Enhanced Antioxidant Enzyme Activities Research Articles

Integrative physiological, transcriptome, and metabolome analysis uncovers the drought responses of two Zanthoxylum bungeanum cultivars

Zanthoxylum bungeanum (ZB) is a medicinal plant that is widely cultivated in arid and semi-arid areas. The drought tolerance mechanism of ZB has not yet been clearly elucidated. Here, the physiological indicators, transcriptome, and metabolome of two ZB cultivars with contrasting drought tolerance (FJ, Z. bungeanum cv. ‘Fengjiao’; HJ, Z. bungeanum cv. ‘Hanjiao’) were analyzed under drought stress. The results showed that HJ was more tolerant to drought stress, with stronger antioxidant enzyme activities, higher contents of soluble sugar, soluble protein and proline as well as lower content of malondialdehyde and H2O2. Transcriptome analysis revealed that there were more differentially expressed genes in FJ than in HJ throughout the drought treatment. Metabolome analysis identified 911 metabolites, which were divided into 10 classes. The up-regulated metabolites in HJ were mainly amino acids and their derivatives and flavonoids; those in FJ were mainly amino acids and their derivatives and alkaloids. Candidate structural genes related to drought tolerance and key transcription factor genes involved in drought-response pathways were sheltered by weighted gene co-expression network analysis (WGCNA). Conjoint analysis of the transcriptome and metabolome emphasized the importance of respiration metabolism in enhancing drought tolerance. In general, HJ improves drought tolerance by enhancing antioxidant enzyme activities; increasing the intensity of the pentose phosphate pathway; promoting the accumulation of osmotic substances; stimulating the synthesis of abscisic acid, brassinosteroid, and heat shock proteins; and accelerating signal transduction. The results improve our understanding of the molecular mechanism of drought tolerance in ZB and provide new insights for molecular breeding of ZB as well as other crops.

Deep placement of liquid fertilizer at tillering stage influences grain quality, 2-acetyl-1-pyrroline synthesis, and antioxidant response of fragrant rice

In recent years, the deep placement of solid fertilizers has become popular in rice production due to high fertilizer utilization efficiency and productivity. There is limited knowledge about the effect of deep placement of liquid fertilizer at the tillering stage on grain quality and productivity of fragrant rice. Therefore, a two-year field experiment was conducted from 2019 to 2020 with two fragrant rice cultivars Yuxiangyouzhan (YXYZ) and Xiangyaxiangzhan (XYXZ) under four fertilization treatments: no fertilizer application (T1); application of solid fertilizer (150 kg ha −1 NPK; broadcasted 90 kg ha −1 NPK as basal fertilizer and 60 kg ha −1 NPK at the tillering stage, T2); application of liquid fertilizer with 10 % less N (broadcasted 90 kg ha −1 NPK as basal fertilizer and deeply placed 45 kg ha −1 N and 90 kg ha −1 PK at the tillering stage, T3); application of liquid fertilizer with 20 % less N (broadcasted 90 kg ha −1 NPK as basal fertilizer and deeply placed 30 kg ha −1 N and 90 kg ha −1 PK at the tillering stage, T4). The study showed the highest 2-acetyl-1-pyrroline (2AP) content under T3 treatment (2019, 115.35–120.11 μg kg −1 and 112.97–130.30 μg kg −1 , 2020). The proline (PRO) content, proline dehydrogenase (PDH) activity, 1-pyrrolin-5-carboxylic acid (P5C) content, and 1-pyrrolin-5-carboxylic acid synthase (P5CS) activity also improved under T3 and T4 treatments compared with T2 treatment. Besides, the T3 and T4 treatments increased the protein content and decreased the chalkiness degree and chalky rice rate compared with the T2 treatment. Moreover, T3 and T4 treatments improved the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities and reduced the malondialdehyde (MDA) content of the leaves compared with the T2 treatment. Further, the structural equation model revealed that POD and CAT and rice appearance quality had significant positive effects on 2AP content, and that POD and CAT indirectly affected 2AP content by showing a significant positive effect on the PRO. The T3 treatment also showed relatively stable and higher head rice yield and net income in the two-year field experiment. Overall, side deep placement of liquid fertilizer improved the 2AP synthesis, and antioxidant response of fragrant rice and under T3 treatment, the head rice yield was stable and the economic income was higher. Therefore, in the future of agricultural production, it is recommended that farmers use liquid fertilizer with 10 % less N (T3) to improve the quality and stress resistance of fragrant rice and obtain stable and more economic benefits. • Deep placement of liquid fertilizer at tillering stage improved 2-acetyl-1-pyrroline and grain quality of fragrant rice. • Deep placement of liquid fertilizer at tillering stage enhanced antioxidant enzyme activities in leaves of fragrant rice. • The relationship among antioxidant response, 2-acetyl-1-pyrroline, and grain quality in fragrant rice were interpreted. • Optimization of deep placement of liquid fertilizer at the tillering stage yield higher economic income.

