It has been shown that increased concentrations of zinc oxide nanoparticles (nano-ZnO) in the soil are harmful to plant growth. However, the sensitivity of different wheat cultivars to nano-ZnO stress is still unclear. To detect the physiological response process of wheat varieties with different tolerance to nano-ZnO stress, four wheat cultivars (viz., cv. TS1, ZM18, JM22, and LM6) with different responses to nano-ZnO stress were selected, depending on previous nano-ZnO stress trials with 120 wheat cultivars in China. The results found that nano-ZnO exposure reduced chlorophyll concentrations and photosynthetic electron transport efficiency, along with the depressed carbohydrate metabolism enzyme activities, and limited plant growth. Meanwhile, the genotypic variation in photosynthetic carbon assimilation under nano-ZnO stress was found in wheat plants. Wheat cv. JM22 and LM6 possessed relatively lower Zn concentrations and higher leaf nitrogen per area, less reductions in their net photosynthetic rate, a maximum quantum yield of the PS II (F_v/F_m), electron transport flux per cross-section (ETo/CSm), trapped energy flux per cross-section (TRo/CSm), and total soluble sugar and sucrose concentrations under nano-ZnO stress, showing a better tolerance to nano-ZnO stress than wheat cv. TS1 and ZM18. In addition, the chlorophyll a fluorescence parameters F_v/F_m, ETo/CSm, and TRo/CSm could be used to rapidly screen wheat varieties resistant to nano-ZnO stress. The results here provide a new approach for solving the issues of crop yield decline in regions polluted by heavy metal nanoparticles and promoting the sustainable utilization of farmland with heavy metal pollution.

Abiotic stresses limit crop productivity by disrupting water relations, carbon assimilation, nutrient acquisition, membrane stability, and redox homeostasis. Partial root-zone irrigation (PRI), commonly implemented as partial root-zone drying (PRD), is often viewed as a deficit-irrigation strategy to improve water-use efficiency; however, this view underestimates the biological consequences of spatial root-zone heterogeneity. This review evaluates PRI as a spatially structured, priming-like framework for crop adaptation to abiotic stress. Available evidence indicates that localized drying and wet-side water uptake can coordinate root sensing, hydraulic–chemical signaling, abscisic acid delivery, hormone crosstalk, xylem-mediated regulation, and stomatal control. Beyond gas exchange, PRI is associated with photosynthetic maintenance, osmotic adjustment, antioxidant and redox regulation, root architectural plasticity, nutrient acquisition, and metabolic reprogramming. Evidence is strongest for drought, whereas responses to low temperature, salinity, heat-associated evaporative demand, and combined stresses remain more context-dependent. Emerging work also links PRI to rhizosphere restructuring and microbiome shifts, but the causal mechanisms and field reproducibility remain unresolved. We argue that future progress requires matched PRI–deficit-irrigation comparisons, standardized switching thresholds, shared physiological and molecular readouts across crops, high-resolution root biology, and commercially realistic field validation. This framing distinguishes conserved physiological outcomes from mechanisms that may differ among crops, genotypes, and irrigation designs.