Search Results (432)

For over 3000 years, the perennial herb mugwort (Artemisia argyi) has served as a cornerstone of traditional Asian medicine. Its clinical efficacy is driven by a diverse array of specialized metabolites, most notably flavonoids and volatile oils. While B-box (BBX) transcription factors are known to dictate photomorphogenic development and secondary metabolic pathways in plants, this specific gene family has not yet been systematically analyzed in A. argyi. Leveraging a chromosome-level genomic assembly, we comprehensively identified and analyzed the complete repertoire of AarBBX genes, profiling their structural organization, physicochemical attributes, conserved motifs, promoter architecture, and spatial expression dynamics. The AarBBX family segregates into five distinct evolutionary clades and comprises 114 members, exceeding the gene counts in the diploid relatives Artemisia annua (27) and Arabidopsis thaliana (32), a numerical increase potentially attributable to the tetraploid genome architecture of A. argyi. Promoter scanning revealed a high density of cis-acting elements linked to light perception and environmental stress responses. Integrating RNA-seq transcriptomics with tissue-specific expression profiling, we identified prominent candidate light-responsive AarBBX genes that are highly active in green, photosynthetic tissues and acutely responsive to shifts in light conditions, providing a foundation for future exploration of their potential relationship with secondary metabolic pathways, including flavonoid and terpenoid biosynthesis. Furthermore, we validated the potential operational compartments and structural interactions of these proteins utilizing green fluorescent protein (GFP) subcellular localization and yeast two-hybrid (Y2H) screenings. Collectively, these findings provide new insights into the evolutionary trajectory and regulatory potential of the B-box (BBX) proteins in A. argyi, offering a prioritized candidate gene set for subsequent investigations into their potential roles in light-regulated secondary metabolism, including flavonoid and terpenoid pathways. Full article

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant widely detected in aquatic ecosystems, but its subcellular targets and the mechanisms by which it disrupts light resource utilization in photosynthetic protozoa remain poorly understood at concentrations spanning environmentally typical to supra-environmental levels. Here, Euglena gracilis G.A. Klebs was exposed to PFOS at concentrations spanning environmentally typical (0.5 µg/L), hotspot-relevant (5 µg/L), and supra-environmental (50 µg/L) levels. Subcellular distribution, phototaxis, photosynthetic light reactions, and energy metabolism were investigated using isolated chloroplast assays, transcriptomics, and proteomics. TEM-EDS mapping revealed pronounced fluorine signal enrichment, attributable to PFOS, in the eyespot and chloroplasts. Eyespot fluorine enrichment was associated with impaired phototactic motility and an altered light perception threshold. PFOS did not acutely inhibit the maximum photochemical efficiency of photosystem II (Fv/Fm); instead, a transient upregulation of photosynthesis-related genes was observed, which weakened with prolonged exposure, whereas the photosynthetic electron transport rate (ETR) was significantly reduced. PFOS significantly reduced ATP levels and ETR, while Fv/Fm remained unchanged and non-photochemical quenching (NPQ) was elevated. Isolated chloroplast assays revealed that PFOS inhibits Mg²⁺-dependent ATP hydrolytic activity in the chloroplast-enriched fraction and impairs thylakoid electron transport, consistent with impaired chloroplast ATP synthase function, though the specific molecular target and mechanism remain to be conclusively demonstrated. Transcriptomic and proteomic analyses revealed compensatory upregulation of photosynthesis pathways but suppression of ATP synthesis and redox homeostasis. Collectively, our results suggest that PFOS impairs chloroplast ATP synthase function, accompanied by reduced ETR and elevated NPQ. Together with the eyespot-associated phototaxis impairment, these effects suggest that PFOS may dually disrupt light acquisition (behavioral) and light conversion (physiological) in E. gracilis. This dual impairment may compromise the ecological fitness of Euglena in PFOS-contaminated environments, especially under prolonged exposure. It should be noted that the subcellular fluorine mapping is qualitative, the phototaxis assay reflects population-level responses, and the ATP synthase impairment interpretation is indirect; the proposed mechanistic model remains a hypothesis requiring further direct experimental validation. Full article

