فصلنامه فرآیند و کارکرد گیاهی
سال چهارم شماره 1 (پیاپی 11، بهار 1394)

Arsenic is considered as one of the most important environmental contaminant compounds. Arsenic is known to induce oxidative stress in plants by generating various reactive oxygen species and thus increased lipid peroxidation. Phosphorus has some physic-chemical similarities with arsenic which affects its metabolism in plant cell. Malondialdehyde (MDA) is a measure of lipid peroxidation in membrane damage index. In this study، the interaction of arsenic and phosphorus on chlorophyll content and MDA accumulation of I. cappadocica، as a newly-discovered As hyperaccumulator، were investigated in hydroponic experiment. Plants were grown in a medium، embedded with combinations of 50، 200، 800 & 1200 μmol l−1 arsenic and 5، 50، 200، 800 & 1600 μmol l−1 phosphorus، respectively. The chlorophyll and MDA cnotent، hydrogen peroxide (H2O2) concentration، arsenic and phosphorus concentration and boimass of harvestable parts were determined. The highest concentration of arsenic was obtained in plants treated with 1200 μmol l−1 as and 5 μmol l−1 phosphorus. Increased levels of phosphorus led to reduction of arsenic concentration، which confirmed there was an interaction between these two elements in plant. Along with a marked increase in arsenic concentration in the media، a built up in (MDA) and (H2O2) were observed. The insignificant reduction in biomass and chlorophyll content، illustrated the high resistance of this herb to arsenic.

In order to investigate the effects of foliar application of salicylic and ascorbic acids on some physiological characteristics of soybean (Glycine max L. cv. Williams) under salinity stress، a factorial pot experiment was conducted based on completely randomized design with four replications in the summer 2012 in the Yasouj University. Factors were included of four levels of salinity (0، 50، 100 and 150 mM NaCl) and four levels of foliar application (water، salicylic acid (3 Mm)، ascorbic acid (1. 5 mM) and combination of salicylic acid 3 mM and ascorbic acid 1. 5 Mm. Results showed that by increasing salinity، photosynthetic rate، stomatal conductance، leaf chlorophyll، carotenoids and proteins content and leaf area significantly decreased. Leaf water use efficiency significantly decreased by increasing salinity levels، so that maximum leaf water use efficiency obtained in the first salinity level and foliar application of ascorbic acid 1. 5 Mm. Foliar application of salicylic acid 3 mM and ascorbic acid 1. 5 Mm were regarded as the best treatments for mitigation of salinity impact on soybean leaf because of being superior at the highest level of salinity (150 Mm NaCl) for the total leaf chlorophyll and carotenoids content، photosynthesis، water use efficiency and leaf relative water content.

The ability of plants to grow and produce high yields in soils with low zinc (Zn) availability is different among wheat cultivars. However، the physiological mechanism behind Zn efficiency is not currently fully understood and the putative role of Zn transporter proteins in contributing to Zn efficiency has not yet been determined. Therefore، the aim of this study was to compare the expression level of two Zn transporter proteins and catalase activity in different wheat cultivars under Zn deficiency. Three wheat cultivars differing in Zn efficiency including Back Cross (Zn-efficient)، Kavir (Zn-inefficient)، and Durum (Zn-inefficient) were grown in a severely Zn-deficient soil (DTPA-extractable Zn = 0. 2 mg kg-1). Plants were sampled before emergence of main spike and analyzed for expression level of ZIP1 and ZIP5 transporters، catalase activity and Zn concentration in roots and leaves. Results showed that ZIP1 was expressed in the roots of three wheat cultivars، but expression level of this gene in Back Cross root was greater than the other cultivars. Unlike ZIP1 gene، ZIP5 was expressed in the leaves and expression levels were similar in all three cultivars. Zinc concentration in roots and leaves of Back Cross was lower than Zn-inefficient cultivars but catalase activity was significantly higher in this cultivar. Based on these results، Zn-efficiency of cultivars studied might be at least in part due to over-expression of ZIP1 in root and consequently transformation of Zn from soil to plants.

