Photoprotective Capacity Research Articles

Predator-induced defense decreases growth rate and photoprotective capacity in a nitrogen-limited dinoflagellate, Alexandrium minutum

Some dinoflagellates produce toxic secondary metabolites that correlate with increased resistance to grazers. The allocation costs of toxin production have been repeatedly addressed, but with conflicting results. Few studies have considered the potential costs of this defense to the photosystem, even though defense toxins (e.g., karlotoxins and brevetoxins) are closely linked to the photoprotective process. Here, we used chemical cues from copepods to induce paralytic shellfish toxin (PST) production in resource-limited Alexandrium minutum and quantitatively determined the growth rate and potential trade-offs with the photosystem process. The results show that grazer-induced, more toxic A. minutum had larger cell volume, lower cell division rate, and lower pigment content under nitrogen-limited conditions than control cells. In addition, predator cues led to a lower relative abundance of photoprotective xanthophylls and a reduced de-epoxidation efficiency of the xanthophyll cycle under high light conditions, reducing the ability of the cells to resist photodamage. Decreased photoprotective capacity may reflect an overlooked defense cost of toxin production.

Influence of Habitat and Effects of Salt Stress on Biochemical and Physiological Parameters of Glycyrrhiza uralensis.

The seeds of Glycyrrhiza uralensis Fisch. used for cultivating are primarily sourced from wild populations. However, the types of habitats where wild G. uralensis grow are diverse. We studied the effects of salinity on the growth, antioxidant capacity, and photosynthetic physiology of two-month-old licorice seedlings from different habitats to evaluate their salt tolerance. With the increasing NaCl concentration, compared with non-salinized habitats, seedlings originating from seeds collected from salinized habitats showed milder inhibition in root biomass and root volume. Also, the crown diameter increased more significantly. Activities of superoxide dismutase, catalase, and peroxidase are higher. Correspondingly, the electrolyte leakage rate of the leaves is low. Their leaves had a higher photoprotection capacity and potential maximum photochemical efficiency of PSII. Net photosynthetic rate, transpiration rate, and stomatal conductance showed less inhibition under 4 and 6 g/kg NaCl treatment. The content of glycyrrhizic acid and glycyrrhetinic acid in their roots was significantly increased under 2 g/kg NaCl treatment and was significantly higher than that of seedlings from non-salinized habitats under the same NaCl treatment. In conclusion, seeds from salinized habitats show improved tolerance to salt stress at the seedling stage, which is attributed to their superior phenotypic adaptability, strong antioxidant, and especially high light protection ability.

Shining light on diurnal variation of non‐photochemical quenching: Impact of gradual light intensity patterns on short‐term NPQ over a day

AbstractMaximal sunlight intensity varies diurnally due to the earth's rotation. Whether this slow diurnal pattern influences the photoprotective capacity of plants throughout the day is unknown. We investigated diurnal variation in NPQ, along with NPQ capacity, induction, and relaxation kinetics after transitions to high light, in tomato plants grown under diurnal parabolic (DP) or constant (DC) light intensity regimes. DP light intensity peaked at midday (470 μmol m‐2 s‐1) while DC stayed constant at 300 μmol m‐2 s‐1 at a similar 12‐hour photoperiod and daily light integral. NPQs were higher in the morning and afternoon at lower light intensities in DP compared to DC, except shortly after dawn. NPQ capacity increased from midday to the end of the day, with higher values in DP than in DC. At high light ΦPSII did not vary throughout the day, while ΦNPQ varied consistently with NPQ capacity. Reduced ΦNO suggested less susceptibility to photodamage at the end of the day. NPQ induction was faster at midday than at the start of the day and in DC than in DP, with overshoot occurring in the morning and midday but not at the end of the day. NPQ relaxation was faster in DP than in DC. The xanthophyll de‐epoxidation state and reduced demand for photochemistry could not explain the observed diurnal variations in photoprotective capacity. In conclusion, this study showed diurnal variation in regulated photoprotective capacity at moderate growth light intensity, which was not explained by instantaneous light intensity or increasing photoinhibition over the day and was influenced by acclimation to constant light intensity.