Filamentous cyanobacteria in the genus Nostoc show color diversity in their natural habitats, ranging from bright green to yellow–green to brown. In contrast, laboratory cultures are typically uniform in color, which is attributed to differences in light spectrum and intensity. Nostoc contains several bioactive pigments, including phycocyanin, phycoerythrin, allophycocyanin, carotenoids, and scytonemin, which are involved in light harvesting, photoprotection, and UV screening. Variations in light spectrum and intensity regulate the abundance and organization of these pigments, altering colony coloration and affecting photosynthetic performance, stress tolerance, and growth. These changes impact biomass and pigment productivity. In this review, we synthesize recent findings on how light regulates pigment biosynthesis in Nostoc and examine how wavelength, irradiance, and photoperiod influence pigment composition, biomass accumulation, and pigment productivity, considering both underlying photoregulatory mechanisms and cultivation design. This perspective connects photophysiological insights with practical strategies, including staged lighting and LED-based systems, to improve pigment yield while maintaining biomass production. These insights support the future application of Nostoc pigments in food, cosmetic, and pharmaceutical sectors. Full article

Optimizing rice (Oryza sativa L.) plant architectype is an important approach to coordinating the source–sink relationship and unlocking yield potential. In this study, using the large-panicle rolled-leaf variety ST-12 and the small-panicle flat-leaf variety Nipponbare, we systematically compared plant architectype traits, photosynthetic characteristics, biomass accumulation, carbohydrate accumulation and remobilization, source–sink characteristics, and yield under two nitrogen levels in field conditions to test the hypothesis that excessive leaf rolling influences the accumulation and translocation of photosynthetic products and disrupts the source–sink balance. The results showed that Nipponbare exhibited significantly higher yield than ST-12 under both nitrogen levels, attributable to its higher number of productive panicles, grain-filling percentage, and thousand-grain weight. Although ST-12 had a higher single-leaf photosynthetic rate and leaf area index, its top three leaves were excessively rolled, reducing its canopy light interception and canopy photosynthetic rate, thereby leading to significantly lower stem NSC content at heading and biomass accumulation during grain filling compared with Nipponbare. Notably, ST-12 had higher contents of cellulose, hemicellulose, and lignin in the stem at heading, directing more pre-anthesis photosynthetic products into structural carbon, while the translocation of non-structural carbohydrates to grains was not affected. Further analysis revealed that ST-12 had a lower source capacity, sugar–spikelet ratio, source–spikelet ratio, and source–sink ratio than Nipponbare, whereas its total spikelet number and sink capacity were significantly higher. Correlation analysis showed that source characteristic indices and the source–sink ratio were positively correlated with yield, grain-filling percentage, and thousand-grain weight, while sink characteristic indices were negatively correlated with these traits. In conclusion, excessive leaf rolling impairs canopy photosynthesis, leading to a large sink but weak source imbalance. For large-panicle varieties, a higher source–sink ratio, not simply larger sink size or total biomass, is the key to high yield. Full article

Background/Objectives: The high temperatures associated with climate change represent an important constraint for tomato production in tropical regions, affecting plant growth, reproductive development, and fruit metabolic composition. In this context, protected cultivation systems capable of modifying greenhouse microclimates may help reduce thermal stress and maintain crop productivity. Methods: This study evaluated the effects of two protective environments, diffuse agricultural film (AF) and twin-walled polycarbonate panels with laminar water flow (P), on the agronomic performance and fruit metabolic traits of five grape–tomato hybrids grown under tropical conditions. Microclimatic variables, vegetative growth, yield components, postharvest behavior, and fruit quality attributes were evaluated, with emphasis on carotenoid accumulation. Results: Compared with the agricultural film environment, the polycarbonate system reduced global radiation and photosynthetically active radiation (PAR) and was associated with an increase in yield of approximately 25%, an increase in fruit number of approximately 13%, and an 8% increase in fruit diameter. In addition, some hybrids cultivated under the polycarbonate system showed greater lycopene and β-carotene accumulation, indicating that microclimate moderation may favor carotenoid-related fruit quality depending on genotype. Principal component analysis revealed a clear separation between cultivation environments, with the polycarbonate system more closely associated with yield-related and canopy development traits, whereas the agricultural film environment was linked to biomass accumulation and selected physicochemical attributes. Among the evaluated hybrids, BS IGR0104, Jacy, and GI7545 showed the most favorable combination of agronomic performance and fruit quality traits. Conclusions: These results demonstrate the importance of climate-adaptive protected cultivation systems and hybrid selection for improving tomato productivity under tropical heat conditions. Full article

