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Water stress is the major factor limiting plant productivity and quality in most regions of the world. In the present study, a two-year field experiment was conducted to determine the influence of putrescine (Put) on phytochemical, physiological, and growth parameters of Salvia officinalis L. under different irrigation regimes. The highest stem dry weight (56.05 and 65.21 g m−2) plus leaf dry weight (124.51 g m−2) were predicted in irrigation regimes of (20 and 40%) plus 20% available soil water was depleted (ASWD), respectively. Total phenolic content (TPC) was increased significantly under the irrigation regime of 80% with the application of distilled water in spring. TPC showed an increasing trend with increases in Put concentration under all irrigation regimes in both spring and summer. The highest total flavonoids content (TFC) in wavelengths of 415 and 367 nm were predicted in 2.25 mM Put. The highest ascorbate peroxidase (APX) activity (0.13 μmol mg−1 protein) was predicted in the irrigation regime of 20% with the application of distilled water in spring and summer. There was a significantly negative correlation coefficient between APX, TPC, and TFC. Indeed, there was a decreasing trend in APX and an increasing trend in TPC and TFC with increases in Put concentration under the irrigation regime of 20% ASWD. The highest hydroxyl radical scavenging activity (HRSA) values were obtained under irrigation regimes of 49.27% and 20% ASWD in spring and summer, respectively. There was an increasing trend in endogenous Put with increases in the Put concentration. The responses of compatible osmolytes to irrigation regime can be expressed by quadratic model, suggesting maximum proline (0.52 mg g−1), total reducing sugars (TRS) (0.37 mg g−1), xylose (0.68 mg g−1), and mannose (0.37 mg g−1) values would be obtained in irrigation regimes of 68.33%, 48.33%, 53.75%, and 56.25% ASWD, respectively.

As far as we know, there is no information on the effect of Achillea residuals on controlling weeds when considering the effective compounds of the aerial parts of this plant. Thus, in a pot experiment, the allelopathic effect of dry material from the flower, leaf and stem of Tanacetum polycephalum L. and 9 Achillea spp. (Achillea santolina L., A. millefolium L., A. nobilis L., A. conferta DC., A. vermicularis Trin., A. beibersteinii Afan., A. talagonica Boiss., A. tenuifolia Lam., A. aleppica DC.) applied to the soil on the growth of redroot pigweed (Amaranthus retroflexus L.) seedling was tested. Five different ratios of aerial dry material of different species as residues (at 0, 10, 20, 40, and 50 g kg− 1 dry weight) were used in the pots. Achillea residual had a significant effect on the growth of redroot pigweed. Achillea vermicolaris, A.conferta, A. aleppica, and A. nobilis were the most effective species at stopping the growth of redroot pigweed. Based on the results of GC/MS analyses, 152 different compounds were found in the essential oil of Achillea spp. Partial least squares regression between effective doses for controlling redroot pigweed and allelochemical compounds of Achillea species showed that cis-Menth-2-en-1-ol, α-Terpinyl, propionate and Bornyl acetate had the most effect on inhibiting the growth of redroot pigweed. Our research revealed that the Achillea genus has a lot of potential as a bioherbicide. This means that its leftovers or mulch could be used as a good cover crop to get rid of redroot pigweed.

Dracocephalum kotschyi Boiss has safe anticancer properties, and is regarded as an endangered plant in Iran. The indiscriminate use of chemical fertilizers and the resulting environmental damages made it essential to shift to utilizing organic fertilizers and soil amendments for increasing the water and fertilizer efficiency in sustainable agriculture. This study aimed to investigate the changes in yield and essential oil compositions of Dracocephalum kotschyi in response to azocompost, vermicompost, nitroxin, and urea under different irrigation regimes. To investigate the effects of both nutrient inputs and water availability on yield and essential oil composition of D. kotschyi, at a semiarid site of Iran, a split-plot experiment was conducted based on a randomized complete block design with three replications in 2018–2019. The main plots were four irrigation regimes including irrigation up to field capacity after depletion of 20% (unstressed control), 40% (mild stress), 60% (moderate stress), and 80% (severe stress) soil available water. The subplots consisted of unfertilized control and four fertilizer sources (urea, nitroxin, vermicompost, and azocompost). The highest biomass was observed through vermicompost application in unstressed treatment at the third harvest (4058.9 kg ha−1). Moreover, the highest essential oil content was obtained under water deficit stress in the first harvest. The highest essential oil yield was also produced with application of vermicompost (40.90 kg ha−1) and azocompost (40.42 kg ha−1) under unstressed conditions at the third harvest. In harvest summations, urea fertilizer had the highest essential oil yield under unstressed control (75.19 kg ha−1), mild (64.79 kg ha−1), and severe (65.63 kg ha−1) stress conditions, while it was produced from nitroxin treatment under moderate stress (53.63 kg ha−1). Geraniol, dl-limonene, cis-sabinene hydrate, neral, geranial, methyl geranate, and geranyl acetate were the main components of the essential oil profile. D. kotschyi showed different responses to water availability in conjunction with various fertilizer sources. Therefore, we can say that it tries to make better response to different conditions for its survival and development by changing essential oil content and compounds. Our findings suggest that organic fertilizers, especially vermicompost, can improve soil properties and essential oil yield. Finally, based on the results of this study, urea is recommended for unstressed, mild, and severe water stress conditions, and nitroxin for moderate conditions.

