Functional Plant Biology最新文献

Consistent yield and production of high-quality fruits are key drivers for sustainable apple industry. Apple flowering and fruiting can be limited by non-structural carbohydrates. Apples flower profusely, and as strong sinks, both flowers and fruits compete with vegetative parts of the tree for carbohydrate allocation. Low sugar availability results in inconsistent blooms and regular cropping disruptions, leading to low yields and substantial economic losses. Various crop load thinning strategies are used to reduce crop load and improve carbohydrate allocation for better fruit quality and return bloom. The implementation times of these strategies in the current season can significantly alter the sugar balance, affecting flower formation in the following season. This review examines various roles of non-structural carbohydrates in apple tree physiology, with a focus on flower and fruit development. It appraises the fundamentals of effective carbohydrate management for achieving long-term sustainability in apple production. A dual carbon transport system in apples ensures a more stable and efficient supply of sugars to the sinks and enables carbohydrates to perform essential roles in signalling, structural support during flower formation, floral metabolism, pollination, fruit set, fruit development, fruit metabolism, and fruit quality enhancement. Understanding the vital functions of carbohydrates in tree dormancy, flowering and fruiting calls for a more efficient implementation of fruit thinning strategies at the earliest possible time during the reproductive phase.

Fusarium solani strain K (FsK) and arbuscular mycorrhizal fungi (AMF) are soilborne symbionts that colonize plant roots and modulate stress responses. While most studies focus on individual microbial partners, understanding multipartite microbial interactions under realistic conditions is essential for designing effective inoculants. Here, we investigated the individual and combined effects of FsK, Funneliformis mosseae (F. mosseae), and Rhizophagus irregularis (R. irregularis) on tomato (Solanum lycopersicum) performance under drought and salinity stress in a greenhouse experimental set up. Under stress conditions, each endophyte showed enhanced root colonization. Co-inoculation with multiple microbes diminished this effect, however the functional outcomes were not directly dependent on the extent of microbial establishment. Under drought, FsK consistently promoted shoot growth, water retention, and ABA accumulation, while AMF improved nutrient status. Co-inoculation with FsK and F. mosseae led to synergistic improvements in physiological traits, but only under drought conditions. In contrast, salinity responses were less consistent and revealed functional divergence among microbial partners. These findings demonstrate that context-specific microbial combinations can enhance stress resilience in tomato.

Agropyron species are recognized as pivotal components of arid grasslands because they supply drought-resistant forage and support ecosystem recovery. To systematically evaluate the drought resistance of this genus, this study examined 13 populations of Agropyron species (three populations of Agropyron cristatum, six populations of Agropyron cristatum var. pectinatum, and four populations of Agropyron mongolicum) under three soil moisture gradients (80%, 50%, and 30% of field capacity) at the seedling stage. A multi-dimensional assessment framework was constructed by integrating morphological and physiological traits using a membership function model and grey relational analysis. The results indicated that drought stress significantly increased root length by 21.54%, leaf water content by 12.99%, and proline accumulation by 31.56%. Agropyron species mitigate desertification through key drought survival strategies, including stomatal regulation, osmoprotectant accumulation, and enhanced antioxidant activity. Based on the membership function scores, drought tolerance was ranked A. cristatum > A. mongolicum > A. cristatum var. pectinatum. These findings establish quantitative criteria for selecting drought-resistant germplasm and reveal the phenotypic plasticity strategies in Triticeae. Moreover, they indicate that A. cristatum represents a key scientific resource for ecological stabilization and desertification control in the arid regions of Xinjiang.

Background: Drought is a major abiotic stress and a global threat to sustainable agriculture, severely constraining maize (Zea mays L.) productivity. It is estimated that drought stress can cause up to 15-20% grain yield losses in maize worldwide. Understanding the morpho-physiological and biochemical responses of different maize cultivars under drought conditions is essential for developing drought-tolerant varieties.

Methods: This study investigated the impact of drought stress on two maize cultivars, Haq Nawaz (drought-sensitive) and CIMMYT PAK (drought-tolerant), at three developmental stages: seedling, flowering, and grain filling. Morphological parameters (plant height, leaf length), physiological traits (chlorophyll a and b, proline, membrane stability index, soluble sugars), and biochemical components (nitrogen (N), phosphorus (P), and potassium (K)) were analyzed under well-watered and drought-stressed conditions using standard protocols.

Results: Drought stress significantly reduced plant height, leaf length, and chlorophyll content at all growth stages, with the greatest reduction observed during grain filling. Under drought, chlorophyll a and b were markedly affected, particularly in the sensitive cultivar. Proline, membrane stability index, soluble sugars, and potassium levels increased by 23.34%, 2.67%, 18.24%, and 5.72% in CIMMYT PAK, and by 24.09%, 9.05%, 22.97%, and 6.77% in Haq Nawaz, respectively. Conversely, nitrogen and phosphorus contents decreased by 5.88% and 6.19% in CIMMYT PAK, and by 6.29% and 19.34% in Haq Nawaz, respectively.

