Barley Shoots Research Articles

The potential of wild barley (Hordeum vulgare subsp. spontaneum C. Koch.) to improve early shoot and root traits of cultivated barley

The potential of wild barley (Hordeum vulgare subsp. spontaneum C. Koch.) to improve early shoot and root traits of cultivated barley

Registration of Newly Released Hull Less Food Barley (<i>HondiumVulgare L.</i>) Variety, ‘Sena’, for High Potential Barley Growing Areas in Ethiopia

Twenty hull less barley genotypes from the local crossing program and germplasms introduced from ICARDA were evaluated in a multi-location variety trial to identify stable genotypes with high grain yield, desirable agronomic characters and good level of disease resistance. Results of combined analysis showed that genotype (G5 and G19) with pedigree name <i>TOCTE/M112/6/VMORALESCBSS04M00436T-11M-0Y-0M-3M-0AP and PENCO/CHEVRON-BAR/3/LEGACYU//PENCO/CHEVRON=BAR CBSS04Y00048S-23Y2M-0Y-0M-0Y-0AP--0TR-0TR </i>exhibited the highest mean grain yield with good agronomic performance and good level of disease resistance across the testing environments, while genotype. Accordingly, the two varieties were promoted to variety verification trial in 2022, and genotype G5 released in 2023; this genotype was named Sena. The variety showed good physical grain quality, coupled with high grain yield of 5.2 t/ha. Sena variety is suitable to the high potential barley growing areas. This variety is characterized by early maturity, white seed color, has good physical grain quality, resistance to leaf rust and scald, moderate resistance to net blotch, moderate tolerance to barley shoot fly, lodging tolerance and good biomass yield. The variety’s demonstration and seed multiplication is underway. Therefore, cultivation of the new variety in the higher altitude areas of major barley growing environments of the country is highly recommended. Six-rowed semi hulled barley Sena was developed by Sinana Agricultural Research Center (SARC), Southeastern Oromia region, Ethiopia. If the variety is sufficiently demonstrated, scaled up and adopted by farmers, it can play significant role in increasing hull less barley production and productivity thereby increasing the income of farmers and can also be source of raw material for local market engaged in the <i>kolo</i> production.

Bacterial crude oil and polyaromatic hydrocarbon degraders from Kazakh oil fields as barley growth support

Bacterial strains of the genera Arthrobacter, Bacillus, Dietzia, Kocuria, and Micrococcus were isolated from oil-contaminated soils of the Balgimbaev, Dossor, and Zaburunye oil fields in Kazakhstan. They were selected from 1376 isolated strains based on their unique ability to use crude oil and polyaromatic hydrocarbons (PAHs) as sole source of carbon and energy in growth experiments. The isolated strains degraded a wide range of aliphatic and aromatic components from crude oil to generate a total of 170 acid metabolites. Eight metabolites were detected during the degradation of anthracene and of phenanthrene, two of which led to the description of a new degradation pathway. The selected bacterial strains Arthrobacter bussei/agilis SBUG 2290, Bacillus atrophaeus SBUG 2291, Bacillus subtilis SBUG 2285, Dietzia kunjamensis SBUG 2289, Kocuria rosea SBUG 2287, Kocuria polaris SBUG 2288, and Micrococcus luteus SBUG 2286 promoted the growth of barley shoots and roots in oil-contaminated soil, demonstrating the enormous potential of isolatable and cultivable soil bacteria in soil remediation.Key points• Special powerful bacterial strains as potential crude oil and PAH degraders.• Growth on crude oil or PAHs as sole source of carbon and energy.• Bacterial support of barley growth as resource for soil remediation.

Intercropping of Narrow-Leafed Lupin (Lupinus angustifolius L.) and Barley (Hordeum vulgare L.) Affects the Flavonoid Composition of Both Crops.

Barley (Hordeum vulgare L.) is a common cereal crop in agricultural production and is often included in legume-cereal intercropping. Flavonoids, a major class of secondary metabolites found in barley, are involved in plant defense and protection. However, the effect of intercropping on barley flavonoids remains unknown. Herein, an intercropping system involving barley and lupin (Lupinus angustifolius L.) was studied. Intercropping increased the level of luteolin in lupin roots. Lupin-barley intercropping considerably increased genistein, rutin, and apigenin in barley shoots. Genistein and apigenin were also detected in intercropped barley roots and rhizosphere soil. The three flavonoids have been reported as defense compounds, suggesting that lupin triggers a defense response in barley to strengthen its survival ability.

