Is it possible to determine physiological quality and best conditions of storage of soybean seeds by isothermal calorimetry?

Abstract

• Isothermal calorimetry can detect the reason for soybean seeds low germination power. • Specific enthalpy change during soybean seeds imbibition show three phases with respect to seeds water content. • For a vigorous root protrusion, the enthalpy change value due to water–seed interaction for the three phases should be similar. Seeds of soybean, cv. DM5.8RR of two different physiological qualities were germinated and monitored by isothermal calorimetry and imbibition methods. Also, seeds stored at 25 °C under different vapor pressures were analyzed. Results showed that those seeds with lower physiological quality, lot 1 (germination power of 62%) had a much higher speed of water uptake than seeds with a germination power of 93%, lot 3. Thus, endothermic peaks could be observed in the specific thermal power time curves of germination of seeds of lot 1 which were related to anoxia. Seeds of lot 3 with different initial water content, iWC, showed three phases of imbibition where the third also involved metabolism. Apparently, when the enthalpy change value of water–seed interaction of the three phases is similar, roots protrude with vigor. Such was the case for soybean seeds with 0.084 and 0.101 g g −1 iWC.