نشریه روابط خاک و گیاه
پیاپی 20 (زمستان 1393)

In this study, possibility of substituting date palm fibers, as a growth medium, for coco peat was investigated. First, moisture absorption, retention and loosing rate in date palm fibers, coco peat, peat moss, perlite and soil were examined by completely randomized blocks design in two time periods (3 and 5 days), with two groups of materials (date palm fibers- peat moss- perlite and coco peat-peat moss-perlite) in 11 treatments and 3 replications. To find the best treatment in each group, the response surface methodology and desirability function were used, and finally the optimized treatments for capability of holding moisture in the medium were statistically compared to other treatments. Results indicated that potential of absorption and loosing rate of moisture in coco peat, peat moss, date palm fibers, perlite and soil was decreased, respectively. Maximum amount of water holding capacity occurred in date palm fibers’ group by combination of 65-20-15% in 3 days and 75-10-15% in 5 days and in coco peat group with combination of 75-20-5% in 5 days.

In this research, the possibility of using dried leaves of pine (Pi), tire-rubber wastes (TR) and rice hull (Ri) as tomato growth media in soilless culture system was investigated. Tomato seeds were grown in sterilized sand and after one month, the seedlings were transplanted to various growth media including dried leaves of pine- perlite (Pi:Pe), dried leaves of pine- rubber wastes (Pi:TR), cocopeat- perlite (Co:Pe), perlite- mica (Pe:Mi) and rice hull- perlite (Ri:Pe), each one at two ratios of 50:50 and 75:25. After two months, at the beginning of reproductive stage, tomato plants grown at Pi:Pe and Pi-TR were harvested. Tomato plants in the Co-Pe, Pe:Mi and Ri:Pe treatments were harvested during the reproductive stage. Plant height, root and shoot dry matter, concentration of K, P, and Zn in roots and shoots and fruit yield were measured. Results showed that plant height and root and shoot growth of Pi:Pe and Pi:TR media were significantly less than Co:Pe medium, at both 50:50 and 75:25 ratios. Zn concentration was greater in the Pi:TR medium with 50:50 ratio as compared to other treatments. According to the results, a combination of dried pine leaves and tire rubber wastes as growth media in soilless culture system of tomato had significant limitations such as low ability for retaining water and nutrients and toxicity of Zn released from tire rubber wastes. Therefore, it wouldnt be possible to use a combination of dried pine leaves and tire rubber wastes as growth media in soilless culture system without performing special chemical treatments on them.

Carbon dioxide (CO2) enrichment in greenhouses could be used for reduction of production time and increasing plant growth and quality. To evaluate the effects of different concentrations of CO2 on growth traits of two ornamental Ficus species (Ficus benjamina and Ficus elastica), a split plot experiment, based on completely randomized design with three replications, was conducted in the greenhouse of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. Treatments included two species of ornamental Ficus (Ficus benjamina and Ficus elastica) and three concentrations of CO2 (380 (control), 700 and 1050 mg/L). The results showed that with increasing CO2 concentration from 380 mg/L to 1050 mg/L, number of leaves and leaf area were significant at 5% probability level and root/shoot ratio, fresh weight of shoots and plant height were significant at 1% level. Interaction of Ficus species and CO2 concentration was not significant in all traits. In general, increasing CO2 concentration was effective on improvement of physiological and morphological traits of these two ornamental Ficus species.

In order to investigate the effect of different iron (Fe) sources on lettuce yield, under the sodium bicarbonate stress conditions, a greenhouse experiment was carried out with two factors including Fe source in three forms (Fe-EDDHA, Fe nano chelate and nanofertile) and sodium bicarbonate at three levels (0, 5, and 10 mM) with three replications. Three weeks after transplanting, seedlings were treated with sodium bicarbonate for 30 days. Results showed that dry weight of shoot and root decreased significantly by elevating the sodium bicarbonate concentration in nutrient solution. In response to higher sodium bicarbonate concentrations, chlorophyll a, b and maximal quantum yield of PSII photochemistry (Fv/Fm) decreased in all Fe treatments, while, the lowest reduction of these parameters was observed in plants grown with Fe-EDDHA. Sodium bicarbonate stress caused a reduction in Fe concentration of leaves and roots, such that at 10 mM sodium bicarbonate concentration, and nanofertile Fe source, Fe content in shoots decreased 64.88% as compared to control. Based on the obtained results, the Fe-EDDHA, due to its higher solubility and availability, has more potential to be absorbed by lettuce, and for this reason, increased growth of the lettuce. Therefore, due to the importance of Fe in nutrition of plants, application of Fe-EDDHA under alkali conditions is the best source of Fe supply for lettuce.

