摘要
Despite its negative impacts on plant functioning,climate change benefits plants at the cellular level.For example,the stimulation of C3 photosynthesis by elevated CO_(2)can increase N2 fixation by 73%and grain yield by 10%–11%.The global elevated atmospheric CO_(2)concentration has already decreased the nitrogen content in C3 crop species and C3 woody vegetation by 14%and 21%,respectively,regardless of added nitrogen fertilizer.^(15)N-feeding experiments have shown that,after 19 h under elevated CO_(2),the^(15)N concentration in the stems,roots plus rhizomes,and whole plants of Scirpus olneyi(S.olneyi)decreased by 51%,63%,and 74%,respectively.Moreover,S.olneyi showed reduced NH_(4)^(+)assimilation under elevated CO_(2),which decreased the amino acid contents in the stems by 25.6%for glycine and 65.0%for serine,and that in the roots plus rhizomes by 2%for gamma-aminobutyric acid(GABA)and 80%for glutamate.Wheat grain protein has also been found to decrease by 7.4%under elevated CO_(2)due to reductions in threonine,valine,iso-leucine,leucine,and phenylalanine.The mineral nutrient contents in grains of rice and maize were similarly found to decrease under high CO_(2)by 1.0%and 7.1%for phosphorus,7.8%and 2.1%for sulfur,5.2%and 5.8%for iron,3.3%and 5.2%for zinc,10.6%and 9.9%for copper,and 7.5%and 4.2%for manganese,respectively.In general,mineral concentrations in C3 plants are predicted to decrease by 8%under elevated CO_(2),while total non-structural carbohydrates(mainly starch and sugars)are expected to increase.These decreases in grain protein,amino acids,and mineral nutrients could double the incidence of global protein-calorie malnutrition and micronutrient deficiency—especially in Africa,where agricultural soils are inherently low in nutrient elements.Additionally,the increase in total non-structural carbohydrates(mainly starch and sugars)in cereal crops could elevate diabetes incidence due to heavy reliance on starchy diets.The negative effects of elevated CO_(2)on rice,maize,and wheat—the world's three major staple crops—suggest an increase in global food insecurity with rising atmospheric CO_(2)concentration.
基金
supported by the Nanfan special project,CAAS(YBXM2408)
the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSIAF-202303)to Huihui Li
a grant from Sanya Municipal Program for Science and Technology Innovation(2022KJCX87)
the Nanfan special project,CAAS(YBXM2319),to Jun Zhao。
