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Crop plants all over the world face an array of environmental threats among which drought is found to be the most deleterious. The present investigation was carried to test the efficacy of exogenously supplemented sodium nitroprusside (SNP), a nitric oxide donor, and polyamine (PA) putrescine (PUT) in mitigating the effects of polyethylene glycol (PEG)-imposed drought stress in in vitro grown seedlings of Solanum lycopersicum. PEG treatments at different concentrations (1, 2, 5, 10, and 15%) were assessed for their impact on plant growth parameters based on which 10% PEG was chosen as effective drought treatment. Varying concentrations of SNP (100, 150, and 200 µM) and PUT (0.1, 0.3, and 0.5 mM) at different combinations were studied for their mitigating effects. The results revealed that among the combinations tested, SNP (150 µM) + PUT (0.3 mM) resulted in effective mitigation of drought stress in S. lycopersicum seedlings. SNP and PUT supplementation enhanced the growth parameters such as shoot and root length and plant fresh weight (FW). Further, the relative water content (RWC), chlorophyll, and proline contents were significantly enhanced in the experimental plants as compared to the control. Effective reduction in the malondialdehyde (MDA) and hydrogen peroxide (H2O2), a significant increase in the antioxidant enzymes, and the transcriptional level upregulation of antioxidant genes and drought-responsive genes were observed in the treated plants as compared to the control. These results suggest that exogenous supplementation of SNP and PUT has a positive influence on alleviating the drought stress in S. lycopersicum.

Salinity stress is one of the most important global problems that afflicts and limits the growth and development of turfgrass in arid and semi-arid areas. Therefore, this experiment was conducted to evaluate the effects of the interaction between gamma-aminobutyric acid (GABA) and salinity (NaCl) on perennial ryegrass (Lolium perenne L.). Perennial ryegrass plants were treated with three concentrations of GABA (0, 50, and 100 mM) and NaCl (0, 50, and 100 mM) for two months. Multivariate analysis of variance revealed that GABA, salinity, and their interaction had significant effects on the majority of measured traits. In shoots and roots, the application of salinity increased the Na+/K+ ratio, as well as proline, total soluble carbohydrates and protein (TSP), malondialdehyde (MDA), and hydrogen peroxide (H2O2) content, but reduced relative water content, membrane stability index (MSI), total chlorophyll content, and shoot and root growth. When GABA was applied in saline conditions, Na+ did not accumulate, the Na+/K+ ratio decreased, and the amount of K+ content increased significantly in shoots and roots, thereby allowing plant growth to resume. Peroxidase (POD) and superoxide dismutase (SOD) activities increased significantly (51.83% and 322%, respectively), whereas H2O2 and MDA contents decreased significantly (34.4% and 67%, respectively). In addition, the construction of a biplot, heatmap, and correlation plot fortified the positive effects of GABA on perennial ryegrass growth in saline conditions. GABA may help to alleviate salinity damage through its involvement in osmotic adjustment (proline and TSP), reducing the Na+/K+ ratio and limiting oxidative damage in cells with a dramatic increase in POD and SOD activity. Therefore, the application of GABA is an alternative technique for improving turfgrass tolerance to salinity.

NMR-based metabolic profiling of polar extracts of somatic embryogenic and organogenic cultures of the medicinal plant Cymbopogon schoenanthus subsp. proximus were studied. Regeneration through somatic embryogenesis was done on media containing 2,4-D and BAP while organogenesis was achieved on media containing NAA and BAP. Fifty-two metabolites were identified in embryogenic calli (EC), organogenic calli (OC), regenerated embryogenic shoots (ES), and organogenic shoots (OS). Chemometrics and cluster analysis were used to depict the correlation between the groups investigated. Metabolic profiles revealed unique metabolites in ES (serine and lactate) and in OS (2-hydroxyisobutyrate, tyrosine, histamine and homoserine). Quantitative differences as manifested by relative concentrations through heat map and fold change analyses were significant in the following comparisons: calli type, embryogenic tissues, organogenic tissues, and shoot type. In a comparison of calli types, proline, asparagine and arginine were upregulated in EC and sucrose was upregulated in OC. When comparing embryogenic tissues, monosaccharides were upregulated in EC, while proline, pyroglutamate and 4-aminobutyrate were upregulated in ES. Upon comparison of organogenic tissues, trigonelline increased by 17-fold in OS; however, monosaccharides were upregulated in OC. Finally, when comparing shoot types, 4-aminobutyrate, betaine and proline were upregulated in ES, while mono- and disaccharides were upregulated in OS. The embryogenic system was characterized by accumulation of stress related metabolites (proline); however, glycolate was identified only in the organogenesis system. The present work contributes to the understanding of the metabolic characteristics and differences between the two regeneration systems as manifested by profiles of EC, OC, and their regenerated shoots. Metabolic characteristics of two regeneration systems (somatic embryogenesis and organogenesis) of Cymbopogon schoenanthus were examined using NMR-based profiles of calli and their regenerated shoots, revealing clear qualitative and quantitative differences between the two systems at the studied developmental stages.

The question of whether food webs are resource or predation controlled is crucial for the development of sustainable IPM strategies in agriculture. Many IPM studies focus on top–down control, while little is known about bottom–up effects. Here, we unravelled the bottom–up interactions between rosy apple aphid (RAA) Dysaphis plantaginea and 13 apple cultivars in north-eastern Belgium. Population dynamics, apple leaf damage, preference and performance measurements were used to determine the interactions between RAA and apple cultivars. Seasonal abundances and RAA-infested shoots were significantly affected by the cultivar. The cultivars Fuji, Granny Smith, Jonagold and Cripps Pink harboured clearly higher numbers of aphids compared to other cultivars, especially Red Delicious. Regarding leaf damage degree, Fuji was significantly the most impacted, while the lowest damage was recorded on Red Delicious. The potential apparent competition among apple cultivars was evaluated using RAA overlap diagrams. By acting as a potential source of RAA, a particular cultivar can considerably affect other nearby cultivars. In host selection bioassays, significant differences in the choice behaviour of RAA were found in the laboratory for different apple cultivars. Other important findings from the reproduction–offspring performance bioassays revealed that while Fuji stimulated high production of nymphs, their development remained retarded on Fuji, compared to especially Boskoop on which significantly lower numbers of nymphs occurred. Our study provides a promising insight into the importance of studying apple–RAA interactions within an eco-friendly RAA management tactic.

Key message A 7.9 kb deletion which contains a cyclin-dependent protein kinase inhibitor leads to determinate growth and dwarf phenotype in cucumber. Abstract Plant architecture is a composite character which are mainly defined by shoot branching, internode elongation and shoot determinacy. Ideal architecture tends to increase the yield of plants, just like the case of “Green Revolution” increased by the application of semi-dwarf cereal crop varieties in 1960s. Cucumber (Cucumis sativus L.) is an important vegetable cultivated worldwide, and suitable architecture varieties were selected for different production systems. In this study, we obtained a novel dwarf mutant with strikingly shortened plant height and determinate growth habit. By bulked segregant analysis and map-based cloning, we delimited the dw2 locus to a 56.4 kb region which contain five genes. Among all the variations between WT and dw2 within the 56.4 kb region, a 7.9 kb deletion which resulted in complete deletion of CsaV3_5G035790 in dw2 was co-segregated with the dwarf phenotype. Haplotype analysis and gene expression analysis suggest that CsaV3_5G035790 encoding a cyclin-dependent protein kinase inhibitor (CsSMR1) be the candidate gene responsible for the dwarf phenotype in dw2. RNA-seq analysis shows that several kinesin-like proteins, cyclins and reported organ size regulators are expressed differentially between WT and dw2, which may account for the reduced organ size in dwarf plants. Additionally, the down-regulation of CsSTM and CsWOX9 in dw2 resulted in premature termination of shoot apical meristem development, which eventually reduces the internode number and plant height. Identification and characterization of the CsSMR1 provide a new insight into cucumber architecture modification to be applied to mechanized production system.

Barley (Hordeum vulgare L.) is one of the major strategic crops in Ethiopia. Average yield is low due to low-yielding varieties, biotic and abiotic constraints. Farmers are concerned with quantity while the malting industries need to ensure quality. There has been a general belief by the industry that two-row barleys are better than the six-row types in terms of quality but farmers are inclined to six-rows for higher yield. Evaluation was performed to identify a variety with desirable yield and quality standards. Single-trait selection for yield or quality traits has so far been the breeders’ target with less emphasis on multiple traits’ selection. The current research aims to identify a high-yielding variety with acceptable quality based on multiple selection criteria. Analysis of variance showed higher location variance for yield with no interaction effect. Stability analysis exhibited significant interaction effect for malt extract and protein content. Two genotypes MOATA and IBON-HI68 were identified with stable malt extract and protein content. ‘MOATA’ has been released with a higher mean yield (5.1 t/ha), lower protein (10.2%) and beta glucan (2.5%) contents, higher friability (73%) and malt extract (81.3%) while IBON-HI68 has been maintained as a parent material for future crossing program. MOATA is less susceptible to shoot fly damage (22%), scald and net blotch (44%). Its peculiar compact spike and dropping awns imply quality merits. In conclusion, multiple traits selection index has proved successful in identifying the first six-row malting barley variety in Ethiopia.

