mohammad javad arvin

Silica nanoparticles can reduce the adverse effects of abiotic stresses by modulating several physiological processes. However, there is little information about how these effects are mediated under heavy metal stress. This study investigated the role of silicon nanoparticles in mitigating the toxicity of cadmium chloride in tomatoes (Solanum lycopersicum L.) was investigated. Silicon nanoparticles were used at levels 0, 25, 50, and 100 mg/l, and cadmium chloride at three levels of 0, 100, and 200 µM. The results showed that 200 μM cadmium treatment resulted in a decrease in plant fresh weight and length, ascorbate and glutathione levels in shoots and roots, but increased cadmium, malondialdehyde, H2O2, and protein content compared to the level 0 cadmium treatment. 50 mg/l nanosilica treatment resulted in an increase in plant fresh weight and length, an increase in ascorbate and glutathione levels, and a decrease in cadmium, malondialdehyde, H2O2, and protein content compared to the level 0 nanosilica treatment. Cadmium stress increased the activity of superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase, and glutathione-S-transferase, and the treatment of 50 mg/l silicon nanoparticles under cadmium stress enhanced the activity of these enzymes. The maximum increase in the activity of enzymes by silicon nanoparticles showed that these nanoparticles play a significant role in detoxifying reactive oxygen species and reducing oxidative stress induced by cadmium.

Tomato leaf curl Palampur virus (ToLCPalV) is a destructive bipartite begomovirus which recently is responsible for huge losses to tomato and cucurbits production in Iran. In this research, the effect of the silicon element, growth regulators including salicylic acid (SA), methyl jasmonate (MJ), brassinosteroids (BR), silicon element (Si) and their interactions to response of ToLCPalV infection of the greenhouse cucumber was studied. The study was performed as factorial experiment based on randomized complete block design and carried out under greenhouse conditions in pots. Before planting, cucumber seeds were presoaked separately in SA (0.5 millimolar), MJ (5 micromolar) and BR (1 micromolar). Subsequently, two or three-leaf stage of cucumber seedlings was sprayed by Si solution (1 ml/lit), one week before agroinoculation with ToLCPalV infectious clone. To analyze morphological and chemical characteristics, plant growth parameters including fresh weight and plant height parameters and amount of the catalase, peroxidase, polyphenol oxidase, ascorbate peroxidase and guaiacol peroxidase enzymes were assessed 30 days post agroinoculation with ToLCPalV infectious clone. Results indicated that, SA and combination of MJ+Si and BR+Si treatments resulted in raising the enzyme levels which leads to delay in appearance of ToLCPalV symptoms and decrease fresh weight and plant height parameters of plants. Based on the results of this research, application of plant growth regulators with or without silicon element including SA, MJ, MJ+Si and BR+Si could be resulted in increasing resistance in greenhouse cucumber against ToLCPalV infection.

Watermelon mosaic virus (WMV) is one of the most important viruses of cucurbit plants. In this research, the reaction of 10 cantaloupe and eight watermelon Ajili (Jabani) inbred lines was evaluated under greenhouse conditions against a WMV isolate. Results indicated that only the inbred line of cantaloupe selfing 2 showed a delay in symptoms development which attributed to low disease severity index and average absorbance in ELISA test. Therefore, it was considered as resistant inbred line to the virus. While the inbred lines 3, 5, 6 and 8 were moderately susceptible and 4, 7, 10 and 11 were susceptible to the virus. Among watermelon inbred lines, 2 and 5 were found to be susceptible, whereas other accessions did not show any disease symptoms and also their severity index were recorded to be zero. Furthermore, results of enzyme-linked immunosorbent assay (ELISA) and RT-PCR tests showed that the later accessions are resistant to WMV. To assess the virus's impact on plant biomass, cantaloupe and watermelon inbred lines were mechanically inoculated with the WMV. Results indicated that the susceptible cantaloupes and watermelons against WMV were found to have significantly lower fresh leaves, dry stems and biomass than control plants (non-inoculated). Collectively, the cantaloupe inbred lines 1 and 2 and watermelon inbred lines 1, 3, 6, 7, 8 and 11 used in this study are probably resistant against WMV and can be recommended in breeding programs to establish more resistant crops.

