Humic acid ameliorates copper toxicity by maintaining cell growth, cell wall stability, plasma membrane fluidity and integrity, and metabolism homeostasis, and activating plant hormone signal transduction in citrus roots

The current research revealed the effects of Cu-HA treatments on nonstructural carbohydrates (NCs), total flavonoids, total soluble proteins (TSPs), total phenolics (TPS), total free AAs (TFAAs), and total coumarins, as well as gene expression and metabolite profiles in Xuegan roots. This study aimed to validate the hypothesis that HA alleviates Cu toxicity via maintaining cell growth, CW stability, plasma membrane fluidity and integrity, and primary and secondary metabolism homeostasis, and activating plant hormone signal transduction in roots