Conclusions: The results demonstrate that drought stress negatively affects maize growth and metabolism, with more pronounced impacts on the sensitive cultivar. The higher accumulation of osmolytes (proline and soluble sugars) and better maintenance of K⁺ content in CIMMYT PAK indicate its superior adaptive mechanisms to drought-induced oxidative stress. These findings highlight the importance of screening drought-responsive morpho-physiological and biochemical traits to identify tolerant genotypes. The insights gained could support breeding programs aimed at enhancing drought tolerance in maize grown under water-limited environments.

Water use efficiency (WUE) is a key index to predict the impact of climate change on ecosystem carbon and water cycles; the tradeoff of stem and leaf traits determine the WUE and resource competitiveness of individual plants. Four altitudinal gradients of 3400 m, 3500 m, 3600 m, and 3700 m were selected as experimental sites in Gahai Wetland on the Ruoerge Plateau. The Mantel Test method and the standardized major axis estimation (SMA) method were employed to examine the relationship between stem-leaf tradeoff and WUE of Kobresia tibetica in alpine peat swamps at different elevations. The results showed that with the increase of altitude, the surface water area decreased gradually, and the height and fractional vegetation cover of wetland community, stomatal conductance (Gs), and transpiration rate (Tr) of Kobresia tibetica showed a decreasing trend (P < 0.05).WUE, photosynthetically active radiation (PAR), vapor pressure deficit (VPD), and the height, fractional vegetation cover, and root-shoot ratio of Kobresia tibetica showed an increasing trend (P < 0.05). The leaf area (LA), leaf thickness (LT), specific leaf area (SLA), stem length (SL), and WUE of Kobresia Tibetica showed different correlations at different elevations. With the increase of altitude, the tradeoff between stems and leaves of Kobresia tibetica changed from stems to leaves, the tradeoff between LA and LT changed from favoring LA to LT, stem and leaf configuration changed from long stem-large LA to short stem-small LA, the net photosynthetic rate (Pn) and WUE increased, and the structural cost and photosynthetic efficiency return of Kobresia tibetica leaves changed from 'high-input-slow return' to 'low-input-fast return'. It reflects the ecological strategy of synergistic adaptation between stem and leaf morphology and photosynthetic characteristics of plants in alpine peat swamp in a heterogeneous habitat.

Wheat ( Triticum aestivum L.) is a key global crop threatened by freezing stress, which limits growth and productivity. Cyclophilins regulate critical plant processes, but their role in freezing tolerance remains unclear. In this study, functional assays were conducted exclusively in Arabidopsis thaliana to evaluate cold tolerance. Controlled freezing stress simulations (-5℃) revealed improved stress tolerance traits in transgenic overexpression (OE) plants. TaCYP2 -OE lines significantly improved survival rates (56-60%) vs. 33% in wild-type line (WT) after 2 days stress. Physiological analyses revealed that TaCYP2 -OE lines reduced membrane damage (32-33% lower relative electrolyte leakage and 32-38% lower malondialdehyde content) and elevated proline accumulation (27-31% higher), while the superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and lactate dehydrogenase (LDH) activities were significantly higher in TaCYP2 -OE lines compared to WT under 2 d stress. Reverse Transcription-quantitative PCR (RT-qPCR) showed that the antioxidant genes, including AtSOD , AtPOD , AtCAT and ascorbate peroxidase ( AtAPX ), as well as the stress regulatory genes dehydration-responsive element-binding protein 1a ( AtDREB1a ) and late embryogenesis abundant protein ( AtLEA ) of TaCYP2 -OE lines were significantly higher than those of WT at 1 day stress. Therefore TaCYP2 enhances freezing tolerance via membrane protection, osmotic balance, and reactive oxygen species (ROS) detoxification. These findings confirm that TaCYP2 positively regulates freezing stress tolerance and contributes to enhanced cold tolerance in Arabidopsis, with implications for wheat improvement.

Blue carbon, or carbon fixation, can reduce global CO2 emissions through green ecosystems. The capacity of mangroves to fix atmospheric CO2 is five times higher than tropical or terrestrial land plants. Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) is one of the most important enzymes for improving photosynthetic efficiency, but a range of sugar phosphates can restrict its activity. The AAA+ protein, RuBisCo activase (RCA), releases this inhibitory sugar-phosphate bound in the active site of RuBisCo by ATP hydrolysis. The present study focuses on understanding the mechanism by which RuBisCo activase regulates RuBisCo in mangroves. In terrestrial plants, RCA supports RuBisCo activity under stress; however, its efficiency diminishes under prolonged or extreme conditions, thereby limiting CO2 fixation. Mangroves, adapted to salinity, may harbour more stress-resilient mechanisms that help maintain photosynthesis. In silico analysis also revealed that mangrove RCA may exist in a hexameric form, with both the α- and β-isoforms indicating a level of structural diversification. Here, we describe a comparative study of RCA isoforms between terrestrial plants and mangroves, highlighting their structural and functional variations in response to environmental stress. We also investigated whether RuBisCo and its molecular chaperone, RCA, contribute significantly to CO2 sequestration in mangroves, or if their roles are minimal or even functionally divergent due to the prevalence of alternative carbon metabolic pathways in these stress-resilient environments.

