Search Results (53)

In this paper, the first demonstration of a highly strained In_0.8Ga_0.2As/In_0.2Ga_0.8Sb type-II superlattice structure grown on InAs substrates by molecular beam epitaxy (MBE) for long-wavelength infrared detection was reported. Novel methodologies were developed to optimize the As and Sb flux growth conditions. The quality of the epitaxial layer was characterized using multiple analytical techniques, including differential interference contrast microscopy, atomic force microscopy, high-resolution X-ray diffraction, and high-resolution transmission electron microscopy. The high-quality superlattice structure, with a total thickness of 1.5 μm, exhibited exceptional surface morphology with a root-mean-square roughness of 0.141 nm over a 5 × 5 μm² area. Single-element devices with PIN architecture were fabricated and characterized. At 77 K, these devices demonstrated a 50% cutoff wavelength of approximately 12.1 μm. The long-wavelength infrared PIN devices exhibited promising performance metrics, including a dark current density of 7.96 × 10⁻² A/cm² at −50 mV bias and a high peak responsivity of 4.90 A/W under zero bias conditions, both measured at 77 K. Furthermore, the devices achieved a high peak quantum efficiency of 65% and a specific detectivity (D*) of 2.74 × 10¹⁰ cm·Hz^1/2/W at the peak responsivity wavelength of 10.7 µm. These results demonstrate the viability of this material system for long-wavelength infrared detection applications. Full article

Nanobiotechnology applications in plant tissue culture have improved the development and physiology of explants, resulting in plants with high genetic homogeneity and phytosanitary quality. Silver nanoparticles (AgNPs) are well-known for their microbicidal properties, but their biochemical effects on plants require further exploration. In this work, green-synthesized AgNPs were evaluated in strawberry in vitro culture, photosynthetic pigment production, and acclimatization. AgNPs produced by Lysinibacillus fusiformis were characterized. Strawberry explants were grown in vitro on MS medium with 0, 100, 200, and 300 mg L⁻¹ AgNPs at 24 ± 2 °C and a photoperiod of 16:8 h light/dark. Shoot height and number, number of leaves, number of roots, and root length were evaluated, and chlorophyll (a, b, and total) was quantified. Rooted shoots were acclimatized ex vitro on substrates containing 0 and 200 mg L⁻¹ AgNPs. The results showed that low AgNPs concentrations had a positive impact on shoot multiplication, development, and rooting, but at higher concentrations, the effects decayed. However, chlorophyll production improved with increasing AgNP concentration. Shoots treated with AgNPs showed higher ex vitro survival. Our study has direct implications for the profitability and sustainability of commercial strawberry production. Full article

This study investigates how different types of microplastics (MPs)—fibers, glitter, plastic bags, and plastic bottles—influence heavy metal uptake in lettuce (Lactuca sativa L.), a commonly consumed leafy vegetable. A controlled eight-week pot experiment was conducted in a greenhouse using contaminated loamy sand soil (polluted with Cd, Pb, Cu, and other metals) collected from a smelter-impacted area. Microplastics were added at a concentration of 70–80 mg/kg, and lettuce seedlings were grown under phytotron conditions (22 ± 2 °C, 60 ± 5% RH, 16 h light/8 h dark) without fertilizers or external contaminants. Plant roots and shoots were harvested, and heavy metals were analyzed via MP-AES and ICP-MS. The results showed that MPs altered heavy metal mobility, bioavailability, and plant uptake. Copper accumulation in leaves decreased substantially across MP treatments, from 80.84 mg/kg in the control to 26.35 mg/kg (glitter), whereas lead and cadmium concentrations increased significantly in roots under fiber and glitter exposure (Pb increased from 12.13 mg/kg to 33.57 mg/kg and Cd from 1.70 mg/kg to 2.05 mg/kg in fiber treatment). Cobalt accumulation in leaves increased under the plastic bag treatment, indicating MP-specific metal interactions. Root growth was also affected, with fibers promoting elongation and plastic bottles restricting it. Sequential extraction revealed that MPs modified metal partitioning in soil, with Pb and Ni more strongly retained in stable fractions under some treatments. Observed trends in soil pH and organic matter content were associated with changes in metal mobility, highlighting the potential role of soil properties in mediating microplastic–metal interactions. These findings highlight the role of MPs as mediators of heavy metal transport in crops and underscore the need for clear regulatory guidelines that limit microplastic contamination in agricultural soils and promote routine monitoring to safeguard food safety and crop health. Full article