In order to study the effect of seed priming on morphophysiological characteristics of seedlings of chickpea (Cicer arietinum L.) under salinity stress, a factorial experiment based on completely randomized design with three replications was conducted at the Research Center for Plant Sciences, Ferdowsi University of Mashhad, Iran, in 2011. In this study, osmotic solutions of NaCl with electrical conductivity of 0, 4, 8 and 12 dS/m were salinity levels and PEG – 6000 (-0.8 MPa) and CaCl2 (-1 MPa) were used as seed-priming materials. After priming the seeds, they were planted in plastic pots and after 28 days, the seedlings were sampled. Results showed that salinity stress decreased significantly such traits as shoot length, dry weight of shoot, leaf area, membrane stability index and relative water content and increased significantly the proline content of leaves. Leaf area, membrane stability index, relative water content and leaf proline content were significantly increased in seedlings grown from seed priming, as compared to control. Also, interaction of seed priming and salinity showed that these characteristics were significantly increased as compared to control. In general, seed priming with PEG – 6000 (-0.8 MPa) and CaCl2 (-1 MPa) osmotic solutions alleviated negative effects of salinity on pea seedlings. Ameliorative effects of CaCl2 priming were significantly more than PEG

To evaluate the effect of limited application of phosphorus (P) on height and performance quality of geranium (Pelargonium hortorum cv. Bulles Eye), an experiment was conducted in the greenhouse environment, based on completely randomized blocks design, during 2011-2012. Geranium seedlings were cultivated in the pots filled with peat-based substrate (80% peat + 20% garden loam soil (v/v)). Treatments were applied as four levels of nutrient solution (0.2 (control), 0.15, 0.1 and 0.05 mM P). At the end of the experiment, traits such as plant height, number and length of shoots, number of inflorescences, number of flowers in each inflorescence, pedicle length, fresh and dry weight of shoots and roots, number of leaves, leaf area, chlorophyll content of leaves, and leaf anthocyanin content were measured. According to the results, although the application of 0.05 mM P reduced plant height and length of the pedicles, but negatively affected fresh and dry weight of shoots and roots, chlorophyll content of leaves, and leaf number and leaf area, and the produced plants were not marketable. While, reducing the concentration of P in the nutrient solution from 0.2 to 0.1 mM, other than reduction of plant height, did not affect negatively other qualitative traits. Therefore, to achieve proper qualitative traits and reduce the consumption of P by geranium, limiting the application of P up to 0.1 mM is recommended

For comparing the effects of two planting substrates on vegetative growth, flowering rate, fruit appearance and qualities, yield of four bell pepper (Capsicum annum L.) cultivars, a greenhouse 4×2 factorial experiment was done by using a completely randomized design with 4 replications. First factor was 80% cocopeat + 20% perlite and 80% mosspeat + 20% perlite and the second one was four bell pepper cultivars consisted of green Traviata, red Inspratian, orange Aracia, and yellow Taranto. The results showed that mosspeat caused better effects on vegetative growth consist of length and diameter of stem, relative chlorophyll, fresh and dry weight of root and stem and reproductive factors consist of flowering rate, fruit length and diameter, fruit shape index, rigidity and pericarp thickness and it increased fruit number and fresh and dry weight of fruits in each plant in comparison to cocopeat. Amongthe cultivars red cultivar was the superior one for important factors vincluding relative chlorophyll, fresh and dry plant weight, fruit shape index and pericarp thickness. There was significant interaction between cultivar and bed indicating that the response of bell pepper cultivars was varied in different beds