Soil salinization has become a global problem and seriously endangers crop growth and yield improvement. In the present study, soybean (Hefeng 50) seedlings were used as test materials to study the mitigation effect of foliar spraying of different plant growth regulators (PGRs) [50 mg L−1 indole-3-butyric acid potassium salt (IBAK), 50 mg L−1 chitosan oligosaccharide (COS), 2 mg L−1 abscisic acid (ABA), 30 mg L−1 5-aminolevulinic acid (ALA), and 1.2 mg L−1 brassinolide (BR)] on oxidative stress caused by the mixed Saline–Alkali concentration of 110 mmol L−1. The results showed that the application of PGRs promoted the growth of Saline–Alkali stressed plants, where the maximum increase in shoot FW was treated with COS, and in root FW, root length, root surface area, and root volume were obtained with the IBAK treatment. Treatments ABA, ALA, and BR had higher net photosynthetic rates, and the chlorophyll content was considerably increased under COS and BR treatments compared with Saline–Alkali treatment. Moreover, PGRs markedly enhanced the activities of antioxidant enzymes, the concentration of ascorbate (AsA), glutathione (GSH), proline, soluble protein, soluble sugar, sucrose, and starch, and the ratios of AsA/DHA and GSH/GSSG, but reduced the concentration of malondialdehyde (MDA), electrolyte leakage (EL), hydrogen peroxide (H2O2), and superoxide radical (O2·−) in soybean seedlings compared with Saline–Alkali treatment. The principal component analysis revealed that the ranking of PGRs enhancing Saline–Alkali tolerance of soybean seedlings was BR > IBAK > ABA > COS > ALA, and the most effective treatment was BR, which may be assigned to more vigorous antioxidant defense and osmotic adjustment.

The overexploitation of the O horizon, or the litter layer of the soil profile, in the production of ornamental plants, causes the disintegration of the landscape and the loss of soil productivity in preserved areas, which calls for new approaches to address the need for substrates in soilless culture systems. Thus, this study examined the construction of purpose-designed Technosols from construction waste as substrates in the production of ornamental plants. The evaluated treatments were as follows: (CCW) 40% concrete waste, 30% compost, 30% wood chips; (ECW) 40% excavation waste, 30% compost, 30% wood chips; and (AOW) 40% compost, 60% wood chips. A control treatment (CTL) was composed of 50% compost and 50% natural exported soil. The plant species used were Heliotropium arborescens, Lobularia maritima, and Lavandula angustifolia, which were grown for one cycle in an 8-week greenhouse experiment. The pH, electrical conductivity (EC), carbon and nutrient (N, P, and exchangeable cations) contents, and water availability of the Technosols and control treatment, as well as the survival rate, presence of flowers, number of flowers per plant and shoot diameter of the ornamental plants, were evaluated over the experimental period. All treatments had slightly alkaline pH, yet their EC decreased to the levels recommended for growing media considering the evaluated species. The AOW presented the highest initial contents of total C, total N, and available P, and the highest concentration of DOC at the end of the experiment, followed by the CCW Technosol. There were no differences within treatments regarding their initial and final available P contents, and the final available P and mineral N contents in Technosols and control did not differ, thus showing their ability to supply both N and P adequately to plants. A high plant survival rate was observed throughout the experimental period, and the frequency of blooming plants increased for all species regardless of the treatment. The Technosols produced from construction and excavation waste had been shown to provide favorable chemical, physical, and physicochemical conditions for the vegetative development and blooming of ornamental plants with different fertilization requirements and, thus, could be used as alternative to reduce the exploitation of exported natural soils. The plants used in the study had different nutritional requirements, yet they all grew adequately. The Technosol made from concrete waste had the most promising outcome in terms of C and available nutrients (N, P and exchangeable cations) as well as water retention and availability to plants compared to the excavation-based Technosol, besides having comparable results with the control treatment that is commonly used by the producers to grow ornamental and flower plants. Considering that no mineral fertilization was used in this study, further research may assess the use of a controlled fertilization schedule in order to reduce and optimize the use of agrochemical inputs, from small to large-scale growers of flower plants.

Prolonged application of sewage-sludge may cause excessive accumulation of metal(oid)s in soil, leading to phytotoxic effects. Spread of contaminants in soil can probably be hindered by using an effective metal(oid) stabilizer. Pot experiment in open field conditions was conducted for five months to evaluate the metal(oid) (Al, Cu, Zn, Cd and Cr) stabilization potential of red mud (RM) in sludge-amended soil and its effects on growth, yield, oil quality parameters and metal(oid) accumulations in Brassica juncea cultivar Kranti. The test plant was grown at different RM concentrations (0, 5, 10 and 15% w/w) in sludge-amended soil (soil/sludge: 2:1 w/w). As the total and phytoavailable metal(oid) concentrations in sludge were high, its application increased their concentrations in soil compared to the control (no RM and sludge). Increasing RM concentrations in sludge-amended soil effectively stabilized Cd followed by Cr, Cu, Zn and Al, leading to their reduced contents in plants coupled with enhanced growth performance and yield. Maximum plant (root and shoot) biomass (14.9%) and seed yield (40.4%) were found in 10% RM treatment, whereas oil content showed substantial increase with increasing RM treatments in sludge-amended soil. Mustard oil showed low rancidification, high long-chain fatty acids, saturated and polyunsaturated (ω-3 and ω-6) fatty acids within FAO ranges for edible oils under varying RM treatments compared to sludge-amended soil. Furthermore, high oleic and low erucic acid contents in mustard oil indicated a better oil quality under different RM treatments. Metal(oid) contents in seeds under different red mud treatments were within FAO/WHO limits for consumption. Thus, RM applications preferably 5 and 10% (w/w) in sludge-amended soil might be effective in stabilization of metal(oid)s using B. juncea cultivar Kranti coupled with better yield, improved oil quality and metal(oid)s within limits for human consumption.

Cordia subcordata Lam. (Boraginaceae) is a woody tree that grows in coastal wasteland and mangrove edges. Its wood is used for woodcraft, and the tree, which is used in landscaping, also has medicinal and ecological value (e.g., coastal protection). In this study, a shoot proliferation and regeneration system was established for this plant. Callus was induced from terminal young leaf explants on Murashige and Skoog (MS) medium with 1.0 mg L–1 thidiazuron or 1.0 mg L–1 2,4-dichlorophenoxyacetic acid, or optimally with 0.5 or 1.0 mg L–1 of both. Callus differentiated from an average of 35.4% of explants into 3 to 5 adventitious shoots (indirect shoot organogenesis) within 45 d. Optimal shoot proliferation medium was MS medium with 0.8 mg L–1 6-benzyladenine (BA). A higher concentration of BA (1.5 mg L–1) in the presence of α-naphthaleneacetic acid (NAA) enhanced callus induction from the base of shoots and decreased shoot proliferation. On ½MS medium with 0.5 mg L–1 NAA and/or indole-3-butyric acid, adventitious roots were induced from shoots. Within 1 mo, 95.4% of plantlets transferred to a substrate of vermiculite and peat (1:1, v/v) survived.

Micropropagation technique has been recommended for plant tissue rejuvenation/reinvigoration and the improvement of clonal plants production commercially. Concerning the limiting factors on in vitro cultivation of Eucalyptus grandis × E. urophylla hybrid clone, the effects of light intensity on in vitro introduction and multiplication phases were assessed. The experimental tissue was collected from ministumps cultivated in a semi-hydroponic system. The results of light intensity on in vitro introduction and multiplication were evaluated with four treatments (fluorescent lamp/40 µmol m−2 s−1, red/blue LEDs 20 µmol m−2 s−1, red/blue LEDs 40 µmol m−2 s−1, and red/blue LEDs 80 µmol m−2 s−1). The explants’ morphological, anatomical, and genetic characteristics were evaluated at 30 d in the in vitro introduction, and 12 subcultures for in vitro multiplication. Based on the results, the treatments F/L 40 µmol m−2 s−1 and R/B 80 µmol m−2 s−1 are the most suitable during in vitro introduction and multiplication of Eucalyptus grandis × E. urophylla. It provides a higher percentage of responsive explants, shoots per explant, vigor, photosynthetic pigment content, adaxial epidermis thickness, abaxial epidermis, mesophyll, palisade parenchyma, spongy parenchyma, and vascular tissues. Furthermore, it was found that the micropropagated plants are identical clones of the Eucalyptus grandis × E. urophylla selected tree; that is, there was no somaclonal variation during the twelve subcultures on in vitro multiplication.