The present study aimed to investigate the effects of exogenous carnitine treatments on maize seed germination by stimulating lipid metabolism and regulating the mitochondrial respiratory pathway. Maize seeds were grown as control, 5, 7.5, and 10 μM carnitine treatment groups in a germination chamber at 25 °C under dark conditions for 5 d. It was determined that carnitine treatments increased the germination rate (GR), germination index (GI), germination potential (GP), vigor index (VI), root and hypocotyl length, fresh weight (FW), and content of total soluble protein but decreased the total carbohydrate content. It was also found that it increased the activities of α-amylase, isocitrate lyase (ICL), and malate synthase (MS) enzymes, which are critical in the germination process, and upregulated the expression of ICL and MS genes. To clarify the potential of carnitine treatments to promote the participation of lipids in respiration in roots and hypocotyls, lipase, carnitine acyltransferases (CATI and CATII), and citrate synthase (CS) enzyme activities were examined, and significant increases in these activities were detected. It was also found that gene levels of respiratory enzymes cytochrome oxidase (COX), pyruvate dehydrogenase (PDH), and Atp synthase, lipase, and CS proteins were upregulated by carnitine treatment. In support of the enzyme and gene change findings, significant changes were determined in fatty acid contents, free carnitine, and long-chain acylcarnitine levels in seeds, roots, and hypocotyls depending on carnitine application. In roots and hypocotyls, carnitine treatments significantly increased glutamine synthase (GS) and glutamate dehydrogenase (NADH-GDH) activities and gene expression levels, which are closely related to the tricarboxylic acid cycle (TCA). It was also noted that all proteins analyzed at the gene expression level were upregulated by carnitine applications in seeds. In addition, significant increases were recorded in antioxidant enzyme ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities and total ascorbate (AsA) and glutathione (GSH) contents in roots and hypocotyls, while decreases were determined in guaiacol peroxidase (GPX) and catalase activities. Significant changes were recorded in all parameters examined, especially with 7.5 µM carnitine application. The findings suggest that carnitine may promote the transport of fatty acids to mitochondrial respiration by accelerating lipid catabolism in five-day-old maize and contribute to seed germination and growth and development processes by activating other metabolic pathways associated with respiration in this process. Full article

The production of valuable bioactive compounds in the medicinal plant Glycyrrhiza glabra L. (G. glabra) would benefit from biotechnological approaches for the cultivation and induction of metabolite-producing hairy roots. Germination trials were tested to overcome seed dormancy, achieving high germination rates with sulfuric acid treatment. Hairy root cultures of cotyledons using Rhizobium rhizogenes strain 1724 showed the highest transformation efficiency. A fast-growing line, line S, was subsequently exposed to light treatments (red, blue, and blue and red combined) to evaluate their effects on growth, phenolic content, and Ferric Reducing Antioxidant Power (FRAP). Hairy root cultures grown in blue light and in blue and red light combined had higher growth rates than those grown in red light only or in control conditions (dark). FRAP increased over time under all light treatments, including the control, and those cultures exposed to blue and red light combined had higher FRAP than the control. These findings provide valuable insights into conditions for optimal seed germination and hairy root transformation. Treatment of the line S with different qualities of light induced changes in antioxidant capacity and phenolic content, indicating promise for its use in upregulating secondary metabolite production in G. glabra for future biotechnological applications. Full article