A greenhouse experiment was conducted to evaluate the effect of vermicompost and sodium chloride (NaCl) on growth of spinach cv. Viroflay and some chemical properties of post-harvest soil. The greenhouse experiment was factorial, arranged in a completely randomized design with three replications. Treatments included three vermicompost levels (0, 1 and 2% w/w) and four salinity levels (0, 1, 2 and 3 gr NaCl/kg soil, equivalent to 0.7, 4.5, 8 and 11.5 dS/m, respectively). The highest relative yield of spinach shoots was obtained by application of 10% vermicompost, whereas, application of NaCl had no significant effect on relative yield of spinach shoots. Application of vermicompost increased mean leaf area and chlorophyll of shoots, organic matter (OM), electrical conductivity (EC), total nitrogen (N), available phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na) and chloride (Cl) of post-harvest soil. Addition of NaCl increased EC, P, K, Ca, Mg, Na and Cl of post-harvest soil, but had no significant effect on leaf area and chlorophyll content of shoots, OM and N of post-harvest soil. Addition of vermicompost had positive effect on spinach growth and plant nutrients availability in post-harvest soil. However, increased soil salinity, especially when high level of vermicompost is applied, should be considered. Application of NaCl, even up to the salinity of 11.5 dS/m, didn’t decrease significantly the spinach yield. Therefore, Viroflay cultivar could be introduced as a relatively resistant to salinity; although, before any recommendations, it is needed to do further experiments, especially under field conditions, to confirm the results of this study

The possibility of using some organic wastes as growth media for English daisy, plus some fertilization methods, was investigated in a factorial experiment, based on a completely randomized blocks design with 45 treatments and three replications. The first factor was different growth media and the second factor was three methods of fertilization including without fertilization (control), fertilization as leaf spraying and soil fertilization. In this research, 15 substrates were used by mixing different ratios of municipal-wastes compost, tea-wastes compost, azolla compost and garden soil. The garden soil was a mixture of 60% loam soil, 20% manure, 10% leaf compost and 10% sand (v/v). Results showed that maximum growth was observed in the medium containing garden soil, municipal-wastes compost, azolla compost, each substrate one-third (v/v), and the medium which contained garden soil and municipal-wastes compost in a 1:1 ratio. Azolla compost alone was not suitable for growth of English daisy as significant responses were not obtained in most growth indices. Although the effect of nutrition method was not significant on most growth indices in this experiment, the soil fertilization had better impacts as compared to other methods. Therefore, it seems that combination of garden soil, municipal-wastes compost and azolla compost, along with soil fertilization, is the most suitable substrate for English daisy, which improves the growth of this plant.

Biofertilizers are important sources for plant's supplementing nutrition program, which have significant effect on reduction of costs and adverse effects of mineral fertilizers on the environment. This research was conducted as two different experiments. In experiment 1, effect of biofertilizer (0, 1 and 1.5 L nitroxin/ 500 m2), paclobutrazol (0, 25 and 50 mg/L) with/without pinching, and in experiment 2, effect of biofertilizer (0, 1 and 1.5 L nitroxin per 500 m2) and nitrogen fertilizer (0, 200 and 300 mg/L urea) were studied on some morphophysiological characteristics of Chrysanthemum (Chrysanthemum frutescence). Both experiments were arranged as factorial based on a completely randomized design with three replications. In experiment 1, maximum stem height (38.14 cm) was recorded in 1.5 L nitroxin without paclobutrazol and pinching. The 1.5 L nitroxin + 25 mg/L paclobutrazol treatment showed the highest values of number of flowers, fresh and dry weight of shoots, fresh and dry weight of flower and number of shoots. Also, the highest amount of chlorophyll a and b, carotenoides, total soluble carbohydrates and protein content was obtained in this treatment. Plant height, number of flowers and number of shoots were reduced significantly with increasing paclobutrazol concentration from 25 to 50 mg/L. Application of paclobutrazol significantly decreased plant height and increased plant width as compared to pinching. In experiment 2, better growth rate, flowering and physiological characteristics were obtained by application of biofertilizer and urea together, as compared to using them alone. The highest number of shoots and flower per plant, highest values of chlorophyll a and b, carotenoids, total soluble carbohydrate and protein content were obtained in 1.5 L nitroxin /500 m2 + 200 mg/L urea treatment. Number of flowers was significantly increased by extension of plant width. According to the results of the second experiment, nitroxin biofertilizer could reduce application of mineral nitrogen consumption in Chrysanthemum frutescence

