CO effects on the waterlogging response of 'Gisela 5' and 'Gisela 6' (Prunus cerasusxPrunus canescens) sweet cherry (Prunus avium) rootstocks.

Climate change is submitting countries of the Mediterranean arc to periods of drought alternating with heavy rain and waterlogging. Eventual floods along with the rising CO in the atmosphere present an unpredictable scenario that affects crop survival. The effect of both stresses combined has been studied in sweet cherry plants. 'Gisela 5' and 'Gisela 6' were evaluated as rootstocks of the sweet cherry cultivar 'Burlat'. Plants were placed in a controlled-climate chamber for 7days, then they were submitted to waterlogging for another 7days and the response to this stress and the subsequent recovery were studied (7 more days). The experiment was carried out at 400μmolmol CO (ambient CO) and 800μmolmol CO, at 26°C, and plant water status and growth, net CO assimilation, transpiration, stomatal conductance, water potential, chlorophyll fluorescence, relative water content, anions content, proline, lipid peroxidation, soluble sugars, and starch were measured. Differences in the response and in its intensity were detected in both rootstocks. Some parameters - such as photosynthesis, soluble sugars, starch, TBARS, and NO - varied depending on the CO conditions and the waterlogging effect. Elevated CO was able to increase photosynthesis and thereby help plants to overcome waterlogging.