Arbuscular Mycorrhizal Fungi that colonize the roots of plants growing on lands contaminated by heavy metals may influence the phytostabilization process reducing the translocation of metals to the aboveground parts of the plant. This study aimed to evaluate the effects of soil amendments (lime and lignite) on the concentration of the bioavailable form of heavy metals (CaCl2 extraction) in soil and on the colonization of Arbuscular Mycorrhizal Fungi in the roots of Lolium perenne when cultivated in contaminated soil. During the experiment, the bioavailability of Pb, Cd, and Zn in soil was significantly reduced after application of the amendments, causing an increase of L. perenne shoot dry biomass. It was observed that the higher dose of lime (0.5%) resulting in amplified values of relative mycorrhizal intensity. However, independently of the dose, the treatments increased the occurrence of arbuscules in L. perenne roots, with the highest value observed after the application of 0.25% lime with 5% lignite. The results for the first time present the effect of lime and lignite application on the L. perenne roots colonization by Arbuscular Mycorrhizal Fungi indicating the increase of occurrence of arbuscules. These findings suggest that in order to explain the different responses of Arbuscular Mycorrhizal Fungi to the applied treatment further investigations are needed to identify the spore morphology. The results of the experiment were implemented to stabilize heavy metals during remediation of a spoil heap in Ruda Śląska, Poland.

Members of the auxin/indoleacetic acid (Aux/IAA) gene family in plants are primary auxin-responsive genes that play important roles in many aspects of plant development and in responses to abiotic stress. Recently, 33 Aux/IAA have been identified in the apple genome. The biological responses of MdIAAs to salt stress are still unknown. In this study, Malus zumi, Malus baccata, and Malus × domestica 'Fuji' plantlets were subjected to salt stress by supplementing hydroponic media with NaCl at various concentrations. M. zumi showed the strongest salt resistance, followed by 'Fuji', and M. baccata was the most sensitive to salt stress. Tissue-specific expression profiles of MdIAAs were determined by quantitative real-time polymerase chain reaction. When apple plantlets were subjected to salt stress, most of salt-responsive MdIAAs were up-regulated by 1 h, 3 h, and 6 h in roots, shoot tips, and leaves, respectively. Highly expressed MdIAAs in roots, especially for M. zumi, consisted with the salt tolerance of apple rootstocks. Transgenic apple calli were tolerant to salt stress when over-expressed salt-responsive genes, MdIAA8, -9, and -25. These results provide clues about salt resistance in these three Malus species, which helps apple breeding of salt tolerance by genetic transformation.

Heather, Calluna vulgaris, is a key species of European dry heath and central determinant of its conservation status. The established Calluna life cycle concept describes four phases—pioneer, building, mature, and degeneration—distinguishable by growth and vitality characteristics of undisturbed plants grown from seeds. However, little is known about the life cycle and ageing of plants subjected to severe disturbance, although measures to this effect (burning, mowing) are common in heathland management. We studied the vitality of over 400 heather plants by examining multiple morphological (plant height, long shoot and inflorescence lengths, flowering activity), anatomical (growth rings) and environmental (management, nitrogen deposition, climate) attributes. We found Calluna vitality to be mainly determined by the aboveground stem age, and that severe disturbances promote vigorous vegetative regeneration. Ageing-related shifts in the habit and vitality of plants resprouting from stem-base buds is similar to that of seed-based plants, but the former revealed higher vitality when young, at the cost of a shorter life span. In contrast, plants originating from decumbent stems resemble building-stage plants but apparently lack the capacity to re-enter a cycle including stages other than degeneration-type. As a consequence, we supplemented the established heather life cycle concept with a post-disturbance regeneration cycle of plants derived from resprouting. We conclude that management of dry lowland heathlands should include rotational small-scale severe disturbance to support both seed germination and seedling establishment as well as vegetative regeneration chiefly of young heather plants capable of resprouting from buds near rootstock.

The secondary salinization of soil in facility agriculture is becoming increasingly serious. Cucumber is a moderately salt-sensitive crop, but because of the weak root system and poor resistance to salt stress in cucumber seedlings, it is sensitive to the accumulation of salt in facility soils. Hydrogen, a selective antioxidant and signal molecule, is nontoxic and harmless, and can repair damage in plants under stress. Therefore, the aim of the present paper was to understand the specific mechanism by which hydrogen-rich water (HRW) alleviated salt stress in cucumber seedlings (Cucumis sativus L.). Our results showed that the addition of 50% saturation HRW significantly promoted seedling growth, development and photosynthetic efficiency. Pretreatment with HRW significantly alleviated salt stress symptoms, including the inhibition of fresh and dry weight, root length, lateral roots, and the root/shoot ratio of cucumber seedlings. Pretreatment with HRW increased the chlorophyll content, chlorophyll a/b ratio, and photochemical reaction efficiency, and reduced energy dissipation. These responses to HRW pretreatment were consistent with significant decreases in the superoxide anion, hydrogen peroxide, and malondialdehyde contents and the degree of lipid peroxidation, and increases in the activities of SOD, POD, CAT, APX and GR, and the contents of ASA and GSH in cucumber seedlings under salt stress. In addition, HRW pretreatment under salt stress inhibited the expression of the protein kinase ROP1, which promoted the production of reactive oxygen, but upregulated the protein kinase LecRLK. The transcription factor TGA5, which was involved in osmotic stress, ion stress and ROS clearance, and the expression of NHX1 and SOS2, which were parts of the SOS signaling pathway. HRW enhanced the expression of genes that encoded antioxidant enzymes, including SOD, CAT and POD, and the expressions of GR and APX2, which were key genes in the ASA-GSH cycle under salt stress. Taken together, these results suggested that HRW enhanced the active oxygen scavenging ability in cucumber seedlings, promoted the redox balance in cells, and reduced the degree of oxidative damage in plants under salt stress by reducing the content of active oxygen. Therefore, the application of HRW might be a promising strategy for improving salt stress tolerance in cucumber seedlings.

An efficient encapsulation method was developed for artificial seed production in Alpinia galanga. Shoot buds obtained from in vitro proliferated plantlets on Murashige and Skoog (MS) medium containing 2.5 mg/l 6-benzyladenine (BA) was used for encapsulation. Calcium-alginate matrix composed of 3% sodium (Na) alginate and 100 mM calcium chloride (CaCl2.2H2O) was optimum for uniform, firm synseed preparation. Highest germination and plantlet conversion (87%) was obtained on MS medium containing 2.0 mg/l BA and 0.5 mg/l α-naphthalene acetic acid (NAA) under light/dark (16/8 h) photoperiod. Synseeds stored at 4 °C exhibited 85% and 23% germination after 30 days and 120 days respectively. In vitro grown plantlets were hardened successfully to field condition with 76% survival rate. 8 random amplified polymorphic DNA (RAPD) markers were used to check the genetic stability of regenerated plants. A monomorphic banding profile confirmed the genetic similarity of plants obtained from synseeds.

Salinization of soil is a major problem affecting many plant physiological processes. The use of arbuscular mycorrhizal fungi (AMF) plays a key role in improving the growth and the crops yield. The aim of this study was to evaluate the combined effects of salt stress and AMF on agro-physiological and biochemical responses of Stevia rebaudiana Bertoni. The experiment was carried out in a completely randomized design with ten replicates under the green house conditions. Stevia plants were inoculated with AMF consortium (MC) or with Rhizophagus irregularis (Ri) on the presence (80 mM of NaCl) or the absence (0 mM of NaCl) of salt stress. The results showed that plant height, dry biomass of shoots and roots parts, mycorrhizal frequency and intensity, relative water content, chlorophyll fluorescence, stomatal conductance, chlorophyll a, and total chlorophyll were significantly reduced by 29%, 72%, 36%, 84%, 65%, 24%, 17%, 60%, 28.50%, and 40.9% respectively under salt stress. These changes were associated with a significant increase in antioxidant enzymes (activity of polyphenol oxidase, peroxidase, superoxide dismutase, and catalase), electrolyte leakage, lipid peroxidation, and hydrogen peroxide contents. The application of AMF (MC and Ri) improved growth and physiological parameters through rising the activities of antioxidant enzymes and reduction of the oxidative damage caused by the salt stress. The better results were recorded with MC-inoculated plants. These findings suggested that AMF could be an effective strategy to alleviate the adverse effects of salt stress on Stevia rebaudiana.

In this study, the effects of Ag-ZnO nano-composites (NCs) on the germination of peanut (Arachis hypogaea) and kidney beans (Phaseolus vulgaris) have been investigated. Two synthesis techniques have been utilized including green Synthesis and sol–gel method to compare their effect on germination of both types of beans. Various inquring approaches including XRD, Scanning Electron Microscopy (SEM), EDX and UV–vis spectroscopy were employed to characterize the synthesized Ag-ZnO NCs. The XRD pattern showed that the synthesized powdered Ag-ZnO nano-composites have a highly crystalline pure structure without any secondary phase. SEM disclosed the spherical-shaped Ag NPs and rod-like ZnO NPs for green and sol–gel synthesis, respectively. The EDX spectra confirmed the materials through respective peaks of Ag, Zn and O which validates the synthesis of Ag-ZnO NCs. The different concentrations of nanostructures (100 ppm, 500 ppm and 1000 ppm) have been applied on peanut and kidney beans to study the variation in germination rate. The germinability, germination rate percentage, mean germination time (MGT) and root and shoot lengths are employed for consideration of variations in germination rate. In contrast to 1000 ppm concentration, both types of seeds present potential results at 500 ppm for green synthesis as well as sol–gel synthesis approach. This research is highly suitable for researchers for choice of suitable synthesis method as well as for food industry for the improvements in germination rates.