Treatment effects of phosphorylated Chrysanthemum indicum polysaccharides on duck viral hepatitis by protecting mitochondrial function from oxidative damage

To define the underlying mechanism of the beneficial role of Chrysanthemum indicum polysaccharides (CIPS) and phosphorylated Chrysanthemum indicum polysaccharides (pCIPS) in duck viral hepatitis (DVH), we evaluated the protective effects of the CIPS and pCIPS against DVH in terms of antioxidation and mitochondrial function. Fluorescence probes and several assay kits were used to determine the oxidative stress and mitochondrial dysfunction in vitro and vivo. Additionally, transmission electron microscopy was applied to observe the changes of mitochondrial ultrastructure in the liver tissue. Our results indicate that the CIPS and pCIPS significantly enhanced the survival of duck hepatitis A virus type 1 (DHAV-1) infected ducklings. Moreover, the CIPS and pCIPS suppressed oxidative stress and preserved mitochondrial function, such as enhanced antioxidant enzyme activity, increased ATP production, and stabilized mitochondrial membrane potential (MMP). Meanwhile, the results of hematoxylin-eosin (HE) staining and serum biochemical examination demonstrated that treatment with the CIPS and pCIPS could decrease focal necrosis and infiltration of inflammatory cells, which in turn reducing liver injury. Furthermore, the CIPS and pCIPS were able to preserve liver mitochondrial membrane integrity in DHAV-1 challenged ducklings. Notably, the pCIPS was significantly outperformed the CIPS on all measures of liver and mitochondrial function. These results suggested that mitochondrial homeostasis plays an important role in alleviating oxidative damage in the livers, and the hepatocyte protective effects of the CIPS were enhanced after phosphorylation modification.

Sodium hydrosulfide alleviates aluminum toxicity in Brassica napus through maintaining H2S, ROS homeostasis and enhancing aluminum exclusion

Hydrogen sulfide (H2S) is a gaseous mediator that plays versatile roles in plant growth and stress responses. However, the regulatory functions of H2S in plant responses to aluminum (Al) stress remain elusive. We observed that application of 20 μM of NaHS (H2S donor) or 0.2 mM of hypotaurine (HT, H2S scavenger) significantly mitigated the inhibition of rapeseed root growth caused by Al stress (150 μM). Exposure to Al for 6 h induced significant H2S accumulation and high levels were maintained thereafter, owing to the elevation of cysteine (83.73 %), L-cysteine desulfhydrase (LCD, 92.32 %), and cyanoalanine synthase (CAS, 11.23 %), and the inhibition of O-Acetyl-l-serine (thiol) lyase (OAS-TL, 15.13 %). Addition of HT significantly scavenged the prolonged H2S accumulation caused by Al stress. Exogenous NaHS maintained the H2S homeostasis through increasing OAS-TL activity (34.99 %) and inhibiting LCD activity (25.72 %), and cysteine level (39.53 %). Moreover, exogenous NaHS mitigated oxidative damage by enhancing antioxidant enzyme activity (SOD 26.27 %, POD 28.62 %, CAT 400.5 % and APX 92.68 %) and proline content (19.85 %). It also decreased root cell wall Al accumulation (20.52 %) by decreasing PME activity (24.64 %) and facilitating pectin methylation (16.74 %). Similar alleviative effects were observed when HT was added. These results suggest that H2S functions differential roles in Al stress response in rapeseed seedlings, depending on its local concentration and duration. Prolonged high H2S emissions might contribute to Al toxicity, while moderate exogenous H2S improves Al tolerance through controlling H2S and ROS accumulation and enhancing Al exclusion through replenishing antioxidant reservoirs and facilitating pectin methylation. It is therefore important that further study investigates how to orchestrate endogenous H2S levels and improve plant stress tolerance.