Cyanobacterial harmful algal blooms (cHABs) are increasing due to eutrophication and climate change, as is irrigation of crops with freshwater contaminated with cHAB toxins. A few studies, mostly in aquatic protists and plants, have investigated the effects of cHAB toxins or cell extracts on various aspects of photosynthesis, with variable effects reported (negative to neutral to positive). We examined the effects of cyanobacterial live cultures and cell extracts (Microcystis aeruginosa or Anabaena flos-aquae) and individual cHAB toxins (anatoxin-a, ANA; beta-methyl-amino-L-alanine, BMAA; lipopolysaccharide, LPS; microcystin-LR, MC-LR) on photosynthesis in intact plants and leaf pieces in corn (Zea mays) and lettuce (Lactuca sativa). In intact plants grown in soil or hydroponically, overall net photosynthesis (P_n), but not Photosystem-II (PSII) electron-transport yield (Φ_PSII), decreased when roots were exposed to cyanobacterial culture (whether with intact cells, cells removed, or cells lysed and removed) or individual toxins in solution (especially ANA, which also decreased rubisco activity); cyanobacterial culture also decreased leaf chlorophyll concentration. In contrast, Φ_PSII decreased in leaf tissue vacuum-infiltrated with cyanobacterial culture or the individual toxins, LPS and MC-LR, though only in illuminated (vs. dark-adapted) leaves, and none of the toxins caused significant decreases in in vitro photosynthesis in thylakoids. Principal component analysis indicated unique overall effects of cyanobacterial culture and each toxin on photosynthesis. Hence, while cHAB toxins consistently impacted plant photosynthesis at ecologically relevant concentrations, the effects varied depending on the toxins and the mode of exposure. Full article

Dianthus cruentus Griseb. (Caryophyllaceae) is an herbaceous perennial native to Greece with a strong ornamental potential when used as a pollinator-friendly component of xeric gardens and green roofs, where it is valued for its tolerance of poor, dry soils, and its showy colorful inflorescences. Aiming to develop an efficient mass propagation protocol appropriate for the introduction of the species as a novel floricultural crop, the in vitro seed and clonal propagation of a Greek native xeric ecotype were investigated in this paper for the first time. A total of 90–100% of the seeds, after being stored in the dark at room temperature for 12 months, germinated when incubated at 10 to 25 °C after their surface sterilization and transfer in vitro. Sixty-day-old seedlings grown in vitro were then used as a source of nodal explants for the initial establishment of micropropagation cultures, more efficiently on MS medium with 0.1 mg L⁻¹ 6-benzylaminopurine (BA). In the multiplication stage, either normal or hyperhydric micro-shoots were used as explant sources, assessing the possibility of incorporating usually discarded material in the propagation procedure. Different solid media were tested, with the highest multiplication indices (5.1) recorded in an MS medium containing 0.1 mg L⁻¹ BA and 0.05 mg L⁻¹ NAA, regardless of explants’ hyperhydricity, while an MS medium containing 0.1 mg L⁻¹ BA and 12 g L⁻¹ agar proved optimal for the effective reversal of hyperhydric explants (MI: 5.2). Despite higher hyperhydricity and reaction rates being observed when hyperhydric explants were used, modifications in the multiplication medium proved to be highly effective in controlling hyperhydricity, with the highest number of normal shoots (2.4–2.6) produced in BA-containing media. Micro-shoots rooted readily in ½ MS medium (60–100%), with rooting rates and quality positively affected by the presence of 0.5 mg L⁻¹ IBA in the rooting medium and the absence of cytokinins in the multiplication one. Rooted micro-shoots were successfully acclimatized ex vitro at high rates (65–100%), their origin influencing their acclimatization and morphology. Thus, the concurrent use of normal and hyperhydric shoots in the proposed micropropagation protocol is proven to be both feasible and desirable, as it is able to significantly increase efficiency and facilitate the sustainable exploitation and dissemination of D. cruentus as a promising multivalent horticultural crop. Full article

