مجله پژوهشهای گیاهی (زیست شناسی ایران)
سال بیست و هفتم شماره 5 (زمستان 1393)

Benzo (a) pyrene (BaP) is an important part of diesel exhaust particles. Diesel exhaust particles have been shown to express adjuvant activity for sensitization against common allergens. The aim of this research is to elucidate the effects of BaP, as a major part of DEP, on the pollen allergenicity. Sunflower plants were treated with different concentrations of Benzo (α) pyrene (BaP) and allergenicity of the pollen extracts were compared by means of skin test, as well as analysis of blood eosinophil count and total IgE level in the guinea pigs. Non-treated and BaP-treated pollen were studied by SDS-PAGE for BaP-induced changes in protein banding profiles and also allergen band(s) were detected by immunoblotting method. Results showed that although non-treated pollen are effective in inducing allergic symptoms but allergenicity of BaP-treated pollen was increased considerably. SDS-PAGE showed protein banding profiles of pollen were changed and two new bands with molecular weight of 19 and 22 kDa appeared in BaP-treated pollen. Immunoblotting studies showed a band with molecular weight of 22 kDa in BaP-treated pollen that react strongly with anti-IgE, but there is not any similar band in non-treated pollen.

Structural characteristics, as the basic characters for managements of forests stands, were studied in Rikhalan coppice forest, southeast Marivan, Kurdistan province. The selected site is a good model of utilized stands of northern Zagros forests. A quadratic plot with an area of 0.5 ha were selected, then structural characteristics of stands including species composition, origin of trees (seed or shoot), number of sprouts in sprout-clumps, diameter of sprouts at 0.5m height, height of four sprouts in each sprout-clump, as well as the largest and smallest diameters of sprout-clumps crowns were measured on all trees. Furthermore, basal area, crown area and diameter of sprout-clumps were calculated. Based on results, the stand type was pure type of Brant`s oak (Quercus brantii) and all of trees were in coppice form. Low values of the mean diameter of sprouts (5.4 cm) and sprout-clumps (20.5 cm) showed that the studied stand was young. The mean value of sprout heights were low (lower than 4 m), which illustrate a one-storey stand. Diameter distribution of the studied stand showed an even-aged form. Furthermore, the best regression model for height-diameter curve of the stand was quadratic model. Totally, the studied stand was pure with no woody species diversity and with a little structure diversity, so its sustainability could be considered as unstable. Silvicultural activities such as tending operations and enrichment of the stand are recommended.

Salinity is a major environmental stresses that Causes severe damage to crops and horticultural crops and also reduce plant biodiversity. Plantation of resistant species is one of the activity to cope on soil and water salinity. Therefore, the identification of salt tolerant species is inevitable. Site conditions of species can affect on plant resistance in the face of environmental stresses. Seeds of four species of wild almond (Amygdalus scoparia, A. arabica, A. elaegnifolia, A. haussknechtii) of three height classes were collected in Karebas site to determine the effect of altitude on the salinity tolerance of wild almond species. Factorial experiment in a completely randomized design with three replications (5 plants per replication) were chosed to determine the salinity torerance of two month almond seedling under salt stress by irrigation with different concentrations of sodium chloride solution whit five leveles (control, 25, 50, 75 and 100 mmol). The results showed that vegetative plant, pigments and plant biomass reducted and accumulation of proline increased by incrising the salt concentration. Amygdalus arabica was resistance species among the four species to salinity. Biomass, growth rate and plant pigments have been decreased and cocentraton of proline have been increased by increasing the altitude. The absorption of copper, zinc, iron, manganese, potassium have been decreased and absorption of magnesium, sodium, chlorine, nitrogen, phosphorus, and calcium increased by Increasing the salinity.

