Methodological problems in measuring carbohydrate accumulation and remobilization in wheat stem have led to inconsistent results. However, the assessment of an individual internode eliminates the underestimated accumulation and remobilization, and accordingly, improves their accurate calculation. Therefore, the present study aimed at measuring the amount of dry matter accumulation and remobilization in different internodes, as well as evaluating the possible associations between the two parameters at the internode level. Moreover, the influence of the stored reserves on the grain yield of wheat cultivars grown under contrasting conditions was examined. Eighteen cultivars were evaluated under well-watered (WW) and terminal drought stress (DS) conditions at a Mediterranean climate during 2007–2009, as well as under WW conditions in a subtropical climate during 2014–2015. Time-dependent changes in the weights of the internodes were measured after anthesis. The highest mean of dry matter accumulation and remobilization and contribution percentage of reserves to grain yield were observed in the lower internodes, followed by the penultimate and peduncle. The maximum weight of each stem internode generally correlated positively with the remobilized dry matter of that internode. Grain weight per spike was not related to dry matter remobilization of the internodes under all WW conditions. However, a significantly positive correlation was found between this trait and dry matter remobilization of the lower internodes under DS condition of the Mediterranean climate. Interestingly, the significant association was refuted by employing stem remobilization in the analysis, indicating the importance of the internode level in studying such associations.

Stem reserve remobilization plays a prominent role in maintaining the stability of wheat grain yield. The present study aimed at comparing the amount of dry matter remobilization by employing both the entire stem and the separately weighted internodes in 18 wheat cultivars. To this end, the cultivars were examined under well-watered and terminal drought stress conditions at a Mediterranean climate during 2007–2009. They were also examined under well-watered condition in a subtropical climate during 2014–2015. Time-dependent changes in the weights of the entire stem as well as those of the internodes (peduncle, penultimate, and the lower internodes) were measured after anthesis. Results showed that the lower internodes remobilized their stored dry matter much earlier than the peduncle and penultimate. Moreover, in the majority of cultivars, the amount of entire stem dry matter remobilization was observed to be lower than that of the cumulative internode remobilization (i.e., sum of the remobilized dry matter from the individual internodes). This indicates that the employment of the entire stem for the calculation of the dry matter remobilization might underestimate this trait. Depending on the cultivars and the environmental conditions, the amount of underestimated remobilization was also found to range from 4 to 202 mg. Therefore, for the more precise measurement of the carbohydrate remobilization in wheat stems, the separate measurement of this trait in each internode is highly recommended.

Genetic variability of 84 accessions of three Ziziphus species including Z. spina-christi, Z. nummularia and Z. mauritiana were analyzed using a combination of morphological traits and translation initiation codon (ATG) polymorphism. Both morphological and molecular data revealed a high level of inter and intra specific variations among the accessions. Accordingly, 90.49% of amplified fragments were polymorphic among the accessions with the mean values of 0.37 for polymorphic information content (PIC), 3.31 for resolving power (RP), and 1.95 for marker index (MI). The phylogenetic clustering clearly delineated the entire germplasm into three well supported distinct clusters according to the species sources. According to the Nei's genetic identity, Z. spina-christi and Z. nummularia were the most similar species and had high differentiation with Z. mauritiana. Moreover, the highest values for Shannon's information index (I = 0.505) and gene diversity (h = 0.347) were recorded in Z. spina-christi indicating there is higher genetic diversity compared with two other species. Four private alleles were identified in two species which could be beneficial for accessions authentication in argumentative situations. Moreover, results of the Mantel test showed there were moderate correlation between molecular and morphological matrices. In addition, estimation of bivariate correlations revealed there were significant positive and negative correlations between different variables, which offer a practical application of this information during phenotype based selection in ber improvement programs. The results of this investigation highlight the efficiency of translation initiation codon polymorphism for genetic characterization and accurate authentication of Ziziphus accessions as well as detecting and tagging morphologically important traits in this genus that would be helpful for implementation of effective conservation strategies and even broaden current genetic diversity.