Organic amendment and green manuring are two agricultural practices highly recommended to improve sustainability in agriculture since they show numerous beneficial effects on both soils and crops. The main aim of the present study was to evaluate the effect of both, specifically organic fraction municipal solid waste (OFMSW) compost and horse bean (Vicia faba L., cv minor) green manure, combined separately or together with a mineral fertilization using synthetic products and in comparison with a mineral fertilization alone (control), on a top-quality tobacco crop (dark fire-cured Kentucky) grown in the cultivation district of Central Italy (High Tiber Valley, Tuscany region) in 2020 and 2021. The following parameters were measured: (i) leaf emergence rate (LER, leaves day⁻¹); (ii) crop growth rate (CGR, kg dry biomass ha⁻¹ day⁻¹); (iii) root weight density (RWD, mg cm⁻³); (iv) yield of cured product (CLY, Mg ha⁻¹). Analytical determinations were carried out on soil, sampled at the 0–0.3 m depth (organic matter, %; total N, %; NO₃-N, mg kg⁻¹; C/N; P and K, mg kg⁻¹), and on plant biomass (total N, %; NO₃-N, kg ha⁻¹). Soil water retention measures were also made. Water productivity (WP, kg cured product m⁻³ gross crop evapotranspiration, ET_c gross), irrigation water use efficiency (IWUE, kg cured product m⁻³ seasonal irrigation volume) and N agronomic efficiency (NAE, kg cured product kg⁻¹ mineral N applied by synthetic fertilizers) were calculated. Both the applications of OFMSW compost and horse bean green manure increased soil content of organic matter and main nutrients (N, P and K), as well as C/N, when compared with control conditions. There was an increase in soil water content in C conditions over the entire soil matric potential interval (0.04 to 1.2 MPa) with a maximum value at 1.2 MPa in both years. Both practices appeared promising for tobacco cultivation and could help to better address the nitrogen needs of the crop during the season and reduce potential water pollution due to nitrates. Considering the amount of synthetic nitrogen fertilizer saved by using both organic soil amendment and green manuring, there should be fewer potential carbon emissions due to the production, transportation and field application of synthetic nitrogen fertilizers. Full article

Previous studies have shown that light quality and quantity affect methane emissions from plants. However, the role of photoperiod in plant-derived methane has not been addressed. We studied the effects of two photoperiods—long-day (16 h light/8 h dark), and short-day (8 h light/16 h dark)—on growth and methane emissions of lettuce (a long-day plant), mung bean (a short-day plant), and tomato (a day-neutral plant) under a temperature regime of 22/18 °C. All species were grown under both light durations. First, seeds were germinated in Petri dishes for one week, then plants were transferred to pots and randomly assigned to one of the two experimental conditions. Under each condition, twelve plants were grown for 21 days; at that time, plant growth and physiological traits, including plant dry mass, growth index, photosynthesis, chlorophyll fluorescence, total chlorophyll, nitrogen balance index, flavonoids, and anthocyanin, were measured. Lettuce plants under the short-day photoperiod had the highest methane emissions. Long-day plants that were exposed to short-day conditions and short-day plants that were exposed to long-day conditions were stressed; day-neutral plants were also stressed under short days (p < 0.05). All three species had decreased total dry mass under short-day conditions, most likely because of decreased photosynthesis and increased transpiration and stomatal conductance. Methane emission was positively correlated with shoot/root mass ratio, nonphotochemical quenching and anthocyanin; but was negatively correlated with stem height, dry mass, photosynthesis, water-use efficiency, total chlorophyll, and flavonoids (p < 0.05). This study revealed that, besides light intensity and quality, light duration can also affect methane emissions from plants. Full article

Large quantities of cover crop residues in the soil, combined, or not, with the inoculation of seeds with diazotrophic bacteria, can increase organic matter (OM) and protect soil microorganisms, such as arbuscular mycorrhizal fungi (AMF) and dark septate endophytic (DSE) fungi. Thus, the use of these sustainable biotechnologies can benefit microbial interactions, soil fertility and rice production in the Brazilian Cerrado region. In this study, we evaluated the effects of maize and Urochloa ruziziensis, intercropped or individually, as cover crops and an inoculation of Azospirillum brasilense on the chemical (fertility) and biological (C–microbial biomass and C–CO₂ released) attributes of soil and the effects of root colonization by AMF and DSE on the yield of rice grown in succession in highlands. The experiment was conducted under field conditions, in a typical dystrophic Red Oxisol. The experimental design consisted of randomized blocks arranged in strips, incorporating a combination of eight residual cover crops: ((1) maize, (2) maize–I (I = inoculation of seeds with A. brasilense), (3) Urochloa (U. ruziziensis), (4) Urochloa–I, (5) maize + Urochloa–I, (6) maize + Urochloa–I, (7) maize–I + Urochloa and (8) maize–I + Urochloa–I). This was accompanied by two treatments of rice as a successor crop (inoculated or not with A. brasilense), with four replicates, totaling 64 experimental units. A cover crop and rice seed inoculation prompted increases in OM and AMF relative to DSE, while the inoculation of rice, regardless of the cover crop treatment, increased the soil’s P content. The combination of maize + Urochloa–I and inoculated rice as the next crop generated increases in its sum of bases (SBs) and cation exchange capacity (CEC). There was a 19% increase in rice grain yields when the seed was inoculated. Full article