English

Sewage sludge is used as fertiliser and contains nutrients required for plant growth. It also contains contaminants that can leach into crops. The effects of sewage sludge on kale plants were investigated. Mixture ratios of 50:50 and 20:80 for soil and sludge were prepared. The soil-sludge blends were analysed for selected metal residues. Kale seedlings of 10-13 cm were planted on the different soil-sludge combinations. Leaf lengths were measured 21 days post transplanting for four weeks. After sixty days, the leaves were analysed for metal residue levels and antioxidant enzyme activities. The results showed higher metal concentrations in soil blended with industrial sludge than in soil mixed with domestic sludge. The highest growth of plants was observed after 28 days in plants grown on 50% soil-industrial sludge mixtures. Superoxide dismutase and glutathione peroxidase activities were higher in plants grown on soil applied with sewage sludge when compared to enzyme activities in plants grown on sludge-free soil. The high levels of metals and enhanced antioxidant enzyme activity observed were attributed to the contaminants in the sewage sludge. Preassessment of sewage sludge to be used as soil manure is recommended to safeguard the health of plants and, indirectly, humans who consume the crops.    Key words: Sewage sludge, metals, pollutants, plants.

Overexpression of Asr6, abscisic acid stress-ripening protein, enhances drought tolerance and modulates gene expression in rice (Oryza sativa L.)

Rice ( Oryza sativa L.), being a paddy crop, is particularly susceptible to drought, reducing its yield drastically. Abscisic acid stress-ripening proteins (Asr) are a family of plant-specific ABA-induced low molecular weight hydrophilic proteins encoded by the stress-regulated gene. This work substantiates the biological role of rice Asr6 against drought stress by its overexpression in rice. The Asr6 overexpressing (OE) lines showed better overall growth than wild-type (WT) plants reflected by their longer shoot length with higher biomass and enhanced density of the lateral roots. The decreased level of MDA and electrolyte leakage, higher proline content, less ROS accumulation, and enhanced antioxidant enzyme activities (SOD, APX, and CAT) were observed in OE lines as compared to WT plants during drought stress. The OE lines showed better recovery than WT plants after drought stress at the reproductive stage, in the terms of the increased number of panicles and total grain yields. The transcriptome analysis revealed that Asr6 regulates the expression of a wide spectrum of genes related to hormone metabolism, stress (abiotic and biotic), transcription factors, antioxidant activity, photosynthesis, signalling, transport and secondary metabolites. Interestingly, the genes related to jasmonic acid biosynthesis (up-regulation of LOX and AOS) and signalling (up-regulation of COI1 and down-regulation of JAZ proteins) were differentially expressed in OE lines, which were further validated by qRT-PCR analysis. Our findings demonstrate, Asr6 to be a positive regulator commonly involved in tolerance to drought stress and may regulate a novel JA-dependent signalling pathway in rice for drought tolerance. • Overexpression of Asr6 can improve drought stress tolerance in rice. • Asr6 promotes lateral root growth leading to higher root biomass as compared to wild type plants under drought condition. • Asr6 transgenic rice maintains redox homeostasis on exposure to drought. • Asr6 alters the expression of jasmonic acid biosynthesis and signalling pathway genes.