Foetid juniper (Juniperus foetidissima Willd.) is one of the most important coniferous species faced with multiple threats and it is difficult to propagate it with sexual reproduction. Therefore, the main goal of this study was finding appropriate salt concentrations and growth regulators for shoot regeneration and rooting of J. foetidissima under in vitro conditions and also shortening time of mass production. The effects of 6 different basal culture media (Olive Medium (OM), Murashige and Skoog (MS), Driver and Kuniyuki (DKW), Woody Plant Medium (WPM), 1/2 MS, and 1/4 MS) on shoot proliferation and two different methods of root induction on explants were investigated. Results revealed that OM culture medium supplemented with 6-benzylaminopurine (BAP) (1 mg L−1) and indole-3-acetic acid (IAA) (0.1 mg L−1) was the best medium for shoot proliferation of J. foetidissima (P

The aim of this study was to determine the biological control possibilities of Pseudomonas savastanoi pv. savastanoi (Psv) by using epiphytic and endophytic bacteria isolated from the roots and shoots of healthy olive trees. A total of 336 bacterial isolates (196 epiphytes and 140 endophytes) were recovered and diagnosed by using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF–MS). In dual culture tests, 81 bacterial strains inhibited pathogen development at different degrees. The highest inhibition value (A-index) was determined in Bacillus megaterium HZEP7 with a 5.24 A-index value, followed by B. subtilis HZEN1 (4.85) and Pseudomonas koreensis HZEN27 (4.83). Mechanisms of antagonist bacterial strains for siderophore and protease production were also investigated by in vitro tests. The strains to be used in vivo tests were determined according to high antagonistic effects and B. subtilis HZEN1, B. megaterium HZEP7, P. koreensis HZEN27, and B. pumilus HZEP29 strains were selected for in vivo tests. In the carrot slices inoculation, the highest inhibition value was detected in B. subtilis HZEN1 with 98.78%, followed by B. megaterium HZEP7 (94.49%), P. koreensis HZEN27 (92.09%), and B. pumilus HZEP29 (90.26%) isolates. Similar to carrot slices in sapling inoculation tests, all bacterial isolates inhibited gall formation. The highest inhibition value was determined in the B. subtilis HZEN1 isolate with 78.72%, followed by B. megaterium HZEP7 (60.87%), P. koreensis HZEN27 (46.09%), and B. pumilus HZEP29 (44.87%) isolates. The obtained results showed that B. subtilis HZEN1, B. megaterium HZEP7, P. koreensis HZEN27, and B. pumilus HZEP29 isolates could be used against Psv, the causal agent of the olive knot disease, as a biocontrol agent.

Nepenthes khasiana Hook. f. is a critically endangered, carnivorous, endemic species of the Assam and Meghalaya and belongs to the monotypic family Nepenthaceae. An efficient micropropagation protocol was optimized for the propagation and ex-situ conservation of elite germplasm of the species from axenic shoot tip culture. The axenic cultures were established through in vitro seed germination, which envisage the prolonged seed germination time (180 Days) and poor seed germination (25%) in the species. Application of GA3 (500 ppm) enhanced the seed germination upto 89%. Half-strength Murashige and Skoog (MS) medium fortified with 4.4 µM BAP was reported to be the ideal medium and 96.81% shoot formation was observed in N. khasiana shoot tip explants. The highest shoot proliferation of 21.22 ± 0.78 shoots per explants with 10.5 ± 0.5 cm mean shoot length was recorded. The in vitro raised shoots rooted in half salt strength MS medium fortified with IBA (4.9 μM) and 92.11% rooting was recorded with average 17.58 ± 0.87 roots per shoot and 5.5 ± 0.29 cm root length. In-vitro raised plantlets were shifted to the glass house with 65% success rate. Thus, the protocol developed might be useful for the ex-situ conservation of germplasm and commercialization of species to cope up with the ever increasing medicinal and ornamental demands of the species.

Several structural attributes associated with the buds of shoot apices of angiosperms have been related to protection both at the mechanical and chemical defense levels. Although several characteristics related to the protection of shoot buds are known in different taxa of Sapindales, their occurrence in the neotropical genus Homalolepis (Simaroubaceae) are still unknown. Homalolepis includes 28 species mostly with extra-Amazonian distribution, occurring mainly in the Brazilian domains of the “Cerrado” and the Atlantic Forest. Its species vary widely in terms of habit, many of which are considered adaptations to the environments in which they occur. In this study, usual light and scanning electron microscopy techniques were applied in order to analyze the morphoanatomical and histochemical characteristics associated with the protection of apical and lateral shoot buds in phanerophyte (H. arenaria Devecchi & Pirani (Devecchi & Pirani), H. glabra (Engl.) Devecchi & Pirani and H. insignis (A.St.-Hil. & Tul.) Devecchi & Pirani) and geophyte (H. pumila Devecchi & Pirani, H. salubris (Engl.) Devecchi & Pirani and H. suffruticosa (Engl.) Devecchi & Pirani) species. Glandular prophylls, cataphylls, suberized layer on the leaf primordium, colleters, non-glandular trichomes, as well as a secretory canal with precocious development in the leaf primordium are among the characteristics that can be considered strategies for the protection of shoot buds in the studied species. Such structures are related to physical (cataphyll and suberized layer) and chemical (prophylls and secretory canal) protection or both (trichomes), against desiccation or attack by herbivores.

Livestock grazing is one of the most common utilization methods and exerts a significant effect on the carbon allocations between the above- and belowground components of a grassland ecosystem. The major aim of this study were to evaluate the proportions of 13C allocation to various C pools of the plant-soil system of a meadow steppe ecosystem in response to changes of stocking rate. In situ stable 13C isotope pulse labeling was conducted in a long-term grazing experiment with 4 stocking rate. Plant materials and soil samples were taken at eight occasions (0, 3, 10, 18, 31, 56 and 100 days after labeling) to analyze the decline in 13C over time, and their composition signature of 13C were analyzed by the isotope ratio mass spectrometer technique. We found a significantly greater decline in assimilated 13C of shoot and living root for the heavily grazed swards compared to other stocking rates, with the highest relocation rate of 13C into soil C pool compared to other fractions. In addition, light grazing significantly allocated 13C assimilates in the belowground pool compared to other stocking rates, especially in the live root and topsoil C-pools. In this study, the effects of grazing on the carbon transfers and stocks within the plant-soil system of the meadow steppe were highly grazing pressure dependent. Plant-soil system in light stocking rate presented the highest C utilization efficiency, however, plants allocated more C to soil C pools with heavily stocking rate.

The aggravation of soil cadmium (Cd) pollution is a serious threat to human food health and safety. To reduce Cd uptake and alleviate Cd toxicity in staple food of wheat, a completely random experiment was performed to investigate the effect of exogenous ascorbic acid (AsA) on Cd toxicity in two wheat varieties (L979 and H27). In this study, the treatments with combinations of Cd (0, 5, and 10 µmol L−1) and AsA (0, 50, and 200 µmol L−1) were applied in a hydroponic system. Toxicity induced by Cd inhibited biomass accumulation; decreased wheat growth, photosynthesis, and chlorophyll content; increased lipid peroxidation; and reduced activity of superoxide dismutase (SOD), but stimulated catalase (CAT) and peroxidase (POD). The addition of AsA significantly improved the growth status by increasing the wheat biomass, chlorophyll content, photosynthetic rate, protein concentrations, and antioxidant enzyme activity. Besides, AsA significantly decreased Cd concentration of shoot and root by 14.1–53.9% and 20.8–59.5% in L979 and 23.7–58.8% and 22.1–58.1% in H27 under Cd5, and 23.7–53.6% and 16.6–57.1% in L979 and 21.5–51.6% and 15.3–54.0% in H27 under Cd10, respectively. Malondialdehyde (MDA) accumulation was decreased remarkably with the addition of AsA by 31.2–32.9% in L979 and 27.1–45.2% in H27 under Cd10, respectively. Overall, exogenous application of AsA alleviated the Cd toxicity in wheat plants by improving the wheat growth, soluble protein content, photosynthesis, and antioxidant defense systems, and decreasing MDA accumulation.

