Effects of zinc on growth and physiological characteristics and transformation enrichment of Arthrospira platensis Gom

This study investigated the effects of zinc on growth and physiological characteristics and transformation enrichment of Arthrospira platensis Gom. The findings revealed that the group treated with zinc (batch additions) at a concentration of 12 μmol/L showed the highest growth rate. Compared to the control group, the contents of soluble protein, phycocyanin, and chlorophyll-a increased by approximately 61%, 48%, and 42%, respectively, while the activities of superoxide dismutase (SOD) and catalase (CAT) rose by 56% and 54%, respectively, and malondialdehyde (MDA) contents decreased by 25%. This treatment can alleviate the degree of damage to the donor side (W_k), increase the electron transfer energy on the receptor side (S_m, V_J, M_o), and improve the maximum light energy conversion efficiency per unit reaction center (F_v/F_m), light energy absorption (ABS/RC), electron transfer energy (ET_o/RC), and photosynthetic performance index (PI abs), Reduce heat dissipation values of the reaction center (DI_o/RC). Ultrastructural analysis revealed transverse and longitudinal walls with white salt crystals, intact and clearly visible thylakoid membranes, significant increase phycobilisomes, lipid droplets (oil droplets) and carboxysomes, bubble and vacuole structures are distributed in the surrounding area. Key metabolic pathways involved upregulated purine (adenosine, hypoxanthine) and gluconate metabolism.