Enhanced Cadmium Phytoextraction by Rapeseed (brassica Napus) under Future Climate Conditions As a Consequence of Better Photosynthetic Performance

Cd is one of the most significant environmental constraints to plant growth, nevertheless, how future climate can affect Cd-plant interactions is not yet investigated. This study aimed to investigate the underlying physiological mechanisms responsible for the potential of Brassica napus to remediate Cd-contaminated soil under changing climate. B. napus was grown in Cd amended soil (0, 1, 10, 50, and 100 mg kg−1) under current climate (CC, 21/14 °C, 400 ppm CO2) and future climate (FC, 25/18 °C, 800 ppm CO2) conditions. FC conditions increased B. napus tolerance to Cd by increasing phytoextraction efficiency. The decrease in Cd concentration under FC conditions was accompanied with increased aboveground biomass, resulting in lower bioconcentration factor values. However, the total Cd uptake index for shoots and thus phytoextraction potential were considerably higher under FC conditions. The better photosynthetic performance of B. napus under FC conditions was predominantly associated with reduced transformation of active PSII RCs to non-QA-reducing forms due to their structural changes to ‘heat sinks’ or due to OEC inactivation. With less heat dissipation under FC conditions, the light use efficiency was higher, and the inhibition of photosynthetic rate was mitigated, resulting in higher aboveground biomass production and thus enhanced phytoextraction efficiency.