JWSS - Journal of Water and Soil Science

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In order to find suitable cultivar and N-topdress rates in corn planted after wheat harvest, a field experiment was conducted in Isfahan University of Technology Experiment Farm located at Shervedan, Falavarjan in 1994. The experiment design was a split plot with a randomized complete block arrangement and four replications. Main plots were four N-topdress rates (0, 90, 180, and 270 kg/ha) and the subplots were three corn hybrids (S.C.I08, S.C.301, and D.C.370). N-topdress rates had no effect on the stages of plant development (50% emergence, transition, pollination and physiological maturity). Also there were no significant effects on the number of leaves per plant, LAI, plant height and plant dry weight measured at pollination stage for different N-topdress rates. As expected, plant development stages differed among hybrids except that of time until 50% emergence. Differences in the number of leaves per plant, LAI, plant height and dry weight of plant measured at pollination stage were highly significant among hybrids. D.C. 370 had the highest values for all of these characteristics. Dry matter accumulation during growing season increased as the N-topdress rates were increased for the hybrids. Also N-topdress rates x hybrid interaction was significant for biological yield. Grain yield, number of seeds per ear, 100-seed weight and biological yield were affected by N-topdress rates and hybrid. Higher grain yield of D.C. 370 can be attributed to greater number of seeds per ear. The results of this study suggest that D.C. 370 with 90 kg/ha N-topdress rate can be used after wheat harvest in Isfahan.

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Optimum rice population densities and the response of rice yield and yield components to population densities and planting pattern are important factors helping rice producers and researchers to achieve maximum productivity. For this reason, a randomized complete block design experiment was conducted during the summer of 1995 at Isfahan University of Technology Research Farm located at Lavark, Najafabad. Zayandeh-rood cultivar was transplanted with three seedlings per hill at row spacing of 15, 25 and 35 cm and hill spacing of 10, 15 and 20 cm under flooded conditions. Row spacing influenced the plant height significantly at heading and anthesis stages. Wider row spacing, enhanced days to 50% heading and anthesis and consequently grain filling duration and ripening stage coincided with unfavorable conditions at the end of the season, which decreased the percentage of maturity. Although number of tillers per unit area increased, tillers per plant decreased as row spacing was reduced. Narrow row spacing limited vegetative growth after anthesis and thereby growth rate of panicle increased. With reduction of row spacing, without any change in the percentage of full grains per panicle and grain weight, number of panicle per unit area increased but number of grains per panicle decreased. At greater row spacing, grain yield per unit area decreased although grain yield per plant and harvest index increased. Although, effects of hill spacing were similar to those of row spacing, hill spacing usually did not influence plant characters, yield components and grain yield significantly. Stepwise regression and path-coefficient analysis revealed that number of panicle per unit area is the most important yield components. It also showed that indirect effects of panicle per unit area on yield through its association with grain per panicle prevented real effects of grain per panicle on yield. Fifteen × 15 cm spacing produced maximum yield which is probably recommendable for rice production in Isfahan.

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In order to study the effects of rate and time of nitrogen application on vegetative characters, i.e., yield and yield components of rice (Zayandeh-rood variety), an experiment was conducted at Isfahan University of Technology research farm during summer 1996. Four N rates including (60, 90, 120 and 150 KgN/ha) and four splitting form (1- all N applied before transplanting 2- 1/3 N applied before transplanting, 1/3 at the beginning of tillering and 1/3 at the emergence of first panicle in 50% hills 3- 1/2 at the beginning of tillering and 1/2 at the emergence of first panicle in 50% hills 4- 1/3 at the beginning of tillering and 2/3 at the emergence of first panicle in 50% hills) were evaluated in a factorial experiment which was arranged in a randomized complete block design with 3 replications. Plant height, number of tillers per unit area and days to heading and maturity increased with an increase in the rate of fertilizer application. Grain yield and number of panicles per square meter increased when the N rate was raised to 120 Kg N/ha, while application of 150 Kg N/ha resulted in the reduction of grain yield and number of panicles. Nitrogen rate increases did not have any significant effect on number of grains per panicle. The grain weight did not follow any particular trend at different application rates, but harvest index and percentage of filled grains were decreased as the N rate increased. The percentage of nitrogen content of plant was increased as a result of higher N - rate at heading and harvest times. Treatments containing base application of nitrogen resulted in an increase in plant height, number of tillers, plant dry matter, grain yield and number of panicles per square meter, although it caused a reduction in harvest index. The number of grains per panicle and grain weight did not follow any particular trend under the influence of time of application, although plant nitrogen content increased with a delay in time of fertilizer application.

