Padrões de viabilidade para sementes do semiárido aplicando o teste de tetrazólio

Abstract

The conservation and sustainable management of forest ecosystems are intrinsically dependent on the quality of seeds used in reforestation and degraded area restoration programs. Seed quality assessment is based on germination tests, which require a considerable amount of time. In contrast, the biochemical tetrazolium test emerges as a rapid and efficient alternative for determining seed viability. In this context, the accurate evaluation of seed viability and vigor is essential for the success of such programs. Furthermore, aiming to improve precision and efficiency in seed assessment, computational phenotyping has emerged as an innovative tool that employs image processing and algorithms to automatically and accurately analyze morphological and physiological seed traits. This study aimed to determine viability classes by integrating the tetrazolium test with computational phenotyping, as well as to establish methodologies for germination testing of Peltophorum dubium (Spreng.), Piptadenia stipulacea (Benth.) Luckow & R.W. Jobson, and Mimosa tenuiflora (Willd.) Poir. The tetrazolium test methodology was defined using a completely randomized design (CRD) in a 2×3+1 factorial scheme, with two tetrazolium solution concentrations, three staining periods, and one control treatment (standard germination test), with four replicates of 25 seeds each. In the germination test (control), seeds were placed in transparent plastic boxes between two sheets of moistened germination paper, using water in a volume equivalent to 2.5 times the substrate weight, in a Biochemical Oxygen Demand (B.O.D.) chamber at 30 °C. For preconditioning, the same procedure was applied for 16 hours. After this period, seeds were cut, and cotyledons containing embryos were immersed in 2,3,5-triphenyl tetrazolium chloride solutions at concentrations of 0.05% and 0.075% for 1.5, 2.5, and 3.5 hours, in a B.O.D. chamber at 40 °C, in the dark. Subsequently, individual seed analyses were performed, observing structural parts and assessing color and physical condition to classify seeds as viable or non-viable. Seeds were grouped into three distinct classes: Class 1 – viable seeds with high vigor; Class 2 – viable seeds with low vigor; and Class 3 – non-viable seeds. The establishment of viability classes for M. tenuiflora, P. moniliformis, and P. dubium represents a promising approach for the rapid evaluation of seeds from these species, reinforcing the importance of the tetrazolium test as a fast and effective method for forest seed analysis