Phosphorus (P) deficiency reduces plants ability for water uptake. In this work, possible intensifying influence of P deficiency on the effect of drought stress was studied in two cultivars of tomato (Behta and Piazar) plants. Plants were cultivated at adequate (0.25 mM) or low (0.05 mM) P supply under well-watered (100% of field capacity) or drought stress (60% of field capacity) conditions for 8 weeks in perlite under greenhouse conditions. Shoot and root dry weight, chlorophyll fluorescence parameters and net photosynthesis rate decreased under both P deficiency and drought conditions more pronouncedly in Behta than Piazar. Leaf concentration of chlorophylls decreased while anthocyanins concentration increased under P deficiency conditions. In contrast, drought stress resulted in reduction of anthocyanins concentration. Soluble carbohydrates and free amino acids concentrations increased under P deficiency, drought conditions or both. However, components of leaf water relations were not influenced by these treatments. Results showed that, two studied cultivars were different regarding P deficiency and drought stress tolerance. However, P deficiency did not strengthen the effect of drought stress. Increase in the concentration of soluble sugars and free amino acids and reduction of stomatal conductance that promotes water uptake ability and reduces water loss, respectively, involved in prevention of the intensifying effect of P deficiency on drought stress in tomato plants.

Astragalus compactus L. seeds were collected fromTehran of Iran. Plants were grown in growth chamber under 16 h daily light periods and leaves, stems, prdicle and cotyledon leaves explantn from three- week- old sterilized seedlings cut and infected with Agrobacterium rhizogenes Strains 15834, 2659 and WT.Hairy roots obtained from leave and stem explants but did not induce hairy roots of cotyledon and pedicle explants of Astragalus compactus.Strain 2659 resulted in the highest amount of hairy root formation in this Species. Strain 15834 was beneficial but not as effective as strain 2659. In contrast to these two strain, strain WT did not induce hairy roots in any of the explants used in this study. Thus, this strain seems to be totally avirulent to Astragalus compactus.

Sustainable management of natural resources as national assets requires comprehensive information about existing relationships in nature such as the relationship between vegetation and soil. Forest managers often need obvious and low cost signs to understand these changes and problems. For this purpose, two disturbed and undisturbed woodland areas were selected of Zagros forest (each 100 ha) in Ilam city. Systematic-random sampling method (100×200 m) was used to collect data from 50 plots within each site. According to the research objectives the coverage percent of trees and shrubs, presence and absence of understory vegetation and soil samples were taken in each sampling plot. The indicator species in each region was determined using IV method and the relationship between habitat factors and indicator species was also modeled using logistic regression. Results showed that Indicator species distinctly reveal differences in soil properties in these areas. In the presence of both indicator species in undisturbed area (Bromus tectorum L. and Medicago radiata L.), high value of ammonium-nitrogen (NH4-N), cation exchange capacity (CEC) and low value of total neutralizing value (TNV), Bulk density (BD), Electrical conductivity (EC) have prominent role. Among the variables entered in the logistic model in the undisturbed area, high value of EC and BD and on the other hand low amount of NH4-N and organic matter (OM)and opening the canopy are able to predict the presence and absence of dependent variable i.e. Cirsium congestum (Fisch. & C.A.Mey.) and Hordeum bulbosum L. as indicator species.

Drought is a major environmental stress that affects plant morphology, physiology and biochemistry, causing a significant reduction in agricultural production. In order to study the effect of drought stress on physiological traits of anise (Pimpinella anisum L. (a field experiment was conducted at College of Agriculture, University of Zanjan during spring of 2010. The experiment was conducted as a complete randomized block design with three replications. In this study the effect of water stress in three levels, irrigation at all stages of a weekly (control), excision irrigation in the mid-flowering stage to indication signs of stress to 15 days and then re- irrigation, and excision irrigation in grain filling stages to indication signs of stress to 15 days and then re- irrigation were studied. Chlorophyll content index (CCI), assimilation rate, stomatal conductance, transpiration rate and relative water content (RWC) significantly (p 0/05) decreased under drought stress conditions but leaf temperature increased.

