Effect of the transgenerational exposure to elevated CO2on low temperature tolerance of winter wheat: Chloroplast ultrastructure and carbohydrate metabolism

The transgenerational effect of elevated atmospheric CO(2)concentration (e[CO2]) on low temperature response in wheat is still little investigated, through the interaction ofe[CO2], and low-temperature stress has been reported in a single generation. Here, the low temperature-induced modifications of chloroplast ultrastructure and carbohydrate metabolism in wheat after four generations continuously grown under ambient CO(2)concentration (a[CO2]) ande[CO2] (2014-2018) were investigated. The results indicated that the transgenerational exposure toe[CO2] increased the number of grana lamellae and the amounts of osmiophilic lipid droplets, attenuating the negative effect of low temperature on chloroplast ultrastructure. The transgenerationale[CO2] enhanced the activities of antioxidant enzymes (i.e. SOD, POD and CAT) and concentrations of osmotic substances (i.e. proline and soluble sugar), which alleviated the low temperature-induced oxidative damage to the chloroplast ultrastructure. In addition, transgenerational exposure of wheat toe[CO2] increased activities of vacInv and cwInv, while decreased fructokinase activity, which affected the sucrose metabolism in wheat leaf. These findings elucidated that transgenerational exposure toe[CO2] could improve low temperature tolerance of winter wheat, which provide novel insights to the response of wheat to future climate change.