Protein products of SARS-CoV-2 spike (S) coding gene sequence, were all analyzed and compared to other SARS-CoV S proteins to elucidate structural similarities of spike proteins. A homology modeling of SARS-CoV-2 S protein was obtained and used in molecular docking studies to find binding affinities of spike protein for angiotensin-converting enzyme 2 (ACE2). The two most important binding sites of S protein, namely, RBD and CTD, critically responsible for binding interactions, were identified. Finally, binding affinity of RBD and CTD domains of S protein with narcotic analgesics are studied. Moreover, interactions of ACE2 receptor- S protein with narcotic compounds when mixed with small molecule adjuvants to improve the immune response and increase the efficacy of potential vaccines, were taken into consideration. In-silico results suggest that the combination of narcotine hemiacetal with mannide monooleate shows a stronger binding affinity with CTD, while carprofen-muramyl dipeptide and squalene have stronger binding affinities for the RBD portion of S protein. Thus, a suitable combination of these narcotic is proposed to yield potent site-blocking efficacy for ACE2 receptor against SARS-CoV-2 spike proteins.

Edge states of a few-layer silicene nanoribbon (FSNR) have potential applications in spintronic and nanodevices. Quantum transport properties of zigzag superlattice FSNR exposed to vertical electric field and Rashba spin-orbit coupling (RSOC) are studied within the tight-binding based non-equilibrium Green's function approach. In addition, the topological insulator-band insulator phase transition of FSNR and the influence of adding a new layer on edge states of conduction electrons have been investigated. Calculations demonstrate that the external electric field applied perpendicularly to the FSNR device, results in gap opening and metal-semiconductor and metal-semimetal phase transition. Further, we found that different topological phase transitions, quasi-topological insulator-band insulator and topological insulator-band insulator by applying a vertical electric field. Meanwhile, results reveal that by tuning the RSOC strength, we can control the spin current. This controllability of spin and quantum transport in FSNR may contribute to potential applications in silicene-based devices and the development of spintronic.

In this paper, the SARS-CoV-2 spike encoding gene sequences were analyzed to find the structural homology of S proteins. The S protein of SARS-CoV-2 was obtained from homology modeling and the protein-protein docking was performed to elucidate sites active in S protein for ACE2, dipeptidyl peptidase 4 (DPP4), chemokine receptor 5 (CCR5), and AXL. The two crucial binding sites of S protein, known as RBD and CTD, were investigated. Three-dimensional structures of 8 possible RBD/CTD-receptor complexes were evaluated using molecular dynamic (MD) simulations. The best simulation models of the SARS-CoV-2 S protein active sites with the receptors were obtained for the ACE2 receptor (PDB:6VW1), providing 99.5% and 98.5% coverage for CTD and RBD, respectively. The SARS-CoV- 2 S protein may connect with the ACE2 receptor via the RBD sites of the S protein and the ACE2 peptidase domain (PD), which can be blocked by encoding gene sequence in the active sites of S protein, offering an attractive protection approach against this novel SARS-CoV-2 virus.

In this paper, we investigate the electrical transport of two-terminal trilayer graphene and silicene flake (bilayer and monolayer nanoribbons) in the absence and presence of nanopores and DNA molecule by using Green's function method. The passage of the DNA molecule through the nanopore significantly changes the transport properties. It is found that passing double-stranded DNA through trilayer graphene nanopore (tGNP) causes the metal-semiconductor quantum phase transition and in trilayer silicene nanopore (tSNP) increases the energy gap. The transport properties of DNA strands passing through nanopores depend on the thickness of the nanopores, the leads and the location of the electrodes. It has been shown that in tSNP and tGNP the energy gap with monolayer connections is larger than that of the bilayer connections. The computational results show reduction in electron transmission for both types of nanopores. These results can be useful for making a DNA sequencing devices.