Effects of 0.1 mM MeJA as an elicitor on the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and contents of phenolics and flavonoids during 4-72 hours in Scrophularia striata cell culture were studied. Decreasing in SOD activity was observed during first 12- hours after 0.1 mM MeJA treatment and then increased. Activity of CAT enzyme was increased in 0.1mM MJ treated samples significantly in comparing to the control, while POD activity was increased 12 hours after treatment. To study of MeJA mechanism, H2O2 content and lipid peroxidation were investigated. H2O2 content was increased after 8 hour post treatment with MeJA while lipid peroxidation was not changed. The amount of total phenols in control and treated cells showed a gentle slope rising levels of phenolic compounds and 0.1 mM MeJA significantly increased total phenolic compoundes in S. striata cells culture 48 and 72 hours after treatment. Also, flavonoids significantly increased in treated cells compared with controls 24 hours after treatment toward the first 12 hours. Increasing in antioxidant capacity and phenolics and flavonoids contents after elicitation is in accordance with decreasing in oxidative stress index.

Burning is known as an influencing factor on the natural vegetation of semiarid rangelands, which may increase or decrease plant diversity. This research was aimed to compare plant diversity at different times after two burning events in a semiarid rangeland. Three adjascent sites, control, burnt at 2004 and burnt at 2008, were selected in Jowzak,Northern Khorasan Province, and studied during spring and summer 2010. Canopy cover, Importance value (IV), diversity, richness and evenness indices were compared between the sites. Result indicated significant differences in plant diversity indices (plant diversity and species richness) between the control and 2004 sites, with no difference being found between 2008 with the other sites. In conclusion, burning had increased the plant diversity after two years, and its effects were intensified after six years. Nevertheless, replacement of perennial grasses and shrubs by annual herbs and ephemerals, in the burnt site, may decrease community stability against the environment harshness.

In studies that were done in relation to position of presence and dispersal of Papaver genus species, during two vegetative season 1389 and 1390 in some of the ruderal and segetal environments of inside of Hamedan and its biotops, totally 4 species (papaver macrostomum Boiss., Papaver piptostigma BIENERT ex FEDDE., Papaver fugax POIR., Papaver argemone L.) of this genus were observed and collected. These studies showed that observed species mostly belong to ruderal species which have selected more disturbed environment, inside and margin of farm lands (specially wheat farms) also left agricultural environments and also in some cases pavements cleft for their life existence. Species of this genus were not seen out of the mentioned environments, especially in semi natural environments (apophyt), which can be a reason for their perfect adaptation with anthropogenic environments. Totally 160 localities were selected and studied randomly, which all indicat species presence of this genus in ruderal and segetal environments of Hamedan city, with hemeroby degrees between H3- H5. Except of papaver macrostomum BOISS. that also was observed in urban central areas, the other observed species present far from urban traffic areas and mostly grow in rubbles and left farm lands.

Breaking seed dormancy is an essential step towards germination improvement in Hordeum vulgare ssp. spontaneum. This study was conducted to evaluate the effects of physical, chemical, hormonal and stratification treatments on Hordeum spontaneum seed dormancy. In the current research two highly dormant genotypes of Hordeum spontaneum (TN1350 and TN951) were evaluated. To this purpose, 25 seeds in four replications were placed in 9 cm petri dishes containing filter paper saturated with distilled water (control), chemical or hormonal solutions. To induce the stratification treatments, seeds were kept in 35˚C (heat stratification) or 5˚C (cold stratification) for periods of 2, 4, 6 and 8 weeks. Results indicated that heat stratification increased germination significantly. Germination percentage of seeds under 35˚C treatments increased since the second week of treating and reached the maximum in the fourth week (47.5% in TN951 and 86.25% in TN1350). Results showed that GA3 in all used concentrations was the most effective hormone in inducing germination compaired to other used hormons in this study. The highest germination percentage in Hordeum spontaneum seeds was observed in 100 mg/l GA with increased germination percentage up to 68.75% in TN1350 and 31.25 in TN951. Results of this study revealed that seed dormancy in Hordeum spontaneum can be overcomed by GA3, and heat stratification. On the other hand, seed dormancy was apparently deeper in the genotype with darker seeds)TN951(which were also less affected by after ripening treatments.