UV protection and insecticidal activity of microencapsulated Vip3Ag4 protein in Bacillus megaterium

In this study, secretable Vip3Ag4 protein was encapsulated in Bacillus megaterium and used for quantitative bioassays, in order to determine the UV photoprotective capacity of the cell, for preventing inactivation of the insecticidal activity of the protein. The non-encapsulated and purified protein was exposed to the UV light showing a LC50 of 518 ng/cm2 against Spodoptera littoralis larvae, whereas the exposed encapsulated protein exhibited 479 ng/cm2. In addition to the capability to accumulate Vip3 proteins for the development of novel insecticidal formulates, the B. megaterium cell has demonstrated to provide moderate protection against the deleterious action of UV light.

Phytochemical screening, antioxidant properties, and photo-protective activities of Salvia balansae de Noé ex Coss

Abstract The present study evaluated the potential of Salvia balansae from the Aures Mountains as a source of natural bioactive compounds. Leaves, flowers, and stems were extracted separately using methanol, ethanol, and acetone. Phenolic compounds were quantified colorimetrically and identified using liquid chromatography coupled with mass spectrometry (LC-MS). Antioxidant capacity was assessed using six different in vitro assays, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 1,1-diphenyl-1-picrylhydrazyl, cupric reducing antioxidant capacity, ferric reducing antioxidant power, ferrous ion chelating, and phenanthroline assay, while the photo-protective capacity was evaluated using the sun protective factor. The methanolic flower extracts revealed the highest O-diphenol and phenolic levels (287.9 ± 0.50 and 147.87 ± 0.21 µg GAE/mg, respectively), whereas the acetonic and ethanolic leaf extracts contained the highest flavonoid (72.17 ± 0.12 μg QE/mg) and flavonol (35.28 ± 0.05 μg QE/mg) levels, respectively. LC-MS was used to identify 18 phenolics, including quinic acid (5.051–69.69 ppm), luteolin-7-o-glucoside (7.802–44.917 ppm), apigenin-7-o-glucoside (3.751–68.507 ppm), and cirsiliol (2.081–15.608 ppm), distinguishing this Aures taxon. Principal component analysis and unweighted pair-group method with arithmetic mean revealed variability in phytochemicals, antioxidant properties, and photo-protective activity influenced by biological activities and the compound content. Overall, S. balansae demonstrated promising photo-protective capacity, the presence of key bioactive compounds, and wide-ranging antioxidant potential, presenting this endemic plant as a valuable source of natural antioxidants and photo-protective agents with pharmaceutical and cosmetic applications.

Evaluation of Spirulina spp. Crude Extract Revealed Antimicrobial, Antioxidant and UV Photoprotective Properties

The antimicrobial, UV photoprotective and antioxidant capabilities of Spirulina spp. methanolic extracts were determined using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS). Notable compounds were reported to be 5 fatty acid methyl esters, 4- methoxyallocinnamic acid, 2-ethylhexyl esters and bumetrizole. Moreover, these metabolites contained functionalities including hydroxyl, alkyl and carbonyl, as supported by the FTIR result. After 24 h, there was no zone of inhibition in the antibacterial activity as measured by the agar well diffusion method at doses of 30, 50 and 70 g/mL. The ABTS radical scavenging assay revealed that the methanolic Spirulina spp. exhibited an inhibitory concentration of 1,047.91 g/mL for antioxidant activity and SPF values of 0.40, 0.23 and 0.93 were calculated using Mansur’s equation for concentrations of 30, 50 and 70 g/mL, respectively. The results of the study showed the potential of cyanobacterial extracts as a bioactive ingredient in cosmetic product development. HIGHLIGHTS Methanolic extraction of Spirulina spp. comprises 5 fatty acid methyl esters, 4-ethoxyallocinnamic acid 2-ethylhexyl esters and bumetrizole characterized by GC-MS. Constituents of the extract contain functional groups including –OH, –C–H and C=O. The extracts were classified as weak radical stabilizers, confirmed by ABTS assay and possessed UV photoprotective capacity confirmed by the in vitro SPF assay. GRAPHICAL ABSTRACT

