Interspecific competition effect on photosynthetic response to simulated climate change in pea and wild mustard leaves

Abstract

The aim of this study was to investigate the response of photosynthetic parameters of pea (Pisum sativum) and weed wild mustard (Sinapis arvensis) under simulated climate conditions. Two climate scenarios were investigated: current climate (21 ºC, 400 ppm CO2 and drought) and warmed climate (25 ºC, 800 ppm CO2 and drought. Plants were grown in pots filled with a mixture of field soil, perlite and fine sand (volume ratio 5:3:2) in monoculture (Mono) (15 plants per pot) and multicultural (Mix) (9 crop plants and 6 weeds) interspecific competition conditions. CO2, temperature and drought stress exposure lasted two weeks. Under drought effect grown plants were watered only 50 % of norm during exposure time. Gas exchange measurements were performed by a portable gas analyzer LI-COR 6400 with randomly selected youngest fully expanded leaves on the last (14th) day of the experiment. Drought stress statistically significant decreased all investigated gas exchange parameters under both climate conditions. Interspecific competition effect was not so pronounced as drought. Under current climate conditions competition had not changed the photosynthetic rate of pea significantly, while the photosynthetic rate of wild mustard decreased statistically significant, compare to monoculture grown plants. Under current climate and drought effect conditions interspecific competition had not changed the photosynthetic rate of both plants. Under future climate conditions photosynthetic rate has increased for both plants, compare to current. Interspecific competition had no statistically significant effect on well-watered plants. Meanwhile under warmed climate and drought stress effect interspecific competition had led to opposite changes of photosynthetic rate, i.e. for pea it decreased (p<0.05) and for wild mustard it increased (p<0.05), compare to monoculture. [...]