To study the effects of foliar application of putrescine (distilled water (0), 0.75, 1.5, and 2.25 mM) and water deficit stress (20%, 40%, 60%, and 80% available soil water depletion (ASWD)) on the physiological, biochemical, and molecular attributes of Salvia officinalis L., a factorial experiment was performed in a completely randomized design with three replications in the growth chamber. The results of Real-Time quantitative polymerase chain reaction (qRT-PCR) analysis showed that putrescine concentration, irrigation regime, and the two-way interaction between irrigation regime and putrescine concentration significantly influenced cineole synthase (CS), sabinene synthase (SS), and bornyl diphosphate synthase (BPPS) relative expression. The highest concentration of 1,8-cineole, camphor, α-thujone, β-thujone, CS, SS, and BPPS were obtained in the irrigation regime of 80% ASWD with the application of 0.75 mM putrescine. There was high correlation between expression levels of the main monoterpenes synthase and the concentration of main monoterpenes. The observed correlation between the two enzyme activities of ascorbate peroxidase (APX) and catalase (CAT) strongly suggests they have coordinated action. On the other hand, the highest peroxidase (PO) and superoxide dismutase (SOD) concentrations were obtained with the application of 0.75 mM putrescine under the irrigation regime of 40% ASWD. Putrescine showed a significant increase in LAI and RWC under water deficit stress. There was an increasing trend in endogenous putrescine when putrescine concentration was increased in all irrigation regimes. Overall, the results suggest that putrescine may act directly as a stress-protecting compound and reduced H2O2 to moderate the capacity of the antioxidative system, maintain the membrane stability, and increase secondary metabolites under water deficit stress.

Descurainia sophia has potential use as an oil crop because of its high productivity, high seed oil content, and unique fatty acid composition. With regard to oil fatty acid composition, obtainable oil from this plant can be of interest to the food and non-food industries such as pharmaceuticals, cosmetics, bio-fuels, paints, and lubricants. The aim of this research was to determine the effects of various nitrogen (N) rates and different irrigation regimes on oil productivity and composition as well as on potassium (K) and phosphorus (P) parameters in D. sophia. The field experiment was arranged as split-plot in a randomized complete block design with three replications. The main plots were three irrigation regimes: 0.1 maximum allowable depletion or deficiency (MAD) of available soil water (ASW) (I1), 0.2 MAD of ASW (I2), and 0.4 MAD of ASW (I4) in 2010 and 0.2 MAD of ASW (I2), 0.4 MAD of ASW (I4), and 0.8 MAD of ASW (I8) in 2011. Sub-plots were three N rates: 0 (N0), 200 (N200), and 300 (N300) kg N ha−1. In the first year, there was no significant difference between irrigation regimes in terms of oil yield, while oil yield decreased when plants were exposed to drought stress in comparison with the well-water condition in the second year. The application of N increased oil yield; although there were no significant differences between N200 and N300 under any irrigation regime, the highest oil yield being observed at N application rate of 200 kg ha−1 for the I1 (561.4 kg ha−1) and I2 (256.1 kg ha−1) regimes in 2010 and 2011, respectively. Accumulation (per ha) of 21.9–29.7 kg P (50–68 kg P2O5) and 102.1–126.3 kg K (123–152 kg K2O) was required to produce 256.1–561.4 kg ha−1 of oil yield. Overall, for most of the traits studied over the 2 years, the response of D. sophia was mainly due to N rate rather than irrigation treatment. Linolenic, linoleic, and oleic acids comprised about 70% of the fatty acid composition. The results obtained here suggest that D. sophia oil yield, P and K uptakes, and levels of saturated and polyunsaturated fatty acids are positively influenced by increasing available N under different irrigation regimes.

