Determinação do grau de umidade de sementes de ipê-do-cerrado Tabebuia ochracea ((Cham.) Standl.) pelos métodos de estufa e forno de microondas

Abstract

As humidity is one of the factors that most influence upon the process of seeds deterioration in forest species, the use of both fast and effective methods for determining seeds humidity degree can aid in their preservation. With the objective of determining an appropriate methodology to determine the ipê-pity-savannah ( Tabebuia ochracea (Cham.) Standl.) seeds humidity, four lots of seeds collected in Machado-MG had their humidity level determined in two stages. In the first stage of the experiment greenhouse methods were tested at 105ºC/24 h with different repetitions and recipients weights. In the second stage the greenhouse method that resulted in smaller variation among the repetitions obtained in the first stage was compared with the microwave oven method using different procedures and times of exposure. The conditions of the greenhouse method that resulted in smaller variation of results in the determination of ipê-pity-savannah seeds humidity were 103ºC/17 h with the use of aluminum capsules and one-gram seed weight. The smallest variations of results between the greenhouse methodogy 103ºC/ 17 h and the microwave oven take place when the time period to determine the humidity of ipê- pity- savannah seeds is five minutes.