Laser‑Induced Cuticle Removal Improves Foliar Zinc Uptake in Row Crops

We evaluate a handheld 450 nm continuous-wave diode laser (FLB-02) to selectively remove epicuticular wax on leaves of zucchini, cowpea, okra, and cotton, and quantify 24-h zinc (Zn) uptake by ICP-OES. Parameter screening identified a forgiving operating window centered at 1.33 m/s with ~3–4 W, yielding uniform, non-destructive ablation of the wax layer. After treatment, a minimal Zn dose (~30 µL) was applied to the laser-processed areas; at 24 h, contralateral leaves showed increased Zn relative to Zn-only controls, consistent with facilitated entry followed by species-dependent redistribution. The clustered ablation onsets of ~1.5–2.5 W across species support a dose-controlled surface mechanism rather than species-specific resonances. We outline practical SOP-oriented handling, current limitations (pooled composites; single 24-h endpoint), and planned next steps, including biological replicates, time-course mobility mapping, additional nutrients/formulations, and scale-up to gantry/sprayer-mounted delivery. Overall, these results indicate that small, well-placed high-permeability windows can meaningfully increase early Zn uptake without full-leaf coverage.