Expressão de enzimas durante a germinação de sementes de sempre-vivas

Abstract

The Eriocaulaceae is a family of plants that are popularly known as sempre-vivas and widely distributed, mainly in the tropics. The Espinhaço Mountain Range which covers Minas Gerais and Bahia, is considered as the main center of diversity of this family that includes the species Comanthera elegans (Bong.) L.R.Parra & Giul and Comanthera bisulcata (Koern.) L.R.Parra & Giul among the most known. Due to the disorganized extractivism in the last decades, mainly due to the high commercial value that the inflorescences represent as ornamental plants, some species are already endangered. In this context, studies that involve the knowledge of the germinative process of these species are of fundamental importance in order to obtain a commercial production of inflorescences that will amortize the effect of this indiscriminate collection. It was the purpose of the study to evaluate the expression of enzymes during the germination process of the sempre-vivas seeds using the electrophoresis technique. For the evaluation of the physiological potential of seeds, the germination test and the germination speed index (IVG) of seeds maintained at temperatures of 25-15 °C and photoperiod of 16-8 hours were performed for Comanthera elegans and 20 -15 °C with photoperiod of 16-8 hours for Comanthera bisulcata. The expression of the enzymes esterase (EST), malate dehydrogenase (MDH), alcohol dehydrogenase (ADH), superoxide dismutase (SOD), catalase (CAT) and endo-β-mannanase were evaluated during the germination process. The expression of these seeds was evaluated in dry seeds (S), protrusion (Pro), at the appearance of the primordial leaf (FP), at the beginning of normal seedling formation (Pla) and dormant seeds (SD) at the end of the germination process. The image analysis for the quantification of the enzymes was done using ImageJ® software measured in pixel 2 . The highest values of germination and viability were observed in C. elegans seeds. As the germination process occurs in C. bisulcata and C. elegans species is observed the increase in the expression of the enzyme CAT and reduction of EST. There is a variation in the expression of the enzymes SOD, ADH and MDH in seeds of both species during the germination process. The enzyme endo-β-mannanase exhibit the highest activity levels in seeds with root protrusion in both species.