Iron (Fe) chlorosis is an important nutritional problem in quince trees. But, quince rootstocks differ in their tolerance to Fe deficiency in calcareous soils. Tolerance to Fe deficiency of seedling rootstocks of quince, pear and crataegus and clonal rootstock of quince A was evaluated by exposure to two levels of Fe (3 and 50 µM) in the presence or absence of 10 mM bicarbonate in soilless culture. According to results of this study different rootstocks had various responses to Fe deficiency stress. In Fe-deficiency stress conditions, rootstocks of pear and crataegus showed the lowest severity of chlorosis among the studied rootstocks and had the highest plant height, number of leaves and Fe concentration in leaves and roots. Activity of guaiacol peroxidase enzyme in these two Fe-tolerant rootstocks was less affected by Fe deficiency. In contrast, seedling rootstock of quince showed the highest severity of chlorosis along with the decrease in activity of guaiacol peroxidase (-74.19%) and ascorbate peroxidase (-52.35%). Quince A rootstock showed better performance than seedling rootstock of quince under Fe deficiency. Results also revealed that despite sufficient Fe level in the media (50 µM), seedling rootstocks exposed to bicarbonate showed Fe deficiency symptoms. In general, it was found out that rootstocks of pear and crataegus were more tolerance to Fe deficiency stress

A greenhouse experiment was conducted using corn to study the effect of arbuscular mycorrhiza, organic matter and zinc (Zn) on chemical forms of Zn in a calcareous soil. Experimental setup was factorial, based on completely randomized design with 3 replications. Treatments consisted of 3 levels of Zn (0, 5, and 10 mg Zn per kg soil), 2 kinds of organic manure (sheep manure and municipal waste compost, each at 0 or 1% w/w) and 2 levels of mycorrhiza (no inoculation and inoculation with Rhizophagus intraradices), which were added to a calcareous soil. Plants were harvested 8 weeks after emergence and the soil was used for fractionation of Zn by sequential extraction procedure. Roots were used to determine the degree of colonization. Results showed that inoculation with arbuscular mycorrhiza increased Zn bound to carbonate, organic matter and crystalline Fe-oxides but decreased the Zn bound to Mn-oxides, amorphous Fe-oxides and residual forms. All chemical forms of Zn (with the exception of soluble and exchangeable forms) increased with increasing application of Zn. Application of both kinds of organic manure increased chemical forms of Zn. Symbiosis of arbuscular mycorrhiza, organic matter and Zn increased corn plant-root mycorrhizal colonization

In order to investigate the effect of silicon concentration in substrtae on some physiological, biochemical and growth characteristics of wheat (Triticum aestivum L. cv. Chamran) under available-water deficiency, this experiment was conducted in Ramin Agricultural and Natural Resources University, Khuzestan, Iran, in 2012. The experiment was arranged as factorial, based on randomized complete blocks design with three replications. Treatments included available-water deficiency stress at three levels (non-stress (control), mild stress (-5 atm osmotic pressure) and severe stress (-10 atm osmotic pressure) by solving 175 and 230 grams of polyethylene glycol 6000 per liter of distilled water). The second factor was different levels of silicon (0, 1, 2 and 3 mM/L) in the form of potassium silicate (K2SiO3). Results showed that the effect of water-deficiency stress increased significantly the proline content (74.4%) and silicon concentration of shoots (69.1%) and reduced the soluble proteins content, stomatal conductance, membrane stability index and shoot and root dry weight by 18.6, 66.6, 24.2 37.8 and 51.9%, respectively, as compared to control treatment. Also, the effect of silicon concentration in the nutrients solution, except root dry weight, was significant on the other traits. Silicon had the greatest impact on shoots’ silicon content and led to a 53% increase in this index. The presence of silicon in non-stress treatment had no significant effect on the traits and its effect was enhanced with an increase in stress intensity. Application of 2 and 3 mM/L of silicon increased shoot dry weight by 18 and 21% in mild stress and by 25 and 31% in severe stress conditions, respectively, as compared to no-silicon treatment, and there was no significant difference between these two values