Research in the field of nanotechnology as an emerging field has culminated in the advancement of various branches of technology. The role of iron in reducing abiotic stresses has not been widely studied despite the fact that it is considered an essential element for plant growth. Therefore, an experiment was conducted in 2017 in the greenhouse of Kerman Graduate University of Technology. In this research, the effect of Fe3O4 nanoparticles at five levels of 0, 10, 20, 50 and 100 mg/l on tomato plant subjected to cadmium chloride (CdCl2) stress with three concentrations of 0, 100 and 200 μM was evaluated. The results showed that the 200 μM CdCl2 concentration in the nutrient solution caused a significant decrease in shoot dry weight (56%), root dry weight (65.5%), shoot length (52.6%), as well as root length (56.8%) compared to the control. Besides, MDA and H2O2 content of shoots and roots increased significantly relative to the control. The change in superoxide dismutase (SOD) activity was 232.4% (3.3-fold) in the shoot and 143.5% (2.4-fold) in the root compared to the control. However, the application of 20 mg/L concentration of Fe3O4 nanoparticles was significantly effective for plant growth and improved cadmium toxicity along with reducing the concentration of free cadmium in the plant through the stimulation of various defense mechanisms. In general, the results of this research showed that spraying iron oxide nanoparticle can be useful to protect tomato plants under cadmium stress.

The potato (Solanum tuberosum L.) tuber is the third most important food crop in the world after rice and wheat for human consumption and makes an important contribution to the diet of people worldwide (Haverkort et al. 2009). Global cultivation area of about 19.35 million hectares in 2014 and annual production of nearly 382 million tons and nearly 5 million tons has been reported in Iran (FAO, 2016). Selenium (Se), as an essential part of human nutrition, plays a significant role in a number of metabolic functions and also shelters plants from several abiotic and biotic stresses (Schiavon et al. 2017). Se can affect the quality of vegetables and fruit. Increased cellular content of linoleic acid and sterols and a decreased oleic acid content have been observed in Camelia oleifera plants treated with Se (Song et al. 2015). Se spraying has been used to enhance the selenium content in broccoli (Sindelarova et al. 2015), radishes (Schiavon et al. 2016), basil (Mezeyova et al. 2016), tomatoes (Zhu et al. 2016), grapes (Zhu et al. 2017) and other crops (Puccinelli et al. 2017).

Two field experiments were carried out in Jiroft (57 90 E L. 28 13 N Lat., 625 m above sea level), Kerman, Iran, during 2016-17 (October to Jan) and 2017 (Jan to Apr) with Sante cultivar. In Jiroft minimum and maximum temperatures over growing season were 8 and 40 °C, respectively in first season and 8 and 43 ºC, respectively in the second. Relative humidity was 55-60% in every two years. The soil had a sandy-loam texture, and the acidity (pH), electrical conductivity (EC), absorbable potassium, absorbable phosphorus, total nitrogen and selenium content of the soil extract were 7.50, 2.41 ds m-1, 159 mg/l, 8.80 mg/l, 0.03 % and 0.17, respectively (table 1). This study was carried out as a split plot with three replicates. Experimental treatments included foliar application of nitrogen fertilization on 2 level normal (150kg/h) and high nitrogen (300kg/h) and selenium (Se) (0, 15, 30 and 60 mg/l) as sodium selenate (Na2SeO4) 35 days after plant emergence. During the experiment, morphological traits including plant height, plant fresh weight, tuber weight and tuber yield and chemical and biochemical traits including selenium and nitrogen levels, starch, ion leakage and malondialdehyde, chlorophyll content, Catalase enzymes, nitrate reductase and superoxide dismutase, and some amino acids were evaluated.

Result and disscution:

Overall, it has been shown that nitrogen uptake increases the quantitative traits and decreases the quality of potato tuber cultivars. Selenium application, improving yield, qualitative and quantitative traits, increased selenium accumulation and reduced nitrate accumulation in potato tubers. The lowest amount of nitrate accumulation and the highest selenium accumulation were obtained from 150 mg/l selenium treatment. The highest yield of the tuber was obtained from 150 mg/l Selenium treatment. Although Se is not yet confirmed as an essential micronutrient in higher plants (Turakainen et al. 2004; Rani et al. 2005), many researchers have already shown that selenium (Se) could increase the tolerance of plants exposed to stressful environments (Djanaguiraman et al. 2005; Djanaguiraman et al. 2010). In the present study, potato plants treated with Se resulted in an increase in shoot fresh weight and tuber yield. Se increases the allocation of phytosimulates to grow tubers, so tubers act as a rich source for carbohydrates and selenium accumulation. They also attributed the positive effect of selenium on potatoes to the antioxidant effects of selenium on the plant's aging delay. They reported that selenium fertilization could improve the nutritional value of potato by increasing the level of organic compounds containing selenium in the tubers.

