Journal of Plant Process and Function

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Heavy metals are a major environmental problem and have caused serious concerns because of characteristics of carcinogenesis, non-degradability and biological accumulation. Major part of this material is absorbed by plants and leads to inactivation of some enzyme, decreased protein production and disrupting variety of reactions and many cellular functions and growth and development cessation. The aim of this study was to evaluate the treatment effects of mercuric chloride and cadmium chloride on total soluble protein, soluble sugars content, concentration of proline, lysine and methionine amino acids with catalase, peroxidase and polyphenol oxidase activity in Tajan and the Gonbad wheat cultivars. The Seedlings were treated in three leaflets stage with mercuric chloride at concentrations of 5, 10, 15 and 20 µM and cadmium chloride at concentrations of 0.5 and 0.25 mM as well as control. The experiment were conducted as factorial in a completely randomized design with three replications. The results showed that in both Gonbad and Tajan cultivars, mercuric chloride treatment significantly decreased the total soluble sugars content and polyphenol oxidase and increased the amount of protein, proline, lysine and methionine compared to control. In Gonabd, with increasing concentrations of cadmium chloride, total protein, soluble sugar and lysine contents increased but proline and methionine contents reduced. But inTajan cultivar opposite result was obtained. Tajan is therefore more tolerant than Gonbad. Also in Gonabd cultivar, with concentration increasing of mercury, catalase and peroxidase activity were reduced but in Tajan increased activity of these enzymes. With increasing concentration of cadmium activity were reduced compared to control enzymes. Thus, this study showed that treatment with cadmium chloride and mercury chloride at micromolar and millimolar levels is able to stimulate plant defense mechanisms and makes plants more tolerant against stress.

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Dehydration stress is known as one of the factors limiting the growth and production of crops in Iran. The potassium element plays an important role in plant vital activities and inhibits the destructive effects of low water stress. Use of nanofertilizer in order to accurately control the release of nutrients, can be an effective step towards achieving sustainable agriculture and compatible with the environment. The aim of this study was to investigate the physiological traits influenced by potassium nano-chelated on dehydration tolerance in wheat.
For this purpose, a factorial experiment was conducted in a completely randomized design in a laboratory of Faculty of Sciences, University of Mohaghegh Ardebili, in 2015, with three replications. The first factor was dehydration at three levels of osmotic potential of 8-, 4-, 0 times,, the second factor included two Rasad and Gascogne cultivars and the third factor was potassium nano-chelated with concentrations of 0, 35 and 65 mg / L. The stress was conducted out at stage 3 to 5 leaf. First sampling five days after applying low water stress by polyethylene glycol 6000 and the nano-chelated potassiom spray solution was applied to the leaves. The results showed that the stress increased the activity of the enzymes catalase, peroxidase, polyphenol oxidase and ascorbate peroxidase and metabolites such as soluble sugars, proline and total protein. The Cascogen cultivar showed significant changes in most of the measured traits compared to the observation Rasad significant changes, as a result, this cultivar is tolerant to water stresses.. In general, the application of concentration of 65 mg / l of potassium nano-chelated decreased the effects of stress on measured traits and in some cases, it increases plant defense mechanisms in response to destructive effects of stress such as increasing the activity of antioxidant enzymes and plant adaptation metabolites. Among the concentrations used by nano-chelated, 65 mg / l had the highest effect in 8- barrel stress and could be recommended for farmers in terms of impact.
 
 

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Biochar is a carbon rich product which created under low Oxygen conditions. In this study the effect of Biochar in three levels 0, 0.5 and 1 weight percentage on morphological traits like height, SLA, aboveground and underground biomass, length and volume of root and physiological characteristics such as chlorophylls, gas exchange and electrolyte leakage for two Bromus tomentellus and Medicago sativa species were investigated. Results showed that biochar increased the height of both B. tomentellus and M. sativa which was higher in 0.5 level than 1 percent. However, there were no differences between control and 1 percent of M. sativa. In both species biochar has no effect on SLA. Biochar had no effects on aboveground and below ground biomass for B. tomentellus and significantly increased below ground biomass and no effect on above ground biomass. Both root length and volume increased by biochar. Biochar had no effect on chlorophylls of B. tomentellus but in level 0.5 lead to increasing of chlorophylls for M. sativa. Gas exchange increased by biochar and electrolyte leakage had no significant effect. In general, increasing biochar level reduced morphological traits and increased physiological traits.

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Since about 20% of the world's arable land and 50% of productions in the world are subject to salinity stress, it affects all stages of plant life from germination to seed production. The aim of this study was to investigate the effect of salinity stress on physiological and biochemical characteristics of some wheat cultivars. For this purpose, a factorial experiment was conducted in a completely randomized design with three replications. The first factor was salinity stress at three levels (control, 100 and 150 mM sodium chloride) and the second factor was wheat cultivars (Mihan, Heydari, Saisons and Gascogen). Plants were exposed to stress from two to four leaf stage and normal water was used for control treatment. Sampling was performed 14 days after stress application from treatet and the control samples. The results showed that among the studied cultivars, salinity stress decreased the concentration of chlorophyll a, chlorophyll b, carotenoids, total protein, and increased prolin, eantioxidant enzyme (peroxidase and polyphenol oxidase) activities and fresh weight of stems and leaves in Saison cultivar. Also, salinity stress did not have significant effect on the amino acids lysine and methionine. The activity of antioxidant enzymes is a very important defense mechanism and increasing the activity of peroxidase and polyphenol oxidase enzymes during salinity stress can reduce or prevent oxidative stress. In general, salinity affected wheat cultivars differently, because cultivars deal with salinity stress toxicity using different mechanisms.
 

