Modulation of Dimorphandra wilsonii Rizz. seed germination through H2O2 production in response to Zn interference of the mitochondrial electron transport chain

Integrative effects of zinc and temperature on germination in Dimorphandra wilsonii rizz.: Implications of climate changes

“…Indeed, some species require increased soil temperature as a result of fire to germinate [29]. This means that under current (normal) temperature conditions in Cerrado areas (mean temperature of 25 8C), Zn concentrations in the soil up to 200 ppm are not toxic to D. wilsonii seeds, confirming the Zn tolerance reported by Gomes et al [3]. In a scenario of soil contamination by Zn (>75 ppm), however, as is currently observed in many sites where D. wilsonii occurs naturally [19], temperature increases would constrain seed germination at 30 8C and 35 8C.…”

“…Respiration is the main source of metabolic energy for germinating seeds, and increases in RCO 2 reflect increased ATP availability. Zinc appears to modify ubiquinone sites in complexes I and II, thus disturbing electron transport and resulting in ROS formation [3]. Zinc appears to modify ubiquinone sites in complexes I and II, thus disturbing electron transport and resulting in ROS formation [3].…”

“…The seeds were mechanically scarified and then surface-sterilized in 5% sodium hypochlorite for 5 min and thoroughly rinsed with deionized water before sowing. Seed viability was evaluated by tetrazolium testing, following Gomes et al [3]. 1) moistened daily with 20 mL of the treatment solutions.…”

“…Zinc toxicity in seeds has been shown to be related to its detrimental effects on the mitochondrial electron transport chain, with subsequent oxidative damage resulting from reactive oxygen species (ROS) accumulation [3]. In addition, by interfering with the respiratory pathway, Zn deprives seeds of the energy (adenosine triphosphate [ATP]) needed for germination [3]. Temperature can also modulate respiratory processes, making them slower at lower temperatures or more accelerated at higher temperatures [12].…”

“…We recently investigated Zn tolerance of D. wilsonii seeds, which was found to be associated with the prevention of Zninduced ROS accumulation and oxidative bursts through the activation of antioxidant systems [3]. It is still not clear, however, how D. wilsonii seeds will respond to Zn exposure under more extreme temperature conditions.…”