Soil respiration (SR) is strongly affected by soil water content and soil temperature. The common methods for SR measurement are costly, time consuming, and laborious. The goals of this investigation were (i) to predict SR by artificial intelligence and regression models as new tools in soil science, (ii) to evaluate which methods are better, and (iii) to determine the most influential factors on SR by sensitivity analysis. SR, moisture content, and diurnal and nocturnal temperatures were determined at four stages throughout growing season. The effect of soil moisture content and diurnal and nocturnal soil temperatures on SR was predicted using artificial neural networks (ANN), adaptive neuro-fuzzy inference system (ANFIS), fuzzy inference system (FIS), particle swarm optimization (PSO), partial least squares (PLS), principal components regression (PCR), ordinary least squares (OLS), and multiple regression (MR). The results showed that artificial intelligence methods (except for FIS) had higher performance than regression methods. Among intelligent models, ANFIS could predict the SR more accurate relative to ANN and PSO in terms of statistical parameters (R2 = 0.93, MSE = 0.001, RMSE = 0.037, MAPE = 12.26, VAF = 93.39, RPD = 3.82). ANFIS model was more efficient than others, and time taken to run ANFIS was shorter than the other models. Sensitivity analysis illustrated that soil moisture content was a more influential parameter on SR compared to diurnal and nocturnal soil temperatures. As a result, soil moisture mainly controls the SR in this study.

One of the greatest challenges in recent years is providing enough food to feed the increasing world population, while available freshwater resources become limited. However, effective fertilizer management has also a fundamental role to improve yield quality and quantity. A field experiment was conducted over 2 years, using a split-plot arrangement in a randomized complete block design. The experiments had three water deficit severity treatments: 25% (control), 40% (mild stress), and 55% (severe stress) depletion from the available water. The subplot division consisted of six fertilizer treatments; FR1: unfertilized (control), FR2: 140 kg ha−1 urea; FR3: 105 kg ha−1 urea + 3.3 ton ha−1 vermicompost; FR4: 70 kg ha−1 urea + 6.6 ton ha−1 vermicompost; FR5: 35 kg ha−1 urea + 10 ton ha−1 vermicompost, and FR6: 13.5 ton ha−1 vermicompost. The maximum essential oil (0.97%) was observed under mild water deficit stress. The highest antioxidant activity (DPPH) and superoxide dismutase activity could be monitored under unfertilized and 140 kg ha−1 urea fertilized conditions, respectively. Vermicompost-treated soils reduced antioxidant features, total phenol, and rosmarinic acid content under water deficit. These results indicate that mild drought stress can increases the synthesis of medical compound and vermicomposting can alleviate the impact of drought by conserving soil moisture and improve nutrient uptake. Therefore, the results suggest that using vermicompost as a fast-acting nitrogen amendment can improve the leaf area index.

Sustainable management approaches should be considered to meet gaps between soybean N demand and biological N fixation in poor nutrient soils. Field studies were laid out in 2015 and 2016 to determ...

Salinity stress is one of the main limiting factors of medicinal plant growth and may affect their characteristics and chemical composition. In order to evaluate the response of different species of Iranian mint to salinity stress, an experiment was designed in greenhouse conditions. In this experiment, six Iranian mint species were cultivated in pots under different salinity stress including 0, 2.5, 5, and 7.5 dS/m. The chlorophyll indices (a, b, total, and a/b ratio), carotenoids, total anthocyanin, total phenolic and flavonoid content, antioxidant activity, dry matter yield, and essential oil content were measured in two different harvest stages. Salinity stress affected various measured traits. The results showed that despite the negative effect of salinity stress on photosynthetic pigments, in some ecotypes and species, photosynthetic pigments were not affected by salinity stress. The amount of total phenolic content, total flavonoid content, and total anthocyanin increased in response to salinity stress. The dry matter decreased under salinity stress, but the content of essential oil increased as a result of salinity stress increment. The results of PCA biplot showed that the E16 and E18 ecotypes were separated by a large distance. Among the various ecotypes, E18 had the most desirable traits which can be recognized as a salt‐tolerant ecotype. Also, piperita species was the best among the species in all salinity stress levels., Among the various ecotypes, E18 accounted for the most desirable traits in most of the studied traits and was recognized as a salt‐tolerant ecotype.