Nitrogen forms and native plant traits jointly regulate the competitive ability of invasive plants. This study investigated the invasive species Amaranthus retroflexus and the native species Portulaca oleracea and Medicago sativa. Using a pot experiment, we analyzed their competitive effects under NO₃⁻-N, NH₄⁺-N, CO(NH₂)₂-N and mixed nitrogen (Mix-N) treatments. The results showed that nitrogen addition had no significant effect on the relative yield of A. retroflexus but significantly increased the relative yield of P. oleracea, thereby weakening the competitive advantage of A. retroflexus. In contrast, nitrogen addition had no significant effect on the relative yield of M. sativa but significantly increased the relative yield of A. retroflexus, thereby enhancing the competitive advantage of A. retroflexus. The effect of NO₃⁻-N treatment varied markedly between the two mixed-culture systems: it strengthened the advantage of A. retroflexus when grown with M. sativa yet weakened the advantage when grown with P. oleracea. Further analysis revealed that the competitive advantage of A. retroflexus was associated with the optimization of its photosynthetic traits and nitrogen absorption efficiency. Specifically, it included greater leaf number, leaf area, SPAD value, and leaf biomass. In summary, the competitive performance of invasive plants is not a fixed attribute but rather a dynamic outcome jointly regulated by the interplay between native plant traits and soil nitrogen forms. This provides new insight into the invasion mechanism of alien plants and aids in formulating targeted control strategies. Full article

In plant factories with artificial lighting (PFALs), spectral regulation serves as the predominant factor governing plant growth and development. The implementation of red-enriched spectral regimens during cultivation promotes biomass accumulation, whereas blue-dominant spectra enhance the biosynthesis of phytochemicals and nutritional compounds in plants. Nevertheless, systematic investigations into the effects of staged spectral regimens on both plant development and secondary metabolite biosynthesis remain limited. This study evaluated four distinct stage-specific dynamic lighting regimens (T1–T4) under a constant total photosynthetic photon flux density (PPFD) of 200 μmol·m⁻²·s⁻¹. The treatments utilized three distinct red-to-white photon flux ratios (R:W = 3:1, 1:1, and 1:3) administered sequentially during critical developmental phases of Pak choi: the seedling stage, the early growth stage (15 days after transplanting, DAT), and the late growth stage (16–30 DAT). The effects of these treatments on biomass production, morphological development, photosynthetic pigments, nutritional metabolites, antioxidant levels and radical quenching capacity were evaluated. The results demonstrated that the T4 treatment significantly enhanced biomass production, increasing shoot fresh weight by 51.3% compared to the T1 treatment at the late growth stage. The application of a higher red-light proportion (HR, R:W = 3:1) during the seedling stage significantly increased leaf area by 70% compared to the low red-light treatment (LR, R:W = 1:3). Regarding nutritional quality, while carotenoid content showed no significant differences among treatments, higher blue-light proportions selectively stimulated the biosynthesis of chlorophyll, vitamin C, and soluble proteins. Specifically, the T3 treatment enhanced certain traits during the early growth stage, whereas the T2 treatment best maintained specific antioxidant capacities (FRAP and flavonoids) at the late growth stage prior to harvest. Notably, nitrate levels were not significantly affected by the spectral shifts. This study establishes that the temporal modulation of red-to-white spectral ratios enables the targeted optimization of either crop yield (T4) or specific harvest-stage nutritional attributes (T2) in Pak choi. Full article

