Efeitos de tempos e temperaturas de condicionamento sobre a qualidade fisiológica de sementes de cafeeiro (Coffea arabica, L.) sob condições ideais e de estresse térmico

Abstract

The goal of this work was the evaluation of the adequate times and temperatures for the physiological contitioning and effects of this techinique in the germination on stress conditions, of stored coffee seeds. The experiment was performed in the Seed and Molecular Techniques Laboratories of the UFLA's Agriculture Departament. The seeds used were from the cultivar Acaiá Cerrado. The seeds were harvested in the coffee seed production fields at UFLA and stored at room temperature from August/2000 to January/2001, when they were submitted to physiological conditioning under temperatures of 15, 25 and 35°C for 4, 8 and 12 days of imbibitions in water. The conditioning was dosse in BOD chambers in presence of light and the air was pumped using small aquarium pumps and compressors. After each treatment the seeds were imediately submitted to the determination of the water content and evaluated through the germination and germination speed tests under thermal stress (20 and 35°C) and enzymes eletrophoresis. Seeds without the imbibing treatment were used as control. It was conclued that the water conditioning at 15 and 25°C was efficient in increasing the germination and vigor of coffee seeds under thermal stress conditions, the conditioning at 35°C was not apropriated, the conditioning for four days was the least efficient treatment in improving the physiological quality of seeds, and the physiological conditioning in water was efficient in recovering the vigor, specially at 25°C for 12 days.