Response of seedling barley (Hurdeom vulgar, L.) to foliar fertilization of nano-oxides (Fe, Cu, Mg)

Background. An experiment was conducted at the Grain Technology Laboratory, Crop Department, Faculty of Agriculture, Omar Al-Mukhtar University, during the 2023 season. The experiment utilized a completely randomized design to study the response of barley to foliar application of fine nanoscale iron, manganese, and copper fertilizers. The application was carried out as foliar spray at two different doses, two weeks and one month after sowing, using 3 kg capacity pots with 20 seeds per pot. The experiment included three observations for each treatment, with the nanoscale iron, manganese, and copper oxides applied at a concentration of 1 cmol/L. The data revealed the following: Significant positive response of barley shoots to foliar application of nanoscale iron, manganese, and copper fertilizers in various growth indicators, including shoot weight, shoot length, leaf area, crop growth rate, and specific leaf weight. High significant differences were observed in the effect of nanoscale iron, manganese, and copper oxides on the average shoot weight, crop growth rate, and leaf area. Copper oxide and manganese oxide showed the highest means, followed by iron oxide, compared to the control. Iron oxide exhibited the highest specific leaf weight for barley shoots, followed by copper oxide and then manganese oxide, compared to the control treatment.

Root but not shoot litter fostered the formation of mineral-associated organic matter in eroded arable soils

Erosion leads to a decline in carbon (C) stocks in arable soils and negatively impacts soil functions worldwide. For soil restoration, it is critical to identify the factors that link crop residue quality to effective C sequestration in the soil, primarily through the formation of mineral-associated organic matter (MAOM) and through incorporation into aggregates (oPOM). The widely accepted concept links effective C stabilization with input of high-quality substrates, but studies of C-deficient soils do not support this assumption. Therefore, we aimed to determine the potential of eroded arable soils to stabilize C from barley shoot and root residues, which represent high- and low-quality inputs, respectively. In a year-long laboratory experiment, we added the residues to two soil pairs (eroded and non-eroded) with different soil textures, observed the formation of oPOM and MAOM and identified microbial groups important for substrate transformation. We found that eroded soils retained added residues very efficiently (35–65% bound residue C), making them a high-priority target for C sequestration. Root residues caused more efficient MAOM formation than shoot residues, primarily by direct binding of depolymerized root-C to mineral surfaces without subsequent microbial transformation. This root C stabilization in MAOM was more pronounced in eroded (highly C-undersaturated) soils than in non-eroded soils and in fine-textured soils, which provided more space for microbial colonization and C sorption, than in coarse-textured soils. Shoot residues were decomposed and metabolized by a microbiome rich in efficient bacterial decomposers (Actinobacteria, Xanthomonadales). This led to inevitably higher C losses related to their growth and biomass turnover, and probably also to an intense priming effect on pre-existing MAOM that lowered the efficiency of MAOM formation. Our results argue for crops with robust root systems, or for the inclusion of deep-rooted plants in crop rotations, which could help rapidly restore the C stocks in arable soils.

PEP444c encoded within the MIR444c gene regulates microRNA444c accumulation in barley.

MicroRNAs are small, noncoding RNA molecules that regulate the expression of their target genes. The MIR444 gene family is present exclusively in monocotyledons, and microRNAs444 from this family have been shown to target certain MADS-box transcription factors in rice and barley. We identified three barley MIR444 (MIR444a/b/c) genes and comprehensively characterised their structure and the processing pattern of the primary transcripts (pri-miRNAs444). Pri-microRNAs444 undergo extensive alternative splicing, generating functional and nonfunctional pri-miRNA444 isoforms. We show that barley pri-miRNAs444 contain numerous open reading frames (ORFs) whose transcripts associate with ribosomes. Using specific antibodies, we provide evidence that selected ORFs encoding PEP444a within MIR444a and PEP444c within MIR444c are expressed in barley plants. Moreover, we demonstrate that CRISPR-associated endonuclease 9 (Cas9)-mediated mutagenesis of the PEP444c-encoding sequence results in a decreased level of PEP444 transcript in barley shoots and roots and a 5-fold reduced level of mature microRNA444c in roots. Our observations suggest that PEP444c encoded by the MIR444c gene is involved in microRNA444c biogenesis in barley.

