Germination and vigor protocols for the assessment of the physiological quality of Joannesia princeps seeds

Abstract

The species Joannesia princeps Vell. has been standing out in reforestation programs. The importance of the species and the quality of its co-products, added to the great potential for the recovery of degraded areas, makes the studies of the factors that affect the germination of its seeds, as well as ecophysiological information for the species, of fundamental importance. Protocols for the physiological evaluation of native forest seeds are still scarce. The objective was to test protocols for germination and vigor tests, and to contribute to their standardization, to evaluate the viability of seeds of the species. The seeds were sown in polyethylene trays on different substrates: vermiculite, sand, sand with gibberellin (GA3) and paper roll. The seeds were sectioned longitudinally and the embryo was completely extracted. The seeds and embryos were immersed in a solution of 2,3,5 triphenyl tetrazolium chloride, at concentrations of 0.5% and 1.0%, for a period of 4 hours of staining, with four replications consisting of 25 seeds and kept in a BOD germination chamber, in the dark, for 4 hours at 30ºC. Concomitantly with the germination and tetrazolium tests, the emergence test was carried out in a nursery, following the same procedures described for the germination test. The sand, with or without the use of the growth regulator, promoted the highest percentage of germination (44%) and the best germination speed index. The use of a 1.0% concentration of tetrazolium salt for 4 hours at 30ºC allowed uniform coloring and was efficient for evaluating the viability of J. princeps seeds.