In this research the effect of four concentrations of nickel and copper (25، 50، 100، and 200 µM) on root and shoot length، fresh and dry weight، leaf surface، and photosynthetic pigments (Chlorophyll a، b and carotenoids)، sugar، malondialdehyde، hydrogen peroxide content and antioxidant enzyme activity (CAT and APX) in Okra plants were evaluated. The results showed that in those plants which were treated with all concentrations of copper and nickel، the content of photosynthetic pigments and leaf surface were reduced significantly in comparison with control. In this investigation it was found that shoot and root length، dry weight and fresh weight of shoot and root which were treated with concentrations 50، 100، and 200 µM of cupper and 100 and 200 µM of nickel were reduced significantly when compared with the control. Content of soluble sugars in shoot and root plants which were treated with all concentrations of nickel and concentrations 50، 100، and 200 µM of cupper increased significantly in comparison with the control. Also، content of malondialdehyde، hydrogen peroxide content and antioxidant enzyme activity (CAT and APX) increased significantly in shoot and root plants which were treated with concentrations 50، 100، and 200 µM of copper and nickel when compared with control.

Allelopathic effects of aqueous extract of pagoda tree and creeping jenny on five crop plants including wheat (Triticum aestivum)، barley (Hordeum vuIgare)، corn (Zea mays)، millet (Pennisetum americanum) and chickpea (Cicer arietinum) were investigated in a series of experiments conducted at the faculty of Agriculture، SB University of Kerman، Iran. Experiments were based on RCBD with 3 replications in greenhouse condition and CRD in laboratory condition in which different concentrations of weed leaves extract including (0، 25، 50، 75 and 100% of a stock solution (10%W/V)) were applied on all crop plants at germination and seedling growth stages and different responses were measured. Results showed that the three way interaction effect of alkaloid × concentration × hybrid was significant on the traits in both greenhouse and laboratory. By increasing the concentration of alkaloid، inhibitory effect was also increased. The 100% concentration was most effect and control concentration was least effective. There was a significant difference between the two weeds in terms of allelopathic effects and creeping jenny reduced plants growth more compared to pagoda tree. However، all crops were significantly affected by allelopathic properties. It was concluded that pagoda tree and creeping jenny residues in the field had the potential of allelopathic effects on crop plants therefore should be removed from the field before planting.

Heavy metals are the most important pollutants in the environment. The productiion of toxic metals by human activities has lead to the contamination of soil. The presence of these metals in the soil and their accumulation in plants grown on these soils will have adverse effects on humans and animals. One approach to reduce the accumulation of heavy metals in plants is using of plant hormones. This study was designed to investigate the effects of methyl jasmonate on accumulation of lead on radish (Raphanus sativus L.) in hydroponic conditions. Lead sulfate with four different concentrations (0،250،500 and 750 mg/ L) and methyl jasmonate with three concentrations (0، 0. 01 and 0. 1 mM) were used. The experiment was conducted as factorial in a completely randomized design with three replications. The contents of chlorophyll a and b، proline and Pb accumulation in shoots and roots of plants were measured. The results showed that the lead reduced chlorophyll content and this reduction with 0. 01 mM methyl jasmonate treatment was compensated. In addition، lead and methyl jasmonate significantly increased proline content. As a result، it can be concluded that radish is probably prone to accumulate heavy metals like lead in the edible parts and this toxicity can be reduced by using appropriate concentrations of methyl jasmonate.