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A two-year study (1996-97) was conducted to verify tillage effects on several soil properties and corn yield. The soil (fine loamy, Thermic, typic Haplargids) was treated by conventional (CT) and no-till (NT) systems. Soil organic matter (OM), mean weight diameter (MWD), penetration resistance (Cl), bulk density (BD), total nitrogen (TN) and aggregate size distribution at depths of 0-20 and 20-40 cm were measured.

No-till system caused the OM to be twice as much as that in the conventional tillage system. Total nitrogen in the NT and at depths of 0-20 and 20-40 cm were higher by 30% and 20%, respectively. No differences obtained in bulk density and penetration resistance, but MWD in the NT was 20% and 10% higher than CT in the 0-20 and 20-40 cm depths, respectively. Mean weight diameter of the aggregates in the CT was smaller than that in NT. Aggregates of less than 0.25 mm at 0-20 cm depths were almost 25% higher in CT compared to NT system. The yield in the NT system was significantly lower than CT. Although reduced cultivation could bring a better soil physical condition, low initial organic matter, weak structure and heavy-textured soil produced unsuitable conditions for the crop roots and, consequently, resulted in low yield. Therefore, no-till system in this region would not be recommended.

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In order to determine the most suitable cultivar and N level based on yield and silage value of forage sorghum, an experiment was conducted in summer 1995. The experiment was arranged in a split-plot design with four replications. Two levels of N (300, 500 Kg/ha urea) were the main plots and the subplots were three sorghum hybrids (Sugar graze, Super dan and Speed feed). Seeds were hand sown on June 29 with an inter row space of 50 cm and a final density of 20 plant/m².

The results showed that when the N rate increased, forage yields and percent of protein in forage and silage increased. Also panicle dry weight increased at anthesis. The N rate had no significant effect on other traits. A significant difference was observed among hybrids for all characteristics measured. Sugar graze with a bigger stem diameter was taller and produced higher number of leaves. At anthesis, plant leaf and stem dry weight was also highest for Sugar graze however, the highest panicle dry weight belonged to Speed feed. There was a significant interaction between hybrids and N levels for dry matter production. The percent of leaf, stem and panicle dry matter was highest in sugar graze, Super dan and Speed feed, respectively. The Sugar graze produced the highest forage and dry matter yield. This hybrid produced 30 ton/ha of dry matter and 97 ton/ha of forage, respectively.

 Furthermore, this cultivar had the highest percent of forage crude protein (7.45%) and the least percent of forage crude fiber (25.12%). Ensiling caused a decrease in percentage of crude protein and an increase in crude fiber. The Sugar graze and Speed feed had the highest and lowest dry matter digestibility, respectively. Based on the results obtained from this study, Sugar graze was found to be the most suitable hybrid due to its highest forage and dry matter yield and better silage quality. Higher N rate (500 kg/ha) is also recommended for higher forage yield and higher percentage of protein.

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This study was conducted to evaluate the responses of Iranian commercial genotypes of maize (hybrids and their inbred lines) to callus induction and plant regeneration, using mature embryos. Twenty five genotypes comprising of 12 inbred lines, 11 single cross hybrids, 1 double cross hybrid and 1 composite cultivar were used. Mature embryos of the genotypes were plated on MS and N6 media. Callus induction rates were evaluated using relative growth rate of callus (RGR), callus fresh weight (CFW), callus dry weight (CDW) and callus growth rate (CGR).

