Effect of drought stress on isoprene emission from two major Quercus species native to East Asia

Effect of drought on isoprene emission from 2 major Quercus species native to East Asia is investigated. Three individuals of Quercus serrata and 2 individuals of Quercus crispula continued to emit isoprene under moderate and severe drought conditions, although the emission rates were lower than under normal conditions. Diurnal variation in the isoprene emission rates was monitored in real-time when temperature and light intensity were changed stepwise to imitate natural conditions. Under normal and moderate drought conditions, isoprene emission showed hysteresis with regard to the environmental parameters, but generally followed the common G93 model. Under severe drought conditions, isoprene emission rates were not explained using given coefficients in the G93 model, probably due to a depletion of isoprene substrate.