This research were carried out to evaluate physiological responses of wheat cultivars to salt stress using a factorial experiment cultivars (Chamran، Karchia66، Ghods، Tjan، Atrak، Roshan، Kavir، Mahoti، Alvand، Mahdavi، Niknejad، Biston، Sardari، Felat، Tabasi، Sorkhtokhm، Golestan، Darab2، Azadi) at seedling growth stage in two salinity levels (0 as control and 10 ds m-2 NaCl solution) in Islamic Azad Uni، Shoushtar branch in the year 2012. Acording to cluster analysis، Karchia 66، Niknejad، Mahoti، Mahdavi، Sorktokhm and Tabasi cultivars belonged to the first cluster and tolerated salt stress. Atrak، Qods، Azadi، Tajan، Chamran، Darab2، Ghods and Golestan located in the third cluster and were sensitive to salt tolerance. Results indicated that Atrak، Qods، Azadi cultivars had minimum photosynthesis and seedling dry weight، longest seed emergence time، maximum malondealdehid concentration (cell memberane damage) and leaf Na+concentration. Wheat cultivars belonging to the first cluster had lower leaf Na+concentration and higher K/Na ratio، relative water content، phytosentesis and dry matter under salty stress condition. It seemed that leaf K/Na ratio، relative water content، dry matter and malondealdehid concentration were suitable for salt tolerance wheat cultivar in seedling stage.

Plants exposed to air pollution show returnable and unreturnable biochemical and physiological alterations. So biochemical parameters can provide valuable information about physiological condition of plants that are subjected to air pollution. This study was performed to determine the effects of air pollutants on the amount of proline، protein، calcium and phosphorus in Medicago sativa and Phaseolus vulgaris leaf and root. We also investigated M. sativa and Ph. vulgaris resistance to the air pollution in Arak Oil Refinery area. The plant samples were collected from polluted and non polluted area and the amount of proline، protein، calcium and phosphorus in leaf and root of plants were determined. The results showed that air pollution led to a significant increase of proline in leaf and roots of both M. sativa and Ph. Vulgaris. Air pollution also led to a significant increase of protein concentration in M. sativa (leaf and root)، but a significant decrease of protein concentration in Ph. vulgaris leaf and root. Concentration of calcium in M. sativa leaf and root under air pollution implied a significant increase. However air pollution caused a significant decrease of calcium in Ph. vulgaris root and no significant alteration of calcium rate in Ph. vulgaris root. Air pollution led to a significant increase of phosphorus rate in M. sativa root، but no significant alterations in M. sativa leaf، instead a significant increase of phosphorus rate in Ph. vulgaris leaf and root. In this study، increasing of protein and calcium in M. sativa plant was indicative of its resistance to the air pollution، and changes in biochemical parameters in Ph. vulgaris implied its sensitivity to the air pollution.

Petroleum hydrocarbons as organic contaminants are among the materials that pollute the soil. These compounds and the resutant stress to plants limit selection of suitable species to be planted in hydrocarbon contaminated sites. The aim of this research was to determine the effects of petroleum compounds on germination and morphophysiological characteristics of wheatgrass (Agropyron desertorum). This research was carried out in a randomized complete block for germination experiment and split-plot design in time in randomized complete block for the second part of the experiment in three replications. Results of the first experiment showed that germination percentage، germination rate، mean day of germination and germination energy of wheatgrass had no significant differences between the control and 20% sludge treatment. The lowest germination percentage was observed in 80% sludge. In the second experiment (growth phase) higher growth rate was observed in 20% sludge، and no significant differences were observed in density، color، chlorophyll، proline and relative water content of these two treatments. The results showed that by increasing the level of sludge to 40% and 80%، density، color، growth and chlorophyll content increased but proline content decreased significantly. The difference between 40% and 80% sludge treatments was significant too. In conclusion، native species wheatgrass can germinate in low levels of petroleum contaminants in soil.