Monitoring Root and Shoot Characteristics for the Sustainable Growth of Barley Using an IoT-Enabled Hydroponic System and AquaCrop Simulator

Vertical farming methods are gaining importance in the current era of urbanization and industrialization 5.0. These methods of farming enhance sustainability by consuming less space and reducing carbon emissions and greenhouse gas emissions. The Green Internet of Things (G-IoT) offers greater environmental sustainability by switching to a dormant mode while not in use, thereby consuming less energy. Each farming method has a different effect on the shoot and root growth of the plants. Thus, dedicated farming methods must be identified for each crop according to the type of crop under consideration. This leads to a need to compare and analyze the root as well as shoot growth trends of crops in different cultivation mediums, using different cultivation methods, thereby identifying the most suitable method for the cultivation of the crop. A comparative analysis of barley shoot and root growth in green IoT-embedded hydroponics and substrate cultivation methods has shown that hydroponics exhibits two times more shoot growth than substrate cultivation. Furthermore, the results were verified against the results obtained from the simulator, which confirmed that the hydroponic method of cultivation produced a year-round qualitative product with 17.112 tons of biomass and 8.556 tons of dry yield.

Influence of Brassinosteroids on the Ion-Exchange Properties of the Cell Walls of Roots and Shoots of Barley Against the Background of the Action of Heavy Metals

Influence of Brassinosteroids on the Ion-Exchange Properties of the Cell Walls of Roots and Shoots of Barley Against the Background of the Action of Heavy Metals

Calcium and L-glutamate present the opposite role in managing arsenic in barley

Arsenic contamination in agricultural soils has posed tremendous threat to sustainable crop production and human health via food chain. Calcium and Glutamate have been well-documented in metal(loid)s detoxification, but it is poorly understood how they regulate arsenic-induced toxicity to plants. In this study, the effect of glutamate and calcium at high concentration on arsenic toxicity and accumulation in barley seedling was accessed in terms of plant growth, photosynthetic efficacy, arsenic uptake, translocation and accumulation, antioxidant defense, nutrient uptake and the expression of As transporters. Our results have demonstrated that calcium could effectively ameliorate arsenic toxicity to barley seedlings, which is mainly attributed to its beneficial effect on increasing nutrient uptake, reducing the aboveground arsenic accumulation and enhancing antioxidative defense capacity. However, it is unexpected that glutamate considerably exacerbated the arsenic toxicity to barley seedlings. More importantly, for the first time, glutamate was observed to tremendously facilitate the root-to-shoot translocation of arsenic by 41.8- to 60.8-fold, leading to 90% of the total amount of As accumulating in barley shoots. The reason of this phenomenon can be well explained by the glutamate-triggered enormous upregulation of genes involved in arsenic uptake (HvPHT1;1, HvPHR2 and HvNIP3;2), reduction (HvHAC1;1), translocation (HvABCC7, HvNIP1;1 and HvNIP3;3) and intracellular sequestration (HvABCC1). These findings suggest that calcium and glutamate function as the opposite player in managing arsenic, with calcium being an effective alleviator of arsenic stress to ensure the safe production of crops; while glutamate being a highly efficient phytoextraction agent for phytoremediation of arsenate-contaminated soils.

Cadmium distribution and transformation in leaf cells involved in detoxification and tolerance in barley

Barley is a diagnostic plant that often used in the research of soil pollution by heavy metals, our research explored the detoxification and tolerance mechanism of cadmium(Cd) in barley through pot experiment. We investigated subcellular distribution, chemical forms and oxidative damage of Cd in barley leaves, combing with the transmission electron microscopy and Fourier-transform infrared spectroscopy(FT-IR) to further understand the translocation, transformation characteristics and toxic effect of Cd in cells. The results showed that, the bioaccumulation factors in roots and shoots of barley were ranged of 4.03–7.48 and 0.51–1.30, respectively. Barley reduces the toxic effects by storing Cd in the roots and reducing its transport to the shoots. Compared to the control treatment (0 mg/kg), the percentage of Cd in the cell wall fractions of leaves in 300 mg/kg Cd treatment increased from 34.74 % to 38.41 %; the percentage of the organelle fractions increased from 24.47 % to 56.02 %; and the percentage of soluble fraction decreased from 40.80 % to 5.57 %. We found that 69.13 % of the highly toxic inorganic Cd and water-soluble Cd were converted to less toxic pectates and protein-integrated Cd (50.20 %) and undissolved Cd phosphates (18.93 %). This conversion of Cd was mainly due to its combination with -OH, -NH, -CN, -C-O-C, and -C-O-P groups. Excessive Cd induced a significant (P < 0.05) increase in the levels of peroxidase, malondialdehyde, and cell membrane permeability, which damaged the cell membrane and allowed Cd to enter the organelles. The chloroplasts and mitochondria were destroyed, and eventually the metabolism of intracellular substances was affected, resulting in symptoms of toxicity. Our research provides cellular-scale insight into the mechanisms of Cd tolerance in barley.