Agricultural productivity is increasingly constrained by water scarcity, which affects nearly one-quarter of cultivated land and is projected to intensify due to climate change and escalating freshwater demands. Melatonin is widely recognized as a potent biostimulant that plays a crucial role in mitigating various abiotic stresses, particularly drought, across many plant species. This study demonstrates that exogenous application of melatonin (150 μM; foliar spray) confers protection to Phaseolus vulgaris under moderate water deficit (40% field capacity). A randomized complete block design comprising four treatment groups (n = 30 seedlings per group, five replicates) was employed to systematically evaluate morphological, physiological, biochemical, and molecular responses. Melatonin applications at 21 and 28 days after sowing significantly enhanced shoot elongation, leaf area expansion, and photosynthetic efficiency. Biochemically, melatonin markedly increased the activities of key antioxidant enzymes (ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD)), reduced reactive oxygen species accumulation, elevated proline content by 24%, and decreased electrolyte leakage by 18%, thereby improving osmotic balance and maintaining membrane integrity. Genomic stability was assessed using Inter-Simple Sequence Repeat (ISSR) and Random Amplified Polymorphic DNA (RAPD) markers, revealing that melatonin substantially attenuated drought-induced DNA damage. Marker analysis further demonstrated differential sensitivity, and key statistical indices, including polymorphism information content (PIC), effective multiplex ratio (EMR), and resolving power (RP), exhibited strong linear associations, reinforcing the reliability of molecular diagnostics. Collectively, these results highlight melatonin's multifaceted role in enhancing water-deficit resilience through integrated regulation of physiological homeostasis, oxidative stress mitigation, and genome protection. The findings support melatonin's practical potential as a low-cost, environmentally compatible strategy for improving legume performance in water-deficit environments.

One of the main melatonin metabolites in plants is cyclic 3-hydroxymelatonin (3-OHM), although its potential functions in plant life remain unclear. To understand the importance of 3-OHM in plants in terms of stress tolerance, we investigated whether tolerance to chilling stress could be increased during germination and emergence using exogenous 3-OHM applications in pepper. After being exposed to varying concentrations of 3-OHM for 24 h, pepper seeds were tested for germination and emergence under both optimum and chilling stress conditions. Applying 3-OHM prior to sowing had a positive effect on pepper seed germination and seedling emergence performance under chilling stress circumstances. Concentrations of 10 and 50 μM 3-OHM were determined to be the most effective 3-OHM concentrations, therefore the germination and emergence percentages and rates increased in contrast to control treatments. 3-OHM treatments raised the activity of the enzymes peroxidase, catalase and superoxide dismutase while decreasing the quantities of reactive chemicals such as hydrogen peroxide and thiobarbituric acid in seedlings. Furthermore, treatments had a positive effect on seedling proline content, root length, vigor index and chlorophyl content. In conclusion, increased antioxidant enzyme levels significantly reduce lipid peroxidation in tissues, consequently boosting pepper seed germination and seedling emergence performance.

Alkaline stress severely impairs the growth and yield of Zea mays L. by disrupting physiological and biochemical functions. This study evaluated green-synthesized ZnO and MgO nanoparticles (NPs), prepared using neem and licorice extracts, for mitigating alkaline stress. NPs were nanosized, crystalline, and functionalized by phytochemicals, confirmed by scanning electron microscopy, FT-IR spectroscopy, UV-vis spectroscopy, and energy dispersive X-ray spectroscopy. A pot experiment using NPs (25-200 ppm) under control and alkaline stress assessed morphological, physiological, biochemical, and ionic responses. Alkaline stress reduced root fresh and dry weight to 2.60 and 0.66 g (-59.6%, -31.0%), shoot fresh and dry weight to 2.60 and 0.38 g (-59.6%, -70.0%), and chlorophyll a, b, and carotenoids to 1.31, 0.67, and 2.40 mg g-1 (-62.4%, -54.7%, -62.8%), whereas it increased malondialdehyde (MDA) (244.6%), H₂O₂ (457.7%), and relative membrane permeability (RMP) (55.9%). The combined ZnO (50 ppm) and MgO (50 ppm) treatment improved chlorophyll a, b, and carotenoids to 3.48, 1.48, and 6.45 mg g-1 (165.4%, 120.3%, 168.5%), and total soluble protein (392.8%), total protein (301.0%), proline (105.5%), glutathione (35.6%), and ascorbic acid (44.2%). Antioxidant enzymes increased, with superoxide dismutase at 29.52 U mg-1 (452.8%), peroxidase at 24.44 U mg-1 (862%), and ascorbate peroxidase at 51.62 U mg-1 (560%), whereas MDA, H2O2, and RMP (-78.1%) were reduced. High NP concentrations (ZnO 100 ppm + MgO 100 ppm) were toxic. Moderate ZnO and MgO NP doses enhanced resilience, yield stability, and sustainable agriculture.