Physiological Responses of Pteropyrum aucheri to Short-term Warming in Semi-arid Rangelands (Case Study: Kohpanj Region, Kerman Province, Iran)

Abstract

Scientists predict climate changes and warmer conditions for the world in future. Predicting the warming effect on plant performance is one of the most important challenges in ecological sciences. In this study, the effects of short-term warming on physiological traits of Pteropyrum aucheri as one of the domain shrubs was assessed in riverside of semi-arid rangelands of Kohpanj region, Bardsir, Kerman province, Iran in 2014. Five 5×5 m2 blocks were selected with the same elevation, slope and aspect. In each block, mature individuals of Pteropyrum aucheri were studied in 10 circular plots with 2m diameter during spring and summer. For simulating the warming phenomenon, Open-Top Chambers (OTCs) were placed on 5 plots and other plots were considered as control plots. OTC is applied in natural ecosystems and provides nearly the same growth condition for species with higher temperature. Results showed that the OTCs enhanced monthly average of air temperature (5cm above soil surface) as 1.5 ºC, surface soil temperature of 2 ºC and soil temperatures (5 cm below soil surface) as 1.7 ◦C in warming plots. Results showed that photosynthetic pigments (Chlorophyll a, b and total) were significantly reduced and carotenoid was significantly increased with short-term warming in warming plots (p<0.05). Water content, leaf area and dry matter production were none significantly declined with warming. In general, short-term warming affected photosynthesis performance of Pteropyrum aucheri but biomass was not considerably affected by warming.