Abstract This paper is a new step in helping the treatment of coronavirus by improving the performance of chloroquine drug. For this purpose, we propose a complex of chloroquine drug with graphene nanoribbon (GNR) scheme. We compute the structural and electrical properties and absorption of chloroquine (C18H26ClN3) and GNR complex using the density functional theory (DFT) method. By creating a drug and GNR complex, the density of states of electrons increases and the energy gap decreases compared to the chloroquine. Also, using absorption calculations and spectrums such as infrared and UV-Vis spectra, we showed that GNR is a suitable structure for creating chloroquine drug complex. Our results show that the dipole moment, global softness and electrophilicity for the drug complex increases compared to the non-complex state. Our calculations can be useful for increasing performance and reducing the side effects of chloroquine, and thus can be effective in treating coronavirus.

In this paper, we studied the in silico interaction of angiotensin-converting enzyme 2 (ACE2) human receptor with two bioactive compounds, i.e., nicotine and caffeine, via molecular dynamic (MD) simulations. The simulations reveal the efficient blocking of ACE2 by caffeine and nicotine in the exposure to the spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have selected the two most important active sites of ACE2-S protein, i.e., 6LZG and 6VW1, which are critically responsible in the interaction of S protein to the receptor and thus, we investigated their interaction with nicotine and caffeine through MD simulations. Caffeine and nicotine are interesting structures for interactions because of their similar structure to the candidate antiviral drugs. Our results reveal that caffeine or nicotine in a specific molar ratio to 6LZG shows a very strong interaction and indicate that caffeine is more efficient in the interaction with 6LZG and further blocking of this site against S protein binding. Further, we investigated the interaction of ACE2 receptor- S protein with nicotine or caffeine when mixed with candidate or approved antiviral drugs for SARS-CoV-2 therapy. Our MD simulations suggest that the combination of caffeine with ribavirin shows a stronger interaction with 6VW1, while in case of favipiravir+nicotine, 6LZG shows potent efficacy of these interaction, proposing the potent efficacy of these combinations for blocking ACE2 receptor against SARS-CoV-2.

In this paper, we study electrical properties of AB-stacked bilayer graphene-DNA hybrid nanostructure connected to two semi-infinite monolayer graphene nanoribbon leads. We investigated two types of devices with both zigzag and armchair edges and the results are evaluated by replacing the junction position. Our calculations are based on the tight-binding approximation and the Green's function method in which the electrical transmission, the density of states (DOS) and the local density of states (LDOS) are calculated numerically. In the metallic bilayer graphene device via creating a nanopore and translocating the DNA molecule, the electron transmission reduces and an energy gap opens, so that, the metal-semiconductor phase transition occurs. Also, our results indicate that the model AC leads to a more considerable energy gap than model AB. Our results have important applications in DNA sensing.

Conservation tillage systems and residue management as well as nitrogen application are the effective factors on soil properties and crop yield. This study investigated the influence of these factors on the soil properties and winter wheat yield in the warm, semi-arid region of Jahrom, in south of Iran. The variables were residue management, i.e. keeping (R1) and burning (R2) previous corn residue beside two tillage systems, i.e. chisel plowing (T1) and moldboard plowing (T2); and three levels of nitrogen application i.e., F1 = 0 kg/ha, F2 = 100 kg/ha and F3 = 150 kg/ha. The result revealed that the highest total organic carbon and nitrogen content were obtained when chisel applied in the retained crop residue. But, soil BD was lower with moldboard plowing. It was indicated that chisel plowing can lead to highest yield when combined with retained residue and 150 kg/ha nitrogen.