COPPER CONTENT IN ROOTS AND SHOOTS OF CEREALS UNDERDIFFERENT TYPES OF SALYCILIC ACID TREATMENT

Copper is involved in a number of metabolic reactions that ensure the vital activity of plants; therefore, its deficiency leads to disruption of physiological processes and a decrease of its productivity. In order to increase the contentof cupper in plants, a searching for ways to provide better absorption of copper by roots and enhance its transport to aboveground organs.The use of growth regulators for these purposes, including salicylic acid (SA), seems to be very promising.In this work, we studied the effect of two types of SA treatment (presowingseeds treatment and spraying of plants) on the copper content in the roots and shoots of barley and wheat under optimal conditions of mineral nutrition or under deficiency of this micronutrient in the substrate.The copper content in plants and substrate was determined by the ICP-MS method using a induced plasma mass spectrometer. To assess the intensity of copper influx into plants, the copper biological uptake coefficient was calculated; the intensity of metal ions transport into the shoots was judged on the translocation coefficient. It was found that spraying of plants with SA practically does not affect the amount of copper in the roots and shoots of cereals. In contrast, presowing seed SA treatment contributed to an increase in its content in plants, which was ensure by a more intensive uptake ions by roots, as well as a decrease in the activity of the root barrier and an increase in copper translocation into shoots. It is also important to note that these effects were more pronounced under copper deficiency in the substrate.

Transcriptome profiling of barley and tomato shoot and root meristems unravels physiological variations underlying photoperiodic sensitivity.

The average sowing date of crops in temperate climate zones has been shifted forwards by several days, resulting in a changed photoperiod regime at the emergence stage. In the present study, we performed a global transcriptome profiling of plant development genes in the seedling stage of root and shoot apical meristems of a photoperiod-sensitive species (barley) and a photoperiod insensitive species (tomato) in short-day conditions (8h). Variant expression indicated differences in physiological development under this short day-length regime between species and tissues. The barley tissue transcriptome revealed reduced differentiation compared to tomato. In addition, decreased photosynthetic activity was observed in barley transcriptome and leaf chlorophyll content under 8h conditions, indicating a slower physiological development of shoot meristems than in tomatoes. The photomorphogenesis controlling cryptochrome gene cry1, with an effect on physiological differentiation, showed an underexpression in barley compared to tomato shoot meristems. This might lead to a cascade of suspended sink-source activities, which ultimately delay organ development and differentiation in barley shoot meristems under short photoperiods.

Silicon mitigates potassium deficiency by enhanced remobilization and modulated potassium transporter regulation

Silicon (Si) improves plant growth and development especially under stress conditions. Although Si alleviates growth suppression and deficiency symptoms of several nutrient disorders, underlying regulatory processes have remained indefinite. Here, we analyzed the impact of Si on nutritional, metabolic and transcriptional responses in roots and shoots of barley subjected to potassium (K) deficiency. On the long run, Si nutrition improved root and shoot growth as well as metabolite homeostasis and partly reverted the K deficiency signature of the transcriptome back to adequate only in fully expanded leaves but hardly in roots. In the short term, Si supply to K-starved roots enhanced first the expression of the vacuolar K exporter KCO1 together with root-to-shoot translocation rates of rubidium (Rb) that was used as tracer for K. The typical K deficiency response, marked by upregulation of the K importer genes HAK1 and AKT1, set in a few days later but then at several-fold higher levels. Lower root K and higher shoot K contents in Si-supplied plants indicated more efficient remobilization of root K pools and higher root-to-shoot translocation, which on the long run restored K-dependent metabolic processes in shoots for the sake of continued assimilate provision to roots. These results provide a sequence of physiological processes by which Si partially recovers plants from K deficiency and indicate that Si interferes with systemic K deficiency signaling in roots to alter the regulation of K transporters. • · Mitigation of K deficiency by Si supply relies on an improved metabolic status of the leaves for sustained assimilate provision of roots • Under K starvation, Si enables stronger depletion of the root K pool and enhances K remobilization for root-to-shoot translocation • In K-starved plants, Si activates vacuolar K exporter genes in roots and subsequently stimulates the K deficiency response

