| This study investigated the effects of foliar boron (B) and zinc (Zn) on Physalis alkekengi under four levels of drought stress (0%, 25%, 50%, and 75% of field capacity). Plants were treated with B at 0, 100, 200, and 400 ml/L and Zn at 0, 1, 2, and 3 g/L. Drought stress significantly reduced fruit length (3.5–5.2 cm), weight (13.7–22.8 g), and firmness (1.7–3.5 N). The combined foliar application of B (200 ml/L) and Zn (2 g/L) under moderate drought (50% field capacity) produced the best outcomes. Fruit weight increased by 28%, total soluble solids (TSS) reached 11.6%, chlorophyll content rose to 2.1 mg/g FW, and photosystem II efficiency (Fv/Fm) improved to 0.78. Total phenolics (7.2 mg/g FW), flavonoids (32.3 mg/g FW), and proline (38.5 mg/g FW) also peaked under this treatment, indicating enhanced antioxidant metabolism and osmotic adjustment. Strong correlations were observed between proline and total phenolics (r = 0.90), and between flavonoids and total phenolics (r = 0.86), suggesting coordinated stress-response mechanisms. Principal component analysis (PCA) revealed clear clustering of treatments, separating those with higher fruit quality and metabolite accumulation from treatments with improved photosynthetic efficiency. Overall, foliar B and Zn acted synergistically to alleviate drought stress, stabilize photosynthesis, enhance antioxidant defenses, and improve fruit growth and quality in P. alkekengi. These findings demonstrate that integrated micronutrient management can be an effective strategy to improve plant performance under water-limited conditions, benefiting both productivity and the nutritional value of fruits. |