جستجوی مقالات مرتبط با کلیدواژه "محتوای پرولین" در نشریات گروه "زراعت"

Improvement of plant tolerance to adverse environmental conditions has been proven by phytohormones in various plants species. However, the crosstalks between salicylic acid and jasmonic acid hormones under drought stress conditions have not been studied. Therefore, in this study, changes in the growth rate of aerial and underground organs as well as the proline content of aerial parts and roots of R. damacena to jasmonic acid and salicylic acid during the cource of drought stress conditions at three different times point were investigated.

Clonally propagated plants sown into plastic pots were exposed to constant water shortage at 25, 50 and 100% of field capacity for 11 days. Plants under different drought stress treatment foliar spraied with jasmonic acid (50 μM) and a combination of jasmonic (50 μM) and salicylic acid (1.5 μM). The first foliar application was performed a few days before the first day of the experiment and twice after the start of the water stress at intervals of seven days. Sampling was performed on days 1, 4 and 11 and morphophysiological responses (stem height, root fresh weight, root dry weight, Ionic leakage) and biochemical (leaf proline and root proline) were measured. The experiment was performed in factorial format and in a completely randomized block.

Regardless of hormonal treatment, the measured traits such as stem height, root fresh weight, root dry weight decreased compared to the control and other traits such as leaf and root proline, ion leakage increased compared to the control in drought stressed plants. Plants grown under 25% of FC showed a 4 fold increase in proline content when exposed to JA in contrast to that of control sprayed with distilled water after 4 days. This increase in proline content in shoots and roots was similar. However, non-drought stressed plants which were exposed to JA, did not show such changes. The results show that the combination of SA and JA reduces the amount of ion leakage of leaves and the proline content of roots and shoots by half to the amount produced in plants sprayed with distilled water at 25% of FC and this amount of proline is very close to non-drought stressed plants. The results showed that the loss of fresh and dry weight of roots, which was evident in JA–received plant under 25% of FC can potentially be reversed by combination of SA and JA. This was also truth for stem height.

The drought stress mitigation of SA by reversing JA effects manifested in mitigating cell ion leakage, and increase in root fresh and dry weight. Reducing the root and shoot proline content and leaf ion leakage in plant exposed to combination of JA and SA compared to JA alone indicated a negative regulatory effect of SA on JA on modulating leaf and shoot proline content as a physiological indicator of drought tolerance.

Salinity stress is one of the main factors that limited crop production. Salt stress causes physiological effects by decreasing soil water potential. Azomite is an inorganic mineral that contains more than 60 forms of nutrients (macro and microelements). This material modifies and improves the soil, and the high ionic exchange capacity of this substance has resulted in some of it being used to reduce the effects of salinity stress. Mexican Parsley (Tagetes minuta) is a medicinal plant from Asteraceae family that used in the food and cosmetic industries. The purpose of this experiment was to investigate biochemical response and dry aerial biomass of Tagetes minuta under salinity stress and Azomite application.

A pot experiment was conducted at the research greenhouse of Ferdowsi University of Mashhad as factorial based on completely randomized design with three levels of salinity (0, 30 and 60 mM NaCl in irrigation water) and four levels of Azomite (0, 4, 8 and 12 g/kg soil) in three replications in 2018. The studied traits were included biochemical characteristics (RWC, Electrolyte leakage, chlorophyll a, chlorophyll b, carotenoid, total chlorophyll, antioxidant activity, total phenol, soluble carbohydrates, and proline) and dry biomass. Statistical analysis was performed using Minitab 17 software. The mean comparison was done by Bonferroni test at the 5% probability level. The figure drew by Microsoft Excel software.