Water deficit (WD) irrigation has garnered considerable attention for its potential to enhance crop water use efficiency. However, limited research has been conducted on its ability to improve tomato fruit sweetness-related traits without significantly affecting yield. In this study, we investigated the effects of varying WD levels [T1–T4: 80%, 65%, 55%, and 45% of field capacity (FC)] compared with full irrigation (CK: 90% FC) on tomato fruits from the mature green to red-ripe stages, aiming to evaluate yield, textural attributes, and sugar composition. Notably, the fruit yield per plant under T2 treatment was not significantly different from that under CK. Compared with CK, T2 significantly reduced fruit water content by 2.39% while markedly increasing individual fruit dry weight by 13.61%. At 44 days after flowering, fruit firmness under T2 showed no substantial difference from CK, whereas adhesiveness was markedly elevated by 33.85%. Furthermore, T2 substantially boosted the activities of key Calvin cycle enzymes (ribulose-1,5-bisphosphate carboxylase/oxygenase, glyceraldehyde-3-phosphate dehydrogenase, fructose-1,6-bisphosphatase, fructose-1,6-bisphosphate aldolase, and transketolase) in tomato leaves, thereby increasing the photosynthetic rate and consequently elevating the total sugar content in tomato fruits. Additionally, T2 stimulated the activities of sucrose-hydrolyzing enzymes (acid invertase and neutral invertase) in fruits, leading to increased fructose and glucose accumulation at the red-ripening stage, with respective increases of 69.60% and 34.67% relative to CK. Multivariate classification based on principal component analysis and hierarchical cluster analysis revealed that T2 and T3 were distinctly separated from other treatments in terms of yield, texture parameters, and sugar profiles. These findings provide a valuable strategy for applying WD to improve fruit sugar composition without compromising yield. Full article

The damage caused by herbivores is generally measured as the amount of leaf tissue consumed, without accounting for the fate of the leftover tissue. As a result, the plant defense mechanisms that promote resistance to herbivore feeding by photosynthetically acclimating the rest of the plant to the feeding spot leaf area have not been well exploited. Plant-insect interactions are now becoming better defined with the development of visualization methods that permit spatial whole-leaf assessment of photosynthetic efficiency after herbivore attack. The purpose of our study was to evaluate the spatial heterogeneity of photosystem II (PSII) function at the whole-leaf level before and after herbivory by the Colorado potato beetles. Twenty minutes after Colorado potato beetle (Leptinotarsa decemlineata) feeding, the maximum efficiency of PSII photochemistry (Fv/Fm) decreased significantly, suggesting photoinhibition due to reduced efficiency of the oxygen-evolving complex (OEC). The decreased quantum yield of PSII photochemistry (Φ_PSII) after feeding, at the neighboring area of the feeding spot and at the rest of the leaf area, was attributed to the reduced efficiency of the open PSII reaction centers (Fv′/Fm′), since there was no change in the fraction of open PSII reaction centers (qp). Nevertheless, plant defense elicitation was activated by the photoprotective mechanism of non-photochemical quenching (NPQ) that reduced the singlet oxygen (¹O₂) formation in potato plants in the neighboring area of the feeding spot and at the rest of the leaf area. In addition, the increased production of hydrogen peroxide (H₂O₂) triggered by this increase suggests that it acted as a signaling molecule in the biotic stress defense response. Full article

Intercepted photosynthetically active radiation (IPAR) to biomass method is widely used in plant growth models to simulate biomass accumulation. This method is closely linked to radiation use efficiency (RUE), which can vary by species, cultivars, and location. Although Chinese cabbage (Brassica rapa L.) is a cool-season plant, it is cultivated year-round in South Korea. Therefore, investigating the RUEs of two different ecotypes of Chinese cabbage is crucial for developing accurate plant growth models. In this study, we examined RUEs and other key agronomic characteristics that influence Chinese cabbage growth across different growing seasons. Field studies were conducted to analyze the growth patterns of fall and summer ecotypes and to explore various agronomic traits for developing a leaf area index (LAI) model. Using a multivariate regression method, we developed an LAI model that simulates the leaf area index for both ecotypes across multiple locations in South Korea (R² = 0.92). A total of 218 field data points collected from 35 sites between 2020 and 2023 were used to estimate the RUEs and LAIs of the fall and summer ecotypes. Results indicated that Chinese cabbage demonstrated more efficient photosynthesis in the fall, with RUEs of 2.3 g MJ⁻¹ for the fall ecotype compared to 1.3 g MJ⁻¹ for the summer ecotype based on regional estimation. This difference may be attributed to lower radiation availability per unit of heat growth during the summer season (0.3 MJ °C⁻¹) compared to the fall (0.78 MJ °C⁻¹). The findings of this study will aid plant modelers and enhance the accuracy of simulations for Chinese cabbage growth. Full article

