Spore discharge associated with physiological quality variations and energy metabolism in harvested Lentinula edodes

Abstract

As a sign of mushroom maturity, spore discharge continues accelerating in postharvest Lentinula edodes. However, the relationship between spore discharge quantity and both physiological quality and energy metabolism remains unclear. In this study, spore discharge intensity, the number of spores discharged per unit mass of fruiting body per unit time, was introduced to analyze the variations in physiological quality attributes and energy metabolism associated with spore discharge in harvested Lentinula edodes. The results demonstrated a correlation between increased spore discharge intensity and deteriorating weight loss, firmness, and browning of the fruiting bodies. Moreover, a positive relationship was observed between spore discharge intensity and mannitol, an osmotic substance released alongside spores. Mannitol metabolism is linked to glycolysis, suggesting that the accumulation of mannitol may enhance spore discharge. Significant correlations were identified between the total amount of spore discharge and H⁺-ATPase activity, as well as energy charge, which proved that higher levels of energy metabolism may promote spore discharge. Energy depletion was responsible for the deterioration in the physiological quality during this period. Collectively, a substantial amount of spore discharge needs to be supported by adequate osmotic substances and energy levels, and this result may provide a new perspective on the preservation of edible mushrooms. Delaying the peak of spore release and inhibiting the spore discharge intensity may be directions for maintaining the postharvest storage quality of edible mushrooms.