition, AEC 0144 clone, which is more tolerant of low K supply, but sensitive to water deficit, showed higher K use efficiency under adequate water conditions. Meanwhile, clone VM 01, more tolerant to water deficit, but sensitive to low K supply, showed high K absorption efficiency and low K use efficiency.