The results indicated that genotypes highly varied in both callus induction and plant regeneration. IL8 inbred line, SC7 (IL4×IL8) and SC9 (IL6×IL10) hybrids had the highest callus production capacity (based on CFW and CDW), whereas the highest RGR and CGR were obtained for ILl inbred line and SC9 hybrid. The estimated heterosis based on superior parent showed the highest heterosis for CFW, CDW, RGR and CGR in SC9 hybrid. Genotype × medium interactions for CWD, RGR and CGR were significant. For instance, SC9 hybrid on MS medium and IL8 on N6 medium produced the highest CGR. There was a significant difference between the observation periods [8, 12, 16 and 20 days after planting (DAP)], so that CGR was the least at 8 DAP and increased gradually till 16 DAP, but declined afterward. CGR had a range of 0.51 in IL8 inbred line to 0.74 in SC9 hybrid. Comparisons of the genotype for plant regeneration percent indicated that ILl and IL10 inbred lines as well as SC2 and SC4 single cross hybrids had the highest regeneration rates. Considering plant regeneration as a critical and genotypic dependent factor, it can be concluded that ILl and IL10 inbred as well as SC4 (IL4×IL5, ‘single cross 301’), SC2 (IL2×IL3, ‘single cross 704’) and SC7 hybrids are recommended for use in tissue culture-based breeding programs in maize.

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Soil loss due to erosion is a common problem in most parts of Iran. Reduced soil organic matter and lack of proper agricultural management have intensified the problem in recent years. Conservation tillage systems are becoming more widely used in corn production in other parts of the world because of soil losses due to wind and water erosion and energy inputs. Changes in tillage methods, however, create different environments for the germination, development and maturation of corn plants. Most corn hybrids have been selected and developed under conventional tillage systems but these hybrids mayor may not be well adapted to both systems. This study aims to evaluate the performance of five locally grown corn hybrids under zero and conventional tillage methods. The experiment was conducted for 2 years on a plot of land specified for this study. Experimental design was a split plot with randomized complete block arrangement and four replications.

Seedling and juvenile plant growth were not affected by tillage method and were similar for all hybrids. Plant dry matter was affected significantly by the cropping system and was lower in no-till method. Plant leaf area index and stem diameter reduced significantly in the no-till system. Reduction was greater in the second year of the experiment. Also grain yields were significantly different among years, tillage method and plant genotypes. Yield reduction was highest in the second year of the experiment under no-till cropping system. There was no interaction between tillage method and corn genotypes, indicating that, usually genotypes perform similarly with regard to grain yield under both tillage methods. The results suggest that corn production under no-till system in Isfahan is probably associated with yield reduction.

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Flax (Linum usitatissimum L.), an oilseed crop, is widely adapted and grown in many regions of the world. Oil from regular flaxseed is used as an industrial drying oil because of the high level of linolenic acid (>50 %). However, the oils from new mutant genotypes of flax with a very low linolenic acid concentration (<2 %) are edible. Yellow seed colour can be used as a visual marker to distinguish edible-oil genotypes of flax from those of industrial type that are usually brown-seeded. In this study, different lines of flax with two seed colours (yellow and brown) in combination with two levels of linolenic acid (high and low) were evaluated in a randomized complete block design for agronomic traits, especially seed yield and its components. The results indicated that lines with high linolenic acid concentration had significantly higher seed yield than those with low linolenic acid. However, other characteristics including those of seed yield components were not siginficantly affected by linolenic acid concentration. Seed colour had a significant effect on number of seedling/m², basal branches, capsules per plant and seed yield per plant. Although seedling emergence was lower in yellow-seeded lines, they had more basal branches, capsules per plant and seed yield per plant. Higher seed yield per plant in yellow-seeded lines can be attributed to higher number of capsules per plant as a result of lower seedling emergence and plant density. Seed yield was not significantly different between brown and yellow-seeded lines. Thus, the effect of lower plant density in yellow-seeded lines was compensated by their higher basal branches and number of capsules per plant.