To reveal genetic diversity for effective resistance to five foliar diseases and toxic aluminum ions, the entire collection of wheat species from the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) originating from Ethiopia and Eritrea were studied regarding their traits. The collection contains 509 samples of four wheat species (Triticum aestivum—122 samples; T. aethiopicum—340 samples; T. polonicum—6 samples; and T. dicoccum—41 samples). The majority of accessions are new entries of landraces added to the Vavilov collection as a result of the Russian–Ethiopian expedition in 2012. Wheat seedlings were inoculated with causal agents of leaf rust (Pt), powdery mildew (Bgt), Septoria nodorum blotch (SNB), and dark-brown leaf spot blotch (HLB). The types of reaction and disease development were assessed to describe the levels of resistance. All samples of T. aethiopicum were also screened for seedling and adult resistance to Pt, Bgt, and yellow rust (Pst) under field conditions after double inoculation with the corresponding pathogens. To study tolerance to abiotic stress, seedlings were grown in a solution of Al³⁺ (185 µM, pH 4,0) and in water. The index of root length was used to characterize tolerance. Seedlings belonging to only two accessions out of those studied—k-68236 of T. aethiopicum and k-67397 of T. dicoccum—were resistant to Pt at 20 °C but susceptible at 25 °C. Specific molecular markers closely linked to the five genes for Pt resistance effective against populations of the pathogen from the northwestern region of Russia were not amplified in these two entries after PCR with corresponding primers. Four entries of T. dicoccum—k-18971, k-18975, k-19577, and k-67398—were highly resistant to Bgt. All samples under study were susceptible to HLB and SNB. Under field conditions, 15% of the T. aethiopicum samples were resistant to Pst, both at the seedling and the flag leaf stages, but all were susceptible to the other diseases under study. Among the evaluated samples, 20 entries of T. aestivum, 1 of T. polonicum (k-43765), and 2 of T. dicoccum (k-18971, k-67397) were tolerant to aluminum ions. The identified entries could be valuable sources for the breeding of T. aestivum and other wheats for resistance to biotic and abiotic stresses. Full article

In August 2020, the unusual appearance of crown gall symptoms was observed on the tobacco plants (hybrid PVH2310) grown in fields in the Golubinci (Srem district, Serbia) locality. The causal agent isolated from galls located on tobacco roots formed circular, convex, and glistening light blue colonies, and then dark to olive-green-colored bacterial colonies on a semi-selective D1 medium. Molecular analysis based on multiplex PCR and multi-locus sequence analysis (MLSA) using concatenated sequences of the atpD, dnaK, glnA, and rpoB genes as well as 16S rRNA identified Serbian tobacco isolates such as Agrobacterium tumefaciens (biovar 1). Two duplex PCR methods confirmed the presence of the virD2 and virC genes in tobacco isolates. Pathogenicity tests performed on carrot discs and squash fruits resulted in tumor/gall formation after 12 to 16 days post inoculation, respectively. Pathogenicity was also confirmed on tobacco plants, where isolates caused tumor development 21−25 days after inoculation. API 50 CH generated results regarding the biochemical features of the Serbian tobacco isolates. As A. tumefaciens (biovar 1) as a cause of tobacco crown gall has previously been documented solely in Japan, there is presently no data on its wider occurrence. Therefore, this first detailed investigation of A. tumefaciens isolated from naturally infected tobacco in Serbia will contribute to a better understanding of it at the global level. Full article