Neuroprotective Effect of Polyphenol Extracts from Terminalia chebula Retz. against Cerebral Ischemia-Reperfusion Injury.

Current therapies for ischemic stroke are insufficient due to the lack of specific drugs. This study aimed to investigate the protective activity of polyphenol extracts from Terminalia chebula against cerebral ischemia-reperfusion induced damage. Polyphenols of ethyl acetate and n-butanol fractions were extracted from T. chebula. BV2 microglial cells exposed to oxygen-glucose deprivation/reoxygenation and mice subjected to middle cerebral artery occlusion/reperfusion were treated by TPE and TPB. Cell viability, cell morphology, apoptosis, mitochondrial membrane potential, enzyme activity and signaling pathway related to oxidative stress were observed. We found that TPE and TPB showed strong antioxidant activity in vitro. The protective effects of TPE and TPB on cerebral ischemia-reperfusion injury were demonstrated by enhanced antioxidant enzyme activities, elevated level of the nucleus transportation of nuclear factor erythroid 2-related factor 2 and expressions of antioxidant proteins, with a simultaneous reduction in cell apoptosis and reactive oxygen species level. In conclusion, TPE and TPB exert neuroprotective effects by stimulating the Nrf2 signaling pathway, thereby inhibiting apoptosis.

Effect of exogenous melatonin on antioxidant enzyme activities and membrane lipid peroxidation in avocado fruit during ripening

Melatonin functions as a plant growth regulator, has diverse functions and plays an important role in ripening and fruit senescence. In the current study, we investigated the effect of exogenous melatonin (0.1 mM and 0.5 mM) on reactive oxygen species (ROS) metabolism, membrane lipid peroxidation and antioxidant enzyme activity of avocado (Persea americana Mill. cv. 034) during fruit ripening at 22oC ± 1 and 75-80% relative humidity (RH). The results showed that postharvest fruits treated with 0.5 mM melatonin effectively reduced the accumulation of superoxide anion (O2.), hydrogen peroxide (H2O2) and malondialdehyde (MDA) in the mesocarp of the fruit. In addition, melatonin treatment also significantly promoted the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in avocado. It is suggested that enhanced antioxidant enzyme activity induced by melatonin treatment may contribute to scavenge ROS and alleviating membrane lipid peroxidation in avocado fruit. The results indicate that the MT application might collectively contribute to the delay senescence and maintain postharvest quality of avocado.

Effects of Chitosan Oligosaccharide on Production Performance, Egg Quality and Ovarian Function in Laying Hens with Fatty Liver Syndrome.

Simple SummaryFatty liver syndrome (FLS) often occurs in caged laying hens and can cause decreases in production performance. Chitosan oligosaccharide (COS), degraded from chitin or chitosan, has been demonstrated to prevent metabolic diseases in rodents. In this work, we found that dietary COS supplementation could improve production performance and egg quality in laying hens with FLS. Further study indicated that improved ovarian morphology and function may be involved in these beneficial effects of COS. Specifically, dietary COS supplementation decreased oxidative stress, inflammation and apoptosis in the ovaries of laying hens with FLS. This study provides evidence for the application of COS to improve production performance and egg quality in laying hens with FLS.This study aimed to investigate the role of chitosan oligosaccharide (COS) as an additive in the feed of laying hens with fatty liver syndrome (FLS). Effects on production performance, egg quality as well as ovarian function were determined. A total of 360 Lohmann Pink-shell laying hens (28 weeks old) were randomly assigned to 5 groups (6 replicates × 12 birds). Hens were fed with a basal diet and a high-energy low-protein (HELP) diet supplemented with 0, 200, 400 and 800 mg/kg COS. COS reversed the lowered laying rates, increased feed-to-egg ratios and decreased albumen heights and Haugh units induced by the HELP diet. Additionally, COS improved the ovarian morphologies damaged by the HELP diet. Furthermore, COS enhanced antioxidant enzyme activities, reduced malonaldehyde levels and downregulated the mRNA expressions of nuclear factor kappa B, pro-inflammation cytokine genes and pro-apoptosis-related genes, while it upregulated the mRNA expression of anti-apoptosis-related genes in the ovaries of HELP-diet-fed hens. These findings suggested that dietary COS supplementation could improve production performance and egg quality in laying hens with FLS, and these beneficial effects were linked to improved ovarian morphology, which was attributed to decreased oxidative stress, inflammation and apoptosis in the ovaries.