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A symbiotic relationship exists between the endophytic fungi of the genus Neotyphodium and many cool-season grasses. Endophytes can alter the growth as well as morphological and physiological characteristics of the host plant, thereby influencing the persistence and survival rate of infected plants. This study was conducted to evaluate the effects of endophyte on phenotypic characteristics of Iranian tall fescue (Festuca arundinacea Schreb.) and meadow fescue (Festuca pratensis Huds.). The experiment was set up as a completely randomized design with three replications in a factorial arrangement. The first factor was the two plant accessions and the secondary factor was the endophyte-infected and noninfected plants. The results showed that most of phenotypic characteristics significantly altered as a result of endophyte infection in both tall fescue and meadow fescue plants. Results of analysis of variance showed that the influence of endophyte fungus was positive and significant on tiller number, herbage yield, dry crown weight, dry root weight per plant, and crown depth. Also between plant accessions, there were significant differences for dry herbage yield, crown weight, dry root weight per plant, crown depth, and dry matter percentage. Plant by endophyte interaction was highly significant for crown depth and dry root weight per plant. Therefore, eudophytic fungi can be used to improve phenotypic characteristics in these plants.

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To study the genetic diversity in 100 genotypes of rice, an experiment was conducted at the research farm of Rice Research Institute of Iran. The experimental design was a 10x10 simple lattice. The genotypes, mostly belonging to Isfahan Province and north of Iran, were evaluated on the basis of morphological traits and yield components. The results of analysis of variance demonstrated that the differences among genotypes were highly significant (p < 0/01) for all traits. High values of phenotypic and genotypic coefficients of variation were obtained for most traits, indicating high variability in the traits under study. Factor analysis revealed three factors which determined 90 percent of yeild variation and were named “grain number”, “plant type and structure” and “grain shape”, respectively. Cluster analysis by “Cubic Clustering Criterion” and “Pseudo Hotelling T² Test” grouped genotypes in four clusters. Analysis of variance showed that the differences among clusters were highly significant for most traits.

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A major limitation for higher yield of rice plant is water availability. Water use efficient varieties tolerant to upland conditions could help to relax this limitation. Three separate experiments were conducted to study the effects of water regimes on growth, aerenchyma formation, and nutrient absorption of Iranian rice varieties. In the first experiment, five varieties of rice were grown under three different irrigation levels. The second experiment involved the study of nutrient uptake by Sazandagee and Tarom varieties under four different water regimes, and in the third experiment, the effect of aeration on growth characteristics of Sazandagee rice was assessed in a hydroponics system. Results of the first experiment showed that submerged conditions continuously or after four weeks of initial growth had a significant effect on plant growth. Aerenchyma formation was affected by rice varieties and was less affected by irrigation status. In the second experiment, plant growth characteristics were affected similar to experiment one. Also it was shown that nutrients such as P, Mg, and Fe were absorbed with higher efficiency under submerged conditions. Results of the third experiment revealed that aeration had no significant effect on plant growth characteristics. Based on the results of these three experiments, it can be concluded that better performance of rice plant under continuous or partial flooding is mainly related to higher absorption of some macro - and micronutrients. Therefore, this parameter should be considered in water management programs for rice.

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The significance of haploid plants as genetic and plant breeding tools has been recognized for a long time. Haploid production techniques including anther culture, isolated microspore culture and intergeneric hybridization between wheat × Hordeum bulbosum and wheat × maize have been used to produce homozygous lines which accelerate breeding programs. In this study, wheat × maize hybridization and anther culture techniques were used for haploid production in six wheat genotypes. The results showed that 70.7% of regenerated plants through anther culture were albino plants and only 29.2 % were green, while the plants produced through wheat × maize method were all green. Ploidy variation was not observed in plants regenerated through wheat × maize hybridization. It was concluded that wheat × maize crosses would be an appropriate and practical method for haploid production in different wheat genotypes, which in comparison with the anther culture method has a higher efficiency.

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Endophytic fungi, Neotyphodium spp. symbiotically infect host grasses, Fescue arundinacea Schreb. and F. pratensis Huds. and Mealybug, Phenococcus solani Ferris attacks some forage plants. To evaluate the role of these fungi to control this pest, four genotypes of F. arundinacea and two genotypes of F. pratensis were used. Plant tillers were split into two sections, one section of which was freed from endophyte using a fungicide mixture. The mixture contained 2 grams of active ingredients of Propiconazol and 1 ml of Folicur per liter of water. New tillers from endophyte-infected and endophyte-free plants were transferred into the field. The number of mealybugs was measured after the first visible sign of infestation on roots. To count mealybug, one plant hill of each plot was randomly selected. Hay yield of each plot was measured by clipping the plants 5 cm above ground level. Correlation of hay yield and other growth characteristics with the number of mealybugs on roots as an index for mealybug damage on infested plants was determined. The results indicated that endophyte-free plants were highly infested with mealybug, P. solani compared with endophyte-infected plants that were completely free of P. solani, correlation coefficients showed that there was significant negative correlation between forage yield and mealybug numbers, indicating mealybug damage on infested plants. It seems that endophytic fungi are effective biocontrol factors for some root feeding pest such as mealybug, P. solani.

