Impact of heat waves and drought stress on biomass of pisum sativum and hordeum

Abstract

Future climate warming is expected to enhance plant growth but severe heat waves and droughts may become more frequent in a changing climate. Our objective is to investigate the response of pea and spring barley to heat waves and drought stress including biomass of leaves, stems and roots. For this purpose, plants were grown in a closed growth chambers under ambient climate conditions of 21ºC/400 ppm. A 7-day long heat wave (33ºC/400 ppm) and heat wave with elevated CO2 (33ºC/800 ppm) were applied – single and in combination with drought (i.e. fully and not watered during the heat wave period). After the treatment of heat waves and drought stress plants were left to recover for a 7-day period. Results showed that single 33ºC/400 ppm and 33ºC/800 ppm heat waves had no significant effect on biomass of leaves, stems and roots of spring barley and pea. Combination of 33ºC/400 ppm heat wave and drought stress significantly decreased leaves and stems biomass of spring barley and pea compared to ambient climate and drought conditions. Under heat wave and drought stress with elevated CO2 (33ºC/800 ppm) conditions biomass of different plant parts of pea and spring barley were less negatively affected compared to heat wave and drought stress with ambient CO2 (33ºC/400 ppm). As well as after the 7-day recovery period it was easier to recover biomass for plants who were grown under elevated CO2. This indicates that elevated CO2 mitigated the impact of combined heat wave and drought stress on plants biomass.