Physiological and Biochemical Regulation Mechanism of Exogenous Hydrogen Peroxide in Alleviating NaCl Stress Toxicity in Tartary Buckwheat (Fagopyrum tataricum (L.) Gaertn).

We aimed to elucidate the physiological and biochemical mechanism by which exogenous hydrogen peroxide (H2O2) alleviates salt stress toxicity in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn). Tartary buckwheat “Chuanqiao-2” under 150 mmol·L−1 salt (NaCl) stress was treated with 5 or 10 mmol·L−1 H2O2, and seedling growth, physiology and biochemistry, and related gene expression were studied. Treatment with 5 mmol·L−1 H2O2 significantly increased plant height (PH), fresh and dry weights of shoots (SFWs/SDWs) and roots (RFWs/RDWs), leaf length (LL) and area (LA), and relative water content (LRWC); increased chlorophyll a (Chl a) and b (Chl b) contents; improved fluorescence parameters; enhanced antioxidant enzyme activity and content; and reduced malondialdehyde (MDA) content. Expressions of all stress-related and enzyme-related genes were up-regulated. The F3′H gene (flavonoid synthesis pathway) exhibited similar up-regulation under 10 mmol·L−1 H2O2 treatment. Correlation and principal component analyses showed that 5 mmol·L−1 H2O2 could significantly alleviate the toxic effect of salt stress on Tartary buckwheat. Our results show that exogenous 5 mmol·L−1 H2O2 can alleviate the inhibitory or toxic effects of 150 mmol·L−1 NaCl stress on Tartary buckwheat by promoting growth, enhancing photosynthesis, improving enzymatic reactions, reducing membrane lipid peroxidation, and inducing the expression of related genes.

Optimization of Sonication Parameters to Produce a Cashew Apple Bagasse Puree Rich in Superoxide Dismutase

The effects of ultrasound processing parameters on the extraction of antioxidative enzymes and a toxicity assessment of cashew apple bagasse puree were investigated. Ultrasound directly affects the formation of reactive oxygen species such as H2O2, and consequently, superoxide dismutase, catalase, and ascorbate peroxidase activities. S.O.D. activity increased up to 280% after U.S. processing at 75 W/cm2, 1:3 bagasse: water ratio, and 10 min compared to non-processed bagasse. Therefore, the effect of ultrasound in delaying browning could be correlated to the enhanced antioxidant enzyme activity and decrease in peroxidase activity. At center point conditions (226 W/cm2, 1:3 bagasse: water ratio; 6 min), a decrease of 20% and 50% on POD and PPO activities was observed, respectively. No significant acute toxicity or protective effect was observed in unprocessed and sonicated cashew apple bagasse. Although cashew bagasse processed at 75 W/cm2 prevented nauplii death after 24 h of exposure, this data cannot assure the protective effect once the number of dead nauplii on 100 μg/mL was similar. However, these data indicate a possible protective effect, especially in higher cashew bagasse concentrations. The results suggest that sonicated cashew apple bagasse puree, a coproduct obtained from a traditional valued fruit in Brazil, may be used as a source of antioxidative enzymes, which further has great importance in therapeutics.

Endophytic fungus Serendipita indica accelerates ascorbate-glutathione cycle of white clover in response to water stress.