Having increased the temperature of different regions, global climate change can affect plants’ growth and development. This study aimed to explore the effects of high temperature on sugar beet (Beta vu-lgaris L.) performance at seedling stage (6–8 leaf stage) in two climatic areas of Iran, Karaj and Moghan, with different relative humidity (RH). Eight sugar beet genotypes, S1-92521, SB26, SHR.02.P4, O.T 607, S1‑92685, S1-92615, SB33-H-1 and 31714, were sown in both sites at two dates, April and July as control and high temperature stress treatments, respectively. Maximal quantum yield of PSII photochemistry in dark (Fv/Fm) decreased by high temperature in both sites, with genotypes S1-92521 and O.T 607 showing the highest value in stress treatment in Karaj. Non-photochemical quenching (NPQ), not affected by high temperature in any sites, was, in general, significantly higher in control treatment than in high temperature in the Moghan, which was attributed to high RH not the high temperature. This decreased net-photosynthetic rate (An), significantly, with genotype SB26 having the highest value in Moghan. Under control, S1-92521 showed the highest NPQ. Genotype SHR.02.P4 had the highest biomass in Karaj and under stress treatment in Moghan. Sugar beet genotypes produced higher biomass in Karaj compared with the Moghan. Finally, it was concluded that the adverse effect on sugar beet in Karaj was due to the high temperature, while in the Moghan, it was because of high RH. The genotypes S1-92521, SHR.02.P4 and SB26 were tolerant to high temperature of which the two latter had better performance under high RH condition.

Potato is the most important non-grain food crop in the world. Viruses, particularly potato virus Y (PVY) and potato virus A (PVA), are among the major agricultural pathogens causing severe reduction in potato yield and quality worldwide. Virus infection induces host factors to interfere with its infection cycle. Evaluation of these factors facilitates the development of intrinsic resistance to plant viruses. In this study, a small G-protein as one of the critical signaling factors was evaluated in plant response to PVY and PVA to enhance resistance. For this purpose, the gene expression dataset of G-proteins in potato plant under five biotic (viruses, bacteria, fungi, nematodes, and insects) and four abiotic (cold, heat, salinity, and drought) stress conditions were collected from gene expression databases. We reduced the number of the selected G-proteins to a single protein, StSAR1A, which is possibly involved in virus inhibition. StSAR1A overexpressed transgenic plants were created via the Agrobacterium-mediated method. Real-time PCR and Enzyme-linked immunosorbent assay tests of transgenic plants mechanically inoculated with PVY and PVA indicated that the overexpression of StSAR1A gene enhanced resistance to both viruses. The virus-infected transgenic plants exhibited a greater stem length, a larger leaf size, a higher fresh/dry weight, and a greater node number than those of the wild-type plants. The maximal photochemical efficiency of photosystem II, stomatal conductivity, and net photosynthetic rate in the virus-infected transgenic plants were also obviously higher than those of the control. The present study may help to understand aspects of resistance against viruses.

DOR: 98.1000/2383-1251.1399.7.83.13.1.1608.1610 Extended abstract Introduction: Legumes are the most important source of plant protein and Mung bean has a high nutritional value for humans, as it produces seeds containing high protein percentage. The major problem of salinity in seed germination of higher plants is due to excessive amounts of sodium chloride, osmotic pressure, disruption of nutrient uptake and transport, and direct effects of ionic toxicity on the membrane and enzymatic systems that in turn reduce germination. External use of methyl jasmonate can modulate the effects of various stresses, such as salinity and drought, by increasing the antioxidant activity of the seed. Therefore, the purpose of this research was to evaluate the effect of methyl jasmonate and salinity stress on germination and enzymatic properties of Mung bean. Material and Method: This study was conducted as factorial based on a completely randomized design with three replications during 2015-16 at the laboratory of Department of Agronomy, Tarbiat Modares University. The experimental treatments included four methyl jasmonate solution (0, 50, 100 and 150 mM) and four salinity stress levels (0, 2, 4 and 6 dS/m salinity from NaCl). Petri dishes were placed in a germinator at 25 ° C and in full darkness for 14 days. In this experiment, germination rate and percentage, time to reach 50% germination, alpha and beta amylase, catalase and peroxidase were measured. Results: The results of the experiment showed that the lowest rate of slope and final germination percentage were obtained in 50 and 100 mM solutions of methyl jasmonate. In terms of T50, an increase of 4.7 days was observed per one dS/m increase in salinity stress and the lowest T50 was estimated at a methyl jasmonate solution concentration of 78.68 mM. In terms of the activity of germination enzymes, reduction of 0.031 μmol/ml/min per 1 dS.m increase in salinity stress and the highest amount of α-amylase were estimated 72.6 μmol/ml/min at a methyl jasmonate solution concentration of 73.33 mM. Also, the lowest activity of β-amylase enzyme was 0.79 μmol/ml/min at a concentration of 5.6 dS/m salinity stress and the highest activity of β-amylase enzyme was estimated to be 1.7 μmol/ml/min at a methyl jasmonate solution concentration of 86.67 mM. The highest activity of catalase (25.7 ∆A/mg protein/min) was observed at 14.72 dS/m salinity stress and the lowest activity of catalase enzyme (8.9 ∆A/mg protein/min) was estimated at 5.88 mM methyl jasmonate solution. The highest activity of peroxidase enzyme (22.06 ∆A/mg protein/min) was at 24.3 dS/m salinity stress and the lowest activity of the enzyme peroxidase (2.5 ∆A/ mg protein/min) was determined at a methyl jasmonate solution concentration of 266.66 mM. Conclusions: In general, pre-treatment of methyl jasmonate can reduce the germination time, increase the rate of germination and reduce the oxidative stress in salt stress conditions by improving the activity of germination enzymes, increasing the activity of enzymes, increasing the activity of hydrolyzing enzymes and increasing the easy availability of seedlings to nutrients during germination. Highlights: 1- Germination rate and percentage and morpho-physiological changes of Mung bean seed as affected by methyl jasmonate were investigated. 2- The role of alpha and beta amylase germination enzymes in accelerating the production of Mungbean seedlings under saline conditions were estimated. 3- Methyl jasmonate- induced catalase and peroxidase enzymes activity in resistance to salinity stress were estimated.

