Fisiologia de sementes e metabolismo antioxidativo na emergência de Lecythis pisonis Cambess: inferências sobre temperatura ótima e aptidão climática para a semeadura

Abstract

The climate changes registered in the last decades have triggered a severe loss of biodiversity. High temperatures induce a high reproductive effort of trees that is not translated into high production of viable seeds. The temperature is one of the most important climatic factors to the germination and emergence of seedlings and in this way to identify the adequate one is a preponderant factor for the physiological quality of the seed and seedlings. The species L. pisonis is a promising tree, with economic and ecological relevance, whose propagation in a controlled environment is not yet established. In this context, the objective was to find the optimal temperature for emergence, to analyze the effect of different temperatures on the biochemistry and antioxidant enzymes of the seeds and the climatic aptitude for the sowing of L. pisonis. For this, the seeds of this species were submitted to 10 different temperatures in germination chambers. Germination, vigor and phenotyping of seedlings, biochemistry, oxidative stress enzymes, hydrogen peroxide and malondialdehyde were analyzed in intact seeds and at 10 and 20 days of germination process. The lethal and optimal temperatures for the emergence of L. pisonis seedlings are 20, 20-25 and 30-35 °C, respectively. The amount of hydrogen peroxide at 10 days is reduced along with an increase in the activity of catalase and ascorbate peroxidase enzymes at a temperature of 30-35 °C. The highest amount of lipids found in the seeds of L. pisonis at 10 days is at 30-35 °C, which promotes seedlings with higher quality. The optimal temperature found in the work is confirmed with the temperature range of the places where L. pisonis occurs. Sapucaia sowing is recommended according to maximum and minimum temperatures during the months of August to December in the Atlantic Forest (Espírito Santo, Bahia, Sergipe, Alagoas, Pernambuco, Paraíba and Rio Grande do Norte) and in the Amazon region (Maranhão, Tocantins, Amapá, Pará, Amazonas, Roraima and Acre).