The influence of rising carbon dioxide on maize development: genotypic differences in growth, lignification and folate pathway.

BACKGROUND: Rising atmospheric carbon dioxide (CO2) is a key driver of climate change, making it essential to understand its effects on crop growth and metabolism. This study examines maize C01 (inbred) and B73 (mutant), under elevated CO2 (600, 1200 and 1800 ppm) at three growth stages [40, 70 and 90 days after sowing (DAS)]. RESULTS: At 600 ppm CO2, plant height, leaf area and biomass increased, whereas higher concentrations led to significant declines. C01 accumulated more sugars and total non-structural carbohydrates, whereas B73 showed higher starch levels. Chlorophyll and carotenoid contents decreased under elevated CO2, with the most pronounced reductions at 1800 ppm. Folate content peaked at 70 DAS, with B73 exhibiting consistently higher levels than C01. Lignin accumulation and composition varied across genotypes, tissues and CO2 levels. At 600 ppm, lignin content increased in leaves and stems but declined at 1800 ppm. The syringyl-to-guaiacyl ratio and lignin monomer composition differed between genotypes, with C01 displaying stronger phloroglucinol staining and higher lignin content than B73. Gene expression analysis revealed that key lignin biosynthesis genes (ZmPAL, ZmCAD, ZmCCR, Zm4CL, ZmCOMT and ZmCCoAOMT) were upregulated at 600 ppm but significantly downregulated at 1800 ppm, particularly in B73. CONCLUSION: These findings highlight genotype-specific responses to elevated CO2, emphasizing its influence on maize growth, lignin biosynthesis and folate metabolism. The study provides valuable insights for future crop management and breeding strategies in the face of rising atmospheric CO2 levels. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.