Ascorbate-glutathione cycle is an important pathway for plants to scavenge reactive oxygen species (ROS) under environmental stress conditions. The objective of this study was to investigate the effects of the endophytic fungus Serendipita indica on biomass, chlorophyll concent, ROS levels, antioxidant enzyme activities, and ascorbate-glutathione cycle in white clover under ample water and water stress conditions. The results showed that 46 days of soil water stress distinctly promoted root colonization by S. indica. Under water stress, S. indica inoculation significantly promoted shoot and root biomass, total chlorophyll content, and activities of superoxide dismutases (SOD; e.g., Fe-SOD and Cu/Zn-SOD) and peroxidase in roots, coupled with a decrease in malondialdehyde content in roots. In the ascorbate-glutathione cycle of roots, S. indica also significantly increased the activity of ascorbate peroxidase and glutathione reductase activities in water-stressed white clover, along with the increase in reduced ascorbic acid and reduced/oxidized glutathione contents, thus accelerating the ascorbate-glutathione cycle in inoculated plants to scavenge more ROS (e.g., hydrogen peroxide). As a result, S. indica enhanced the tolerance of white clover in response to water stress by enhancing antioxidant enzyme activities and accelerating the ascorbate-glutathione cycle.

Physiological and Biochemical Responses of Pepper (Capsicum annuum L.) Seedlings to Nickel Toxicity.

Globally, heavy metal pollution of soil has remained a problem for food security and human health, having a significant impact on crop productivity. In agricultural environments, nickel (Ni) is becoming a hazardous element. The present study was performed to characterize the toxicity symptoms of Ni in pepper seedlings exposed to different concentrations of Ni. Four-week-old pepper seedlings were grown under hydroponic conditions using seven Ni concentrations (0, 10, 20, 30, 50, 75, and 100 mg L–1 NiCl2. 6H2O). The Ni toxicity showed symptoms, such as chlorosis of young leaves. Excess Ni reduced growth and biomass production, root morphology, gas exchange elements, pigment molecules, and photosystem function. The growth tolerance index (GTI) was reduced by 88-, 75-, 60-, 45-, 30-, and 19% in plants against 10, 20, 30, 50, 75, and 100 mg L–1 Ni, respectively. Higher Ni concentrations enhanced antioxidant enzyme activity, ROS accumulation, membrane integrity [malondialdehyde (MDA) and electrolyte leakage (EL)], and metabolites (proline, soluble sugars, total phenols, and flavonoids) in pepper leaves. Furthermore, increased Ni supply enhanced the Ni content in pepper’s leaves and roots, but declined nitrogen (N), potassium (K), and phosphorus (P) levels dramatically. The translocation of Ni from root to shoot increased from 0.339 to 0.715 after being treated with 10–100 mg L–1 Ni. The uptake of Ni in roots was reported to be higher than that in shoots. Generally, all Ni levels had a detrimental impact on enzyme activity and led to cell death in pepper seedlings. However, the present investigation revealed that Ni ≥ 30 mg L–1 lead to a deleterious impact on pepper seedlings. In the future, research is needed to further explore the mechanism and gene expression involved in cell death caused by Ni toxicity in pepper plants.

Evaluating the effect of pre-storage application with 1-methyle cyclopropene and salicylic acid for enhancing antioxidant enzyme activity and quality of Date palm fruits during cold storage.

Evaluating the effect of pre-storage application with 1-methyle cyclopropene and salicylic acid for enhancing antioxidant enzyme activity and quality of Date palm fruits during cold storage.

Autophagy and Programmed Cell Death Are Critical Pathways in Jasmonic Acid Mediated Saline Stress Tolerance in Oryza sativa.

Saline stress is the most limiting condition impacting the plant growth, development, and productivity. In this present study, jasmonic acid (JA) was used as a foliar spray on the rice seedlings grown under saline stress. Increase in photosynthetic pigments, anthocyanin, and total protein content was observed with JA treatment while NaCl showed reduction in biochemical constituents and enhanced antioxidant enzyme activity. The leaf cells of NaCl-treated seedlings accumulated more ROS and had more fragmented nuclei, whereas JA decreased the accumulation and fragmentation during saline stress. In NaCl treatment, gene expression analysis showed many fold upregulation in comparison with other treatments. The results suggest that JA acts as a promoter for growth, physiological, biochemical, and cellular contents, as well as ameliorate the effects of saline stress. The expression of genes demonstrated that saline stress may promote autophagy, which leads to autophagic cell death, and improve tolerance to saline stress in rice seedlings via the jasmonic acid signaling pathway. However, the mechanism by which jasmonate signaling induces autophagy and cell death is unknown and requires further exploration.

