Viability of Simira gardneriana M.R. Barbosa & Peixoto seeds by the tetrazolium test

Abstract

-Ecoregion Caatinga presents a great diversity of species with potential for exploitation. Among them 'pereirovermelho' (Simira gardneriana M.R. Barbosa & Peixoto) stands out for its importance in timber and forestry activities. Its seeds germinate slowly. Therefore, the use of tetrazolium test to estimate viability becomes essential when quick answers on seeds quality are wanted. This study has aimed to establish the best concentration of tetrazolium solution and the coloration period for assessing the viability of Simira gardneriana seeds. Initially, seeds were subjected to pre-wetting between paper sheets for 144 hours at 30 °C. Subsequently, the endosperm portion containing the embryo was immersed at four concentrations of tetrazolium solution (0.075, 0.1, 0.5 and 1.0%) and three coloration periods (2, 4 and 6 hours) in the dark under the temperature of 30 °C and another one at 35 °C. The percentage of viable seeds was compared with the results obtained in the germination test conducted on paper substrate at 30 °C in four replicates of 25 seeds. Tetrazolium test was efficient to estimate the viability of S. gardneriana seed and the concentration of 0.075% for six hours at 35 °C was the best condition.Index terms: Rubiaceae, forest seeds, caatinga, germination, conservation.Viabilidade de sementes Simira gardneriana M.R.Barbosa & Peixoto pelo teste de tetrazólio RESUMO -A Caatinga apresenta grande diversidade de espécies com potencial de exploração, dentre estas o pereirovermelho (Simira gardneriana M.R. Barbosa & Peixoto) destaca-se pela importância nas atividades madeireira e florestal. Suas sementes germinam lentamente, com isso o uso do teste de tetrazólio para estimar a viabilidade passa a ser essencial quando se deseja respostas rápidas sobre a qualidade das sementes. Assim, objetivou-se com esse trabalho estabelecer a melhor concentração da solução de tetrazólio e o período de coloração para a avaliação da viabilidade de sementes de S. gardneriana. Inicialmente, as sementes foram submetidas ao pré-umedecimento entre papel por 144 horas a 30 °C. Posteriormente, a porção do endosperma contendo o embrião foi imersa em quatro concentrações da solução de tetrazólio (0,075; 0,1; 0,5 e 1,0%) e três períodos de coloração (2, 4 e 6 horas), no escuro, sob a temperatura de 30 °C e outra a 35 °C. A porcentagem de sementes viáveis foi comparada com os resultados obtidos no teste de germinação, conduzido em substrato papel, a 30 °C, em quatro repetições de 25 sementes. O teste de tetrazólio foi eficiente para estimar a viabilidade de sementes de S. gardneriana, sendo a concentração de 0,075% por seis horas, a 35 °C a melhor condição.Termos para indexação: Rubiaceae, sementes florestais, caatinga, germinação, conservação.

Germination and Viability of Seeds of Caesalpinia pulcherrima Newly Harvested and Stored

“…These results are consistent with Oliveira's (2016) claims that Simira gardneriana seeds present higher viability averages as concentrations increase, at temperatures of 30 °C, but not in the two nor in the four-hour periods. The concentration of 0.075% in the period of two hours also allowed better results in brazilwood (Caesalpinia echinata Lam.)…”

“…Then, with the aid of a scalpel, longitudinal sections were cut in the seeds, obtaining the endosperm portion containing the embryo which was immersed in plastic cups containing 50 ml of a triphenyl tetrazolium chloride solution of 2, 3, 5 at four concentrations of 0.075, 0.1, 0.5 and 1.0%, for three staining periods (2, 4 and 6 hours) in a chamber set at 30 °C in the dark. Four replicates of 25 seeds were used for each concentration, according to Oliveira (2016), with modifications.…”

“…Besides the knowledge of germination conditioning factors, the evaluation of the seeds physiological quality is of fundamental importance for the knowledge of their physical and physiological attributes. In this sense, one of the tests that can be used to provide faster results is the tetrazolium test, which allows the observation of the staining of living tissues, indicating the seed viability (Oliveira, 2016).…”

Testing Darwin's transoceanic dispersal hypothesis for the inland nettle family (Urticaceae)

“…Tetrazolium testing, a widely used alternative means of testing for seed physiological quality (Lamarca & Barbedo ; Oliveira et al . ), was therefore employed (Appendix S3).…”

“…An increase in salinity stress can induce physiological secondary dormancy, delaying germination (Baskin & Baskin 1998); therefore, seeds that did not germinate in our experiment might still be viable. Tetrazolium testing, a widely used alternative means of testing for seed physiological quality (Lamarca & Barbedo 2014;Oliveira et al 2016), was therefore employed (Appendix S3).…”