The effect of plant growth regulators (PGRs) and plastic mulch on the amount of some leaf elements, enzymes and nitrate accumulation in onions under water deficit stress was investigated. The main plots consisted of water deficit stress treatment at three levels (100% water requirement, 80% and 60% water requirement), and subplots including mulch (in two levels of application and no application of dark plastic) and PGRs factor in Six levels (zero, salicylic acid (0.5 mM), methyl jasmonate (5 and 7.5 µM), 24-Epibrassinolide (0.5 and 1 µM). Significant interaction was observed between low water stress and PGRs in the amount of nitrogen, catalase, superoxide dismutase and malondialdehyde enzymes, methionine, isoleucine and proline amino acids, ion leakage, chlorophyll and carotenoids pigmentation. The effect of the PGRs was mainly effective in water deficit conditions. Also, the interaction of water deficit and plastic mulch in addition to these traits was significant on the amino acid valine and tyrosine traits and phosphorus and potassium of leaf and this effect was significant under water deficit condition. Brassinolide growth regulator treatment had the most effect on reducing nitrate in onion bulb. Under non stress, mild stress and severe stress condition, 1 micromolar brassinosteroid reduced 26, 23 and 31 percent of onion nitrate, respectively. Also, plastic mulch under non stress conditions have no effect on reducing the accumulation of nitrate, but under severe stress conditions (60% water requirement), use of plastic mulch detergent reduced the 13% accumulation of nitrate compared with the control

Salinity stress is one of the main limiting factors for optimum agricultural productivity of safflower, Carthamus tinctorius L., in arid and semi-arid regions. It could leads to significant changes in plant biochemical, physiological, and growth traits. Salinity induced endogenous rise in jasmonic acid and its methyl esters (MeJA) has been reported. In the present study, effects of salinity stress (6 and 12 ds m-1) and the exogenous application of MeJA (0.1 and 0.5 mM) on the leaf number, shoot fresh weight, shoot length, chlorophyll a/b, soluble sugar, proline, and malondialdehyde (MDA) contents were investigated in two safflower varieties (Isfahan and IL111). Salinity stress negatively affected the growth of both varieties. Lipid peroxidation was not observed in Isfahan variety, but it significantly increased in the salinity resistant safflower, IL111. Soluble sugar and proline as the important osmoprotectants and free radical scavengers were elevated by salinity stress. Exogenous application of MeJA to the salinity stress-imposed plants slightly improved the growth due to inductions in the rate of photosynthesis; however, MeJA application impaired the growth of non-stressed plants because of induction of stomatal closure and as a result reduced photosynthesis.

Watermelon nuts is widely cultivated in Khorasan Razavi for its edible seed production. Two experiments were therefore, conducted to increase seed production in Bahonar University of Kerman Research Station in 2013 and 2014. In first year, the effects of gibberellic acid (0 and 50 mg/l) and fruit number (1, 2 and 3 fruits /plant) were studied in 4 populations. In second year, the effects of 24- epibrassiniolide (0, 0.5 and 1 micromolar), gibberellic acid (0 and 50 mg/l), Boron (0, 0.1 and 0.2%) and calcium (0 and 0.2%) were studied in one population (Japoni) on growth and seed production. Results from first year experiment revealed that GA increased  the plant lenght (417 cm) compared with control (363 cm). the maximum of fresh biomass (1805 gr) and chlorophyll index (57.5) with application of gibberellic acid in Japony population was observed. Three fruits remained per plant produced more volume (12545 ml/plant) and weight (12223 gr/plant) of the fruit and seed weight (304 gr/plant )  in Japony population. Howevere, the results from second year experiment showed that in treatments containing Br 0.5, 0.1% boron and 0.2% calcium,  highest leaf relative water content (67%) and lowest leaf ion leakage (30%) was found. Moreover,  treatment combination of 0.5 micromolar Br, 0.1% boron, 0.2% calcium and 50 mg/l GA was the most effective treatment for increasing of shoot fresh weight (2490 gr/plant), leaf chlorophyll content (28.2 mgr/gr fresh weight), fruit volume (8486 ml/plant) and weight (8342 gr/plant) and seed weight (228 gr/plant), such that this treatment produced 3 ton/ha seed yield, compared with control which was about 1 ton/ha. This treatment is recommended for watermelon seed production.

