نشریه روابط خاک و گیاه
پیاپی 6 (تابستان 1390)

Strong, tall and healthy stems, as well as green background by means of leaves, are very important characters in marketing of cut flowers including Lily (Lilium). Also, in order to reuse the bulbs for next crop production, they should have enough stored materials and perimeter. This investigation was conducted to evaluate the effects of different media on some vegetative characters of two Lillium cultivars in greenhouse conditions and determine the most suitable medium. The experiment was based on randomized complete design with two cultivars namely Bernini (Oriental) and Cebdazzle (Asiatic) and 4 replicates. Ten treatments of the experiment were organic and mineral media including cocopeat, sand, vermiculite, perlite and mixture of each two media at equal volumes (50: 50). All the pots were fertigated daily by 250 ml of Hoagland half strength solution. Means were compared by Duncan multiple range test at 5% probability level. The results showed superiority of cocopeat over other media in terms of plant chlorophyll content, fresh and dry weight of leaves and stem, leaf area, height, stem diameter, number of leaves, and bulb perimeter in both cultivars. Root length of both cultivars reached the highest using the mixture of perlite and cocopeat. The performance of Cebdazzle cv. against Bernini cv. regarding fresh and dry weight of leaves, leaf area, stem diameter, number of leaves, stem dry weight and root length were better in all the media. While, mean chlorophyll content and fresh weight of stems in Bernini was significantly higher than Cebdazzle.

In order to determine the effect of different substrates on the yield and quality of three pepper cultivars in a pot and tube culture, an investigation was conducted in a greenhouse in Sarkhoon, Bandar-Abbas in 2010. Different substrates including palm waste (100%), peat (100%), palm waste + peat (50:50 V/V), palm waste + peat (25:75 V/V) and waste palm + peat (75:25 V/V) and three cultivars of Rapido (yellow), Roxcy (red) and California wonder (green) were used in a completely randomized experimental design as a factorial experiment with three replications. The results showed that the highest fruit weight, length, diameter and volume, fruit dry matter, total acidity, carotenoids, soluble solids and pH was achieved from Roxcy cultivar, while the highest plant height was related to the Rapido cultivar. None of the traits, except plant height, leaf and root dry matter and total phenol content, were influenced by the substrates. According to the obtained results, palm waste is recommended as a complete or partial substitution for peat substrate in soilless culture.

In calcareous and saline soils, the adverse effect of some ions such as bicarbonate, boron, magnesium, and especially sodium, and the imbalance of nutrients’ concentrations are essential factors which reduce plant growth. A greenhouse experiment was conducted to study the effect of sodium (Na) and magnesium (Mg) on some growth traits and chlorophyll content of pistachio seedlings (cv. Badami Zarand) in perlite. The factorial experiment was carried out as a completely randomized design with four replications. Treatments were three levels of Na (0, 45 and 90 mM NaCl) and four levels of Mg (0, 0.5, 1 and 2 mM MgSO4). Modified Hoagland solution was used for irrigation of the pots. The results showed that increasing Na level significantly reduced leaf dry weight, stem height, leaf area and chlorophyll a content. Increasing Mg level up to 0.5 mM (complete Hoagland) reduced leaf and root dry weight. When Mg concentration was increased to 2 mM, vigorous reduction in leaf dry weight happened, but it didn’t affect significantly the root dry weight. Application of 2 mM Mg reduced the stem height, leaf number and area, chlorophyll a and total chlorophyll by 18, 25, 19, 42 and 41%, respectively. Interaction of salinity and Mg showed that at zero level of Na and with increasing the Mg concentration, the dry weight of aerial parts and roots, stem height and leaf area were reduced significantly. But when the Na concentration was 90 mM, not only they were not reduced, but also the leaf dry weight was increased more than 60%.

In order to study the effects of different levels of nitrogen (N) and molybdenum (Mo) in nutrient solution on quantitative and qualitative traits and nitrate concentration of cucumber (Sultan cv.), a factorial hydroponic-experiment with completely randomized design and three replications was conducted in the greenhouse of Soil Science Department, Zanjan University, in 2009. The concentrations of N in nutrient solution were 238 and 310 mg/L, and Mo was used at the rates of 0.01, 0.1 and 1 mg/L. The results showed that the effects of N and Mo levels were significant (P≤0.01) on plant yield and growth indices such as average weight, length and diameter of fruit and chlorophyll content of leaf. The chlorophyll content of leaf increased but fruit yield and average weight, length and diameter of fruits decreased as the N concentration of the nutrient solution increased. Increasing the Mo level in the nutrient solution decreased the growth indices and yield of cucumber. The highest fruit yield was obtained when the concentration of Mo in the nutrient solution was 0.01 mg/L. But it didn’t have significant difference with 0.1 mg/L treatment. However, the yield decreased significantly as the Mo concentration increased to 1 mg/L. The effects of N and Mo levels of nutrient solution were significant (P ≤ 0.01) on nitrate concentration of the fruits. As the N level of nutrient solution increased, the nitrate concentration of cucumber fruit increased from 1356 to 2122 mg/kg (on dry weight basis), and exceeded the toxicity limit of 1500 mg/L. Increasing the concentration of Mo of the nutrient solution from 0.01 to 0.1 mg/L decreased nitrate concentration of fruits from 1961 to 1703 mg/kg, without decreasing the fruit yield. With an increase in N concentration of the nutrient solution, the fruit concentrations of N, potassium and calcium increased, but those of phosphorus, magnesium and Mo decreased significantly. Also, as the concentration of Mo in the nutrient solution increased, the concentrations of iron, manganese and in fruit increased and that of copper decreased.

