JWSS - Journal of Water and Soil Science

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In vitro salt tolerance of 28 cultivars of durum wheat with native and exotic origins was investigated, using MS medium containing sodium chloride. The resulting calli were subjected to 8 salinity levels including 0, 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8 percent NaCl (w/v). Donor plants of explant (immature embryo) were grown in a recirculating hydroponics and pots in a greenhouse as well as in the field. Assessment of calli was conducted after 0, 8 and 16 days after subculture of calli into the NaCl-contained medium. Callus growth rate, relative callus growth rate and percentages of callus necrosis were measured, using a 8 × 28 factorial experiment layout in a completely randomized design with 3 observations per treatment and 3 replications. Results of analysis of variances showed that among the criteria, relative growth rate of callus was the most reliable, while callus growth rate as not being quantitatively measured, was less devoted. Results of this study revealed that 'PI 40100' and 'Dipper-6' were superior genotypes for in vitro salt tolerance. The high relative callus growth rate and less callus necrosis of these cvs. may indicate their superior genetic potential for in vitro salinity tolerance.

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The antifungal effect of sodium diacetate on inhibiting the growth of some bread spoiling molds was examined both in culture media and in flat bread “In situ”. In the first step, the antifungal effect of different concentrations of sodium diacetate: 0, 1000, 2000, 3000, 4000, and 5000 ppm were examined against Aspergillus sp., Aspergillus niger, Rhizopus sp., and Penicillium sp.

The results indicated that as the concentration of sodium diacetate increased, the mold growth decreased. At 5000 ppm the mold growth was inhibited up to fifth day (the last day of experiment). Based on these results, the antifungal effect of different concentrations of sodium diacetate was evaluated in bread “In situ”. In this stage Aspergillus sp. was selected as the indicator mold. The results indicated that if 3000 ppm of sodium diacetate is used, not only mold growth is inhibited but bread staling can also be prevented. This concentration of sodium diacetate does not have any harmful effect on texture and flavour, and can increase bread shelf life up to four days. Higher concentrations of sodium diacetate can inhibit mold growth completely, but have negative effects on texture and flavour. Therefore, 3000 ppm of sodium diacetate is recommended for increasing bread shelf life.

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To determine the effects of salinity and boron excess in irrigation water on relative growth rate (RGR), net assimilation rate on a leaf weight basis (NAR), and leaf weight ratio (LWR) of pistachio, three pistachio rootstocks (Badami -Zarand, Sarakhs and Ghazvini) were used. Rootstocks were grown in soil in eight-liter polyethylene pots. Sodium chloride treatments were 0, 75,150 and 225 mM NaCl and boron treatments were 0, 20 and 40mg liter^-1. Treatments were applied to the one-year old pistachio rootstock seedlings in three-day intervals with irrigation water. Some plants were randomly selected and destructively harvested before (day 0) and after applying treatments (30 and 60 days after treatments started). Growth and physiological characters were then measured as follows: number of leaves, leaf area, plant height and root length, fresh and dry weights of stem, root and leaf, proline accumulation in the leaf, total chlorophyll, and leaf relative water content (RWC). Results indicated that relative growth rate decreased with time for all treatments and in all rootstocks. Salt treatment significantly reduced both RGR and NAR, whereas LWR showed no significant differences. In all rootstocks, NAR, but not LWR, was significantly correlated with RGR, indicating that NAR was an important factor underlying the salinity-induced differences in RGR among the pistachio rootstocks. Salinity did not affect leaf water potential (ψ), chlorophyll content, and Fv:Fm ratio but increased NaCl concentration and time correspondingly increased proline accumulation in leaves. In addition, Ghazvini rootstock accumulated more proline compared to other rootstocks and was more resistant to salinity treatments. Different boron treatments did not show any significant effect on growth rate nor on measured parameters after two months of exposure to treatments.

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One of the main criteria for salt tolerance is cell membrane stability under stress. Reactive oxygen species (ROS), activity of lipoxygenase (Lox) and lipid peroxidation are considered to be destructive to cell membrane under salt stress. In this study, the effects of 0, 75 and 150 mM NaCI, over a period of 14 days on the activity of lipoxygenease, the amount of hydrogen peroxide (H₂O₂) and malon dialdehyde (MDA. as a lipid peroxidation) in the leaves of Pistacia vera L. (cv. 'Qazvini' and wild 'Sarakhs' pistachio) and 'Mastic' (P. mutica F. & M.) were studied. The results indicated that by increasing salinity Lox activity increased in the leaves of all the three rootstocks. This activity reached a climax on the 7^th day and then decreased on the 14^th day. Among the three species, Mastic reached the highest amount of the Lox activity on the 14^th day with the lowest amount of Lox reduction. The amounts of H₂O₂ in the leaves of all the three rootstocks increased, on the 14^th day the highest amount of hydrogen peroxide was found in 'Mastic' and 'Sarakhs' after treating them with 150 mM NaCl. The amounts of MDA were also reached the highest level in all three rootstocks on the 7^th and 14^th days. The results also indicated the possibility of the use of lipid peroxidation index and Lox activity for selecting salt tolerant Pistacia rootstocks. More studies are needed for understanding the biochemical changes and enzyme activities in Pistacia rootstocks under salt stress.