The effects of soil invertebrates (earthworms) and AM fungus fertilizers were observed alone and together on the growth of Punica granatum and on the reproduction of herbivores (Aphis punicae). Pomegranate plants were grown individually in pots containing sandy, silty, and clay soil. Plants were grown in soil containing: a) no added fauna, b) earthworms, c) AM fungus fertilizers, and d) AM fungus fertilizers and earthworms. As a result of the study, the highest number of shoots were observed in worm + fertilizer applied treatments and the lowest in the only worm used treatments. There was a significant difference between control (Pk) and worm + fertilizer (Psg) groups in shoot number (P

This research aimed to investigate the prospected desirable influences of sowing date, planting density, and soil enrichment with humic acid (HA) on the growth and uptake of macro and micronutrients and their implications on the productivity of sunflower plants grown in dry, saline, and nutrient-deficient environment. Two field trials were conducted in two seasons (2018 and 2019) by planting the sunflower plants on two dates, one early (on May 5) and the other late (on May 30) under three planting densities of 95.2 (high), 71.4 (medium), and 57.1 (low) thousand plants ha−1 and soil enrichment with three rates of HA [0 (HA0), 24 (HA24), and 48 kg ha−1 (HA48)]. Early sowing date with soil HA48 under low planting density was the best combination for optimizing sunflower’s growth, while early sowing date with HA48 under high planting density was best for the macro and micronutrient contents of shoots and seeds, as well as seed, oil (OY), and protein yields. With the application of automatic linear modeling analysis, seed yield, oil%, stem diameter, harvest index, shoot dry weight, plant height, and seed yield plant−1 were selected as the characteristics most contributing to OY in predicting stressed sunflower’s OY. Due to the ever-climate changes, choosing an appropriate sowing date, as a non-monetary practice, and optimal planting density with adequate anti-stress (e.g., HA) substance to enrich the low-fertile saline soils is the safest effective way to maintain global food security and sustainable agricultural development in dry environments.

The objective of the present study was to elucidate the mechanism by which oxalic acid (OA) alleviates cadmium (Cd) stress. Chickpea (Cicer arietinum L.) seeds were treated with 200 µM CdCl2 for 6 days or 3 days followed by the combination 200 µM Cd + 100 µM OA for three additional days. Exogenous OA mitigated the growth inhibition by Cd of both roots and shoots. This positive effect can be attributed to the increased OA exudation from roots and the alleviation of the Cd-induced depletion of endogenous OA in shoots (80% increase versus Cd-stressed). The combination Cd + OA proved to be effective in protecting cell membrane integrity. This beneficial effect was reflected by 36 and 24% decrease in lipoxygenase (LOX) activity in roots and shoots, respectively, and 60% decrease in the accumulation of the harmful aldehyde, 4-hydroxy-2-nonenal (4-HNE) in roots when compared to Cd-treated samples. Besides, OA restored the Cd-imposed disruption of the plasma membrane function. This effect was depicted by an optimal H+-ATPase activity and proton exudation rate. Oxalic acid counteracted the Cd-induced overproduction of hydroxyl radical (OH•) and NADPH-oxidase activity increase, leading to restore a steady cellular redox state. Furthermore, OA modulated the impact of Cd on Cu/Zn-superoxide dismutase (Cu/Zn-SOD), ascorbate peroxidase (APX), and catalase (CAT) activities in chickpea seedlings. Present results indicate that OA is able to alleviate Cd toxicity by protecting plasma membrane integrity and modulating antioxidant activities. Moreover, our findings shed light on the interplay between plasma membrane H+-ATPase and the accumulation and root exudation of OA.

Little is known about phosphorus (P) uptake at deep soil layers, e.g. below 1 m of soil depth. We aimed at tracing P uptake up to 4.2 m of soil depth of different plant species in an arable field using 33P isotope combined with the core-labelling technique. Soil was packed into ingrowth-cores and labelled with H3 33PO4. The ingrowth cores were placed into field plots of intermediate wheatgrass, perennial lupine, rosinweed and curly dock at the depths of 0.2, 1.0, 2.5 and 4.2 m. 33P uptake into shoots was measured by liquid scintillation assay after 4, 6 and 8 weeks of labelling. Root-length and diameter classes were analyzed from the retracted ingrowth-cores. We observed 33P uptake from all the tested soil depths down to 4.2 m. Curly dock with higher root density exhibited greater 33P uptake. Roots below 1 m was responsible for nearly 50 % of the total 33P uptake from all four depth-levels. Also, roots below 1.0 m showed higher 33P concentration per unit root mass, in line with a higher proportion of fine roots at depth. Our data demonstrate that perennial crop species can access deep P beyond 4 m of soil depth, and that the share of total P uptake below topsoil layers can be substantial, possibly related to the shift towards finer roots in deep soil layers. The results also show that the capacity for deep P acquisition highly depends on crop species even under same field conditions. Therefore, future research should focus on identifying crops with efficient P acquisition capacity in deeper soil layers which can potentially improve crop P access, especially under P-limited conditions in the topsoil.

Lead (Pb) is one of the most toxic and harmful pollutants to the environment and human health. Centipedegrass (Eremochloa ophiuroides (Munro) Hack.), an excellent ground cover plant for urban plant communities, exhibits the outstanding lead tolerance and accumulation. Nitrilotriacetic acid (NTA) is an environmentally friendly chelating agent that strengthens phytoremediation. This study explored the effects of different NTA concentrations on the absorption and transportation of mineral elements and Pb in centipedegrass. Following exposure to Pb (500 μM) for 7 days in hydroponic nutrient solution, NTA increased root Mg, K, and Ca concentrations and shoot Fe, Cu, and Mg concentrations and significantly enhanced the translocation factors of mineral elements to the shoot. Although NTA notably decreased root Pb absorption and accumulation, it significantly enhanced Pb translocation factors, and the Pb TF value was the highest in the 2.0 mM NTA treatment. Furthermore, the shoot translocation of Pb and mineral elements was synergistic. NTA can support mineral element homeostasis and improve Pb translocation efficiency in centipedegrass. Regarding root radial transport, NTA (2.0 mM) significantly promoted Pb transport by the symplastic pathway under the treatments with low-temperature and metabolic inhibitors. Meanwhile, NTA increased apoplastic Pb transport at medium and high Pb concentrations (200-800 μM). NTA also enhanced the Pb radial transport efficiency in roots and thus assisted Pb translocation. The results of this study elucidate the effects of NTA on the absorption and transportation of mineral elements and Pb in plants and provide a theoretical basis for the practical application of the biodegradable chelating agent NTA in soil Pb remediation.

Purpose In cold climates, glyphosate residues may linger in soils, with effects on plant–microbe interactions and, consequently, plant performance. Here, we explore the influence of glyphosate residues on the endophytic microbiota (bacteria and fungi) and performance of the perennial nitrogen-fixing weed Lupinus polyphyllus. Methods In a common garden, we grew plants from six populations of L. polyphyllus in glyphosate-treated or untreated control soils, with or without additional phosphorus. We sampled plant microbiota (leaves, roots, nodules) and assessed plant performance based on six traits: height, retrogression probability (i.e. shrinkage), biomass, root:shoot ratio, nodule number, and nodule viability. Results The richness of plant endophytic microbial communities was determined by soil phosphorus level rather than by glyphosate treatment. However, for bacteria, the composition of these communities differed between glyphosate-treated and control soils across plant tissue types; no difference was observed for fungi. The plant bacterial communities in both soil types were dominated by potential nitrogen-fixing bacteria belonging to family Bradyrhizobiaceae, and particularly so in glyphosate-treated soils. Overall, though, these changes in plant bacterial communities had a minor effect on plant performance: the only difference we detected was that the probability of retrogression was occasionally higher in glyphosate-treated soils than in control soils. Conclusion Our findings indicate that glyphosate-based herbicides, when applied at the recommended frequency and concentration, may not have critical effects on the growth of short-lived weeds after the safety period has passed; however, the endophytic microbiota of such weeds may experience longer-lasting shifts in community structure.

Juglans regia L. is a good host for Serendipita indica. Under drought condition, seedlings colonized with S. indica showed higher values in plant height, total fresh biomass, root/shoot ratio, relative growth rate, leaf relative water content and chlorophyll content, gas exchange parameters, maximal photochemical efficiency, photochemical quenching, and effective photosystem II quantum yield than the uncolonized seedlings. It suggested beneficial effects of S. indica on host plants' growth and physiological parameters in response to drought. In comparison with the uncolonized seedlings, S. indica-colonized seedlings showed lower levels in hydrogen peroxide, superoxide anion, malondialdehyde, and relative electrical conductivity under drought condition, suggesting the ability of S. indica to prevent or retard the accumulation of reactive oxygen species and to diminish the oxidative injure. Furthermore, walnut seedlings responded to drought by actively accumulating osmotic regulation substances including soluble protein, soluble sugar, and proline. Root colonization with S. indica was more conductive to the accumulation. Moreover, in response to drought stress, walnut seedlings, regardless of colonization, increased activities of superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione reductase, levels of ascorbate and glutathione, and ratios of reduced ascorbate/dehydroascorbic acid and reduced glutathione/oxidized glutathione in leaves and roots. S. indica colonization induced much more increase in the abovementioned indicators as compared to the uncolonized seedlings. Overall, S. indica colonization alleviated the detrimental effects of drought stress by altering root system, enhancing osmotic adjustment, and repressing the accumulation of reactive oxygen species via stimulating antioxidant system including enzymatic and nonenzymatic components. KEY POINTS: • S. indica stimulated root growth of walnut seedlings under drought condition. • S. indica accelerated osmotic adjustment under drought condition. • S. indica activated antioxidant defense mechanism under drought condition.

