Avaliação do tamanho de tubetes e idade de transplantio nas características fotossintéticas em mudas de Psidium cauliflorum Landrum & Sobral (Myrtaceae)

Abstract

The experiment was carried out at the Experimental Farm of the Center of Agrarian, Environmental and Biological Sciences, in the city of Cruz das Almas, Bahia. The objective was to evaluate the effect of different sizes of root trainers (polypropylene containers) and transplant age on chloroplastin pigment content, chlorophyll a fluorescence emission, and gas exchange on Psidium cauliflorum under field conditions. The seeds were sown in 55 cm3, 180 cm3 and 280 cm3 tubes with Vivato Plus substrate and osmocot fertilized (15-9-12). The experimental design was completely randomized, with six treatments, in a 2x3 factorial scheme, with two transplanting ages (75 and 120 days) and three tube sizes (small, medium and large), with five replications per treatment. The obtained results were submitted to analysis of variance, followed by Tukey at 5% of probability for statistical comparison. It was observed that transplanting age and tube size did not cause significant effects on chloroplast pigment content and chlorophyll a fluorescence variables, except for Car/Chl a+b ratio, between 75 and 120 days (F0) and the maximum quantum yield of FSII (Fv/Fm) in small seedlings between 75 and 120 days of transplanting, respectively. On the other hand, it was observed that the P. cauliflorum seedlings presented significant differences in the gas exchange variables in response to transplanting age and tube size, with transplanted seedlings at 120 days presenting higher values in relation to transplanted seedlings at 75 days.