The potato (Solanum tuberosum L.) is highly dependent on water availability, with physiological sensitivity varying throughout its phenological cycle. In the context of increasing water scarcity and greater climate variability, identifying critical periods where water stress negatively impacts productivity and tuber quality is essential. This study evaluated the physiological response of potatoes under different deficit irrigation strategies in field conditions, and aimed to determine the irrigation reduction thresholds that optimize water use efficiency without significantly compromising yield. Five irrigation regimes were applied: well-watered (T1; irrigation was applied when the volumetric soil moisture content was close to 35% of total water available), 130% of T1 (T2, 30% more than T1), 75% of T1 (T3), 50% of T1 (T4), and 30% of T1 (T5). Key physiological parameters were monitored, including gas exchange (net photosynthesis, stomatal conductance, and transpiration), chlorophyll fluorescence (Fv’/Fm’, ΦPSII, electron transport rate), and photosynthetic pigment content, at three critical phenological phases: tuberization, flowering, and fruit set. The results indicate that water stress during tuberization and flowering significantly reduced photosynthetic efficiency, with decreases in stomatal conductance (gs), effective quantum efficiency of PSII (ΦPSII), and electron transport rate (ETR). In contrast, moderate irrigation reduction (75%) lowered the seasonal application of water by ~25% (≈80 mm ha⁻¹) while maintaining commercial yield and tuber quality comparable to the fully irrigated control. Intrinsic water use efficiency increased by 18 ± 4% under this regime. These findings highlight the importance of irrigation management based on crop phenology, prioritizing water supply during the stages of higher physiological sensitivity and allowing irrigation reductions in less critical phases. In a scenario of increasing water limitations, this strategy enhances water use efficiency while ensuring the production of tubers with optimal commercial quality, promoting more sustainable agricultural management practices.

Climate change has intensified abiotic stresses in agriculture, with drought and metal toxicity being major factors, posing a significant threat to global food security. Silicon (Si), a tetravalent metalloid, emerges as a crucial element in enhancing plant resilience against abiotic stresses through its multifaceted roles at different levels in plants. Multiple studies have demonstrated the beneficial effects of Si on improving water relations, nutrient uptake, structural integrity of the cell wall, mitigation of metal(loid) toxicity, and enhancement of antioxidant activity. At the molecular level, Si regulates stress-responsive genes, modulates transcription factors such as DREB2A and NAC, and promotes enzymatic pathways involved in reactive oxygen species scavenging, underscoring its pivotal role in plant stress adaptation. This review provides an integrated overview of Si uptake, transport, and deposition, highlighting its physiological and molecular mechanisms in water stress adaptation, root morphology, and detoxification of metal(loid) in plant tissues. Furthermore, the ability of Si to induce the expression of antioxidant enzymes and regulate transcriptional networks associated with osmotic and oxidative stress provides plants with a robust molecular framework for resilience. Here we highlight the potential of Si as a central tool for sustainable agriculture, particularly under abiotic stress conditions such as drought and metal(loid) toxicity.

Ascorbic acid (ASC) is a molecule naturally synthesized in plant cells, protecting against abiotic stresses by reducing reactive oxygen species (ROS), which cause oxidative damage. Aluminum (Al) toxicity is the major limiting factor on crop productivity in acidic soils, increasing ROS within cells and impairing the growth and development of plants. Exogenous antioxidant applications are an effective strategy to promote tolerance to abiotic stress. The objective was to evaluate the effect of foliar ASC applications (0, 50, 100, 200, and 400 mg L⁻¹ ASC) and their interaction with Al toxicity (0, 400 µM Al) in Star, an Al-sensitive cultivar of highbush blueberry. Significant increases of 1.6-fold in growth were observed in roots and leaves under treatment with 200 mg L⁻¹ ASC. In the same treatment, increased pigments and antioxidant activity (~1.2- to 2.3-fold) were observed concomitant with reduced lipid peroxidation. Positive correlations between organic acid exudation, the ASC/DHA ratio, and calcium levels were observed, whereas a negative correlation between lipid peroxidation and dehydroascorbate (DHA) was observed. Foliar ASC application also increased the ASC/DHA ratio in leaves and enhanced 2.2-fold organic acid exudation in the 200 mg L⁻¹ ASC treatment. The results suggest that foliar ASC applications improved redox balance and underscore the potential of ASC as a practical solution to enhance resilience in Al-sensitive plants.

Polyploidy is widely used in plant breeding to increase phenotypic variation and potentially improve stress-related traits; however, its effects in common bean remain poorly characterized. Here, colchicine-induced polyploidy was evaluated in Phaseolus vulgaris cv. Zorzal to determine whether tetraploid lines exhibit coordinated changes in stomatal anatomy, physiology, pigment composition, oxidative balance, and ploidy inheritance. Polyploidy was induced using different colchicine exposure regimes and confirmed by flow cytometry. Stomatal traits, gas-exchange parameters, photosynthetic pigments, oxidative stress markers, antioxidant capacity, and multivariate phenotypic relationships were subsequently analyzed in confirmed tetraploid lines. Colchicine treatments successfully generated tetraploid and mixoploid plants, although induction efficiency was highly variable among replicates. Tetraploid lines showed heterogeneous physiological responses, including increases in the photosynthetic rate and stomatal conductance in some genotypes, but no consistent reduction in stomatal pore area index. Pigment composition and antioxidant-related traits also varied among lines, without a uniform response pattern. Multivariate analyses revealed coordinated but highly divergent phenotypic profiles among tetraploid genotypes. Importantly, the induced tetraploids were not stably transmitted to the C1 generation, with a predominance of diploid progeny among the evaluated offspring. Overall, colchicine-induced polyploidization generated substantial physiological variability among independently derived tetraploid plants of P. vulgaris cv. ‘Zorzal’; however, the predominance of diploid individuals among the evaluated C1 progeny indicates limited transmission of the induced tetraploid state to the subsequent generation.

Water deficit constrains common bean (Phaseolus vulgaris L.) production in the acidic Andisols of south-central Chile. We evaluated Bacillus haynesii CamB6 (thermotolerant, Chilean hydrothermal spring) and Microbacterium sp. Se63 (psychrotolerant, Antarctic soil), singly and as a two-strain consortium, for in vitro plant-growth-promoting traits and, via seed bacterization, on P. vulgaris cvs. Manteca and Señorita under simulated water deficit (PEG-8000, 0–15% w/v). The strains showed complementary in vitro profiles: Se63 solubilized more phosphate and produced siderophores and lipase, whereas CamB6 produced catalase, protease, HCN, and more indole-3-acetic acid. Responses in planta were stress- and cultivar-dependent. In the susceptible cultivar Manteca, Se63 alone increased shoot length and seedling dry weight under mild-to-moderate stress but did not rescue germination at 15% PEG, where it did not differ from the non-inoculated control; there, CamB6 was the most effective single strain (germination 31.0% to 52.0%). In the tolerant cultivar Señorita, Se63 alone produced the largest root-length gain under severe stress (100.4 to 208.6 cm) and the thickest roots, while the consortium rescued germination (65.0% to 93.0%), shoot length (+291%) and dry weight (+79%), attenuated lipid peroxidation and raised antioxidant capacity. Combining these extremophile strains therefore yields a stress-conditional, cultivar-dependent benefit in P. vulgaris.