Estímulos químico e mecânico na rustificação de mudas de eucalipto

Resumo

The objective of this work was to evaluate the quality of eucalyptus clone 1528 seedlings after hardening with application of jasmonic acid (JA) and stem bending. The experiment was conducted in two stages: the first, in a protected environment, and the second, in the field. A completely randomized experimental design with seven treatments (control, 2.0, 4.0, 6.0, and 8.0 ìmol L^-1 of JA applied weekly for four weeks and 20 and 40 daily push-ups for four weeks) and five replicates of twenty seedlings. At the end of the treatments, the increase in height, root collar diameter, number of leaves, root and shoot dry matter, and relative chlorophyll index (SPAD) were determined. At 90 days after planting (field), the increases in height and root collar diameter and the height/diameter ratio of the seedlings were evaluated. A clustering analysis by UPGMA showed a formation of three groups: group 1 (control, 2.0, 4.0, and 6.0 ìmol L^-1 of JA), group 2 (8.0 ìmol L^-1 of JA), and group 3 (stem bending). Seedlings that showed the greatest increase in height and number of leaves (groups I and II) during the hardening phase obtained higher increase in height and in the root collar diameter in the field at 90 days after planting. Parameters such as increase in root collar diameter, root regeneration potential, and SPAD quantified during the hardening of seedlings in the nursery are not predictive of higher performance in the field.