A population of Xiphinema americanum-group was recovered in association with stone fruit trees in Isfahan province, center of Iran. A reverse taxonomic approach based upon the large subunit ribosomal DNA (LSU rDNA D2-D3) and the mitochondrial cytochrome c oxidase subunit I (COI mtDNA) gene sequences in integration with morphological studies, revealed that the recovered population belongs to Xiphinema santos. The Iranian population was mainly characterized by 1240–1868 μm long females with 60–84 μm long odontostyle, a = 37.2–51.9 and c = 42.8–54.6. It is further characterized by a lip region having a depression in junction with the body, presence of visible endosymbiont bacteria in ovaries under light microscope, dorsally convex and ventrally slightly concave conical tail with a blunt tip and three juvenile developmental stages. This population was similar to the type population in its morphology; however overlapped and extended morphometric data ranges, as well as differences in some indexes were observed. Compared to a Spanish population of this species, the Iranian population had a close morphology, similar morphometric data ranges and identical LSU and COI sequences. In LSU phylogeny, the relationship between the present and some previously sequenced isolates of the species and some isolates of three species X. georgianum, X. laevistriatum and X. citricolum was not resolved. In COI phylogeny, the clade of the Iranian and Spanish populations appeared as an independent lineage inside an unsupported clade including several species. The comparison with other populations of the species was reported and discussed. A second species, X. primum, that is native to Iran, was recovered from a new locality and characterized molecularly., The financial support of Tarbiat Modares University is appreciated. The authors acknowledge the critically reading of the MS by Dr. Mohammad Reza Atighi. The presented findings in this paper are part of the results of the project number 0-16-16-94176 by the first author entitled “Determination of infestation of pomegranate orchards and nurseries to plant parasitic nematodes with an emphasis on root knot nematodes”.

Cotton is typically grown in warm regions in which salinity and nutrient deficiency stresses are ubiquitous and often simultaneously influence plant growth. Under saline conditions, fertilizer recommendation is highly challenging, since nutrient application may increase or decrease plant salt tolerance, which may complicate prediction of crop yield. So far, no investigations have been conducted in salt-affected soils to determine optimum concentrations of potassium (K) and zinc (Zn) fertilizers based on chlorophyll fluorescence (ChlF) and gas exchange (GEx) responses in upland cotton (Gossypium hirsutum L.). Accordingly, in this study, a factorial experiment was conducted in a complete block design with six replicates under controlled conditions. Treatments included various K2SO4 (0, 50, 100, and 150 kg ha−1), and ZnSO4 (0, 50, and 100 kg ha−1) concentrations applied to soil before planting. Cottonseeds were sown in non-saline soils and soils formerly salinized with natural saline water diluted to 15 dS m−1. One month after sowing, results showed that salinity significantly decreased dry weight, chlorophyll content index, photosynthesis rate (A), leaf to air vapor pressure, transpiration rate (E), stomatal conductance, and minimum fluorescence of dark-adapted leaf, but increased root to shoot ratio (R/Sh). Under salinity, combined application of K and Zn boosted physiological properties including yield of photosystem II photochemistry (ФPSII), A, and E without improving biomass. Combined application of K and Zn at highest concentrations decreased R/Sh by 93% compared to the control. Rate of increase was higher in E than that of A leading to reduction in water use efficiency. High Zn concentration in saline soils increased non-photochemical quenching and energy loss in form of heat. Under non-saline condition, Zn application significantly decreased A probably due to inhibitory effect on electron transfer within photosystem II. K significantly increased stomatal conductance and accordingly E. GEx parameters were more sensitive to used treatments than ChlF parameters. Based on GEx and ChlF responses, the most salt-tolerant cotton seedlings were obtained under combined application of 50 kg K2SO4 ha−1 and 50 kg ZnSO4 ha−1, thus these concentrations are recommended for optimal establishment of cotton seedlings under salinity stress.