Boron (B) has been considered either as a nutrient or as a toxic non-essential element for plants and considerable debate arose recently regarding its functions and mechanisms of action. To gain further detail on the roles of boron in growth, development, and cell viability, Arabidopsis wild-type and mediator18 mutants, these later showing genetically fixed cell death in the pro-vasculature of roots, were germinated and grown side by side in agar-solidified plates with a standard nutrient solution supplemented with increasing concentrations (0.25–8 mM) of boric acid (BA). In the WT and med18-1 mutants, BA exerted a dose-dependent inhibition of leaf formation and primary root growth, but did not significantly promote root branching in the WT or med18-1 mutants, these later manifesting an enhanced lateral root formation capacity under a wide range of BA concentrations. Although the overall effect of BA in roots was growth repressing, no signs of cell death in meristems of primary roots of WT seedlings could be appreciated, instead, it appears to diminish the cell death manifested in pro-vasculature of med18 mutants, which correlates with reduced expression of the ERF115 transcription factor, which is induced in inner tissues upon damage, and recovery of auxin-inducible gene expression within the root tip. Irrespective of the overall growth-repressing effects in the shoot and root systems, it seems clear that important protective functions are orchestrated by BA, which supports cell viability in a mutant with spontaneous tissue damage.

A novel bio-based activated carbon was synthesized from vine shoot, an agricultural waste, by chemical activation method using NaOH as activating agent. Adsorption of acetone, butanol and ethanol (ABE), as main products in ABE fermentation, in the single and multicomponent systems were measured. The experiments were carried out in both equilibrium and dynamic conditions and selectivity of the adsorbent was calculated, accordingly. The adsorption kinetics of the synthesized adsorbent were also investigated. Based on the obtained results, the synthesized activated carbon (AC) shows a very high butanol loading (about 520 mg/g at 10 g/l butanol equilibrium concentration). High butanol selectivity over ethanol and acetone (10.31 and 7.66, respectively), obtained from multicomponent equilibrium experiments, indicated that the vine shoot based activated carbon showed the high affinity toward butanol. This result was also approved by ABE multicomponent breakthrough experiment in which adsorbed ethanol and acetone displaced by butanol during the adsorption process. High butanol capacity, fast equilibrium time, and excellent butanol affinity, makes the synthesized activated carbon a great candidate for butanol adsorption from ABE fermentation products.

Roots are the most essential plant part owing to the uptake of water and nutrients. Therefore, phenotyping of root features is vital for improving soybean cultivars. This study evaluated the root morphological and architectural traits of six soybean cultivars using two-dimensional (2D) root imaging. The cultivars were selected from a previous experiment, based on 6 root phenotypes (total root length [TRL], surface area [SA], average diameter [AD], number of tips, number of forks, and main total length [MTL]) in 372 soybean cultivars, (3 each from the highest 5% and lowest 5%). When plants reached two trifoliate leaves stage, both root and shoot parts were harvested and analyzed. According to the analysis of variance, significant variability was observed between the two groups (highest 5% and lowest 5%) for root and shoot morphological traits, but no significant difference was found regarding most root architectural traits. Among three root phenotypes (TRL, SA, and RV [root volume]), IT 21595 and IT 165432 were the highest and lowest, respectively. TRL exhibited a significant positive correlation with other root and shoot morphological traits, such as SA, RV, leaf area, leaf length, and leaf width. Contrastingly, AD showed a significant negative correlation with those parameters. TRL and SA of all the cultivars were classified based on root diameter classes (0–0.5 mm, 0.5–1.0 mm, and 1.0–1.5 mm). A segment of TRL

The concentrations of cadmium (Cd) and zinc (Zn) in arable lands exceed the maximum permissible levels due to the excessive use of phosphorus fertilizers and fungicides by farmers. The increasing issues related to the application of agrochemicals have lead to the demand for the implementation of sustainable agricultural approaches. Association of arbuscular mycorrhizae with crop plants is an appropriate strategy due to the potential of these microorganisms to augment the metals tolerance of plants through the immobilization of Cd and Zn in an eco-friendly manner. In the present study, 45 d old Zea mays (var. CoHM6) plants inoculated with AM fungi (Claroideoglomus claroideum) were exposed to 1.95 g Zn Kg−1 soil and 0.45 g Cd Kg−1 soil. The major objective of this study was to determine the metabolic alterations in the leaves and roots of mycorrhizal and non-mycorrhizal plants exposed to CdCl2 and ZnSO4. Both non AM and AM plants exhibited alterations in the quantity of primary and secondary metabolites on exposure to Zn and Cd toxicity. Moreover, Zn and Cd-induced accumulation of γ-sitosterol reduced the quantity of neophytadiene (a well-known terpenoid) and aided the production of 3-β-acetoxystigmasta-4,6,22-triene in maize leaves. Mycorrhization and heavy metal toxicity induced significant metabolic changes in the roots by producing 4,22-stigmastadiene-3-one, eicosane, 9,19-cyclolanost-24-en-3-ol, pentacosane, oxalic acid, heptadecyl hexyl ester, l-norvaline, and n-(2-methoxyethoxycarbonyl). In addition, the metal-induced variations in leaf and root lignin composition were characterized with the aid of the FTIR technique. Mycorrhization improved the tolerance of maize plants to Cd and Zn toxicity by stabilizing these metal ions in the soil and/or limiting their uptake into the plants, thus ensuring normal metabolic functions of their roots and shoots.

Sclerotium oryzae Catt. stem rot in rice is a devastating disease affecting rice productivity. Administration of sub-lethal dose (50 µM) of cadmium (Cd) against the pathogenic activity of Sclerotium oryzae on low-land rice (Oryza sativa var. Manika), was investigated. Improvement of shoot length was noticed with an increase in photosynthetic pigments, total carbohydrate, sugar, protein content in co-stressed (Cd + S. oryzae) rice as compared to the pathogen (S. oryzae) treated plant. Reduction of the fungal load was observed in co-stressed rice root tissue as evident by the SEM study. Fungus-treated rice, showed 2.4 fold reductions in protein level in 30 days after inoculation while that reduction was only 1.2 fold in co-stressed plants. In co-stressed rice Cd was traced in the root but not in shoot, leaf, panicle, and grain as evident by atomic absorption spectroscopy and Raman spectrum. An increase of stress-mediated proline (~ 4.2 fold) and other metabolites were found adjusted at co-stressed rice that might be due to Cd induced defense response in rice against S. oryzae. Downregulation of enhanced phenyl ammonia-lyase (PAL) and malondialdehyde (MDA) activity in co-stressed rice as compared to Cd treated plant justifies heavy metal (sub-lethal dose) mediated activation of the defense system of rice. A significant increase in the activity of catalase, guaiacol peroxidase, and superoxide dismutase observed in the co-stressed plant as compared to the pathogen treated plant supports the concept of cellular defense mechanism in rice. Protein band of ~ 29 kDa was disappeared in S. oryze infected rice while co-stressed rice showed a new ~ 23.5 kDa band that might be due to activation of PR-protein mediated defense in rice. The effect of low-dose Cd might be useful in providing defense in paddy crops against pathogen infection.

Vanadium (V) is a multivalent redox-sensitive metal that is widely distributed in the environment. It enters the environment mainly through anthropogenic activities, such as industry, mining, fossil fuel burning, and fertilization, and imposes serious problems for plants, animals, and human health. The adverse effects of V on human health are determined by its movement through the environmental components (i.e., atmosphere, water, and soil). Exceeding the well-defined threshold level of V intake in animals (species-specific) and humans (V > 4500 µg per day) causes diseases such as vasoconstriction, congestion, focal hemorrhage in the lungs and adrenal cortex, congestion, fatty liver, and diarrhea, dehydration, cardiac disturbances, reduction in food intake, or weight loss. The threshold level of V toxicity varies from species to species. Low concentrations of V increased the root length, plant height, and biomass yield due to increased seed germination, chlorophyll, nutrient uptake, and nitrogen utilization. High concentrations of V inhibit protein synthesis, enzyme activities, and ion transport, resulting in stunted plant growth, shoot and root abnormalities, and even plant death. Various soil properties, including organic matter status, pH, calcium, phosphorus, aluminum, and iron (hydr) oxides, are the crucial determinants of V bioavailability and uptake by plants. Alteration in these properties could improve plant growth by inhibiting V uptake. Phytoremediation using microorganisms and organic amendments can be a feasible technique to remediate V-polluted soils. In this review, we concise an overview of V distribution in different environmental components and its impact on plants and human health. In addition, we also discussed the possible remedial approaches to eliminate as well as reduce the V concentration in soil.

