| Abstract [eng] |
Climate conditions, such as elevated CO2, warming, and drought, may have a significant positive or negative impact on plants growing in heavy metal polluted soil. However, the mechanisms involved in Cd accumulation under changing climate conditions have received little attention, and the presence of Cd in growth media at the same time combined with all these climate changerelated variables has not yet been investigated. Therefore, this study aimed to assess Cd phytoextraction efficiency in wellwatered and drought-stressed B. napus plants grown under the ambient CO2 and temperature conditions (ATC, 21/14°C, 400 ppm CO2) and elevated CO2 and temperature conditions (ETC, 25/18°C, 800 ppm CO2). The underlying physiological mechanisms underpinning the obtained results were investigated by studying the Cd (0, 1, 10, 50, and 100 mg kg−1) effect on B. napus photosynthetic performance and nutritional status. The visible leaf lesions, growth retardation, reduction in gas exchange, ChlFrelated parameters, and disturbed balance of mineral nutrients were largely seen only in Cd-50 and Cd-100 treatments but were much more pronounced under ATC conditions at both soil moisture levels. The most important pathways by which Cd affected B. napus photosynthetic efficiency were severe Cu deficiency in shoots, resulting in decreased photosynthetic electron transfer between the cytochrome b6f complex (Cytb6f) and photosystem I (PSI) due to a lack of plastocyanin, and the inactivation of some photosystem II (PSII) reaction centers and ferredoxin-NADP+-reductase (FNR). There was no significant difference in phytoextraction efficiency between ATC and ETC conditions in drought-stressed plants. Meanwhile, in well-watered plants, ETC conditions resulted in significantly more Cd accumulation in Cd-50 and Cd-100 treatments. However, only the Cd-50 treatment significantly increased soil Cd removal rate (to 65%), which showed the opposite trend as BCF and had a strong positive .relationship with shoot DW. |