Contributions of temperature and development state to the morphological variation of Ulva prolifera highlight the source management for green tides

Since 2007, the world's largest transregional green tides caused by Ulva prolifera have periodically occurred in China. The morphology of U. prolifera drastically changes during the drifting period, but the reason for this phenomenon has still been under debate. Our results showed that temperature partly explained the changes in the morphology of U. prolifera, with a determining factor of 0.498. The ratio of highly branched thalli decreased as the temperature increased from around 25 to 30 °C. Because morphological changes and physiological acclimation synergistically occurred in floating macroalgae, we hypothesized that if the morphology of U. prolifera is also determined by its development state, and the U. prolifea thalli with different development states should have distinct morphological and physiological traits even under the same environmental conditions. To test the hypothesis, we investigated the photosynthesis of U. prolifera and found a higher photosynthetic capacity but lower photoprotective capacity in algae that grew in the branched development state compared to those in the unbranched development state. Combined with other field observations and lab experiments, we suggest that both temperature and development state contribute to the morphological changes of U. prolifera. Given the varying trends of temperature during U. prolifera blooms in past eleven years and the initial occurrence of U. prolifera thalli in the branched development state in the source of algal bloom, we emphasize the need for source management of green tides.

Photoprotective effect of topical treatment with Lopezia racemosa extract against deleterious UVB irradiation effects in the skin of hairless mice.

Lopezia racemosa is known as a "mosquito flower or perlilla." It is commonly found in corn crops. In traditional Mexican medicine, this plant is used to treat stomach cancer and urinary tract infections. Likewise, compounds and extracts isolated from plants have shown cytotoxic and anti-inflammatory effects. Theobjective of this study was to evaluate the photochemoprotective effect of topical treatment with the methanolic extract of L. racemosa (MELR) as a photochemoprotective agent against the harmful effects of UV irradiation (UVR) on a bacterial model and hairless mice. The MELR components were separated and analyzed via HPLC-UV-ESI-MS. Antioxidant activity was evaluated by the ability of MERL to scavenge DPPH and ABTS free radicals and by its FRAP capacity. The toxicity of MELR was evaluated in keratinocyte cultures. The photoprotective capacity of MELR was assessed through challenge experiments using models with bacteria and hairless CD1 et/et mice; cytokines related to the damage caused by UVR were also measured. In the methanolic extract of L. racemosa, five metabolites were detected and identified: two isomers of quercetin 6-C glycoside, orientin, quercetin 3-(6″-acetylglycoside) and quercetin 3-(6″-galloylglycoside) 7-(2,3-dihydroxytetrahydro-2H-pyran-4-yl acetate). MELR exhibited DPPH and ABTS radical scavenging properties, in addition to Fe ion reducing activity. MELR showed a photoprotective effect against UVB radiation-induced death in Escherichia coli bacteria. At the histological level, topical treatment of CD-1 et/et mice with MERL reduced the damage caused by UVR. Quantification of interleukins in the blood of mice revealed that the expression of IL-12 was greater in the control group treated with ultraviolet radiation than in the group protected with MELR. The methanolic extract of L. racemosa has photochemoprotective properties.

