Qualidade morfofisiológica de mudas de Euterpe oleracea (Mart.) produzidas em recipientes de diferentes volumes

Abstract

Açaí {Euterpe oleracea Mart.) is an important palm species of the Amazonian biome whose fruits have excellent nutritive and antioxidant properties. Thus, the increasing demand for assai fruits has stimulated the formation of new plantations of this species, what consequently request great amount of seedlings with high morphological and physiological pattems. Currently, assai seedlings are produced in 1.3L polyethylene bags in compliance with the technical recommendation normalized by the "Comissão Estadual de Sementes e Mudas do Pará (CESM-PA)". In this research, it is hypothesized that the production of assai seedling with the same morphological and physiological patterns could be achieved by using smaller recipients. Thus, the objective was to evaluate the effects of polyethylene bags (SP), polyethylene bottles (GP) and polyethylene tube (TBT) with capacities lower than 1.3 L on seedlings growth, biomass allocation and physiological properties. The experiment was consisted of six different recipients or treatments (SP 1.3L, control treatment; SP TOE; SP 0.5L; GP TOE; GP 0.5 L and TBT 0.3L) compared at 65 and 185 days of cultivation on those recipients. Treatment comparisons were performed by assessing different variables related to above-ground growth (plant height, stem diameter, number of leaves and leaflets, and total leaflet arca); biomasses allocation of above ground and root system, leaf water potential, leaf gas exchange, water use efficiency and chlorophyll a fluorescence. On day 65, only slight differences between treatments in terms of above ground growth and biomass allocation were observed. Both physiological and chlorophyll a fluorescence variables did not differ between treatments on this evaluation date. When treatment comparisons were performed on day 185, the highest averages related to above-ground growth and biomass allocation were recorded for seedlings grown in SP TOE.; while both variables were markedly lower in seedlings grown in smaller capacity recipients (SP 0.5L, 0.5L GP and 0.3L TBT). However, no significant differences in leaf water potential, leaf gas exchange, water use efficiency and chlorophyll fluorescence variables were observed between treatments assessed on day 185. The cluster analysis using ali morphological and physiological variables allows concluding that assai seedling production was most suitable on SP TOE.