Respostas estruturais do xilema de Eucalyptus às diferentes condições hídricas

Abstract

Eucalyptus covers a wide range of naturally occurring species, which qualifies its genotypes to grow and develop in much of the world. In addition to having desirable anatomical characteristics for the already established and expanding paper and cellulose sector. In this context, understanding the interactions of environment and genotype is of ecological and industrial importance, since the climate is changing. The objective of the work was to evaluate the adaptive strategies of the xylem traits of eucalyptus clones in different environments with the 33%rainfall exclusion and to relate annually with the meteorological variables, in order to predict the hydraulic adjustments in facing climate changes. Two materials were analyzed: Eucalyptus urophylla and E. grandis x E. camaldulensis at six years of age, at 4 sites in Brazil distributed in a rainfall gradient, in two water conditions: with 100% water (W) and 33% rainfall exclusion (WE). Sites and exclusion had an effect on the traits of the wood. Hydraulic adjustment strategies were adopted with a higher occurrence of tylose and trade off between diameter and frequency of vessels. E. grandis x E. camaldulensis showed the highest number of altered traits (10/13) and with about 9% more proportion of sapwood. Pearson's correlations between meteorological factors and wood traits show different interactions in interspecific behaviors, as well as the condition of water availability. In the estimation of vessel wall thickness, air temperature was present in all equations. Studies of this nature provide an understanding of the dynamics between wood and climate in a 33% rainfall reduction, which has implications for the direct selection of cultivation sites and indirectly for the features handled in breeding programs in the face of climate change.