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Environmental pollution caused by heavy metals due to their non-degradability is a major concern in agricultural soils that threatens food security. Cadmium and mercury are among the two dangerous and carcinogenic pollutants that, in natural ecosystems are increased by human activities and lead to a decrease in protein production, the deactivation of some enzymes, disruption of various reactions and cellular actions, and the stoppage of growth and development. Since the contamination of agricultural land with heavy metals, on the one hand, leads to a decrease in the quality of agricultural products and, on the other hand, is a serious threat to human health, it needs more attention. Therefore, the purpose of this research is to investigate the effect of replanting wheat seeds resulting from the treatment of heavy metals such as cadmium and mercury on some morphophysiological parameters of two wheat cultivars. For this purpose, a factorial experiment was conducted in the form of a completely randomized design with three replications in the greenhouse of the University of Mohaghegh Ardabili. The first factor of wheat cultivars (Morvared and Falat) and the second factor of the experimental treatments include mercury chloride (with a concentration of 10 and 20 μM), cadmium chloride (0.5 mM), and the interaction effects of cadmium with mercury at two levels (10 μM of mercury with 0.5 mM cadmium, 20 μM mercury with 0.5 mM cadmium) were with the control seedlings. The findings showed that, except for the treatment with cadmium under the stress of the toxic metal mercury and the interaction effect of cadmium with mercury, the amount of soluble sugar and total protein, the activity of the catalase enzyme increased, but the activity of the antioxidant enzymes peroxidase and polyphenol oxidase decreased in the Morvared cultivar. The results indicate that the seeds obtained from the foliar treatment of cadmium, mercury and the interaction of these heavy metals and the re-cultivation of these seeds can affect their performance by changing the physiological characteristics. In general, under the stress of mercury chloride and cadmium chloride and their interaction, the Morvared cultivar showed a better reaction than the Falat cultivar. Therefore, based on the results of this greenhouse experiment, it seems necessary to continue research in field conditions.

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Salinity is one of the most important environmental stresses, the increasing spread of which reduces the growth and yield of agricultural plants, in this regard, identifying sugar beet cultivars tolerant to salinity stress to improve quantitative and qualitative yield is of particular importance. For this purpose, research was conducted to investigate the physiological characteristics of some sugar beet genotypes under salt stress in 2019. This experiment was carried out factorially in the form of randomized complete blocks with three replications in Mohaghegh Ardabili University under greenhouse conditions. The experimental factors included different genotypes of sugar beet (9 genotypes) as the first factor and salinity stress as the second factor at four levels (control and 4, 8 and 12 dS/m). The results showed that the effects of salinity stress on chlorophyll content, soluble protein, proline content, soluble sugars and the activity of antioxidant enzymes (catalase, peroxidase and polyphenol oxidase) of different sugar beet cultivars were significant. Higher levels of salinity stress (12 dS/m) caused a significant increase in soluble protein, proline content, soluble sugars and activity of catalase, peroxidase and polyphenol oxidase enzymes compared to other levels of salinity stress and the control treatment. Whereas, the highest content of chlorophyll a, b and total chlorophyll was observed in cultivars number 15 and 4 in the treatment of not applying salt stress. Among the studied genotypes, genotypes No. 6, 15 and 20 had the highest activity of antioxidant enzymes under the condition of 12 dS/m salinity stress. Therefore, at higher levels of salinity stress, resistant sugar beet cultivars prevent the reduction of photosynthetic pigment content by improving the content of compatible osmolytes and antioxidant activities through correct membrane structure.

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Evaluation of the tolerance of different wheat cultivars to environmental stresses, especially salinity stress, and its effect on wheat in different stages of growth is an important factor in choosing them for cultivation under these stress conditions. Therefore, knowing the mechanisms of tolerance to salt stress in wheat will help to choose suitable cultivars for cultivation in areas that are exposed to this stress. The present study was evaluated with the aim of investigating the effect of salinity stress on different varieties of wheat in order to identify the mechanisms involved in the transmission of the defense message of this plant from the biochemical and molecular aspects. The experiment was conducted in a factorial manner based on a completely randomized design, with three replications in the greenhouse of the Faculty of Agriculture of the University of Mohaghegh Ardabili. The investigated factors include salinity stress at three levels (zero, 100 and 150 mM sodium chloride (NaCl)), six wheat cultivars (Quds, Azadi, Arg, Tajen, Flat and Bam) and sampling time (before applying stress was 7, 14 and 21 days after application of salt stress). From the two-leaf stage onwards, the samples of the salinity stress level for the first three days were stressed with salt solution, every day with a concentration of 50 mM, so that the plants would not be shocked by sudden salinity stress. After 3 days, the plants were exposed to stress with concentrations of 100 and 150 mM sodium salt, and normal water was used for the control treatment. The results showed that the amount of proline, total protein, lysine and methionine increased with the increase in salinity stress. Also, under salinity stress, protein accumulation was higher in Bam, Arg and Plat cultivars than Tajen, Quds and Azadi cultivars. As a result, the numbers deal with the toxicity caused by salinity by using different defense mechanisms. In general, according to the results of this research, it can be concluded that salinity changed the studied biochemical traits, and among the cultivars studied, the Arg cultivar showed more tolerance to salinity stress. Also, in general, the accumulation of proteins in Bam, Arg and Plat varieties was higher than Tajn, Quds and Azadi varieties.