Unveiling the intrinsic mechanism of photoprotection in bamboo under high light

The study aims to unveil the intrinsic photoprotection mechanism of bamboo under high light. Bamboo, a fast-growing and regenerative plant, exhibits a wide distribution in temperate, subtropical, and tropical regions. Bamboo frequently exposed to various environmental stresses, including excessive light, which can cause photoinhibition and even photooxidative damage to the photosynthetic apparatus. However, the characteristics and intrinsic mechanism of bamboo photoprotection are still unclear. The photosynthetic performance and photoprotective capacity of 20 bamboo species by the chlorophyll fluorescence parameters are investigated in this study. Based on the results of similar photosynthetic and photoprotective characteristics in diverse bamboo species, moso bamboo (Phyllostachys edulis) is selected as the representative bamboo species for further investigation. The light energy allocation in leaves of moso bamboo under different light intensities is analyzed to reveal its adaptability to light fluctuations in nature. Meanwhile, the expression levels of non-photochemical quenching (NPQ)-related genes in leaves of moso bamboo under high light is analyzed. The results demonstrate that the expression of NPQ-related genes is induced by high light, especially that of PsbSs and VDE is significant, indicating they play important roles in photoprotection. Furthermore, in-planta gene editing of PsbSs and VDE is conducted respectively. The sequencing results reveal that the mutation rates of edited PsbS1, PsbS2, and VDE were 12.48 %, 13.42 %, and 14.43 % respectively. As a result, the NPQ values with edited PsbSs, VDE, and both are all lower than those of control under high light, indicating that the photoprotective capacity of bamboo leaves is weakened after gene editing. These findings contribute to a deeper understanding of the photoprotection mechanism in bamboo and establish a foundation for breeding new germplasm with enhanced carbon fixation capacity and higher bamboo timber yield.

Macroscale structural changes of thylakoid architecture during high light acclimation in Chlamydomonas reinhardtii.

Photoprotection mechanisms are ubiquitous among photosynthetic organisms. The photoprotection capacity of the green alga Chlamydomonas reinhardtii is correlated with protein levels of stress-related light-harvesting complex (LHCSR) proteins, which are strongly induced by high light (HL). However, the dynamic response of overall thylakoid structure during acclimation to growth in HL has not been fully understood. Here, we combined live-cell super-resolution microscopy and analytical membrane subfractionation to investigate macroscale structural changes of thylakoid membranes during HL acclimation in Chlamydomonas. Subdiffraction-resolution live-cell imaging revealed that the overall thylakoid structures became thinned and shrunken during HL acclimation. The stromal space around the pyrenoid also became enlarged. Analytical density-dependent membrane fractionation indicated that the structural changes were partly a consequence of membrane unstacking. The analysis of both an LHCSR loss-of-function mutant, npq4 lhcsr1, and a regulatory mutant that over-expresses LHCSR, spa1-1, showed that structural changes occurred independently of LHCSR protein levels, demonstrating that LHCSR was neither necessary nor sufficient to induce the thylakoid structural changes associated with HL acclimation. In contrast, stt7-9, a mutant lacking a kinase of major light-harvesting antenna proteins, had a slower thylakoid structural response to HL relative to all other lines tested but still showed membrane unstacking. These results indicate that neither LHCSR- nor antenna-phosphorylation-dependent HL acclimation are required for the observed macroscale structural changes of thylakoid membranes in HL conditions.

Evaluation of the Antioxidant, Photoprotective and Wound Healing Capacity of Guazuma ulmifolia lam. Extracts in L-929 Cells Exposed to UV-A and UV-B Irradiation

The UV irradiation causes the generation of reactive oxygen species in the skin that mediate oxidative damage, favoring photoaging and skin cancer. Photoaging can be mitigated with the use of plants with antioxidant capacity. This study sought to evaluate the photoprotection capacity of two extracts of Guazuma ulmifolia Lam., aqueous (G1) and acetonic (G2), on UV-A and UV-B irradiated L-929 cells, besides the wound healing capacity. In the antioxidant evaluation, it was found that the extracts have great antioxidant potential. In the irradiation tests, G2 increased cell viability by 19.99%. Furthermore, both extracts have shown wound healing capacity. There was a significant restoration of the superoxide dismutase and catalase enzymatic activity by G2 and through ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS), two antioxidant compounds were identified: (epi)catechin and procyanidin. The results showed that the extracts are promising antioxidants, and may collaborate in wound healing, with emphasis to G2 which protected cells from UV-A irradiation.

