Different responses of chlorophyll fluorescence parameters of pea and wild mustard to elevated climate and drought stress effect

Abstract

Increasing CO2 and temperature, as well the changes in precipitation have potentially important consequences for crop and weed interactions. Climate change will have obvious consequences for crop yields as any differential response between crops and weeds to changing climate will alter weed-crop interaction and potential crop yield losses. The aim of this study was to investigate the response of chlorophyll a fluorescence of pea (Pisum sativum) and weed wild mustard (Sinapis arvensis) under simulated climate conditions. Two climate scenarios were investigated: current climate (21 °C, 400 ppm CO2 and drought) and elevated climate (25 °C, 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 (15 plants per pot) conditions. CO2, temperature and drought stress exposure lasted two weeks. Under drought effect grown plants were watered only 50 % of norm during exposure time. Chlorophyll a fluorescence measurements were performed by a Plant Efficiency Analyser (PEA) with randomly selected youngest fully expanded leaves on the last (14th) day of the experiment. Elevated climate led to different changes of chlorophyll fluorescence parameters of investigated plants, but the effect of drought was more intensive. The changes of Fv/Fm, which is an indicator of the efficiency of second photosystem (PSII), were statistically insignificant. The increase of specific energy flux per reaction centre (RC) for absorption ABS/RC was followed by an increase of trapping energy (TRo/SCo) under elevated climate and decrease under drought stress effect. The efficiency with which an electron can move from the reduced intersystem electron acceptors to the PSI and electron acceptors (delta(Ro)) was lower under the warmed climate conditions for both plants, compare to current (p<0.05).[...]