In order to investigate the interaction of Methyl Jasmonate (MeJA)and silicon on the yield and its components in tomato plant ‘Dafnis’ cultivar under salinity stress, an experiment as split-plot design was carried out using the Randomized Complete Block design (RCB) and with 3 replications contained 4 observations.  Experiment was done in pots containing 8 kg of sandy soil in a commercial greenhouse for 11 months. The main factor, irrigation water Salinity, was assessed in 3 levels with electrical conductivity (EC) of 0.4 and 6 ds.m-1, MeJA as a sub-factor at 0.5 and 7.5 µM and silicon in the form of sodium silicate in 3 levels of 0.4 and 8 mM. The results showed that with increasing in salinity of irrigation water from 0 to 6 ds.m-1, MeJA level from 0 to 7.5 µM and sodium silicate from 0 to 8 mM, the total yield decreased from 145.1 to 133.5, 144.2 to 136.2 and 141.3 to 136 t. ha-1, respectively. The highest yield was obtained as 147.7 t. ha-1, using 4 Mm sodium silicate and 7.5 µM MeJA in non-saline conditions.

Effects of drought stress and chemical treatments was studied on growth and developmental traits of four barley cultivars using a split- split plot design (RCBD) in Agricultural Research Farm, Kerman University in 2013-14. Main plots consisted of irrigation (control and drought stress after flowering), sub-plots consisted of four barley cultivars (ʻNosratʼ, ʻAfsalʼ, ʻYousofʼ and ʻUH12 lineʼ) and sub-sub plot consisted of control, salicylic acid (0.5 mM) as seed soaking, foliar spray at anthesis and seed soaking foliar spray) and also foliar spray with selenium (40 mg/l using sodium selenate). Drought stress significantly decreased chlorophyll index (10 percent), thousand grain weight (19 percent), grain yield (20 percent), biological yield (11 percent) and harvest index (12 Percent). On the contrary, salicylic acid increased plant height, length of spike and awn, chlorophyll index, thousand grain weight, grain yield, biological yield and harvest index. Foliar spray of plants with sodium selenate increased selenium contents of grains in all cultivars. However, it could be concluded that salicylic acid improved plant performance under normal and drought conditions and selenate application enriched barley grains, and therefore those treatments are commercially recommended.

To investigate the effects of methyl jasmonate growth regulators on growth characteristics, fruit number and fruit yield of ‘Semsuri’ melon, an experiment at the field of Shahid Bahonar University was conducted in summer 2012. Melon (cv. ‘Semsuri’) is widely cultivated in Iran and therefore increasing the fruit yield and quality of this cultivar is necessary. Some growth regulators including Methyl Jasmonate (MJ) may improve growth and development of plants when applied at appropriate low concentrations. Thus, a complete random block experiment at the research field of Shahid Bahonar University was conducted to study the impact of 0, 2.5 and 5µM of MJ applied as seed soaking, foliar spray at 6-7 leaf stages, after fruit set and in combination with treatments on growth and fruit yield of ‘Semsuri’ melon. To promote growth and fruit yield, two times application of MJ is required. MJ reduced leaf ion leakage and increased chlorophyll index, relative water content, flesh thickness, plant fresh weight and fruit yield. Moreover, MJ significantly reduced fruit set that reduces fruit hand thinning. Most effective level of MJ was 5 µM applied at 3 stages. Compared with control, 5µM MJ reduced leaf ion leakage (42 percent), and increased chlorophyll index (45 percent), relative water content (32 percent), flesh thickness (33 percent), plant fresh weight (38 percent), root fresh weight (40 percent) and fruit yield (24 percent with two melons per plant and 19 percent with three fruits per plant).

Salinity is a common abiotic stress that affects plant growth and development as well as crop production in most parts of the world. To study the effects of salt stress and salicylic acid pretreatments on the growth parameters, photosynthetic pigments, photochemical efficiency of photosystem II including: quantum yield of PS II (Ø PSII), maximum quantum yield of PS II (Fv/Fm) and non-photochemical quenching (NPQ) and mineral nutrients (Na+, K+, N, P, Ca2+, Mg2+, Fe, Zn2+, Mn, Cu and B) of Zea mays L. (KSC704) a factoriel experiment was conducted in completely randomized design (salinity in tow levels and salicylic acid in three levels) with 5 replicates. Salt stress reduced growth parameters and photosynthetic pigments (chl a, b and total), carotenoids, quantum yield of PS II (Ø PSII), maximum quantum yield of PS II (Fv/Fm) and increased non-photochemical quenching (NPQ). Moreover, salt stress affected mineral elements in the leaves of the plants. Salinity decreased the amounts of K+ and Cu and increased Na+, P, Ca2+, Mg2+, Fe, Zn2+, Mn and B but the contents of N and Ca2+ were not affected by salinity. SA pretreatment increased photosynthetic pigments and carotenoids, quantum yield of PS II (Ø PSII), maximum quantum yield of PS II (Fv/Fm) and decreased non-photochemical quenching (NPQ). SA application changed the absorption and translocation of mineral elements in the leaves and specifically decreased Na content. Positive effects of SA pretreatment appeared in reduction of salt stress and improving the plants growth.