Cadmium (Cd) is one of the most important heavy metals and its pollution causes toxic effects on plants and human beinges well. Glycine betaine (GB) is an osmoprotectant that its external application leads to decrease stress strains as well as heavy metal accumulation hazards. This experiment was conducted to study the effect of seed priming with GB on Cd reduction of damages in the black seed as factorial based on completely randomized design with 3 replications at the University of Mohaghegh Ardabil in 2012. For seed pretreatment، GB were applied with 0، 50، 100، 150 mM and Cadmium chloride with 0، 0. 25، 0. 5 mM concentrations. In this study، the germination percentage، germination rate، vigor index، length of radical، length of plumule، plumule / radical length ratio، total protein، catalase and peroxidase activity were measured. The results showed that with increasing of Cd concentration، germination percentage، germination rate، vigor index، radical length، plumule length، plumule / radical length ratio، total protein and catalase activity decreased، and Cd damaging effects diminished by increasing of GB pretreatment concentration،. Peroxidase activity enhanced with increasing Cd concentration. Also، higher concentrations of GB intensified enzyme activity.

Half-sib mating is an appropriate approach to estimate additive variance component of quantitative traits. This research was conducted to estimate genetic parameters of physiological traits and their response to drought stress in Dactylis glomerata. Twenty five half sib families derived from poly cross of 25 parental genotypes were evaluated under two moisture environments (normal and drought conditions) according to a randomized complete block design in the research farm of Isfahan University of Technology. Results indicated that drought stress significantly affected forage yield. Significant difference was observed among the families for all of the studied traits except for ratio of total chlorophyll to carotenoid and relative water content. Drought stress increased traits with respect to chlorophyll a/b and prolin in stress condition compared with normal condition while other traits decreased in drought condition. Genotypic coefficient of variation varied between 4. 5 to 31. 08 % under non-stress condition and from 5. 7 to 66. 27% in drought condition indicating high genetic variation in this germplasm. The highest narrow sense heritability was related to total chlorophyll (78%) and the lowest one was related to relative water content (29%) in non stress condition. Also، highest and lowest narrow sense heritability were related to proline content (66%) and relative water content (17%) respectively. Regarding high heritability of proline content and chlorophyll b under drought stress، indirect selection through these traits may facilitate breeding for drought tolerance.

To investigate the effects of Cd and Cd-Sodium nitroproside (SNP) on growth and physiological parameters of Melia azedarach، this experiment was done in a completely randomized design in three replicates and arranged as factorial. Results showed the amounts of Cd and proline in the root of the plant significantly increased as Cd concentration in soil increased. Length and weight of roots decreased with increasing Cd in soil. Increasing cd concentration in soil did not affect the amounts of soluble sugar، relative water content and MDA. SNP compared to treatments without SNP increased the amount of fresh weight of root significantly. Since SNP did not affect almost none of growth the parameters in Melia azedarach، it was concluded that this compound did not play an important role in protection of the plant against heavy metal.

Mung bean is one of tropical and semitropical pulses that is important in food، fodder، green manure and improves soil fertility and is a cheap source of protein in human direct consumption. The use of zeolite in soils with heavy texture، because it keeps moisture and nutrients around the seeds and roots is very important. On the other hand، the application of techniques of improving seed quality such as priming، improves seed germination in condition of nutrients limitation. This experiment was conducted as a factorial in Randomized Completely Block Design (RCBD) with three replications in the farm of the Ramin University in August 2011. Experimental factors included Culture System Optimization (CSO) in six levels Zeolite application+ seed priming (O1)، Zeolite application (O2)، seed pelleting+ seed priming (O3)، seed pelleting (O4)، seed priming (O5) and control (O6) with three mung bean cultivars included Hendi (C1)، NM-54 (C2) and VC11-18b (C3). The results showed that cultivar was a significant effect on all of the traits; however the effects of CSO on spad index، nitrogen harvest index (NHI)، rate of biological yield accumulation and grain yield production rate weren’t significant. Hendi cultivar showed the highest grain filling rate. Combination of Hendi seed pelleting with zeolite and zeolite application and Hendi cultivar were obtained highest of grain yield، grain protein content and harvest index. Priming of Hendi seeds produced the highest biological yield and showed that the reactivity of Hendi cultivar in usage agronomic factors was higher than other cultivars and was promising for green manure planting.