Caracterização morfobiométrica e adequação de testes de vigor e viabilidade para sementes de linhaça

Abstract

The present work aimed to carry out the morphobiometric characterization and adequacy of vigor and viability tests for linseed seeds, as well as to analyze whether the activity of the enzymes of the antioxidative system are related to the vigor of the seeds. Linseed seeds of the pioneer ST cultivar were used. The morphobiometric characterization of the seeds was carried out, measuring the length and width with the aid of a digital caliper and the visualization of integral parts of the seeds through stereoscopic magnifying glasses, performing manual illustrations of the morphology of germination and seedlings. For the accelerated aging test, six lots of linseed seed were used, initially submitted to tests for the characterization of their physiological potential. The accelerated aging test was conducted using the traditional method (100% RH) and with NaCl saline solution (96% RH) and saturated saline solution (76% RH) at 41º C for 24, 48, 72 and 96 h. The activity of the enzymes catalase, ascorbate peroxidase, peroxidase and superoxide dismutase were also determined. The tetrazolium test was conducted using five seed lots and tested four concentrations of tetrazolium salt (0.10%; 0.25%; 0.5% and 1%). A completely randomized design was used. For the initial quality assessment tests, methodology adaptation for accelerated aging, analysis of antioxidative enzymes and tetrazolium test, the averages were compared by Tukey's test (P ≤ 0.05). The morphological characterization of seeds and seedlings provides subsidies that facilitate the correct interpretation of laboratory tests in the evaluation of the physical and physiological quality of seeds. The accelerated aging test and activity of the enzymes of the antioxidative system were efficient to classify the linseed lots in terms of vigor. For the accelerated aging test, it is recommended to use 41°C/48h with saturated NaCl solution (76% RH) and unsaturated NaCl solution (96% RH). The tetrazolium test should be conducted using a tetrazolium solution at a concentration of 0.10% for two to four hours or 0.25% for a period of 1 hour.