The results of this experiment showed that the interaction effects of salinity and Azomite had a significant effect at a probability level of 1% on all of the studied traits. The highest amount of dry biomass (30.25 g.plant), RWC (74.2 %), chlorophyll a (7.5 mg.g-1FW), chlorophyll b (9.26 mg.g-1 FW), carotenoid (16.73 mg.g-1FW), total chlorophyll (33.39 mg.g-1FW) and essential oil content (0.46 %) were observed in treatment without salinity and 12 g/kg soil of Azomite. The highest amount of Electrolyte leakage (83.55 %), antioxidant activity (9727 %), Total phenol (95.10 mg.g-1FW), soluble carbohydrates (114.4 mg.g-1FW) and proline (0.12 µM/gDW) was observed on 60mM salinity and without the use of Azomite. NaCl stress can reduce nutrient uptake by the root of the plant and cause to decrease the growth of plants (Dry aerial biomass), RWC, Chlorophyll a, b, carotenoid and total chlorophyll and increase antioxidant activity, total phenol, soluble carbohydrates, and proline. Azomite in salinity stress increase water holding and inhibited the plants from Na uptake. Therefore it prevents plants from Na toxicity. The result of this study showed that the highest salinity level (60 mM NaCl) and application of Azomite especially at 12 g/kg soil level had the highest effect on ameliorating biomass and biochemical characteristics of the plant.

In order to evaluate the effect of allelopathy of weed extract organs of Convolvulus arvensis and Malva sylvestris on germination and some quantitative characteristics of three varieties of sesame, a factorial experiment was conducted in a completely randomized design in Seed Technology Laboratory of Shahed University in 2016. Factors consisted of three sesame cultivars (Yeluewhit, Halil and Oltan), two weeds (Convolvulus arvensis and Malva sylvestris), plant extracts of root, stem and leaf, in three concentrations (0, 5 and 10%) repeated in three replicates. According to the results of analysis of variance, the treatments had a significant effect on germination percentage, photosynthetic pigments, proline content and protein content. The highest percentage of germination (100%) was observed in Yeluewhith and Oltan cultivars, respectively. In addition, the results of the mean comparison indicated that the extract of Convolvulus arvensis root increased chlorophyll content of seedling Oltan cultivar. Extract of different organs of weeds reduced proline and protein in sesame cultivars. The extracts of weed organs of Convolvulus arvensis and Malva sylvestris also affected germination and growth of sesame cultivars. Malva sylvestris compared to Convolvulus arvensis showed higher potential for the production of allelopathic materials. Since studied weed residues inhibited sesame growth by producing allelopathic chemicals, therefore, it is recommended that proper management of weed residues of Convolvulus arvensis and Malva sylvestris.