One side effect of human activity and global climatic change is more airborne dust. This not only has undesirable effects on human health and the environment, but may also adversely affect many agricultural processes, including herbicide efficacy. This is particularly relevant in parts of the world where dust storms are common and limited rainfall means dust persists on plants for protracted periods. Accordingly, a series of greenhouse dose–response pot experiments was carried out to quantify the effect of a dust concentration of 1,500 µg/m³ on the performance of paraquat, glyphosate, sulfosulfuron and 2,4‐D+MCPA. Dust‐treated and untreated seedlings of Hordeum spontaneum and Sinapis arvensis were sprayed with sulfosulfuron and 2,4‐D+MCPA, respectively, while paraquat and glyphosate were applied to both weed species. The efficacy of glyphosate and paraquat decreased significantly in the presence of dust on both species. Similar results were observed for 2,4‐D+MCPA on S. arvensis. In contrast, the efficacy of sulfosulfuron on H. spontaneum was not affected by dust. In the presence of dust, the doses of glyphosate, paraquat and 2,4‐D+MCPA required for a 90% effect were enhanced by a factor of 1.9 to 2.6. The negative impact on glyphosate efficacy was more pronounced in S. arvensis than H. spontaneum, while it was similar for paraquat. Future studies should consider the amount, duration and composition of dust as well as its impact on other weeds and herbicides. Potential approaches to overcome the detrimental influence of dust on the performance of herbicides were also suggested for future studies.

Blessed thistle (Cnicus benedictus L.) is an abundant resource with huge phytochemical and agronomic potentials. Their variation in response to agronomic techniques needs to be explored. Field stud...

In this study, the interaction between nanoparticles (0, 50, 100, and 150 mg L− 1) and light intensity (100, 200, and 400 µmol.m− 2.s− 1) was evaluated for effectiveness in improving stevia shoot induction by measuring shoot and leaf number, shoot length, fresh and dry weight, nutrient uptake, steviol glycosides, total carbohydrates and DNA damage in both DNA sequence region (promoter and sequence of UGT76G1 gene). The data revealed the highest shoot number in the combination of 150 mg MWCNTs L− 1 and 400 µmol.m− 2.s− 1 and highest leaf number and biomass accumulation (fresh and dry weight) in 50 mg MWCNTs L− 1× 200 µmol.m− 2.s− 1. Shoot length was observed higher in 0 and 100 mg MWCNTs L− 1× 100 µmol.m− 2.s− 1. The highest contents of N, P, K, Ca, Fe, and Mn were recorded under 50 mg MWCNTs L− 1× 200 µmol.m− 2.s− 1 and 50 mg MWCNTs L− 1× 400 µmol.m− 2.s− 1. In contrast, the amount of Zn and Cu was not affected by the two-way interaction. The combination of 50 mg MWCNTs L− 1× 200 µmol.m− 2.s− 1 and 50 mg MWCNTs L− 1× 400 µmol.m− 2.s− 1 increased the total carbohydrate and rebaudioside A. Stevioside was also increased under the combination of 50 mg MWCNTs L− 1 and 200 µmol.m− 2.s− 1. DNA damage in both regions of the DNA sequence under light intensity at low concentrations of MWCNTs (0 and 50 mg L− 1) did not show a significant change but increased with increasing concentration at high light intensities (200 and 400 µmol.m− 2.s− 1). Thus, Cross-talk 50 mg MWCNTs L− 1 and 200 µmol.m− 2.s− 1 might be an optimal condition for stevia growth and metabolism.