Most useful plant-derived drugs have been discovered by follow-up of ethno-medicinal information. Weeds, unwanted and uncultivated plants in agro-ecosystems, generally tend to have high content of bioactive secondary compounds. The main objectives of present research were to gather, analyze, and evaluate the ethno-medicinal information on weed species used by the native people of Jahrom, Iran. All kinds of weeds were repeatedly collected from various agricultural areas through different seasons of 2015. Ethno-medicinal information about these weeds was obtained through direct interviews and open discussions with local informants. Based on the results, 36 weed species belonging to 18 families and 31 genera had traditional medicinal uses. Asteraceae was the most dominant family having highest number of weed species followed by Fabaceae, Brassicaceae, and Polygonaceae. Most of weeds with therapeutic uses had annual life cycle. Leaf was the most widely consumed part of the weeds followed by seed and fruit. The weeds were traditionally used for curing various health problems such as gastrointestinal disorders, body pain, and metabolic disorders. It can be concluded that certain weeds could play a major role in curing the diseases and health improvements in the local people, especially in developing countries. Undervaluation and ongoing destruction of the endemic medicinal weeds in agro-ecosystems may have a negative impact on availability of the unwritten local knowledge about such valuable weeds in the future.

Environmental stresses and rhizosphere microorganisms affect growth parameters and accumulation of active ingredients especially in plants with medicinal properties. The present study examined the effects of chamomile (Matricaria chamomilla L.) seedling inoculation with Pseudomonas fluorescens PF-135 strain on its growth parameters, photosynthetic pigments, proline, malondialdehyde (MDA), and hydrogen peroxide (H2O2) content, and essential oil concentration at both regular watering and water deficit experiments. Based on the obtained results, water deficit stress reduced root dry mass, and flower fresh and dry mass as well. However, amount of H2O2 and MDA in root and shoot tissues were considerably lower in inoculated plants compared to non-inoculated ones under both normal watering and water deficit regimes. It indicates that lipid peroxidation and production of reactive oxygen species has been diminished in inoculated plants. Also, essential oil content in inoculated plants significantly increased compared with that of non-inoculated ones under water deficit stress condition. It can be concluded that P. fluorescens PF-135 strain has an outstanding potential to alleviate adverse effects of water deficit on plant growth, and hence can be used as an excellent PGPR in order to boost chamomile productivity especially under water deficit stress condition.

Chickpea is one the most important legume crops in Mediterranean semi-arid regions and its sustainable production strongly depends on the nutrient management and water availability. Soils of these regions generally have high pH, and low organic matter, which reduce the availability of micronutrients and led to multi-micronutrient deficiencies. For estimating the effect of integrated application of different levels of organic fertilizer (zero, 20 t ha-1, 40 t ha-1) and micronutrient fertilizers (Zn, Fe) on agronomic traits and yield components of chickpea, an experiment was carried out at the highland semi-arid regions in Piranshahr district (36° 40ʹ N, 45° 08ʹ E; 1840 m). Assessment of phenological development revealed that plants grown under control condition (no-organic and micronutrients fertilizer) had a significantly slower development. Assessment of agronomic characteristics showed that application of micronutrients fertilizer substantially increased plant height, first pod height, canopy width, number of the seed, seed weight, economic and biological yield compared to control condition. By increasing the application rate of organic fertilizer its positive effects became more impressive on growth and yield component. The best growth performance was recorded by integrated application of 40 t ha-1 organic fertilizer and micronutrients fertilizers. However, there was no significant difference between fertilizer of Fe and Zn. Overall, the results indicated that the studied site is facing with micronutrient deficiencies and application organic fertilizer can noticeably improve the efficiency of micronutrients fertilizer. A quick and supplementary approach is therefore required for remedy of both Zn and Fe deficiencies in the short term. The finding showed that a substantial yield improvement is possible by integrated application of organic and micronutrient fertilizer.

