Humic acids have been widely used to enhance plant growth and productivity, but the underlying mechanisms are not fully understood. This study hypothesized that humic acids improve plant growth by modulating auxin and cytokinin biosynthesis pathways. The researchers investigated the effects of humic acid on wheat seedling growth and gene expression involved in these pathways. They found that humic acid treatment increased shoot and root growth, root hair length, and biomass. Gene expression analysis revealed up-regulation of genes involved in auxin and cytokinin biosynthesis, including TAA1, YUC1, TAR2.1, GH3.1, GH3.2, PIN9, IPT2, IPT5, LOG3, and LOG5. The study demonstrates that humic acid improves plant growth by stimulating endogenous auxin and cytokinin activities, providing insights into the molecular mechanisms of humic acid's bio-stimulatory effects.Humic acids have been widely used to enhance plant growth and productivity, but the underlying mechanisms are not fully understood. This study hypothesized that humic acids improve plant growth by modulating auxin and cytokinin biosynthesis pathways. The researchers investigated the effects of humic acid on wheat seedling growth and gene expression involved in these pathways. They found that humic acid treatment increased shoot and root growth, root hair length, and biomass. Gene expression analysis revealed up-regulation of genes involved in auxin and cytokinin biosynthesis, including TAA1, YUC1, TAR2.1, GH3.1, GH3.2, PIN9, IPT2, IPT5, LOG3, and LOG5. The study demonstrates that humic acid improves plant growth by stimulating endogenous auxin and cytokinin activities, providing insights into the molecular mechanisms of humic acid's bio-stimulatory effects.