铁元素对毛竹生长的影响机制研究

Iron plays a crucial role in plants and is one of the essential micronutrients required for normal biological development. Both excessive accumulation and deficiency of iron can inhibit plant growth. However, a comprehensive understanding of the mechanisms by which iron affects the growth of Moso bamboo (Phyllostachys edulis) remains lacking. In this study, we investigated the phenotypic and physiological responses of Moso bamboo seedlings to different iron concentrations to determine the optimal iron concentration for their growth. Subsequently, the seedlings were divided into iron-deficient, iron-toxic, and control groups, with samples collected at 1, 4, and 8 days for transcriptomic and physiological analyses. The results indicated that the optimal iron concentration for Moso bamboo growth was 100 μM, which served as the control group. Under conditions of iron deficiency and iron toxicity, 7386 and 7848 differentially expressed genes (DEGs) were identified, respectively. GO enrichment analysis and KEGG pathway analysis revealed that both iron deficiency and iron toxicity significantly enhanced oxidative-reduction and oxidative stress responses in Moso bamboo. Additionally, many genes were enriched in metal ion transport processes and changes in lipid and biomembrane components. Under conditions of iron deficiency and iron toxicity, Moso bamboo cleared reactive oxygen species (ROS) through salicylic acid (SA) and abscisic acid (ABA) signal transduction pathways, regulating phenylalanine and brassinosteroid synthesis pathways. In the iron-toxic condition, the induction of beta-alanine synthesis pathways was more significant, and a greater number of brassinosteroid products helped Moso bamboo combat oxidative stress, indicating that more antioxidants are required under iron-toxic conditions to maintain survival. Metal ion transport primarily functions to regulate ion balance within Moso bamboo under both iron-deficient and iron-toxic conditions. The absorption and transport of mineral elements showed distinct differences under high-iron and low-iron stresses, suggesting that metal ion transport has different roles under these conditions. Additionally, on the 8th day of iron-deficiency stress, nicotinamide metabolism was enriched, and nicotinamide, which has the function of storing and transporting iron ions, indicated that Moso bamboo enhances its ion transport capacity under iron-deficiency stress to maintain survival. Both iron deficiency and iron toxicity affected the composition of cell membranes, but the impact of iron toxicity occurred earlier. Our findings not only deepen the understanding of nutrient dynamic balance and stress adaptation mechanisms in plants but also provide a foundation for subsequent molecular improvement of forest trees and enhancing plant tolerance to iron stress.