PACLOBUTRAZOL DEPENDENT SALT TOLERANCE IS RELATED TO CLC1 AND NHX1 GENE EXPRESSION IN SOYBEAN PLANTS

Paclobutrazol (PBZ) enhances plant resistance to salt stress in two ways: directly, by straight clearance of reactive oxygen species; and indirectly by enhancing antioxidant enzyme activity, photosynthetic efficiency, and metabolite content, and by regulating transcription factors associated with stress. However, the regulatory effects of PBZ under salt stress in soybean are still not well explained and need further investigation. With this aim, the combination effect of salinity (250 mM NaCl) and three different doses of PBZ (5, 10 and 20 ppm) on physiological, biochemical and molecular traits of soybean (Glycine max L.) leaves were studied in soil experiments. Furthermore, physiological parameters (relative growth rate, relative water content), chlorophyll, malondialdehyde (MDA), hydrogen peroxide (H2O2) content and as well as enzymatic antioxidants (SOD, POX, APX, CAT and GST), ion content (Na, Cl) and soybean Na+/H+ antiporter GmNHX1 and chloride channel GmCLC1 gene expressions were investigated. The results showed that PBZ caused a reduction in salt-induced damages and an increase in biomass yield, water status, and chlorophyll. Moreover, PBZ regulated enzymatic antioxidants and alleviated the oxidative damages under salinity. In this study, for a first time it was determined that PBZ increased both GmNHX1 (ABA dependent or independent) and GmCLC1 (ABA independent) gene expressions and reduced Na and Cl concentrations in soybean under salinity. In conclusion, PBZ plays a role as a regulator and stimulant in salt stress response by mostly regulating ion balance in soybean leaves.

Effects of Light Spectra on Morphology, Gaseous Exchange, and Antioxidant Capacity of Industrial Hemp.

One of the most important growth factors in cannabis cultivation is light which plays a big role in its successful growth. However, understanding that how light controls the industrial hemp growth and development is poor and needs advanced research. Therefore, a pot study was conducted to investigate the effects of different colors of light, that is, white light (WL), blue light (BL), red light (RL), and 50% red with 50% blue mix light (RBL) on morphology, gaseous exchange and antioxidant capacity of industrial hemp. Compared with WL, BL significantly increase hemp growth in terms of shoot fresh biomass (15.1%), shoot dry biomass (27.0%), number of leaves per plant (13.7%), stem diameter (10.2%), root length (6.8%) and chlorophyll content (7.4%). In addition, BL promoted net photosynthesis, stomatal conductance, and transpiration, while reduces the lipid peroxidation and superoxide dismutase and peroxidase activities. However, RL and RBL significantly reduced the plant biomass, gas exchange parameters with enhanced antioxidant enzymes activities. Thus, blue light is useful for large-scale sustainable production of industrial hemp.

Hydrogen sulfide alleviates chilling injury in peach fruit by maintaining cell structure integrity via regulating endogenous H2S, antioxidant and cell wall metabolisms

Effects of hydrogen sulfide (H2S) on chilling injury (CI), H2S, antioxidant and cell-wall metabolisms of refrigerated peaches treated with H2S and hypotaurine (HT, H2S scavenger) were investigated in present study. Results revealed that H2S treatment enhanced endogenous H2S content, which was associated with increased related H2S synthase enzymes activities, while HT showed the opposite results. Moreover, H2S treatment induced the accumulation of ascorbic acid, glutathione and the enhancement of antioxidant enzymes activities compared to control and HT, contributing to lower hydrogen peroxide content and superoxide radical production. Furthermore, H2S suppressed the increase of cell-wall degradation enzymes accompanied by higher levels of water-insoluble pectin, 24% KOH-soluble hemicellulose and cellulose, while HT accelerated these components degradation. Therefore, results indicated that H2S mitigated CI of refrigerated peaches by regulating H2S, antioxidant and cell-wall metabolisms, maintaining higher H2S and antioxidants contents, suppressing cell-wall degradation, thereby contributing to redox homeostasis maintenance and cell structure integrity.