Light environments within plantation forests vary significantly with stand degradation. This study investigated how light-related factors change along degradation gradients in Robinia pseudoacacia L. (black locust) plantations and how these changes influence understory herbaceous vegetation and regeneration. An R. pseudoacacia plantation at the Zhongmu State-owned Forest Farm, ZhengZhou, China was studied across three degradation levels (least degraded, moderately degraded, and severely degraded). Integrated analyses were employed to assess light–vegetation relationships under different stand densities. The results indicated that canopy openness (CO), photosynthetically active radiation (PAR), and light transmittance increased significantly with increasing degradation severity, whereas the leaf area index (LAI) declined. Specifically, differences in LAI among degradation levels were observed in all density stands. CO, TDR, and PAR showed degradation-related differences in medium- and high-density stands, while other light variables varied under specific density–degradation combinations. Furthermore, herbaceous biomass declined, canopy cover showed a fluctuation trend, and species diversity increased. Significant correlations were observed between multiple light parameters and herbaceous attributes. Overall, variations in the light environment were closely associated with understory vegetation dynamics. Moderate degradation was linked to higher herbaceous diversity, whereas regeneration density exhibited a non-monotonic response across degradation levels, with the lowest value under moderate degradation rather than a continuous decline under severe degradation. Full article

Managing tillage intensity and diversifying crop rotation are important sustainability levers for conservation agriculture (CA) with the potential to enhance crop resilience, resource efficiency, and yield stability. Accordingly, this study aimed to determine the effect of reduced tillage intensities and cereal–legume rotation systems on the agronomic and physiological performance of rainfed durum wheat grown under Mediterranean semi-arid conditions. To this end, a two cropping seasons field experiment was conducted in northeast Tunisia where the combined effects of two reduced tillage intensities (minimum and no-tillage; MT and NT) and two legume-based crop rotation systems (biennial and triennial; B and T) were compared to the more traditional conventionally tilled monocropping system (CT and M). Crop rotation, particularly when integrated with no-tillage (NT), significantly improved wheat development and grain yield, along with key yield attributes such as thousand-kernel weight and spike density. The interaction between tillage and crop sequence was highly influential; for instance, the NT × T (no-tillage × triennial rotation) combination achieved the highest grain yields (240 and 236 g m⁻² in 2020–2021 and 2021–2022, respectively), while the CT × M (conventional tillage × monoculture) interaction resulted in the lowest productivity (143 and 135 g m⁻²). Physiologically, the integration of reduced tillage and legume–cereal rotations optimized the photosynthetic apparatus, as evidenced by significantly improved chlorophyll fluorescence parameters. However, a prominent trade-off was identified: while NT × T maximized productivity, conventional tillage (CT) maintained superior grain protein (18.6%) and gluten concentrations, indicating a nitrogen dilution effect in high-yielding conservation systems. These results demonstrate that while no-tillage and triennial rotations (faba bean–wheat–barley) are robust strategies for climate-resilient yields in semi-arid environments, they must be coupled with optimized nitrogen management to offset quality declines. Consequently, this study establishes the NT × T interaction as a superior model for sustainable rainfed farming, provided that nutrient synchronization is addressed to ensure nutritional security under increasingly unpredictable Mediterranean climates. Full article

