Secagem e resfriamento de sementes de Coffea arabica L. visando o armazenamento em temperaturas supra e sub zero

Abstract

The coffee seeds have limitations regarding conservation, being classified as intermediate to desiccation and storage. One difficulty in establishing methodologies to storage intermediate seeds is the interaction between the water content in the seeds and the storage air temperature. The aim of this study is to investigate storage methodologies at temperatures below freezing. The study was conducted at the Central Seed Laboratory of the Department of Agriculture, Federal University of Lavras with Coffea arabica L., Catuaí Yellow IAC 62 seeds. The study was conducted in three stages, the first phase aimed to evaluate the effect of drying rate on seed vigor of coffee. In the second step, evaluate the cooling effect of coffee beans at temperatures above and subzero, the third step was to determine the storage effect on coffee seeds dried at different speeds. Silica gel was used for quickly drying and saturated salt solutions to slow drying, and the seeds were dried to water contents of 40, 30, 20, 15, 10 and 5% (wet basis). Then the seeds were stored in three different environments, cold room (10 ° C, 45% RH), freezer (-20 ° C) and deep-freezers (-86ºC) and analyzed at zero and four months. Zero time was marked by the balance of the seeds for 24 hours at temperatures of interest. Germination, strong normal seedlings, seedlings with expanded cotyledons, dry matter of seedling, electrical conductivity and tetrazolium were used to access the physiological quality of seeds. For the biochemical analyzes, the enzymatic systems were analyzed: superoxide dismutase (SOD) and catalase (CAT) by means of electrophoretic profile of isoenzymes. The faster is the drying, the lower the water content tolerated by seeds. The tolerance of coffee beans at low temperature depends on the rate at which they are dried and water content thereof. The storage for four months does not affect the germination of coffee, but affects their vigor.