In the present study Klein tunneling in a single-layer gapped graphene was investigated by transfer matrix method under normal magnetic field for one and two magnetic barriers. Calculations show that electron transmission through a magnetic barrier is deflected to positive angles and reduces as the magnitude of magnetic field and especially the energy gap increases. This reduction is even more significant in larger fields so that after reaching a specific value of energy gap, an effective confinement for fermions and suppression of Klein tunneling is reached particularly in normal incidence and the conductance becomes zero. Unlike one barrier, the process of tunneling through two magnetic barriers induces symmetric transmission probability versus the incident angle; even, for lower energy gaps, electron transmission probability increases which in turn reduces total conductance via proper changes in the value of the magnetic field and energy gap. In general, it is concluded that confining electrons in asymmetric transmission through one barrier is conducted better than two barriers.

The present paper investigates that the tunneling time for bilayer graphene potential barrier with monolayer graphene leads to all range of energy. Numerical results reveal that parameters such as the incident energy and angle plays a significant role in inducing of the Hartman effect. In contrast to single-layer graphene, in the bilayer graphene, due to the chirality of quasi-particles induction of Klein and Hartman effects occur in the normal incidence case. Moreover, it is demonstrated that even for energy levels above barrier, the Hartman effect is present.

Safflower is one of important crop in semi-arid regions of the world, where the precipitations are limited. In order to investigate the effect of foliar spray of nano-silicon dioxide (10 and 20 mM) and nano titanium dioxide (25 and 50 mM) and water-deficit stress (irrigation after 110 mm evaporation) on growth parameters and yield components of spring safflower a field experiment was carried out at the highland semi-arid region, in, North West of Iran. Water deficit stress significantly reduced morpho-physiological traits such as ground cover, canopy width, leaf fresh mass, leaf are and plant height) as well as yield components (e.g. capitulum diameter, seed mass and seed number per capitulum). However, the plants grown under water deficit condition showed the higher harvest index than well irrigated plants. Comparison of the foliar treatments showed that the both nano-particles (silicon and titanium) improved the plant growth and yield components over the control. However, the effect of nano-silicon was more prominent than titanium. The highest amount of seed oil was recorded under well irrigated condition (irrigation after 60 mm evaporation) with foliar application of nano-titanium. The percentage of palmitic acid, arachidic acid and myristic acid in seed increased by nano-titanium application. Altogether, principal component analysis indicated that spray of 10 mM nano silicon dioxide was best foliar treatments under all moisture regimes.

Water-deficit stress is the most important environmental factors limiting plant growth, and production. Nano-titanium dioxide (nano anataseTiO2) can have various profound effects on the crop physiological, biochemical and morphological characteristics. In the present research, the influences of different concentrations ofTiO2 nanoparticles (NPs) (0, 10 and 40 ppm) and water-deficit stress on Dragonhead (Dracocephalum moldavica L.) were investigated in a factorial experiment based on randomized complete block design with three replications. Results showed that under normal irrigation, foliar application of 10 ppm TiO2 NPs increased plant shoot dry mass and essential oils content. Under water-deficit stress condition, plants treated with 10 ppm TiO2 NPs had more proline and much less H2O2 and malondialdehyde content as compared to untreated plants. Therefore, it can be concluded that proper concentration of TiO2 NPs probably can be used as an exogenous stimuli for improvement of shoot growth and essential oil content in plants. Furthermore, water-deficit stress-induced damages such as oxidative stress and membrane damage can be ameliorated by foliar application of TiO2 NPs at appropriate concentrations.

In this paper, the Hartman effect is investigated in electron tunneling through a barrier on the graphene channel in the presence of Rashba spin orbit interaction (RSOI). Two cases of normal and ferromagnetic channel are considered. The calculated results indicate that the occurrence of the Hartman effect in tunneling process depends strongly on Rashba SOI parameter, incidence angle, energy of the carriers and the ferromagnetic exchange energy of the leads.

Using the transfer matrix method, we study the electron transport through a single-layer graphene superlattice with alternating layers of ferromagnetic and normal regions with Rashba spin–orbit coupling. We show that the transport properties of the system depend strongly on the superlattice parameters. As another result, Rashba spin–orbit coupling manifests to be of crucial importance in controlling the transmission probabilities and Giant Magneto Resistance (GMR).