Tecnologias rápidas para a avaliação da qualidade de sementes florestais

Abstract

Aiming to contribute to research on the quality of forest seeds, focusing on species with potential use in direct sowing, the present work, in its first chapter, sought to describe the state of the art on the rapid tests most used in the evaluation of seed vigor, through the Systematic Literature Review (SLR) and establish protocols for the target species: Handroanthus heptaphyllus (Vell.) Mattos, Croton urucurana Baill, Schinus terebinthifolia Raddi, Jacaranda cuspidifolia (Mart.), Platypodium elegans Vogel and Gallesia integrifolia (Spreng .) Harms. Articles, dissertations and theses were considered, using Google academic, with the keywords: seed; germination; emergency; vigor tests; seed analysis and methodology, from 1990 to 2021, totaling 3,026 recovered files. After applying the inclusion and exclusion criteria, 1.2% (n = 32) of the papers were selected. It was possible to obtain reference procedures on tetrazolium and electrical conductivity, however, the lack of tests in different batches, origins and vintages did not allow the proposition of protocols, making it difficult to standardize the methodologies. In the second chapter, the germination (TG), tetrazolium (TZ) and electrical conductivity (EC) tests were compared in seeds with different vigor conditions, obtained after five aging periods (100% RH at 42ºC) using the species H. heptaphyllus, J. cuspidifolia and G. integrifolia. In EC the seeds were immersed in 20 ml of deionized water for 24 hours. For the TZ, they were soaked in water for 24 hours and then exposed to a solution of 2, 3, 5 triphenyl tetrazolium chloride, at concentrations of 0.5 and 0.075%, for 24 hours, at 36, 35 and 40°C, respectively. Germination percentage (%G), normal seedlings (%PN) and germination speed index (IVG) were also evaluated. Spearman's correlation (%G, EC, TZ, %PN and IVG), and polynomial regression (%G, %PN and IVG as a function of EC) according to the aging times, indicated for H. heptaphyllus and G. integrifolia a strong (0.60 < r ≤ 0.90) and very strong (0.90< r < 1) association between all variables, in addition to high coefficients of determination (R2= 0.85; 0.70; 0.70 and 0.82; 0.86; 0.79) obtained 71 and 61% of viable seeds by TZ, and EC of 224.06 and 406.34 µs.cm-1.g-1 respectively. While for J. cuspidifolia, the correlation was weak (r ≤ 0.30) for EC and the other variables and moderate (0.30 < r ≤ 0.60) between TZ and TG, %PN and IVG, in addition to low coefficients of determination (R2= 0.17; 0.06 and 0.05), obtained 80% of viable seeds by TZ, with EC of 206.96 µs.cm-1.g-1. The TZ and CE tests were sensitive to separate seeds with different vigor levels for H. heptaphyllus and G. integrifolia, but for J. cuspidifolia CE was not efficient.