Optimum level of calcium (Ca) in saline soils is a critical factor in controlling the toxic effect of some ions, especially in plants sensitive to sodium (Na) and chlorine (Cl) damage. To evaluate the effect of salinity and supplementary calcium (S-Ca) on vegetative growth, fruit yield and concentration of some nutrients in roots, shoots, and fruits of strawberry (Fragaria ananaassa Duch) cv. Selva, a greenhouse experiment was carried out in 5×3 factorial experiment arranged in a completely randomized design with three replications. Treatments included three levels of salinity (0, 20, and 40 mM as NaCl) and five levels of supplementary Ca (0, 5, and 10 mM added to nutrient solution, 0.5 and 1% foliar application as CaCl2). The results showed that addition of NaCl to nutrient solution, negatively affected root and shoot dry weight and fruit fresh weight. Reduction of shoot dry weight and fruit fresh weight were higher than those of roots. Application of S-Ca not only did not improve the vegetative growth and fruit yield, but rather decreased them. Salinity (NaCl) treatments increased the concentration of Na in roots, shoots and fruits but application of 5 and 10 mM S-Ca levels decreased Na concentration in roots. By addition of NaCl to nutrient solution, the shoot Ca concentration was decreased in some treatments, but roots and fruits’ Ca concentration was not affected. Application of S-Ca increased Ca concentration in all organs of strawberry plants. By application of NaCl, potassium (K) concentration was decreased in roots, but increased in fruits and was not affected in shoots. K concentration did not change in roots in the S-Ca applied treatments, but decreased in shoots and increased in fruits. Simultaneous application of salinity and S-Ca decreased roots’ magnesium concentration in all treatments and shoots and fruits’ concentration in some treatments. In general, although supplementary Ca increased its concentration in different plant organs, but was not effective in alleviation of the negative effects of salinity on vegetative growth and fruit yield of strawberry plants.

Addition of sewage sludge (SS) in soil causes increasing soil organic matter, which in turn improves soil physical properties, and could supply part of the nutrients required by plants. For comparison of SS application and chemical fertilizer treatment (CFT) on yield and concentration of some macro and micro nutrients in spinach, a greenhouse factorial experiment, arranged in a completely randomized design (CRD), was conducted with three replications. The first factor included SS levels (0, 10, 20, 40 and 80 gr kg-1) and the second factor was soil textural classes (clay loam, sandy loam and sandy). A CFT was also used to compare its affect with that of SS levels. Results showed that addition of all levels of SS caused significant increase in the weight of spinach shoots in three soil textures. Application of all SS levels caused significant increase of nitrogen (N), phosphorous (P), iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) concentration in spinach shoots. With SS application, none of the nutrients’ concentration in spinach reached the toxic level. The amounts of cadmium (Cd) and lead (Pb) were not detectable in shoots. However, in frequent application of SS, especially at high levels, it is necessary to measure and detect these elements in plants. Effect of fertilizer in increasing yield and concentration of nutrients was less than the 40 and 80 gr kg-1 SS treatments. Considering the Fe and Zn deficiency in calcareous soils, application of SS can be effective for combating this deficiency. Prior to any recommendation of SS application, the results of this research need to be verified under field conditions.

With increasing of population, water resources’ pollution has been intensified and new and inexpensive methods are needed for remediation and improvement of water quality. Nickel is a necessary element in low concentrations for survival of the ecosystems, but in high concentrations is harmful and considered as a dangerous pollutant. This element pollutes water resources through different sources such as municipal and industrial wastewaters. Phytoremediation with aquatic macrophytes is a new, effective and inexpensive method for improving water quality and wastewater. In this study, Phytoremediation of nickel (Ni) from a hydroponic system by coontail (Ceratophyllum demersum L.), a native hydrophyte of most rivers in Iran, was investigated. After optimum pH determination (pH=7), this plant was cultivated within 14 days in a contaminated Hoagland nutrient solution which had four different concentrations of Ni (0, 1, 2, 4, and 6 mg/L). By daily measurement of Ni concentration in cultivation solution and also initial and final concentrations of this element in the plants, the Ni-phytoextraction potential was evaluated, and biological effects of Ni on coontail were studied by calculation of biomass production index. Maximum Ni removal efficiency was 50%, which was observed in the 1 mg/L Ni treatment. Maximum transfer factor and uptake index were 338.65 and 5.05 mg, respectively, obtained in 6 mg/L Ni treatment. Minimum and maximum biomass production-index (1.27 and 3.6 g/day, respectively) was related to 6 and 0 mg/L of pollutant concentrations. The conclusion of this research was that Ni phytoremediation in hydroponic systems with coontail is conceivable and evaluation of its potential is recommended for industrial wastewaters.