ABSTRACT Plant growth, stress adaptation, and productivity depend on the continuous exchange of information between hormone signaling and metabolic networks. Although major phytohormones have been widely studied through their biosynthesis, receptors, and downstream transcriptional modules, these pathways are still often presented as linear systems. This view does not fully explain how plants integrate carbon status, nutrient availability, redox balance, cellular energy, and developmental signals under changing environments. In this review, we present plant hormone signaling and metabolism as a reciprocal regulatory network in which hormones reshape metabolic flux, while metabolites feedback to control hormone biosynthesis, transport, perception, degradation, and signal output. We synthesized evidence across salicylic acid, gibberellins, auxin, abscisic acid, strigolactones, ethylene, jasmonates, cytokinins, brassinosteroids, and melatonin, showing that sugars, amino acids, organic acids, lipid derivatives, sulfur metabolites, and redox signals act as shared regulatory nodes. This integrated perspective reveals that core metabolic signals such as sucrose, trehalose-6-phosphate, 2-oxoglutarate, citrate, malate, reactive oxygen species, glutathione, ascorbate, cysteine, and tryptophan coordinate multiple hormone pathways across tissues, developmental stages, and stress contexts. We further highlight emerging tools, including hormone atlases, live biosensors, spatial omics, single-cell omics, isotope tracing, genome editing, and computational network modeling, as essential approaches for moving from descriptive pathway maps to predictive systems biology. By defining hormone metabolism crosstalk as a central principle in plant biochemistry and physiology, this review provides a conceptual framework for identifying engineering targets that can improve crop resilience, nutrient use efficiency, and growth stress balance under future agricultural conditions.
ABSTRACT Drought-induced reduction in crop yield is becoming a serious threat worldwide, especially in arid to semiarid regions. The introduction of medicinal plants into cropping patterns in arid regions is a suitable alternative to conventional crops because of their high demand and market value. Keeping in view the situation, an experiment was planned under natural arid conditions to screen out the best psyllium varieties in less time for cultivation in arid regions. The experiment included three psyllium varieties (V1 = Gujrat isabgol-2, V2 = Vallabh isabgol and V3 = Jawahar isabgol-4) and three irrigation regimes (control = CK, partial rootzone drying = PRD and deficit irrigation = DI) and was carried out in a completely randomized design with eight replications. The results of our experiment revealed that although cell stress indicators (electrolyte leakage, relative cell injury, methylglyoxal, malondialdehyde, and hydrogen peroxide contents) were less and photosynthesis, water relationships, and membrane stability were greater in the control irrigation, the activities of enzymatic and nonenzymatic antioxidants were greater in the PRD and DI regimes. Among the water deficit treatments, more water potential, proline contents, ascorbic acid contents, membrane stability index, and yield were recorded in the PRD than in the DI. Among the varieties, V3 performed the best under water deficit conditions, whereas variety V2 presented the lowest values. It was concluded that under less water availability, the combination of the PRD with the variety V3 optimized physiological and yield outcomes by sustained higher relative water contents (77.10%), mesophyll conductance (0.67 mol CO2 m−2 s−1 bar−1), photosynthesis (15.10 µmol of CO2 m−2s−1), and membrane stability index (78.80%). Consequently, maximized water use efficiency (0.21 g L−1) and antioxidant activities, leading to higher yield (0.76 g plant−1). Future research should focus on integrating PRD with other water management techniques like mulching, osmoprotectants spray to enhance its efficacy under water deficit conditions.