In order to investigate the effects of irrigation water salinity on root traits and absorption of sodium (Na+) and potassium (K+) by wheat cultivars, a factorial experiment, based on completely randomized design with 3 replications, was ‎conducted under greenhouse conditions. The main factor was 7 wheat genotypes]Ghods, Marvdasht and Bahar (sensitive to salinity) and Arg, Bam, Sistani and Singh-2 (tolerant to salinity)] and the second factor was ‏three levels of irrigation water salinity [1.3 (control), 5 and 10 dS/m]. In this study, the effect of salinity stress on root growth traits including root dry weight, root/shoot ratio, root volume and length, Na+/K+ ratio and grain yield were assessed. Results showed that increasing the salinity of irrigation water increased Na+/K+ ratio significantly, other studied traits were decreased significantly, and 10 dS/m salinity treatment caused the most negative effects. Means of the measured traits showed superiority of Arg, Bam, Sistani and Singh-2 cultivars, as compared to three other cultivars. Also, in all the studied traits, the highest percentage of reduction in 10 dS/m salinity, compared to control, was for Marvdasht cultivar, which shows the sensitivity of this genotype. Therefore, considerable superiority of some root characteristics and Na+/K+ ratio in salinity tolerant cultivars of ‎wheat may be useful for screening the salinity tolerant wheat genotypes

In order to assess the physiologic responses of two wheat genotypes to different levels of salinity and nitrogen (N) at tillering stage, a factorial experiment, based on completely randomized design with three replications, was performed under greenhouse conditions. Treatments were two wheat cultivars [Tajan (susceptible to salt stress) and Bam (resistant to salt stress)], five levels of salt stress ‎‎[control (1.3), 6, 8, 10 and 12 dS/m)] and two levels of N (75 and 150 kg N/ha). Results indicated that in all salinity treatments, application of 150 kg N/ha increased chlorophyll b content, total soluble proteins, SOD activity, and decreased MDA content of both ‎genotypes. Salinity decreased relative water content (RWC) of both genotypes. However, N fertilizer did not have significant effect on the mentioned parameter. In this respect, genotypic differences for salinity tolerance and fertilizer uptake caused higher levels of the N fertilizer to be more effective on Bam genotype than Tajan genotype. These results suggest that N fertilizer, as a primary nutrient for ‎physiological compounds, may alleviate the adverse effects of salinity stress on wheat at sensitive stage of tillering

In silver cypress (Cupressus arizonica), rooting of cuttings is not easily possible. To optimize the rooting properties of cuttings of this plant, a factorial experiment was conducted as multi-factor, based on a completely randomized block design with 4 replications and 4 cuttings in each replicate. In this study, four different types of cuttings (consisting of above-terminal, above-basal, below-terminal and below-basal), each 15 cm long, were taken from distal and proximal parts of a 15-year old silver cypress tree. Cuttings were treated with different concentrations of indole butyric acid (IBA) (2000, 3000, 4000 and 5000 mg/L) and were grown in different rooting media (pure peat, peat+ perlite (v/v), leaf compost and fine sand). Results showed that applied treatments had significant effect (P≥0.01) on rooting percent and callus formation, root length and number of roots. Most of the cuttings were decayed on leaf compost medium. The lowest level of rooting, root length and number of roots were obtained with below-terminal and then above-terminal cuttings in the fine sand medium. Cuttings were harvested after 6 months and rooting percent, callus formation, root length and number of roots were assessed. The highest rooting percentage, root length and number of roots were achieved from below-basal cuttings in peat+perlite medium treated with 3000 mg/L IBA

Due to low organic matter content in most of the cultivated soils of Iran and occurrence of drought stress in plants because of low precipitation, application of sewage sludge compost has been recommended for increasing soil organic matter content and improving soil fertility, increasing crop tolerance to water deficit and improving crop yield. So, in this study, the effects of soil moisture and sewage sludge compost levels were investigated on leaf chlorophyll index and some growth traits of alfalfa (Medicago sativa L.) in greenhouse conditions. A factorial experiment, based on randomized complete blocks design with three replications, was conducted with two factors of soil moisture conditions at three levels (0.81FC-FC, 0.56FC-0.75FC and 0.35FC-0.50FC) and sewage sludge compost at four levels (0, 15, 30 and 60 g/kg of soil). Results showed that the effect of soil moisture levels on leaf chlorophyll index was dependent on the level of sewage sludge compost. Soil water deficit significantly decreased shoot and root dry weights and plant height (P<0.01). The sensitivity of alfalfa shoot to soil water deficit stress was greater than its root. Application of 15 and 30 g sewage sludge compost per kg of soil significantly increased leaf chlorophyll index, shoot and root dry weights, plant height and shoot to root dry weight ratio (P<0.01). The interaction effects of soil moisture and sewage sludge compost on leaf chlorophyll index, shoot and root dry weights, plant height and shoot to root dry weight ratio were significant (P<0.01). The highest shoot and root dry weights, plant height and shoot to root dry weight ratio were observed at 30 g sewage sludge compost per kg of soil and 0.81FC-FC soil moisture level. Also, the results showed that application of 30 g sewage sludge compost per kg of soil alleviated water deficit-induced adverse effects on alfalfa plant.