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To determine the role of endophytes in conferring valuable physiological characteristics on and induction inducing cold tolerance in two species of festuca, an experiment was done at Isfahan University of Technology in 2002. Endophyte-infected and non-infected clones from two genotypes of tall fescue and one meadow fescue were prepared and coded 75,83 and 60 respectively. The clones were exposed to cold treatments at 6, -2 and –10C and compared with control treatment at 20C. After three weeks of cold treatments, relative water content of leaf and crown, cell membrane stability (electrolyte leakage), percentage of membrane damage and finally proline content of leaf were measured. The presence of endophyt caused an slight increase in relative water content of leaf and crown. There was considerably higher proline in endophyte-infected plants compared with non-infected ones in both stress and non-stress conditions. Endophytic fungi had strong effects on maintenance of membrane stability and on the decrease of electrolyte leakage at all temperature levels. Among plant genotypes, 83 preformed better for some characteristics, specially in the presence of endophyte, and showed higher cold tolerance.

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In order to evaluate endophyte effect on plant earliness, compatible host-endophyte combinations including four genotypes of tall fescue and two genotypes of meadow fescue were selected and used in this study. One tiller-part of each genotype was treated using a fungicide mixture of Propiconazole and Folicur. New tillers of endophyte-infected and endophyte-free plants were planted in the field according to a complete block design with three replications. The traits including days to head emergence, days to 50% anthesis, days to maturity initiation, number of heads (as a weekly measurement), total seed weight, net seed weight and empty seed weigh were measured. Results showed that endophytes can enhance head emergence, maturity initiation and periodical seed yield. Days to 50% anthesis, and days to maturity initiation were also reduced. Head numbers in some genotypes increased up to 2 times. Increase in net seed yield may show some physiological alterations in plant such as hormonal balance alteration which may provide better seed setting in infected plants. Based on this study, we concluded that endophytic fungi can induce earliness in infected host plants.

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Seed traits are an important measure of the effects of endophytic fungi in Festuca genus. In this study, endophyte-infected (E⁺) and un-infected (E^-) clones of the same tall fescue genotypes were used to investigate the effects of endophyte on the seed production and associated traits. Endophyte infection resulted in 32.8% increase of total seeds by weight, 34.6% seeds per plant, and 30.6% panicles per plant, but other seed components were not affected by endophyte. Significant phenotypic variances were observed for traits except for 1000 seed weight. Plant genotype×fungal status interactions occurred for seed per plant. These interactions occurred largely because of variation in different plant genotypes. Genetic variance for this trait in E⁺ was greater than E^- for both years, suggesting that the endophyte can mask plant genotypic variance. The results indicated that endophyte had a positive effect on seed production but could result in overestimating of plant genetic variance for some traits. In conclusion, breeding strategies should consider presence or absence of endophyte and the possible effects on variances.

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Fescues (Festuca spp) are widely distributed in the temperate regions and are used for turf, forage and soil conservation. Though seed traits are important measures of the effects of endophytic fungi on their host, little information is available in this respect for Festuca. In this study, endophyte-infected (E⁺) and endophyte-free (E^-) clones of the six fescue genotypes were used to investigate the effects of endophyte on seed production. The relationships between seed traits plus direct and indirect effects of components on seed yield were also studied. Endophyte infection resulted in 38.1% to 249% more seed yields in some genotypes, though some were not affected by this symbiotic relationship. Correlations between traits and also results of stepwise regression were influenced by the presence of the symbiotic fungi. Path analysis showed that endophytic fungi changed direct and indirect effects of components on seed yield. In endophyte containing clones, panicle fertility had the most direct effects and number of panicle per plant and seed per panicle the most indirect effects on seed yield. In E- clones, panicle fertility had the highest indirect effects and other components had direct effects on seed yield. The results suggested that breeding strategies for increasing seed yield in fescue should consider the presence or absence of endophyte in germplasm.