IntroductionMungbean (Vigna radiata L.) is an important, environment friendly staple food legume with rich source of proteins, vitamins, and minerals for human. Drought stress is one of the most adverse factors of Mungbean growth and productivity. Proper nutrition under stress conditions could partly help the plant to tolerate different stresses. Zinc plays a key role in the synthesis of proteins, DNA, and RNA. By consumption of zinc, it is possible to improve the growth status of the plant in stress conditions. Various studies were carried out to understand the effect of nanoparticles on the growth of plants. For example, Hong et al. (2005) and Yang et al. (2006) reported that a proper concentration of nano-TiO2 was found to improve the growth of spinach by promoting photosynthesis and nitrogen metabolism. Nano-particles have high reactivity because of more specific surface area, more density of reactive areas, or increased reactivity of these areas on the particle surfaces. Thus, the objective of this research was to investigate the effect of foliar application of Zno2 in common and nanoparticles forms on growth traits and yield of mungbean (V. radiata L.) under drought stress condition.
Materials & MethodsExperiment was carried out as a split plot in complete randomized block design with four replications in Shahrood Agricultural Research Center during the growing season of 2011-2012. Water stress at three levels (control, cutting of irrigation in 50% flowering and 50% pod setting stages) were assigned as main plots and zinc oxide foliar application in five levels (control, 5 and 10 gl-1 nano sized zinc oxide and 5 and 10 gl-1 non-nano-scale zinc oxide) were randomized in sub-plots. According to soil analysis experiment results, the soil was loam and having pH=7.8; EC=1.5 (dS/m); 0.4% of organic carbon; 0.08% N; 10, 280 and 1.1 ppm of P, K and Zn respectively. Zinc spraying on leaves was done two times at 40 and 55 day after planting. The plots were 24 m2 with 6 sowing rows, 4 m long. Seeds were placed at 3 to 5 cm depth in each row. Irrigation operations were performed until the emergence once every 7 days. Afterwards at 50% flowering and 50% of pod formation stages, irrigation was disrupted. Intended traits were measured in the end of crop season. All data collected were subjected of analysis of variance (ANOVA) using MSTATC software procedure and the significant treatment means were separated using Duncan's multiple range test.
Results & DiscussionResults showed that the drought stress at flowering and podding stages decreased the height, number of branches, chlorophyll a, b, grain and biological yield in comparison to control treatment significantly, but the effect of drought stress at podding stage was more than drought stress at flowering. Water deficit in the plant disrupts many cellular and whole plant functions, having a negative impact on plant growth and reproduction. Thus, it is one of the most yield limiting factors as it affects growth and development. Seed protein and proline content increased under drought stress significantly, while there was no significant difference for carotenoid content between treatments. Foliar application of Zinc in common and nanoparticles forms increased the height, proline content, grain and biological yield in comparison to control treatment significantly. The results showed that foliar application of 10 grams per liter nano zinc oxide in normal and drought stress at flowering and podding stages increased the grain yield by 6.6, 3.6 and 5.4 percent in comparison to no spraying treatments respectively. The maximum effects of Zinc on increasing of traits was found by foliar application of 10 grams per liter nano zinc oxide, 10 grams per liter zinc oxide, 5 grams per liter nano zinc oxide and 5 grams per liter zinc oxide respectively. With the completion of Micro-Nutrients consumption through spraying, the growth state of plant can be improved in stress conditions. Liu et al. (2005) reported that nano-Fe2O3 promoted the growth and photosynthesis of peanut. Prasad et al. (2012) reported that nano-scale zinc oxide particles increased stem and root growth and pod yield of peanut as compared with ZnSO4 application. Reduction of particle size results in increased number of particles per unit of weight and specific surface area of a fertilizer that should increase contact of fertilizer with plant leading to increase in nutrient uptake. Nanoparticles have high reactivity because of more specific surface area, more density of reactive areas, or increased reactivity of these areas on the particle surfaces. These features in nano-scale simplify their absorption in plants.
ConclusionMungbean growth characteristics could positively influence by foliar application of zinc oxide as nano and micro-particles in drought stress conditions. But, the effects of nano-scale zinc oxide particles on plant growth and yield was more in comparison to micro particles zinc oxide in stress and non-stressed conditions.

This research was carried out to identify drought tolerant genotypes on the basis of physiological, phonological and morphological traits and drought tolerance indices in bread wheat. Twenty wheat genotypes were assessed in two field experiments based on randomized complete block design with three replications under non-stress and drought stress conditions in Dryland Agricultural Research Sub-Institute, Sararood, Kermanshah. The studied traits were number of grains per spike, peduncle length, spike length, plant height, 1000-grain weight, days to heading, days to physiological maturity, grain yield, flag leaf area, relative water content, a, b and total chlorophyll, proline content, water retained in cut leaves, cell membrane stability and leaf water potential. Futhermore, drought tolerance indices based on grain yield under stress and non-stress conditions were also evaluated. The results showed that there is significant genetic variation among the studied genotypes for improving drought tolerance. Results of the yield index (YI), yield tolerance index (YTI), mean productivity (MP), geometric mean productivity (GMP), tolerance index (TOL), stability tolerance index (STI) and stress susceptibility index (SSI) identified relatively similar genotypes as the drought tolerant genotypes, but according to the high and significant correlation coefficients among MP, GMP, HMP and STI indices with grain yield under both stress and non-stress conditions, these indices were suitable to identify the high yielding genotypes under both conditions. According to these indices, the genotypes 72YRRGP, T179, T189, 914GB, MARAGHEH(1379-80) and Sardari were detected as the drought tolerant genotypes. Correlation coefficient analysis also revealed that among the evaluated traits, proline content of flag leaf, cell membrane stability and spike length had the stronger relationship with stress tolerance index (STI) and are introduced as the most important traits for selecting drought tolerant genotypes in this research.

