Action of elevated CO2 and high temperatures on the mineral chemical composition of two varieties of wheat

Two varieties of spring wheat were cultured in temperature gradient tunnels with two CO2 concentrations and two different temperatures. We discuss the effects of these three variables on the mineral chemical composition of th e plant samples, separated into fractions. taken during two phases: a few d ays before anthesis and at harvesting. The variety of the plant and the CO2 concentration were the variables found to exert the greatest influence, the glumes and rachis, the straw and the rest of the stem (without the last internode) being the parts of the plant that most frequently showed different values owing to the effect of thr var iables. The nutrients N and Mg were the most sensitive to differentiation i n the plants owing to the action of the variables. Iron was seen to be less sensitive. as was P.