Secondary Active Transporters Decrease Cytokinin Flow into Barley Shoots and Inhibit their Growth under Phosphate Deficit

Secondary active transport is one of the most important mechanisms controlling cytokinin distribution between shoots and roots which enables the adaptive growth reaction of barley. Concentrations (ng/g of fresh mass) and contents (ng/organ) of different forms of cytokinins were determined in shoots and roots of barley plants by immunoassay. It was shown that under phosphate deficit the maintenance of root growth, inhibition of root branching and decline in shoot mass of barley plants (Hordeum vulgare 'Prairie') was due to decline in shoot cytokinins and their accumulation in the roots. Protonophore carbonyl cyanide-m-chlorophenylhydrazone as an inhibitor of secondary active transport leveled off hormonal reaction to phosphate deficit: it prevented accumulation of cytokinins in roots, increased their content in shoots and changed the percentage of zeatin and its derivatives in total cytokinin content in roots and shoots. A data analysis showed that in roots, protonophore did not change significantly the content of ribosides and nucleotides of zeatin, while uptake of free zeatin by cells was significantly affected by the protonophore and its content decreased dramatically. The role of secondary active trans-membrane transfer is discussed in the context of cytokinins transport from roots to shoots under phosphate deficit

Using Portable X-ray Fluorescence Spectroscopy for Inexpensive and Quick Determination of Micronutrients in Barley Shoots

ABSTRACT Determination of elemental concentrations in plant tissue samples is critically important for analyzing their nutritional content. Micro-elemental analysis mostly relies on inductively coupled plasma (ICP) spectrometry techniques, which are expensive, time-consuming, laborious, and complicated. Portable X-ray fluorescence (pXRF) spectroscopy is widely applied in earth sciences but is rarely practiced to quantify elements in plant samples. In this pilot study, the reliability of pXRF results was compared with that of ICP-mass spectrometer (MS) to determine concentrations of four micronutrients zinc (Zn), iron (Fe), copper (Cu), and cadmium (Cd) in barley (Hordeum vulgare L.) shoot samples. Ground barley samples were scanned with the pXRF instrument. The concentrations of Zn recorded using this method correlated well with the ICP-MS results (R 2 = 0.80), while Fe and Cu concentrations showed moderate correlations (R 2 = 0.57 and 0.42, respectively). However, no significant correlation was found between ICP-MS- and pXRF-derived concentrations for Cd (p > .05). This work demonstrated the potential of pXRF as a reliable and cost-effective alternative to ICP methods for determining Zn in plant samples as it allows the analysis of a greater number of samples in a short period at considerably less expense.

Lignite derived humic products and cattle manure biochar are effective soil amendments in cadmium contaminated and uncontaminated soils

Cadmium (Cd) contamination in soils is a global environmental concern. Amending soil with low cost carbonaceous materials, such as humic substances and biochars, may provide cost effective and environmentally sound alternatives to traditional remediation technologies. Two lignite derived humic substance products, nano humus and humic powder, and a cattle manure biochar, were used as amendments in loamy sand and silt loam soils to ascertain their impact on Cd, with barley (Hordeum vulgare L.) as the response organism in a greenhouse experiment. Soil Cd had the greatest influence on barley shoot biomass, decreasing by 28% in silt loam and 37% in loamy sand relative to the control. With or without Cd addition, the beneficial effect of nano humus and humic powder were pronounced. Nano humus and humic powder (high rate), increased root biomass by 248 and 100% in uncontaminated soils, respectively; and increased by 186 and 55% in Cd contaminated soils. Biochar increased shoot biomass in soils by 32% without Cd, and 127% with Cd. Barley responded differently to amendments in two textured soils. Results of this research will help develop cost effective remediation techniques using humic materials and cattle manure biochar as soil amendments in Cd contaminated soils.