A 2-year (2017-2018) field experiment was performed to specify if the foliar application of putrescine (PUT) under optimum and water-deficit stress (WDS) conditions would favorably affect leaf gas exchange, greenness, chlorophyll fluorescence parameters, pigments, sodium (Na), potassium (K), as well as yield and content of the essential oil (EO) relationships in

Uncovering the genetic basis of photosynthetic trait variation under drought stress is essential for breeding climate-resilient walnut cultivars. To this end, we examined photosynthetic capacity in a diverse panel of 150 walnut families (1500 seedlings) from various agro-climatic zones in their habitats and grown in a common garden experiment. Photosynthetic traits were measured under well-watered (WW), water-stressed (WS) and recovery (WR) conditions. We performed genome-wide association studies (GWAS) using three genomic datasets: genotyping by sequencing data (∼43 K SNPs) on both mother trees (MGBS) and progeny (PGBS) and the Axiom™ Juglans regia 700 K SNP array data (∼295 K SNPs) on mother trees (MArray). We identified 578 unique genomic regions linked with at least one trait in a specific treatment, 874 predicted genes that fell within 20 kb of a significant or suggestive SNP in at least two of the three GWAS datasets (MArray, MGBS, and PGBS), and 67 genes that fell within 20 kb of a significant SNP in all three GWAS datasets. Functional annotation identified several candidate pathways and genes that play crucial roles in photosynthesis, amino acid and carbohydrate metabolism, and signal transduction. Further network analysis identified 15 hub genes under WW, WS and WR conditions including GAPB, PSAN, CRR1, NTRC, DGD1, CYP38, and PETC which are involved in the photosynthetic responses. These findings shed light on possible strategies for improving walnut productivity under drought stress.

Because water resources for irrigation are limited worldwide, it is essential to embrace proper water-saving practices. Field studies were laid out as a factorial split experiment in a randomized complete block design with three replications in 2015 and 2016 to determine the effect of wheat straw mulch (0 and 7.5 tons ha−1) under different irrigation treatments (100%, 80%, 60%, and 40% of the required water) on the physiological characteristics, grain yield, and oil content of sesame (Sesamum indicum L.) genotypes (Borazjan 2, Halil, and Jiroft). Seed yield, 1000-seed weight, seed number, and capsule number were decreased by 64%, 65%, 60%, 70%, and 66%, respectively, as a result of increments in water deficit (from 100 to 40%). However, the application of 7.5 tons ha−1 of mulch mitigated the negative effect of water stress as said factors decreased only by 42%, 40%, 46%, 44%, and 45% as a result of increments in water deficit (from 100 to 40%). Catalase activity (CAT), superoxide dismutase (SOD) activity, proline content, and water use efficiency (WUE) increased with increases in water deficiency, while relative water content (RWC), photosynthetic pigment, and leaf area index (LAI) decreased as water stress rose from 100 to 40%. Applying 7.5 tons ha−1 of straw mulch in 60% available water can be considered a promising management strategy due to both reduction in irrigation water requirements and improvement of low-yield sesame fields in water-deficient areas.

The continuous trend of global warming and increasing interest toward cultivating sugar beet (Beta vulgaris L. ssp. vulgaris var. altissima Döll) in tropical regions led us to conduct this study to investigate the effect of high temperature on sugar beet at initial growth stages. Thirty one genotypes were incubated at two temperatures (20 °C and 30 °C) in laboratory for germination test. The same genotypes were assessed for physiological parameters at 30 °C in greenhouse, too. Increasing temperature decreased germination indices with a high variability among the genotypes. Seed vigor index and seminal root length were decreased higher than other indices. The genotypes with higher greenness index had higher total dry mass, leaf area and leaf temperature depression (LTD), and those with higher seed vigor index indicated great quantum efficiency of PSII (Fv/Fm) values. ‘S1-92521’ produced high records in both laboratory and greenhouse experiments. Although ‘S1-92521’ showed good tolerance in both laboratory and greenhouse experiments, totally, sugar beet genotypes had different performance at two experiments. According to the results, seed vigor index could be used as a screening tool in laboratory, and LTD and Fv/Fm were considered as good criteria for screening heat-tolerant genotypes in greenhouse.

Worldwide, purslane (Portulaca oleracea L.) is well-known for its fatty acids and antioxidants. To investigate interaction effects of nitrogen and mycorrhiza under water deficit stress on agronomic...