To date, limited research has been done worldwide on uptake and translocation of nanoparticles (NPs) by plants. To evaluate such processes, soybean (Glycine max L.) was cultured in modified Hoagland nutrient solution containing Fe3O4 NPs with concentration of 60 mg/L, and 33 mg/L iron chelate (Fe-EDTA) was taken as control. After 28 days, the strength of magnetic signal was measured in different organs of the soybean by vibrating sample magnetometer (VSM) instrument. Result showed no magnetization signal from the control plants, but signals with various strengths were found in the tissue samples of the treated plants. Strong magnetic signal in soybean leaves clearly indicated the uptake and translocation of Fe3O4 NPs by roots and xylem. The strongest magnetic signal (138 memu/g) was detected in roots, and transfer coefficient of NPs from roots to leaves was about 0.9 percent. Exudates and surface charge of roots caused accumulation of magnetite NPs on soybean root's surface. A small fraction of particles moved through simplastic pathways into the xylem and streamed to leaves via sap flow. NPs were accumulated in the crown more than other aerial parts, due to vascular change in structure (root to shoot). In summary, results demonstrated that Fe3O4 NPs can be taken up by soybean and be translocated to other plant tissues in molecular form

High carbon dioxide (CO2) concentration in atmosphere has direct effects on plants activities. In order to investigate the effect of increased CO2 concentration from 380 to 700 and 1050 mg/L on some chemical and physiological characteristics of Amaranthus tricolor under three salinity treatments (0, 150, and 300 mM NaCl), an experiment was conducted in Research Greenhouse of Ferdowsi University of Mashhad, Iran. The results showed that interaction of salinity and CO2 in traits such as total dry weight, electrolyte leakage, relative water content and Na + uptake was significant at 1% probability level. However, interaction of CO2 and salt stress in plant traits such as proline and total carbohydrates did not show any significant difference (p<0.01). The highest relative water content was measured in 700 mg/L CO2 treatment, when the plants were irrigated with distilled water (no salinity stress). Application of 700 and 1050 mg/L CO2 treatments, at the highest salinity level, reduced electrolyte leakage by 26 and 19 percent, respectively, as compared to CO2 control treatment

The aim of this study was to improve the quantitative and qualitative characteristics and vase life of rose (Rosa hybrida cv. Dolcvita). For this purpose, an experiment was conducted in a randomized complete design with 7 treatments and 4 replications in a commercial rose-growing greenhouse, equipped with soilless culture, adjacent to Yasouj city, Iran. Treatments included: Control, 200 and 400 mg/L humic acid (HA), 200 mg/L HA + 2 mM puterscine (Put), 200 mg/L HA + 4 mM Put, 400 mg/L HA + 2 mM Put and 400 mg/L HA + 4mM Put. Different factors such as flower stalk height and diameter, flower bud height and diameter, leaf area, leaf chlorophyll content and vase life were measured. Results showed that maximum fresh weight, dry weight, flower bud height and diameter, flower stalk height and diameter, leaf area and leaf chlorophyll content were observed in treated plants with HA and HA+ Put. The tallest flower stalk (84.75 cm) was seen in 400 mg/L HA + 2mM Put and the shortest flower stalk (55.25 cm) was obtained in untreated plants (control). The highest vase life was observed in treated plants with HA and HA + Put as compared to control. The lowest vase life (10.12 days) was observed in untreated plants. According to the results of this ressearch, application of HA and Put for improving the vegetative traits and vase life of rose cv. Dolcvita in soilless culture is recommendable