Effects of elevated CO_2 concentration on the growth of wheat seedlings under different water potential and nutrition concentrations

On the basis of hydroponic experiment,this pot study included five nitrogen concentration levels(N0、N1、N2、N3、N4),three PEG concentration levels(P0、P1、P2),and two CO2concentrations(370 ± 50 μmol·mol-1; 700 ± 50 μmol·mol-1). We studied the growth,dry matter accumulation and distribution,and water relation of wheat seedlings in different conditions. The results showed that plant height,shoot dry weight,root weight,biomass,and leaf water potential reached their maximums at N1P0,and so were the effects of elevated CO2 concentration. Maximal root length and root to shoot ratio appeared at N0P0 and N1P2respectively. The biggest influence of elevated CO2 arose under the same condition. High CO2 concentration could mostly improve the growth of wheat seedlings at appropriate condition. At the same time,elevated CO2 could improve leaf water potential of wheat seedlings,which reduced the negative effects of PEG stress to some extent. Therefore,elevated CO2 concentration would improve the growth of wheat and remit the negative effects of mild water stress,whereas subtle effect might beobserved if wheat growth was under severe drought.