Effect of Exogenous Treatment with Nitric Oxide (NO) on Redox Homeostasis in Barley Seedlings (Hordeum vulgare L.) Under Copper Stress

The protective mechanism of nitric oxide (NO) in regulating tolerance to Cu-induced toxicity in shoots of barley (Hordeum vulgare L.) was studied. The experiment consisted of four treatments based on additions to basal nutrient solutions (BNS): control (CTR), Cu (200 µM), SNP (500 µM), and Cu (200 µM) + SNP (500 µM) over a period of 10 days. Treatment with Cu significantly reduced seedling growth and photosynthetic efficiency concomitant with an increase in reactive oxygen species contents, lipid peroxidation markers, and antioxidant enzyme activities, indicating that Cu induced oxidative stress. Furthermore, growth inhibition of Cu-treated plants was associated with a reduction in photosynthetic pigments and maximum photosystem II efficiency as well as a strong decrease in levels of glutathione (GSH) and ascorbate (AsA). Addition of a nitric oxide (NO) donor, sodium nitroprusside (SNP), to the growth medium alleviated Cu toxicity by decreasing Cu uptake and enhancing antioxidant capacity, as indicated by increased contents of GSH and AsA. The application of SNP decreased oxidative stress and lipid peroxidation by suppressing lipoxygenase activity and enhancing some antioxidant enzyme activities. The results obtained indicate the potential of exogenously applied SNP in the management of metal toxicity. Hence, NO generating compounds have potential agronomical applications when cultivating in contaminated areas. Our findings indicate that NO can alleviate Cu toxicity by affecting the antioxidant defense system and maintaining the glutathione-ascorbate cycle status, suggesting that SNP treatment protects proteins against oxidation by regulating the cellular redox homeostasis.

Short-term interactive effects of copper and cadmium on barley growth, metal uptake, and oxidative damage

The present study aimed at investigating the response of spring barley (Hordeum vulgare L.) across different endpoints (morphological, physiological, and biochemical) to short-term single and combined copper (Cu) and cadmium (Cd) exposure. Barley seedlings were exposed for 5 days to Cd and Cu (0.1–100 mg L−1) individually and in binary combinations. Binary mixture toxicity was evaluated using the concentration addition concept and toxic unit approach. Single metal treatment reduced barley height and biomass, altered the content of photosynthetic pigments, and induced lipid peroxidation. Plant growth (measured as plant height and biomass) and lipid peroxidation showed high sensitivity to combined Cu–Cd treatment and Cu–Cd mixture induced greater than additive effect on these endpoints. The uptake and accumulation of Cu and Cd were considerably influenced by the interaction among these metals. Cu reduced Cd accumulation in plants, while Cd had no influence on Cu accumulation in barley roots and shoots. Analysis of mixture effects across different endpoints revealed that mixture effects are endpoint dependent and different types of interactions were manifested. Overall, the present study shows that the same test design for single and mixture toxicity assessment for several endpoints cannot always be used to predict mixture effects and type of interaction.

Interactive effects of hydrogen sulphide and silicon enhance drought and heat tolerance by modulating hormones, antioxidant defence enzymes and redox status in barley (Hordeum vulgare L.).

Recent changes in climate have reduced crop productivity throughout much of the world. Drought and heat stress, particularly in arid and semi-arid regions, have seriously affected barley production. This study explored the separate and interactive effects of silicon (Si) and hydrogen sulphide (H2 S) on plant growth and mitigation of the adverse effects of heat stress (DS) and drought stress (HS) in a barley pot experiment. The impacts of simultaneous DS + HS were more severe than individual stresses due to increased ROS production, malondialdehyde (MDA) content and higher electrolyte leakage (EL), thereby leading to reduced water, protein and photosynthetic pigment content. Exogenously applied Si and H2 S alleviated the DS-, HS- and DS + HS-induced effects on barley by reducing ROS production, MDA and EL. A single application of H2 S or Si + H2 S increased plant biomass under all stress conditions, which can be ascribed to higher Si accumulation in barley shoots. A single application of Si or H2 S significantly increased plant biomass. However, Si + H2 S was the most effective treatment for metabolite accumulation and elevating activity of antioxidant enzymes to prevent toxicity from oxidative stress. This treatment also modulated osmolyte content, enhanced antioxidant activity and regulated the stress signalling-related endogenous hormones, abscisic acid (ABA) and indole acetic acid (IAA). Exogenous treatments regulated endogenous H2 S and Si and resulted in higher tolerance to individual and combined drought and heat stress in barley.