Gall is a kind of heteromorphy in plant tissues that is induced by various parasitic organisms, mainly insects, and generally served as nutrition and protection from both abiotic factors and natural enemies. Gall in willow trees (Salix babylonica) is the effect of a series of morphogenetic changes in plant cells in contrast the Eriophydae mites attack.In this research in summer 1389,early and late spring 1390 and spring 1391 randomly sampling from healthy and infected offshoot of willow trees of Najvan park, Isfahan city was done. Changes in chlorophyll a, b and total, carotenoid, reduced and total Suger content, anthocyanin, phenolic compounds and proteins were studied. The amount of chlorophyll a, b and total, carotenoid, reduced and total Suger and protein content had statistically significant decrease in infected branches compared to normal offshoots. But the amount of anthocyanins and phenolic compounds in infected twigs were more than healthy one.These increases were statistically significant. Reduction in the amounts of photoshynthetic pigments and protein were the cause of oxidative damage in gall branches. Since the host survival causes remaining of parasite,therefore accumulation of anthocyanin and phenolic compounds in infected branches rises plant resistance against oxitative stresses.

Drought stress stimulates reactive oxygen species production in plant chloroplast and reactive oxygen species cause peroxidation of lipid membrane and destruction of cell membrane. Moldavian dragonhead Dracocephalum moldavica L. is one of the aromatic and medicinal plants which use as healing of wound. In this research gibberlin use in order to control oxidative stress to tolerate water shortage and fluctuation in leaf pigments and total phenol were investigated. Therefore, an experiment was conducted in factorial design based on completely randomized design with four replications. Irrigation factor were in three level Fc (without stress), 2/3FC (moderate stress) and 1/3FC (severe stress) and gibberellic acid were in two level including and 100 mM. The results of experiment showed that by increasing of stress severity chlorophyll a, b and a+b content decreased. However, flavonoid, anthocynin and phenol content increased. Because of dehydration effect, β-carotene and xanthophyll content increased only in moderate stess. Gibberellic acid increased cholorophyll content, Hill reaction rate and phenol content. But There was no considerable change in Flavonoid and anthocyanin amount. According to result, exogenous gibberellic acid increased drought response of Moldavian dragonhead with various mechanism and trigger to increase phtosythesis rate in plant.

Polianthes (Polianthes tuberosa L.) is one of the most important cut flower worldwide and in Iran. A CRD-based factorial experiment was conducted to evaluate the effect of SNP on qualitative and quantitative parameters of this popular cut flower. Sodium nitroprusside was used at 1 and 10 µM along with control (distilled water). The highest vase-life was obtained with 1µm which increased vase-life for three extra days compared to control. The highest percent of floret opening was also gained in 1µM SNP. The percent of floret wilting, floret abscission, and stem weight reduction was also decreased at both concentrations of SNP. The lowest electrolyte leakage was found in 1µm SNP and this trait was decreased 1.5 times than control. The findings of the present research showed that vase-life was increased at both concentrations of SNP. Meanwhile, activity of antioxidant enzymes such as GPX and APX was increased at both concentrations but the activity of CAT was increased just at 1 µM. Furthermore, the activity of PPO and PAL enzymes was significantly decreased at both concentrations. Consequently, it appears that these compounds improved postharvest quality by reducing free radicals of oxygen, conserving membrane integrity, increasing the synthesis of phenolic compounds and decreasing the activity of PPO.

Effects of propyl gallate, an inhibitor of plastid terminal oxidase involved in ‎chlororespiration, on photosystem II efficiency in Dunaliella salina were investigated, ‎using chlorophyll a fluorescence transient measurements. Trated cultures with propyl ‎gallate concentrations of 0.1, 0.5, 1, 2 and 4 mM showed that photosystem II efficiency ‎increased in the presence of concentrations up to 1 mM and chlororespiration process ‎was inhibited at propyl gallate concentrations of 1 and 2 mM. Nonetheless, no negative ‎significant effect was observed on photosystem II electron flow. However, the ‎fluorescence intensity drastically decreased and almost reached a plateau in 4 mM ‎propyl gallate-treated cells. Such reduction was also found for Fv/Fo (the activity of the ‎water splitting complex), Φpo (efficiency of quantum yield of primary photochemistry) ‎and ΦEo (quantum yield for electron transport). The decrease of these parameters was ‎also coordinated with appearance of fluorescence intensity increase at 300 µs step. The ‎data showed that the decrease of photosystem II efficiency in the presence of 4 mM ‎propyl gallate is because of its effects on water splitting complex on the donor side of ‎photosystem II. Therefore, it may be supposed,