Symbiodiniaceae photophysiology and stress resilience is enhanced by microbial associations

Symbiodiniaceae form associations with extra- and intracellular bacterial symbionts, both in culture and in symbiosis with corals. Bacterial associates can regulate Symbiodiniaceae fitness in terms of growth, calcification and photophysiology. However, the influence of these bacteria on interactive stressors, such as temperature and light, which are known to influence Symbiodiniaceae physiology, remains unclear. Here, we examined the photophysiological response of two Symbiodiniaceae species (Symbiodinium microadriaticum and Breviolum minutum) cultured under acute temperature and light stress with specific bacterial partners from their microbiome (Labrenzia (Roseibium) alexandrii, Marinobacter adhaerens or Muricauda aquimarina). Overall, bacterial presence positively impacted Symbiodiniaceae core photosynthetic health (photosystem II [PSII] quantum yield) and photoprotective capacity (non-photochemical quenching; NPQ) compared to cultures with all extracellular bacteria removed, although specific benefits were variable across Symbiodiniaceae genera and growth phase. Symbiodiniaceae co-cultured with M. aquimarina displayed an inverse NPQ response under high temperatures and light, and those with L. alexandrii demonstrated a lowered threshold for induction of NPQ, potentially through the provision of antioxidant compounds such as zeaxanthin (produced by Muricauda spp.) and dimethylsulfoniopropionate (DMSP; produced by this strain of L. alexandrii). Our co-culture approach empirically demonstrates the benefits bacteria can deliver to Symbiodiniaceae photochemical performance, providing evidence that bacterial associates can play important functional roles for Symbiodiniaceae.

Microplastics elicit an immune-agitative state in coral

Microplastic pollution in the ocean is a major problem, as its pervasiveness elicits concerns the health impacts microplastics may have on marine life (such as reef-building corals). As a primary endpoint, the organismal lipidome can define the weakening of fitness and reveal the physiological context of adverse health effects in organisms. To gain insight into the effects of microplastics on coral health, lipid profiling was performed via an untargeted lipidomic approach on the coral Turbinaria mesenterina exposed to ~10 μm polystyrene microparticles for 10 days. Considerable microplastic accumulation and obvious effects relating with immune activation were observed in the coral treated with a near environmentally relevant concentration of microplastics (10 μg/L); however, these effects were not evident in the high level (100 μg/L) treatment group. In particular, increased levels of membrane lipids with 20:4 and 22:6 fatty acid chains reallocated from the triacylglycerol pool were observed in coral host cells and symbiotic algae, respectively, which could upregulate immune activity and realign symbiotic communication in coral. High levels of polyunsaturation can sensitize the coral cell membrane to lipid peroxidation and increase cell death, which is of greater concern; additionally, the photoprotective capacity of symbiotic algae was compromised. As a result, coral physiological functions were altered. These results show that, realistic levels of microplastic pollution can affect coral health and should be a concern.

Guijing2501 (Citrus unshiu) Has Stronger Cold Tolerance Due to Higher Photoprotective Capacity as Revealed by Comparative Transcriptomic and Physiological Analysis and Overexpression of Early Light-Induced Protein

Cold is one of the major limiting factors for citrus production, particularly extreme cold waves. Therefore, it is of great importance to develop cold-tolerant varieties and clarify their cold tolerance mechanisms in citrus breeding. In this study, comparative transcriptomic and physiological analyses were performed to dissect the cold tolerance mechanism of Guijing2501 (GJ2501), a new satsuma mandarin (Citrus unshiu) variety with about 1 °C lower LT50 (the median lethal temperature) relative to Guijing (GJ). The physiological analysis results revealed that GJ2501 is more cold-tolerant with less photoinhibition, PSII photodamage, and MDA accumulation, but higher POD activity than GJ under cold stress. Comparative transcriptomic analysis identified 4200 DEGs between GJ and GJ2501, as well as 4884 and 5580 up-regulated DEGs, and 5288 and 5862 down-regulated DEGs in response to cold stress in GJ and GJ2501, respectively. “Photosynthesis, light harvesting” and “photosystem” were the specific and most significantly enriched GO terms in GJ2501 in response to cold stress. Two CuELIP1 genes (encoding early light-induced proteins) related to the elimination of PSII photodamage and photoinhibition were remarkably up-regulated (by about 1000-fold) by cold stress in GJ2501 as indicated by RT-qPCR verification. Overexpression of CuELIP1 from GJ2501 in transgenic Arabidopsis protected PSII against photoinhibition under cold stress. Taken together, the cold tolerance of GJ2501 may be ascribed to its higher photoprotective capacity under cold stress.