Lichens represent a fundamental symbiotic association between fungi and photosynthetic organisms, such as algae or cyanobacteria, and are widely regarded as sensitive indicators of environmental change. Lichens’ capacity to colonize a wide range of ecological niches is attributed to their distinctive physiological characteristics, notably, their lack of protective cuticles and ability to uptake water and nutrients directly from the atmosphere. Concurrently, lichens are highly vulnerable to airborne contaminants, making them critical bioindicators of air quality. However, the survival of lichens is increasingly influenced by intensifying global change via agriculture, industrial activities, and vehicular emissions. Organic and inorganic pollutants can adversely affect lichen physiology by inducing pigment degradation, disrupting membranes, and altering lichen diversity. The synergistic stressors associated with global change, such as increasing temperatures and shifts in precipitation regimes, exacerbate the effects of atmospheric deposition and oxidative stress on lichens. Here, we present existing knowledge on lichens’ ecological functions, elucidate the mechanisms underlying their sensitivity to air pollution, and assess their utility for environmental monitoring amid accelerating global change. By recognizing lichens as dynamic ecological indicators, we underscore their dual role in sustaining ecosystem processes amidst rapid global change. Full article

Olive tree cultivation occupies a central place in Algerian agriculture and is of considerable economic and cultural importance. Several production factors strongly influence the quality of olive oil. Among the determinants of this quality, the vegetative growth of the olive tree plays a crucial role, as it controls photosynthetic capacity, the distribution of assimilates, and fruit filling. These physiological mechanisms directly influence oil percentage, as well as fatty acid and phenolic compound compositions, and consequently, sensory characteristics such as bitterness and pungency. This study examines the quantitative relationships between vegetative growth, chemical parameters, and sensory attribute interactions that are still poorly understood using seven representative olive cultivars: local varieties (Chemlal, Bouchouk Lafayette, Blanquette de Guelma, Sigoise, and Limli) and European varieties (Frantoio and Belgentéroise). Vegetative growth was characterized by the average shoot length; fruit oil content was expressed as a percentage on a dry basis, and fatty acids were analyzed by gas chromatography after derivatization. The total polyphenol content was determined by spectrophotometry and expressed as concentration, and oxidative stability was measured using the Rancimat method. Sensory analysis was conducted by a trained panel in accordance with international recommendations. The results indicate substantial positive correlations between vegetative growth parameters, oil concentration, olive oil composition, and those sensory attributes related to polyphenols, for all varieties studied. This functional consistency suggests that improvement in one parameter is generally associated with improvement in others. The Algerian variety Chemlal stands out for its optimal performance profile in agronomic, chemical, and sensory aspects compared to the other varieties. These preliminary results suggest that optimizing oil characteristics is directly linked to the physiological and biochemical performance of the olive tree, thus confirming the relevance of a systems approach in the selection and management of olive varieties. Full article

Yellow pitaya (Hylocereus megalanthus) is highly photosensitive and therefore strongly influenced by light availability. In winter, insufficient sunlight often induces a “yin–yang effect”, characterized by physiological disparities between the sunlit and shaded sides of east–west-oriented orchards. To elucidate the effects of supplemental lighting parameters on flowering, yield, and fruit quality of shade-grown yellow pitaya, we systematically examined four factors: lighting angle (45°, 60°, 90°), power (12, 15, and 18 W), duration (3, 4, and 5 h per day), and lighting period (10, 20, and 30 days). Compared with no supplemental lighting (net photosynthetic rate = 10.60/11.73 μmol m⁻² s⁻¹, yield = 903/3536.5 kg ha⁻¹, net profit = 6435/72,675 CNY ha⁻¹ in two seasons), a 90° angle in the first season and a 60° angle in the second season increased the net photosynthetic rate by 45.87% and 60%, yield by 165.98% and 145.16%, and net profit by 373.82% and 159.42%, respectively. 18 W lighting power raised average yield and net profit by 176.37% and 278.7%, while 5 h lighting duration enhanced them by 161.29% and 267.66%. Meanwhile, a 20-day lighting period increased yield and profit by 128.91% and 240.6% on average. The recommended parameter set of a 60°/90° angle, 18 W power, 5 h duration, and 20-day lighting period markedly improved photosynthetic performance, yield, and net economic returns of shaded-side yellow pitaya. These improvements were attributed to enhanced carbon assimilation and reallocation from source to sink tissues, which contributed to higher fruit yield and quality and effectively mitigated winter shading stress. Full article