Glycine betaine (GB) is one of the osmotic plant-protecting members that accumulate in response to abiotic stresses. An experiment was، therefore، conducted to test whether GB application at various concentrations (0، 10، 20 and 30 mM) through seed soaking or foliar spray methods would protect cucumber seedlings، subjected to chilling stress. At two true leave stages، after GB treatment، the seedlings were exposed to chilling six h/day at 3°C for 6 days. Results showed that GB pre-treatment improved growth parameters of seedlings subjected to chilling stress and provided significant protection against chilling stress compared to non-GB-treated seedlings. GB prevented chilling injuries with increasing chlorophyll، proline content and antioxidant activities and decreasing electrolyte leakage، malondialdehyde and hydrogen peroxide content. The highest cold tolerance was obtained with 20 and 30 mM GB application and seed soaking method provided better protection compared to foliar spray method.

Salinity stress is one of the important limiting factors in agricultural crops production. In order to evaluate salicylic acid (SA) application effects on lettuce growth parameters under salinity stress condition, a factorial experiment in a randomized complete block design (RCBD) with three replications was carried out in greenhouses, Faculty of Agriculture, University of Ilam, Iran. Factors examined in this study were salinity stress at 3 levels (0, 75 and 150 mM NaCl) and SA at 4 concentrations (0, 0.25, 0.5 and 1 mM). The results showed that SA significantly increased growth parameters of lettuce plants under salinity stress condition and reduced adverse effects of stress. With increased salinity severity, proline and malondialdehyde content and antioxidant activity increased but growth parameters decreased. In high concentrations of SA, all the measured parameters were increased while the malondialdehyde content was decreased. In general, SA application with an increase in proline content and antioxidant activity, and a decrease in peroxidation rate of cell membrane lipids led to decrease in adverse effects of salinity stress on lettuce plants.

Investigation of physiological responses to water deficit in sesame (Sesamum indicum L.) genotypes can help to identify effective mechanisms of plant resistance to stress. Therefore, chlorophyll content, proline, soluble carbohydrates, net photosynthesis rate, stomatal conductance, maximum quantum efficiency (fv/fm), plant height and shoot dry weight in a complete block factorial pot experiment with three replications were conducted at the College of Agriculture, Isfahan University of Technology, Isfahan, Iran. Four levels of irrigation included irrigation when the soil, water potential of pots was approximately -0.2 MPa (control) =W1, -0.5 MPa (low water deficit) =W2, -1.0 MPa (intermediate water deficit) =W, and -1.4 MPa (severe water deficit) =W4 and 12 sesame genotypes. The highest reduction in chlorophyll content (46%) in the severe water deficit and the genotype was Non-branching Naz. Net photosynthesis rate, stomatal conductance, total chlorophyll content and maximum quantum efficiency (Fv/Fm) were decreased by 43.8%, 39.6%, 46.6% and 17.7%, respectively, compared to control. Proline and soluble carbohydrate content of sesame genotypes was increased by 129.8% and 35.6%, respectively, under severe water deficit compared to control. Plant height and plant dry weight decreased with severe water deficit by 21.5% and 52%, respectively, due to severe water deficit. Severe water deficit, with negative effects on photosynthetic systems by limiting stomatal conductance and reduce the net photosynthesis rate, was due to the decrease in maximum quantum efficiency. Decrease in maximum quantum efficiency on one side and the chlorophyll content reduction in other side, reduces the photosynthetic production and reduce the yield (dry matter) per genotypes.