Influence of aluminum on seed germination and initial growth of tree species
Aluminum, germination, forest species
In today's world, forest species are becoming more important for the environment, either by sequestering carbon or to provide raw material. Unlike annual, food and pine and eucalyptus species, there is not much information about germination and the effect of aluminum. This chemical element is an important limiting factor for plant development in acidic soils, especially in its Al+++ form. This study was divided into two phases. In the first phase, 5 germination experiments were carried out in BDO using increasing doses of aluminum chloride (0, 50, 100, 200 and 400 µM) with the forest species: rosewood (Dalbergia nigra (Vell.) Allemao ex Benth. ), sabiá (Mimosa caesalpiniifolia Bentham), canga mimosa (Mimosa acustitioula Bentham), erythrina (Erythrina verna Vell.) and ingá (Inga laurina (Sw.) Willd.), evaluating germination percentage (%G), speed index germination rate (IVG), root and shoot dry mass, seed water content, pH, electrical conductivity, sugar content, proline, protein, peroxidase and alpha amylase activities, Ca, Mg, K and P content in solution. In the second phase, 6 more experiments were installed in simple or complete nutrient solution with increasing doses of aluminum chloride (0.50,100, 200, 400 and 800 µM) using the species above. Root length, root growth rate (TCR), relative root elongation (ERR%), root and arial mass part were evaluated. The results suggested that aluminum did not influence % G in all species tested, but influenced IVG in sabiá and jacarandá from Bahia. The absorption of water in erythrine and sabiá was not influenced by Al, but the presence of this element in the solution increased the exudates and sugar contents, Ca, Mg, P and K, pH and electrical conductivity in the solution. Aluminum and soaking time influenced the proline, protein and guaiacol peroxidase and α-amylase activities. It was found that for ingá the effects of aluminum were more expressive in complete solution, for this species aluminum influenced the CR , TCR and aerial part dry mass, no nodulation occurred in any treatment. In erythrine there was influence of aluminum, CR, TCR, ERR, root and shoot dry mass, root volume, root area and nodulation and in sage plants the effects of aluminum were not very clear for this species, suggesting a high tolerance to this element.