Atmospheric CO 2 enrichment effect on the Cu-tolerance of the C 4 cordgrass Spartina densiflora

PÉREZ-ROMERO, JESÚS ALBERTO; IDASZKIN, YANINA LORENA; DUARTE, BERNARDO; BAETA, ALEXANDRA; MARQUES, JOÃO CARLOS; REDONDO-GÓMEZ, SUSANA; CAÇADOR, ISABEL; MATEOS-NARANJO, ENRIQUE

JOURNAL OF PLANT PHYSIOLOGY

ELSEVIER GMBH

Año: 2018 vol. 220 p. 155 - 166

0176-1617

A glasshouse experiment was designed to investigate the effect of the co-occurrence of 400 and 700 ppm CO2 at0, 15 and 45 mM Cu on the Cu-tolerance of C4 cordgrass species Spartina densiflora, by measuring growth, gasexchange, efficiency of PSII, pigments profiles, antioxidative enzyme activities and nutritional balance. Ourresults revealed that the rising atmospheric CO2 mitigated growth reduction imposed by Cu in plants grown at45 mM Cu, leading to leaf Cu concentration bellow than 270 mg Kg−1 Cu, caused by an evident dilution effect.On the other hand, non-CO2 enrichment plants showed leaf Cu concentration values up to 737.5 mg Kg−1 Cu.Furthermore, improved growth was associated with higher net photosynthetic rate (AN). The beneficial effect ofrising CO2 on photosynthetic apparatus seems to be associated with a reduction of stomatal limitation imposedby Cu excess, which allowed these plants to maintain greater iWUE values. Also, plants grown at 45 mM Cu and700 ppm CO2, showed higher ETR values and lower energy dissipation, which could be linked with an inductionof Rubisco carboxylation and supported by the recorded amelioration of N imbalance. Furthermore, higher ETRvalues under CO2 enrichment could lead to an additional consumption of reducing equivalents. Idea that wasreflected in the lower values of ETRmax/AN ratio, malondialdehyde (MDA) and ascorbate peroxidase (APx),guaiacol peroxidase (GPx) and superoxide dismutase (SOD) activities under Cu excess, which could indicate alower production of ROS species under elevated CO2 concentration, due to a better use of absorbed energy.