A Comparative Study between Onion Peel Extracts, Free and Complexed with β-Cyclodextrin, as a Natural UV Filter to Cosmetic Formulations

The growing concern regarding the adverse effects of synthetic UV filters found in sunscreens has spurred significant attention due to their potential harm to aquatic ecosystems and human health. To address this, the present study aimed to extract and microencapsulate sensitive bioactive compounds derived from by-product onion peel (OP) by molecular inclusion using β-cyclodextrin as the wall material. Identification and quantification of bioactive compounds within the extract were conducted through high-performance liquid chromatography (HPLC-DAD) analysis, revealing quercetin and resveratrol as the primary constituents. The photoprotection capacity, evaluated by the sun protection factor (SPF), revealed a protection factor comparable to the value for a synthetic UV filter. The produced microparticles presented high antioxidant capacity, significant photoprotection capacity, encapsulation efficiency of 91.8%, mean diameter of 31 μm, and polydispersity of 2.09. Furthermore, to comprehensively evaluate the performance of OP extract and its potential as a natural UV filter, five O/W emulsions were produced. Results demonstrated that microparticles displayed superior ability in maintaining SPF values over a five-week period. Photoprotection evaluation–skin reactivity tests revealed that both extract and microparticles absorb UV radiation in other regions of UV radiation, revealing their potential to be used as a natural UV filter to produce a sustainable and eco-friendly value-added sunscreen.

Comparation of the Aqueous Extraction Methods of the Tarenaya Aculeata Leaves in Relation to the Chemical Composition and Photoprotector, Antibacterial and Antioxidant Potentials

Medicines and cosmetics based on natural products have been in demand since ancient times. This study aimed to compare extracts and fractions of T. aculeata, obtained by different extraction methods, in addition to evaluating the antioxidant, antibacterial and photoprotective capacity of the samples. The chemical differentiation of the content different extracts and fractions were evaluated using statistical programs and the levels of phenolic compounds and tannins were evaluated using spectroscopic methods. The results of the statistical analysis showed greater similarity in the extracts obtained by the infusion and decoction methods. The toxicity assay by Artemia Salina showed that the aqueous extracts obtained by all methodologies are non-toxic, promising for its use as a cosmetic, and antioxidant activity was more evident for the fractions. Broad-spectrum antibacterial activity was attributed to both extracts and fractions. In order to obtain a sustainable photoprotective product, the aqueous extracts were selected and incorporated into a commercial cream in order to obtain a multifunctional product, the aqueous extract obtained by the infusion method being the one that presented the best sun protection factor results (17.27), with good results of stability.

Determination of Photoprotective Capacity of Topical Gel Formulations Containing Bioactive Compound Rutin and Evaluation of Physicochemical Stability

Determination of Photoprotective Capacity of Topical Gel Formulations Containing Bioactive Compound Rutin and Evaluation of Physicochemical Stability

Brassinolide alleviated drought stress faced by bulbil formation of Pinellia ternata by reducing ROS metabolism and enhancing AsA-GSH cycle

