Impact of short-term heat wave single and in combination with drought on gas exchange parameters of barley

Abstract

In this study there were examined the short-term (3-day long) impact of heat wave (31 ºC vs. 21 ºC) single and in combination with drought (i.e. fully and not watered during the heat wave period) on gas exchange parameters of barley (Hordeum vulgare L.) plants grown in growth chambers at control environment, as well as the recovery following stress. Short-term heat wave by itself has had minor or no effect on soil water content, photosynthetic rate, stomatal conductance and intercellular CO2 concentration during the heat wave period, although increased transpiration rate and decreased water use efficiency, but all these parameters fully recovered after one-day regeneration period. In contrast, the combination of heat wave and drought brought much more pronounced negative effect on soil water content and gas exchange parameters, whereof not all could return to the control value after one-day regeneration period. Hence, the obtained results showed that at the early development stage barley plants may by capable to cope with short-term heat wave event under future climate, if they would be well watered, but heat wave in conjunction with drought could bring irreversible changes in their leaf physiology.