To study the effects of water stress and plant density on the qualitative and quantitative characteristics of artichoke (Cynara cardunculus var. scolymus), a two-year field experiment was carried out in a semi-arid region in 2016 and 2017. The experimental treatments were arranged as split-plot in a randomized complete block design with three replications. The main plots were three irrigation treatments of 40, 60 and 80% field capacity and sub-plots consisted of four planting densities of 2, 4, 6 and 8 plant m−2. The results showed leaf area, dry matter, and chlorophyll (a, b, and total) concentration decreased by water deficit stress, whereas proline concentration was increased by water deficit stress. Dry matter and LAI were significantly affected by plant density, so that the highest dry matter and LAI in all irrigation treatments were observed at the populations of 6 plants m−2. An increase of plant density decreased concentrations of chlorophyll a and b and total chlorophyll in artichoke leaves. The various irrigation treatments and plant densities influenced total polyphenol and yields of caffeic and chlorogenic acids. Among irrigation treatments, the highest yield of caffeic acid, chlorogenic acid and total polyphenol (5.14, 8.24, and 5.01 g m−2, respectively) belonged to the non-stressed control. In addition, the highest yield of caffeic acid, chlorogenic acids and total polyphenol (5.90, 9.38, and 5.60 g m−2, respectively) were observed at the population of 6 plants m−2. For both of these factors, the yields of these compounds were completely affected by dry matter yield.

Chitosan and its components have beneficial effects on a wide variety of plant species. Yet, their effects on wheat plants under drought stress are not well known. So, a field experiment was laid out in order to evaluate the effect of chitosan nanoparticles (NPs) on wheat. The wheat seeds were sown in plots. Then, the chitosan NPs were added to them through soil and foliar application at tillering, stem elongation, and heading stages. Results indicated that the drought stress significantly decreased majority of the studied traits compared to the normal irrigation. Application of the NPs especially 90 ppm increased leaf area (LA), relative water content (RWC), chlorophyll content, photosynthesis rate, catalase (CAT), and superoxide dismutase (SOD) activities, yield, and biomass compared to the control. Finally, our results highlight that usage of the chitosan NPs especially 90 ppm can mitigate adverse effects of drought in the wheat under drought stress.

To select and introduce the best rapeseed genotypes under withholding irrigation, two field experiments were carried out in seasons 2015–2016 and 2016–2017 in Iran. Factorial arrangement of...

Little is known about the essential oil content and yield, and physiological and morphological traits of Thymus species including Thymus fedtschenkoi, Thymus kotschyanus, Thymus migricus, and Thymus transcaucasicus. This is the first report on the presence and absence of Thymus species influenced by elevation, precipitation, and temperature. Therefore, the objectives of this study were to investigate the effects of geographical and environmental parameters and species variations on plant growth, quality, and the presence or absence of Thymus populations of Iran. The plants of four different Thymus species were collected at the full flowering stage over 2017 and 2018 from different provinces of Iran. Presence-only modeling method called Maxent was used to predict geographic distributions of species. The impact of climate variability on the qualitative and quantitative properties of populations was higher than the soil physical and chemical characteristics. Temperature was the most important factor that influenced the presence of Thymus species, followed by elevation and precipitation (for T. kotschyanus, the importance of precipitation was greater than elevation). Thymus species are most common in cool to moderate annual temperatures that are elevated enough. Mean total flavonoid in 2018 was higher than that in 2017 across populations due to drought stress. Averaged across locations and years, essential oil yield was in the order of T. kotschyanus > T. migricus > T. fedtschenkoi > T. transcaucasicus. Carvacrol was the main component of T. migricus essential oil from Yam. T. migricus essential oil from Kechi-gala and all populations from T. kotschyanus, T. fedtschenkoi, and T. transcaucasicus had thymol as the main component. The selection of desirable suitable areas and genotypes for cultivation of plants is the first step due to a great effect on the quality and quantity of production.

Strigolactones (SLs) have been implicated in many plant biological and physiological processes, including the responses to abiotic stresses such as drought, in concert with other phytohormones. While it is now clear that exogenous SLs may help plants to survive in harsh environmental condition, the best, most effective protocols for treatment have not been defined yet, and the mechanisms of action are far from being fully understood. In the set of experiments reported here, we contrasted two application methods for treatment with a synthetic analog of SL, GR24. A number of morphometric, physiological and biochemical parameters were measured following foliar application of GR24 or application in the residual irrigation water in winter wheat plants under irrigated and drought stress conditions. Depending on the concentration and the method of GR24 application, differentiated photosynthesis and transpiration rate, stomatal conductance, leaf water potential, antioxidant enzyme activities and yield in drought conditions were observed. We present evidence that different methods of GR24 application led to increased photosynthesis and yield under stress by a combination of drought tolerance and escape factors, which should be considered for future research exploring the potential of this new family of bioactive molecules for practical applications.