Drought occurs frequently because of global climate change. The involvement of brassinolide (BR) in regulating plant tolerance to stress is one of its research hotspots. Bulbil formation and development of Pinellia ternata is the key to its yield formation. However, drought in spring and waterlogging in summer often occur in the bulbil development process, which seriously affects the yield and quality of P. ternata. The study investigated the effects of BR and BR biosynthesis inhibitors (propiconazole, PCZ) on formation and growth of P. ternata bulbil under spring drought and rehydration condition. The results showed that BR treatment improved the biomass of P. ternata by increasing the bulbils formation, tillers numbers, and fresh weight of bulbils, tuber, steam and leaf when compared with control or PCZ groups both in drought and rehydration condition. Compared with the control or PCZ groups, BR application significantly elevated the photosynthetic pigment contents, PSⅡ photoprotective capacity, osmosis-regulating substance levels, and active ingredients contents in P. ternata both in drought and rehydration conditions, which promoted the growth of P. ternata. In addition, BR application enhanced antioxidant contents (AsA, GSH, AsA/DHA ratio, GSH/GSSG ratio) and enzymes activities (SOD, APX, DHAR, MDHAR), but reduced the levels of membrane lipid peroxidation and reactive oxygen in P. ternata both in drought and rehydration conditions. This study revealed that BR application could help P. ternata to cope with the drought stress during bulbil formation periods by improving AsA-GSH cycle and diminishing ROS damage.

A new isoflavonoid derivative, evaluation of the antioxidant capacity and phenolic content of Genista lobelii DC

The phytochemical investigation of both chloroform and ethyl acetate extracts of Genista lobelii DC from an Algerian endemic plant led to the isolation of a new isoflavonoid Aspalathoidin compound (1) and nine known compounds (laburnetin, isokaempferide, retamasin B, ephedrodin, sakuretin, isoprunetin, genistein −7-O-β-glucoside, derrone-4′-O-methyl ether and eriodictyol-7,3′-dimethylether). Twelve phenolic compounds were identified in ethyl acetate and n-butanol extracts through a qualitative investigation of phenolic compounds using HPLC. Finally, both extracts were estimated for their phenolic and flavonoid contents as well as the evaluation of their antioxidant activity using five different assays DPPH, CUPRAC, ABTS, GOR and the sun protection factor SPF was determined as an index of the photoprotective capacity of the G.lobelii DC extracts. The extract of chloroform and ethyl acetate has good antioxidant and includes significant levels of phenolic and flavonoid components.

Integrating Non-photochemical Quenching (NPQ) Measurements for Identifying Flood-Tolerant Soybean Genotypes in the Era of Climate Change

Climate change has negatively affected agriculture worldwide, including soybean production. Studies have shown that rising temperatures and extreme weather events like droughts and floods significantly reduce soybean yields. Developing flood-tolerant soybean genotypes is crucial for ensuring food security. Conventional breeding programs are limited by laborious and imprecise visual rating methods for flooding tolerance identification. High-throughput platforms for plant phenotyping using imaging techniques offer potential solutions, but they lack information on underlying physiological mechanisms. Non-photochemical quenching (NPQ) is a molecular adaptation in photosynthesis that dissipates excess light energy, protecting plants from damage. This study aimed to integrate NPQ measurements into high-throughput phenotyping procedures to identify flooding-tolerant soybean genotypes. The study evaluated 160 soybean genotypes for flooding tolerance, identifying those with higher grain yield potential. Subsequently, ten genotypes were selected for monitoring NPQ responses under flooded conditions. Results showed that genotypes with higher grain yields also exhibited superior NPQ performance, suggesting a positive correlation between flooding tolerance and energy dissipation capacity. Among these genotypes, 58I60 RSF IPRO, 64HO130 I2X and BRS 525 displayed superior potential and could be further exploited in breeding efforts, considering their grain yield capacity, plant leaf area, and photoprotective capacity under flooding conditions. These findings suggest that integrating NPQ measurements into high-throughput phenotyping platforms can aid in identifying flood-tolerant soybean genotypes for breeding programs, leading to more resilient crops in the face of climate change. Further field studies are warranted to validate these hypotheses and improve crop models for future climate scenarios.