Drought poses a severe threat to global wheat production and world food security. This study was conducted to evaluate bread wheat genotypes for drought tolerance based on different morphological, biochemical, and physiological traits. The responses of 25 bread wheat genotypes of Pakistani origin were evaluated based on morphological, biochemical, and physiological traits under optimal (70% water holding capacity (WHC)) and drought stress (35% WHC) conditions. Sufficient genotypic variability was noted in the tested genotypes on the morphological (shoot length, relative leaf water contents, and seedling dry weight), biochemical (membrane injury index, leaf free proline, and total soluble phenolic contents), and physiological traits (chlorophyll meter value, intercellular CO2 concentration (Ci), stomatal conductance (gs), photosynthetic rate (A), ratio of photosynthetic rate and intercellular CO2 concentration (A/Ci), transpiration rate (T), and instantaneous water use efficiency (WUEins)) under both control and drought stress conditions. The principal component analysis (PCA) under drought stress showed 78.3% variability of morpho-biochemical traits and 67.0% of physiological traits. Bi-plot of PCA showed the genotypes SQU-2, SQU-4, SQU-10, and SQU-11 are tolerant under drought stress and grouped based on high A, and A/Ci. Similarly, the genotypes SQU-8, SQU-9, SQU-14, SQU-15, SQU-16, and SQU-24 were also tolerant and grouped based on high WUEins and Ci under drought stress. In conclusion, significant genotypic variability was found among the tested wheat genotypes based on morphological, biochemical, and physiological traits, which can be used in future breeding programs to develop drought-tolerant bread wheat genotypes. The genotypes SQU-9, SQU-10, SQU-7, and SQU-13 had better growth under drought stress than other genotypes due to the accumulation of free proline and soluble phenolics which helped maintain tissue water status and sustained the photosynthesis.

Abstract Lactuca indica L. (Asteraceae), a wild lettuce, is used as a vegetable and in traditional medicine. This study aims to establish in vitro propagation protocol and evaluate lactucin and antibacterial property from in vitro and natural plant tissues. Leaf blades and petioles were cultured in vitro on Murashige and Skoog (MS) medium supplemented with various concentrations of 6-benzylaminopurine (BAP) and 1.2 mg L–1 indoleacetic acid (IAA). Leaf petioles and a lower BAP concentration (0.5 mg L–1) were optimal for direct shoot induction, while the leaf blade and a higher BAP (4 mg L–1) concentration performed best for callus induction. When the callus was subcultured, 98.7% of samples regenerated plants on MS medium supplemented with 1.5 mg L–1 BAP and 0.5 mg L–1 IAA. MS medium containing 1 mg L–1 IAA was best for in vitro rooting. A high-performance liquid chromatography analysis of the in vitro samples revealed a higher amount of lactucin (sesquiterpene lactones) in the root than the callus and the leaf, whereas in naturally grown plants, higher lactucin amounts were obtained from the juvenile root followed by the root of the flowering plant and juvenile leaf as the lowest concentration. All tissue extracts showed antibacterial activity against Pseudomonas fuscovaginae (a rice pathogen) and Escherichia coli, which was directly proportional to amount of lactucin produced. This in vitro regeneration and phytochemical investigation will facilitate the further exploitation of this useful wild plant.

Potassium (K+) deficiency is one of the most abiotic constraints reducing plant growth and productivity. The use of silicon (Si) has been reported to alleviate abiotic stresses in plants. However, data regarding the roles played by this element in mediating K+ deficiency are still scarce. Therefore, the present work was carried out to investigate the possible involvement of Si in mitigating the negative impact of K+ deficiency on cultivated barley Hordeum vulgare L. (var. Rihane). Plants were hydroponically grown either under K+ sufficient nutrient solution containing 3 mM K+ or in K+-deficient medium containing 10 µM K+ without or with Si (1 mM). Shoot growth, shoot water content, leaf osmotic potential, shoot K+ concentration, photosynthetic activity, chlorophyll fluorescence, soluble sugar concentrations, and shoot phenolic compound contents and their antioxidant properties were determined. Results showed that shoot growth, shoot K+ concentration, and gaseous exchange were reduced by K+ deficiency. Photosynthesis decrease was mainly linked to sugar accumulation in leaves. Except for K+ concentration, a beneficial effect of Si was observed. A modulation in the accumulation of polyphenols and their antioxidant capacities has been observed. Overall, the data indicate that the beneficial effects of Si on barley plants grown under K+ deficient medium were mainly due to increased growth and photosynthetic activity but not through an improvement of shoot K+ concentration and phenolic compound accumulation and related antioxidant capacity suggesting a possible use of Si as a fertilizer to correct the deleterious effects of nutritional stress.

The present study has been carried to investigate the interaction and effect of plasma activated water (PAW) on pea seeds. PAW is produced with the interaction of air plasma with water that forms reactive oxygen–nitrogen species in it. Our results with surface morphological study shows that PAW treatment removes the wax from the surface of peas and modifies their hydrophobic surface to hydrophilic. Wettability study shows decrease in water contact angle with seed surface after PAW treatment. Also, PAW treatment improves germination rate, viability index and mean germination time compared to control. Further, the study reveals that the grown plants have higher roots and shoots length, fresh and dry weight, increased chlorophyll ‘a’ and higher sugar and protein concentration compared to control. Although electrolytic and phenolic leakage from pea leaves did not show any significant difference in PAW and control-treated seeds, results obtained from antioxidant analysis clearly show an increased antioxidant enzymatic (SOD (EC no. 1.15.1.1), CAT (EC no. 1.11.1.6), APX (EC no. 1.11.1.11), and POD (EC no. 1.11.1)) activity mainly in the roots in seedlings grown from seeds treated with PAW. However, no significant difference in H2O2 concentration in the pea plant was observed. Hence, our study indicates potential role of seed pre-treatment with PAW to improve germination and plant growth.

The application of controlled-release fertilizer was an effective measure to improve the fertilizers utilization, increase yield, and reduce environmental pollution. This study aimed to explore the effects of application times and frequency and fertilization ratio of controlled-release compound fertilizer with different nutrient release periods on apple production. The experimental design consisted of controlled-release compound fertilizers with nutrient release period of 3 months (C3), controlled-release compound fertilizers with nutrient release period of 6 months (C6), and common compound fertilizer (CCF). The treatments included (1) one-time application of C6 in March (B-C6); (2) one-time application of C6 in October (H-C6); (3) one-time application of 50% C3 and 50% C6 in March (B-(50C3 + 50C6)); (4) one-time application of 70% C3 and 30% C6 in March (B-(70C3 + 30C6)); (5) common compound fertilizer (CCF) with one-time application of CCF in March (B-CCF); and (6) common compound fertilizer with three-time application of CCF in March, June, and October (CT). The index of apple yield, apple tree growth index, fruit quality, and soil nutrient status were evaluated in 2-year filed production system. The results indicated that the treatment of B-(50C3 + 50C6) significantly improved the growth of apple trees on trunk diameter, plant height, new shoot growth and chlorophyll content, and the apple yield increased by 8.82%. By comprehensive comparison of yield, soil nutrients, and fruit tree growth indexes, the treatment with (B-(50C3 + 50C6)) was considered to be the best controlled-release fertilizer application method.

Plantlets of Hemidesmus indicus (L.) R. Br. (Indian sarasaparilla) were developed in vitro in two different types of culture vessels and closure types—(1) culture bottles with polypropylene screw-caps and (2) conical flasks with cotton plugs both containing Murashige and Skoog medium with 1.0 mg L−1 6- benzylaminopurine, 0.5 mg L−1 kinetin, and 0.1 mg L−1 indole-3-acetic acid. Shoots proliferated in the bottles exhibited production of (i) a few leaves with reduced leaf area, (ii) wiry and brittle stem, and (iii) less number of shoots, whereas, the shoots developed in culture flasks were of superior characteristics with healthy leaves. The leaves developed in bottles revealed the presence of under-developed cuticle, lower palisade/spongy ratios, undifferentiated epidermal layers, abnormal and non-functional stomata, absence of periderm, and unorganized ground and vascular tissue systems preceded the development of hyperhydrated shoots. The use of a conical flasks culture system promoted the development of natural anatomical features in plantlets. Overall, the type of culture vessel remarkably influenced the growth and development of in vitro-derived plantlets of H. indicus which could be explored for commercial propagation of this multipotent medicinal plant. Compared with glass bottles, cotton plugged flasks improved shoots formation, morpho anatomical parameters, rooting, and survival of in vitro plantlets of Hemidesmus indicus.