Salvia L. is a large genus of Lamiaceae with 58 species in Iran. Essential oils, terpenoids, derivatives of phenolic acids and flavonoids are the main secondary metabolites constituents of Salvia species. Pharmaceutical properties of the Salvia plants are mainly due to antioxidant activities of these metabolites. In this project, for the first time some phenolic compounds (rosmarinic acid, salvianolic acids A and B) of the leaves and roots from four Iranian wild species of salvia were isolated and measured by HPLC method. Based on our results, leaves and roots of S. verticillata were the richest sources of rosmarinic acid (41.53±0.88 and 5.99±0.19 mg/g DW, respectively). Salvianolic acid B varied from 26.89±4.95 mg/g DW in the leaves of S. officinalis to 75.71±2.74 mg/g DW in the leaves of S.nemorosa. Also, the highest content (10.68±3.12 mg/g DW) of this phenolic compound was determined in the roots of S. nemorosa. The leaves of S. officinalis and the roots of S. nemorosa with values of 4.55±0.77 and 6.68±1.85 mg/g DW had the highest contents of salvianolic acid A. The results showed that the leaves were rich in phenolic acids and among them, salvianolic acid B was the most abundant constituent and rosmarinic acid and salvianolic acid A were in the next place. In conclusion, our results suggested that some Iranian wild species such as S. verticillata and S. nemorosa with high capacity of production and storage of phenolic acids can be introduced as potent natural sources for medicinal purposes.

Silicon was reported to have beneficial effects on the growth, protection against biotic and abiotic stresses of plants, but the effects of Si and the relation between accumulation of phytochelatins, none structural carbohydrate (NSC), K and Si are poorly studies. For this purpose, the effect of silicon (Si) on time-before flowering on the changes of NSC and phytochelatins, K and Si in two rice cultivars (Shiroudi and Ause) differing in salt stress was studied. The experiment design was a standard factorial plot with four replicates and the treatments were with four silicon levels 0, 0.25, 0.5 and 0.75 Si (g /kg soil), in sand culture. Significant decrease in NSC was observed in response to Si in the two cultivars roots, both the amount of phytochelatins from rice leaves and roots under Si increased with the Si level in the sand culture p≤0.05. the results indicated that at shiroudi and Aus cultivars, the Si variable were predicted 97% and 79% are related to leaf area and 82% and 95% to dry weight leaf, respectively. These results suggest that either the Si might also play an important role in consumption of NSC in leaves and roots or the transport of it was decreased in the roots. Among the parameter were examined in this experiment, phytochelatins were play an important role in changing concentration Si. The Si and K contents in roots and leaves were significantly increased with increased Si level in the sand culture p≤0.05.

Oak Libani groups were belong to dentate oaks which distributed in the north of Zagros mountains(Iran). This group have two species in Iran: Quercus libani and Q. trojana. Q. trojana reported as a new speceis for the flora of Iran and distinguished by bellow characters: It is typically a small tree and easily identified by its semi-evergreen, small, subcoriaceous elongated and regularly sinuate-dentate leaves. Its nearest relative, Q. libani G. Olivier, differs from Q. trojana by its longer petioles, greater numbers of aristate teeth and bigger fruits. Quercus trojana is rather variable, especially in leaf size and shape, the number of teeth on the leaf margins and in the indumentum. Leaf hairs, if present, are stellate with (2-)3-8(-14) rays. The leaves are densely stellate-hairy on the abaxial surface.