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  Some industrial processes, such as plating and gold mining, utilize cyanide, which entering in their effluents. Because cyanide compounds are toxic contaminants, the waste-containing cyanide must be treated before discharge in the environment. Several methods are available for cyanide removal or detoxification. Natural degradation, alkaline chlorination, and oxidation with hydrogen peroxide are the most common methods in full-scale plants. Because of technical and economical concerns related to these methods, biological treatment processes have recently come under consideration. In phytoremediation, plants potential for pollutant removal is used. The main objective of present study is to investigate feasibility and potential of phytoremediation of cyanide-polluted soils by non-woody plants. The experiments carried out in this study were a completely random factorial design procedure, with three replications. Three non-woody plants: sorghum (as a cyanogenic cereal plant) and fescues with and free of endophyte (as grasses), were examined. Analysis of variance of the data obtained on soil cyanide reduction and cyanide accumulation in plants showed that phytoremediation is a suitable technique for low concentration of cyanide-polluted soils. Besides, it was been found that sorghum has a better soil cyanide removal efficiency than fescues, so that a significant portion of soil cyanide will accumulate in sorghum tissues.

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This experiment was conducted to investigate the genetic diversity, identify traits explaining yield variation, recognize relationships between traits and classify accessions in a Iranian and forign germplasem of tall fescue. Forty six Iranian and foreign tall fescue accessions were surveyed for Phenological, morphological and agronomical characters in a randomized complete block design with three replications in field for 2 years. Significant differences were observed for all of the characters, indicating broad variation in this germplasm. Iranian accessions had a better performance for most of the traits in both years indicating their high potential for developing commercial varieties in breeding programs. Basis on stepwise regression analysis, crown width justified the majority of hay yield variation, followed by establishment rate, percentage of dry matter, height and number of stem. Hence, these characters could be used for selecting high yielding cultivars. Factor analysis revealed 4 factors which explained more than 80 percent of the total variation and confirmed the results of regression analysis. Using UPGMA method, cluster analysis revealed five groups. Accessions with similar country of origin or same ecological conditions were grouped in same cluster. Regarding the morphological characters the best accessions were identified to be used in the further breeding projects.

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Iron chlorosis is an important disorder of plane trees (Plantanus orintalis L.) in green space of Isfahan city. Before using reclamation methods for correcting Fe chlorosis, it is necessary to find a suitable index for evaluating plant Fe status. Therefore, activity of glutathione peroxidase (GP) enzyme and concentration of carotenoids and chlorophyll a and b pigments, as physiological indices of active Fe, were compared to total Fe concentration in leaves to evaluate Fe status in plane trees. For this purpose, severity of chlorosis of plane trees at different regions of Isfahan city was recorded. Then, 73 trees with different severity of chlorosis symptoms were selected and their leaves were sampled on July 2009 and 2010. Concentration of Fe, chlorophyll a and b and carotenoids in leaves as well as activity of GP enzyme were measured. Results showed large variation in leaf Fe concentration between young and old leaves and also between leaves with different chlorosis severity symptoms. No correlation was found between leaf Fe chlorophyll concentration and severity of chlorosis symptoms. Also, concentrations of chlorophyll a in young and old leaves with very severe chlorosis symptoms were 44 and 37% smaller than that in young and old leaves with slight chlorosis symptoms, respectively. Concentration of chlorophyll b in young and old leaves with very severe chlorosis symptoms were 40 and 37% smaller than that in young and old leaves with slight chlorosis symptoms, respectively. Concentration of carotenoids varied among young and old leaves with different severity of chlorosis symptoms. Activity of GP in young leaves was also reduced by intensifying severity of chlorosis symptoms. According to the result of the present study, activity of GP enzyme and leaf concentration of carotenoids and chlorophyll a, as suitable physiological indices of active Fe, had close correlation with severity of Fe chlorosis in plane trees. Also, deficiency of active Fe in leaves is a probable reason of chlorosis symptoms in plane trees.