Impact of the Arbuscular Mycorrhizal Fungus Funneliformis mosseae on the Physiological and Defence Responses of Canna indica to Copper Oxide Nanoparticles Stress.

Copper oxide nanoparticles (nano-CuO) are recognized as an emerging pollutant. Arbuscular mycorrhizal fungi (AMF) can mitigate the adverse impacts of various pollutants on host plants. However, AMF’s mechanism for alleviating nano-CuO phytotoxicity remains unclear. The goal of this study was to evaluate how AMF inoculations affect the physiological features of Canna indica seedlings exposed to nano-CuO stress. Compared with the non-AMF inoculated treatment, AMF inoculations noticeably improved plant biomass, mycorrhizal colonization, leaf chlorophyll contents, and the photosynthetic parameters of C. indica under nano-CuO treatments. Moreover, AMF inoculation was able to significantly mitigate nano-CuO stress by enhancing antioxidant enzyme activities and decreasing ROS levels in the leaves and roots of C. indica, thus increasing the expression of genes involved in the antioxidant response. In addition, AMF inoculation reduced the level of Cu in seedlings and was associated with an increased expression of Cu transport genes and metallothionein genes. Furthermore, AMF inoculations increased the expression levels of organic acid metabolism-associated genes while facilitating organic acid secretion, thus reducing the accumulation of Cu. The data demonstrate that AMF–plant symbiosis is a feasible biocontrol approach to remediate nano-CuO pollution.

Impact of summer heat stress inducing physiological and biochemical responses in herbaceous peony cultivars (Paeonia lactiflora Pall.) from different latitudes

As global temperatures continue to rise, heat stress and its severity are projected to advance as a major abiotic stress, seriously limiting the growth and production of herbaceous peony (Paeonia lactiflora Pall.), especially in low-latitude areas. Therefore, determining the ravaging effects of heat stress on the growth and development of herbaceous peony has become a prerequisite for expanding the cultivation area of this world-renowned ornamental crop. Comprehensive research on physiological and biochemical responses to summer heat stress was conducted between low-latitude and midlatitude herbaceous peony cultivars at low latitudes. Field observations showed that the stay-green (SG) duration varied among the cultivars from different latitudes and had a direct correlation with the level of heat damage. As the heat stress intensified, chlorophyll (Chl) contents and Chl fluorescence were decreased in the six cultivars. On the contrary, the relative electrical conductivity (REC) increased sharply, with the low-latitude ‘Hang Baishao’ presenting the lowest REC among the six cultivars before August 15 (with the highest temperatures). Photosynthetic curves showed more sustained photosynthesis in ‘Hang Baishao’, ‘Meiju’ and ‘Bo Baishao’. Based on principal component analysis (PCA) and subordinate function value analysis, ‘Hang Baishao’ was deduced as the most heat-tolerant cultivar, whereas ‘Zhuguang’ as a most heat-sensitive cultivar out of the six cultivars. The oxidative stress analysis between the two cultivars indicated an over-accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) with lower antioxidant enzyme activity in ‘Zhuguang’ than ‘Hang Baishao’. The results imply that heat-tolerant ‘Hang Baisao’ exhibited minimal heat damage and a delayed SG duration based on its enhanced antioxidant enzyme activity and heat acclimation under high-temperature stress. This study could provide insights into the responses and adaptions of peonies to heat stress and aid in the breeding of excellent peonies with improved heat resistance under ever-changing climatic conditions.