Salt stress causes ionic, osmotic and oxidative stresses in plants. Salicylic acid (SA) is a plant-produced phenolic compound that can function as growth regulator. In this study, the role of SA pretreatment in inducing tolerance to oxidative stress induced by salt in maize plants was investigated. In this research, effects of SA in three levels (control, soaked in water and soaked in solution of 0.1 mM salicylic acid) and also salt stress (0 and 80 mM NaCl) were studied. Salinity decreased growth parameters but increased lipid peroxidasion and electrolyt leakage. In addition, salt stress decreased the content of ascorbate pool and phenolic compounds and increased the activity of antioxidant enzymes including ascorbate peroxidase (APX), catalase (CAT) and peroxidase (GPOD). Meanwhile, SA pretreatment reduced lipid preoxidation and electrolyte leakage by increasing the nonenzymatic antioxidants such as ascorbate pool and phenolic compounds but the activity of ascorbate peroxidase (APX), catalase (CAT) and peroxidase (GPOD) which were reflected in improving the plants growth. However, it was concluded that SA was able to induce protective reactions via increasing quantity and activity of these antioxidants under salt stress conditions.

Two experiments were conducted to study the impact of salt stress and salicylic acid (SA) on seed germination and plant growth of maize (SC704) under field conditions in the city of Kerman in 2010. For germination experiment, SA seed pretreatments included; control, water soaked, SA soaked in 0.1 and 0.2 mM for 24 hours and salt treatment included; control, 40 and 80 mM NaCl. All seed germination parameters including germination percentage, mean germination time, germination uniformity, radicle and root length and seedling dry weight were adversely affected by salt stress. SA especially at 0.1 mM improved all parameters significantly, especially under salt treatment. Under field conditions (40 mM salinity), 0.1 mM SA improved chlorophyll, relative water content, membrane permeability, fresh and dry weight of forage, comb length, grain yield, 1000 seed weight, water use efficiency and K+ in leaf. However, leaf Na+ content was significantly lower when SA was used. Thus, it was concluded that seed pretreatment with SA could be used commercially to improve plant performance and yield in maize under salt stress conditions.

It is now widely accepted that calcium (Ca) deficiency is linked to potato (Solanum tuberosum L.) tuber disorders and improved tuber health is expected through increased Ca availability. The purpose of this study was to optimize the Ca concentration in Murashige-Skoog (MS) basal medium for microtuber production and determine microtuber mineral composition, especially Ca content. The response of cultivars Bintje and Russet Burbank to the Ca concentration in the media including 3 (control), 10, 15, 20, or 25 mM was different for most parameters measured. Ca at 10 mM concentration improved overall performance of Bintje but not Russet Burbank, compared to controls (3 mM Ca). Higher levels of Ca in the medium were somewhat toxic to both cultivars. Increased Ca concentration in the medium did not affect final shoot fresh weight (SFW) in Bintje but reduced it in Russet Burbank compared with control medium. Ten mM Ca increased microtuber number by 19% in both cultivars. It also increased microtuber fresh weight by 19.5% in Bintje with no effect on Russet Burbank. Mean tuber weight was not affected in Bintje but was decreased by 17% in Russet Burbank. Harvest index in both cultivars was slightly improved at 10 mM Ca but higher levels reduced this index significantly. Microtuber tissue Ca content was greatly increased by Ca treatment in both cultivars. Maximum increase was observed at 15 mM Ca (70%) and 10 mM Ca (61%) in Bintje and Russet Burbank, respectively. Ten mM Ca also increased P (25%) and K (19%), in Bintje whereas in Russet Burbank only P was increased up to 20% at this level of Ca. Unlike Zn, accumulation of other microelements were affected rather differently in two cultivars. Ten mM Ca had no reducing effects on Fe, Mn and Cu accumulation in Bintje whereas it had significant reducing effects in Russet Burbank. It is concluded that the conventional concentration of Ca in MS medium (3 mM) is not high enough for optimum microtuberization. Hence, it appears that optimization of the Ca concentration is necessary for each cultivar.