Mitigating Drought Stress in Physalis alkekengi: Synergistic Effects of Foliar Boron and Zinc on Photosynthesis and Metabolite Accumulation

This study investigated the effects of foliar boron (B) and zinc (Zn) on Physalis alkekengi under four levels of drought stress (۰%, ۲۵%, ۵۰%, and ۷۵% of field capacity). Plants were treated with B at ۰, ۱۰۰, ۲۰۰, and ۴۰۰ ml/L and Zn at ۰, ۱, ۲, and ۳ g/L. Drought stress significantly reduced fruit length (۳.۵–۵.۲ cm), weight (۱۳.۷–۲۲.۸ g), and firmness (۱.۷–۳.۵ N). The combined foliar application of B (۲۰۰ ml/L) and Zn (۲ g/L) under moderate drought (۵۰% field capacity) produced the best outcomes. Fruit weight increased by ۲۸%, total soluble solids (TSS) reached ۱۱.۶%, chlorophyll content rose to ۲.۱ mg/g FW, and photosystem II efficiency (Fv/Fm) improved to ۰.۷۸. Total phenolics (۷.۲ mg/g FW), flavonoids (۳۲.۳ mg/g FW), and proline (۳۸.۵ 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 = ۰.۹۰), and between flavonoids and total phenolics (r = ۰.۸۶), 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.

کلیدواژه ها:

Photosynthesis ، Fruit Firmness ، Total soluble ، Antioxidant metabolism ، photosystem II