The plant growth regulator gibberellic acid (GA) and the herbicide glyphosate were examined for their possible interactions with growth and phenolic metabolism in soybean [Glycine max (L.) Merr. Cv. Hill] seedlings. GA caused increases in phenylalanine ammonia-lyase activity (PAL) (per axis basis) above those of the control seedling levels 48 h after treatment in light-grown seedlings. This effect increased to two-fold greater than control levels by 72 and 96 h after treatment. In dark-grown plants, GA had no effect on PAL levels at 24 h, reduced levels at 48 and 72 h, and increased PAL at 96 h. Early studies in our lab reported that glyphosate increased PAL levels, and also reduced hydroxyphenolic compound accumulation in both light- and dark-grown soybean seedlings. Treatments of GA plus glyphosate caused additive increases in PAL activity in light-grown seedlings, but GA lowered glyphosate’s increase in PAL levels at 48–96 h after treatment in dark-grown seedlings. GA had little effect on hydroxyphenolic compound levels in either light- or dark-grown seedlings. GA treatment alone did not significantly affect root elongation, but stimulated hypocotyl and epicotyl elongation and caused marginal reversal of glyphosate inhibition of elongation in roots, hypocotyls, and epicotyls in light-grown plants. These results show some differential effects of GA and glyphosate on growth and phenolic metabolism, and their interactions that are dependent on plants grown in light or darkness. Full article

During the winter of 2018, leaf blight on florist’s daisy (Chrysanthemum morifolium L.) was noticed in Egypt. The disease, which was identified as caused by Alternaria alternata, was widely spread and led to serious damage for the exportation sector of this crop. Therefore, a study was conducted to better understand what can be conducted to minimize the problem in the future. Isolates were gathered and evaluated on five chrysanthemum cultivars (i.e., ‘Feeling Green Dark’, ‘Talitha’, ‘Chrystal Regan’, ‘Arctic queen’, and ‘Podolsk Purple’) grown in a greenhouse. The objectives were to isolate and identify the phytopathogen and detect the resistant degree of these cultivars with emphasis on the early growth stages of the crop. The results showed that ‘Podolsk Purple’ was the most resistant cultivar against the different isolates during the rooting and seedling growth stages. ‘Chrystal Regan’ was very susceptible to the different isolates. In addition, the isolate from ‘Feeling Green Dark’ was the strongest, which negatively affected the chlorophyll content and its fluorescence parameters besides other measured vegetative and anatomical features. The findings indicated that the best anatomical characters of the stem and leaf, like the thickness of cuticle and cortex, stem diameter, xylem vessel diameter, and thickness of epidermis as well as lamina thickness were recorded in the ‘Podolsk Purple’ cultivar. This study highlighted that by using the right cultivars, chrysanthemum can be cultivated during the winter season under Egyptian conditions. These results can be a part of solution to overcome the leaf blight caused by A. alternata on chrysanthemum during the early growing stages. Full article

The geomagnetic field (GMF) is a natural component of the biosphere, and, during evolution, all organisms experienced its presence while some evolved the ability to perceive magnetic fields (MF). We studied the response of 14-3-3 proteins and the plasma membrane (PM) proton pump H⁺-ATPase to reduced GMF values by lowering the GMF intensity to a near-null magnetic field (NNMF). Seedling morphology, H⁺-ATPase activity and content, 14-3-3 protein content, binding to PM and phosphorylation, gene expression, and ROS quantification were assessed in maize (Zea mays) dark-grown seedlings. Phytohormone and melatonin quantification were also assessed by LG-MS/MS. Our results suggest that the GMF regulates the PM H⁺-ATPase, and that NNMF conditions alter the proton pump activity by reducing the binding of 14-3-3 proteins. This effect was associated with both a reduction in H₂O₂ and downregulation of genes coding for enzymes involved in ROS production and scavenging, as well as calcium homeostasis. These early events were followed by the downregulation of IAA synthesis and gene expression and the increase in both cytokinin and ABA, which were associated with a reduction in root growth. The expression of the homolog of the MagR gene, ZmISCA2, paralleled that of CRY1, suggesting a possible role of ISCA in maize magnetic induction. Interestingly, melatonin, a widespread molecule present in many kingdoms, was increased by the GMF reduction, suggesting a still unknown role of this molecule in magnetoreception. Full article