Information on the various badnaviruses causing cacao swollen shoot disease (CSSD) or cacao swollen shoot virus disease (CSSVD) in West Africa is scattered. Several strains of the Cacao swollen shoot virus (CSSV) were assumed to cause CSSD; however, several recent studies have led to the discovery that CSSD is actually caused by many species of badnaviruses collectively called CSSD badnaviruses. This review seeks to present an update on the various CSSD-badnaviruses causing CSSD in the West African subcontinent, their geographical distribution, genome variability, species diversity, phylogenetic relationships, and possible origin. A comprehensive search of the scientific literature in relation to terms such as CSSV, CSSD, and CSSD-badnaviruses in Togo, Nigeria, Sierra Leone, Ghana, and Cote d’Ivoire was conducted. A total of seven cacao-infecting badnavirus species accepted by the International Committee on Taxonomy of Viruses (ICTV) were identified in this study to be the cause of CSSD in these countries. These are Cacao swollen shoot Ghana N virus (CSSGNV), Cacao swollen shoot CD virus (CSSCDV), Cacao swollen shoot Ghana Q virus (CSSGQV), Cacao swollen shoot CE virus (CSSCEV, also known as Cacao red vein virus, CRRV), Cacao swollen shoot Ghana M virus (CSSGMV; also known as Cacao red vein banding virus, CRVBV), Cacao swollen shoot Togo A virus (CSSTAV), and Cacao swollen shoot Togo B virus (CSSTBV; previously known as CSSV). All seven ICTV recognized CSSD badnaviruses were detected in the various cacao growing regions of Ghana and were also present in different combinations in other West African countries. Several genetic differences (arrangement of open reading frames (ORFs), genome size, and nucleotide sequences) were observed among the CSSD badnaviruses. Such studies are needed to help in the development of cacao germplasm which is resistant or shows some level of tolerance to CSSD badnaviruses.

Symbiotic N2 fixation depends on a steady supply of carbohydrate to nodules. Sucrose is the main carbohydrate translocated through the phloem to nodules. Some putative sucrose transporter genes have been found in legumes and are highly expressed in nodules. However, none of these are crucial for sucrose transport to nodules. In this study, we characterized a soybean sucrose transporter, GmSUT1, which was highly expressed in nodules and mainly localized in peripheral fixation zone and vascular bundles of nodules. Soybean transgenic composite plants overexpressing GmSUT1 exhibited increased nodule number and dry weight, and improved plant dry weight and N content compared to control plants when inoculated with rhizobia. Furthermore, the inoculated RNAi plants impaired sucrose transport and showed increased shoot sucrose concentration. In nodules, overexpression of GmSUT1 decreased the sucrose concentration and increased hextose concentrations, whereas RNAi plants decreased glucose concentration compared with the control plants. These results in combination with the subcellular localization of GmSUT1 at the plasma membrane indicate that GmSUT1 plays a role in sucrose transport to nodules to promote soybean nodulation.

The rupture of Fundao dam was the biggest environmental disaster of the worlds’ mining industry, dumping tons of iron ore tailings into the environment. Studies have shown that the Fundao dam’s tailings are poor in nutrients and have high Fe and Mn concentration. In this context, our objective was to evaluate the growth performance of two native tree species (Bowdichia virgilioides and Dictyoloma vandellianum) in two treatments: fertilized soil and fertilized tailings. We hypothesize that the high concentrations of iron and manganese in the tailings can impair the growth performance of plants by interfering with the absorption of nutrients made available through fertilization. Soil and tailings samples were collected in the municipality of Barra Longa (MG, Brazil), and then fertilized with mixed mineral fertilizer (“Osmocote Plus 15–9-12” at 7.5 g L−1). The experiment was conducted for 75 days in a greenhouse using 180 cm3 tubes. We evaluate chlorophyll content, maximal PSII quantum yield, root length, shoot length, root:shoot ratio, leaf area, specific leaf area and leaf area ratio, dry mass, macro- and micronutrients concentration in the tissues, and metal translocation factor. Although assuring the adequate levels of the main nutrients to plant growth (N, P, K, Ca, and Mg), the fertilization did not reverse the negative effect of tailing on these species. The high concentration of Fe in the tissues associated with less biomass production, lower plant height, smaller leaf area, bigger specific leaf area, and reduced chlorophyll content indicates a probable phytotoxic effect of iron present in the tailings for D. vandellianum. Our results base further field evaluations and longer experiments, which will facilitate the understanding of the performance of tree species submitted to tailings with fertilization. So far, this study suggests that B. virgilioides are more tolerant to excess Fe from the tailings of Fundao dam than D. vandellianum.

Leaf blight is one important fungal disease of sunflower and it is caused by Alternariaster helianthi. Scanning electron microscopy showed various histological changes in leaf tissues of infected plants. A putative phytotoxin was isolated from the culture filtrate of A. helianthi and was tested on germinating plants. The toxin of highly aggressive A. helianthi isolates inhibited root and shoot lengths and reduced vigor index, while the toxin of less aggressive isolates showed comparatively more root, shoot lengths and higher vigor index of seedlings. The detached leaf technique was used to check pathogenicity of different fungal isolates by comparing leaf spot symptoms on sunflower leaves. A. helianthi isolates Ah-18, Ah-38, Ah-125 of the highly aggressive group resulted in > 50% disease severity, Ah-157, Ah-142, Ah-12 of moderately aggressive resulted in 35-50% and less aggressive isolates Ah-92, Ah-160, Ah-158 resulted in < 35% leaf blight severity. Representatives of each group were profiled for variation in the production of secondary metabolites and proteins. In moderately aggressive Ah-157, Ah-142 isolates, an extra fifth band specific to these isolates was observed under TLC fingerprinting. Maximum retention factor was recorded in Ah-92, 160, 158, while minimum retention factor observed for isolates Ah-18, 38, 125,157 and 142. The only exception was Ah-12 that had a minimum retention factor of 0.394 among the moderately and highly aggressive groups. Secondary metabolite analysis under HPLC of Ah-92, 157, 125 isolates recorded 22 peaks. Isolate Ah-125 with high aggressiveness has a specific peak at 33.86 min in HPLC that was absent in other isolates. Six different masses were observed in MALDI-TOF with a maximum peak at 663.5 with Ah-125 isolate. Highly aggressive isolates showed similar profiling in both native and dissociated proteins with maximum identical banding patterns.

Goats are being used increasingly to manage woody invasive plants in woodland habitats, but their specific impacts on those plants over a period of time during active, periodic browsing has not been documented. This study investigated bark-stripping by goats browsing on common buckthorn in savanna habitats, focusing on possible size-selective feeding and the cumulative effects of repeated, periodic browsing over a 3-year period. When surveyed after the first browsing period, bark was stripped selectively on buckthorn stems 20 to 60 mm in diameter. Approximately 60% of all stripped stems were completely girdled, but only 14-17% of stems were bark-stripped. After five browsing periods, 66% of standing stems displayed bark stripping and 39% were completely girdled. Buckthorn densities were reduced by 90% compared to the first browsing period, the decline resulting mostly from consumption of foliage and terminal shoots of small (60 mm) were largely unimpacted by goats. Relatively few (28%) seedling buckthorn were browsed by goats, although >90% of 2nd-year plants were browsed. Buckthorn can be managed in part via goat browsing, but repeated, periodic browsing over several to many years may be necessary to produce a significant impact, and other techniques will be needed to eliminate large, seed-producing plants.

Silicon (Si) deficiency is one of the most important issues, especially in rice crop. Foliar Si application in rice production is an alternative way to quickly improve not only grain yield but also aroma quality (2-acetyl-1-pyrroline; 2-AP), especially in Thai jasmine rice. The objective of this study was to assess the potential of exogenous application Si as foliar spray in regulating 2-acetyl-1-pyrroline (2-AP) content in KDML105 and RD6 rice grain and in improving yield traits. Overall, growth characters were retained in KDML105, whereas shoot height (14.9 % over the control) and leaf length (23.4 % over the control) of RD6 treated with 2 % Si were significantly reduced. Leaf greenness (SPAD), normalized difference vegetation index (NDVI) and net photosynthetic rate (Pn) of KDML105 were greater than those in RD6, in relation to EVI (enhanced vegetation index), GNDVI (green normalized difference vegetation index), NDVI and OSAVI (optimized soil adjusted vegetation index) detection by UAV sensors. Vegetation indices, GNDVI, OSAVI and EVI exhibited close relation with SPAD (R2 = 0.896), shoot height (R2 = 0.4406) and aboveground biomass (R2 = 0.7791), respectively. Si concentration in flag leaf tissues of KDML105 peaked (1.14 mg g−1 DW) when treated with 2 % Si, whereas it exhibited 1.6 folds increase in rice husk (0.75 mg g−1 DW; R2 = 0.5266) over the control. The content of 2-AP in KDML105 was higher compared with RD6 and was enhanced by 2 % Si treatment (1.39 folds over the control). Yield traits in KDML105 including panicle weight, grain fertility percentage, number of panicles per m2, total grain weight and harvest index (HI) were significantly increased by 2 % Si foliar application over the control. Based on the results, Si foliar application is effective in improving grain yield and in regulating 2-AP aromatic content, which further needs to be tested for temporal variations across locations.