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  Sugarcane is one of the most important sugar crops in the world. Because of semi-arid climate and salinity of its cultivation area in our country, increasing salt tolerance of sugarcane is signifying. To achieve this goal determining salt tolerant cultivars and understanding salinity mechanisms in sugarcane are very important. This study was conducted to evaluate 8 commercial and promising sugarcane cultivars at early stage of growth. A complete randomized design with three replicates and four salinity treatments (0, 0.25, 0.5, 0.75 % NaCl) was used in a hydroponics system. The effect of salinity on absorption, transport and accumulation of Na⁺, Cl^- , K⁺ and Ca²⁺ ions in shoot and root was determined. At high level salt concentration, Cl^- content in shoot and root increased. Result showed that sodium accumulation in sugarcane plants was more than potassium. By increasing salinity level, sodium uptake and its translocation to shoots increased reducing growth and dry matter yield of plants. With rising salt concentration from medium (0.5%) to high (0.75%), content of chloride in shoot and root of NCO-310 was constant showed that this cultivar had genetic ability to avoid Cl^- uptake. CP82-1592 with lowest ratio of shoot / root chloride had minimum transport of Cl^- to shoots. Also this cultivar had high content of Ca²⁺ in shoot and low Na⁺/Ca²⁺ ratio at all salinity levels. CP48-103 had low sodium in shoot and relatively low sodium in root. Thus it probably has genetic potential to avoid sodium uptake. At last, exclusion of Na⁺ and Cl^- to older leaves and tillers was seen in CP82-1592 and CP72-2086 cultivars. According to results, to avoid once of absorption and transport, and exclusion of harmful Na⁺ and Cl^- ions were mechanisms that could be used in salinity tolerance of sugarcane.

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  Soil properties play a significant role in phosphorus (P) sorption. Information about P sorption is limited in Hamadan soils. The objectives of this research were to study the P sorption in twelve soils of Hamadan, assess the capability of different kinetics equations describing P sorption and correlate the P sorption characteristics with the soil properties. The soils were fertilized with 200 mg P kg^-1 as KH₂PO₄. Fertilized soil was incubated at 25±1 ˚C for 2520 h. The incubated samples at 1, 2, 4, 8, 24, 48, 72, 96, 120, 144, 168, 240, 336, 504, 672, 840, 1008, 1176, 1344, 1512, 1680, 1848, 2016, 2186, 2352, 2520 hours after P addition were extracted by two extractants. The soil phosphorous was extracted by 0.5 M sodium bicarbonate (Olsen solution) or by AB-DTPA. Zero order, first order, simplified Elovich equation, parabolic diffusion law and power function equations were fitted on the experimental data. The results showed that P sorption was initially rapid followed by a slow phase. The amounts of P sorption after 2520 h, ranged from 162.7 to 253.84 and 193.37 to 235.11 mg kg^-1 for the Olsen and AB-DTPA methods, respectively. Regarding to higher determination coefficient and lower standard error, Elovich and power function equations were suitable to describe P sorption kinetics. Rate constants of the Elovich and power function equations ranged from 0.036 to 0.49 and 0.157 to 0.304 mg kg^-1h^-1 for Olsen and from 0.074 to 0.76 and 0.184 to 0.382 mg kg^-1h^-1 for AB-DTPA. The trend of the data implied a discontinuity in slope at 336 h, as two region models might better satisfy the trend of the data in to two range ( 0 to 336 and 336 to 2500 hr). At the first section, the P sorption could be describe by simplified Elovich, power function and parabolic diffusion law kinetics equations. Rate constants in these equations varied among the soils. At the second section, kinetics equations could not describe the P sorption. The results of this study indicated that P sorption rates varied among the soils and Fe , Al and CaCo₃ affected on P sorption kinetics.

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  Gypsum affects many physical, chemical and mineralogical properties which in turn influences management, classification and sutability of the soils. This is the reason why accurate measurement of gypsum in soil is very important. In most of the soil science laboratories, the method of acetone ,in spite of its too much limitation, is being used as a standard method. The purpose of this research was to compare different gypsum determination methods and to find the most suitable one. The study areas include Jafarabad of Borkhar and Sepahanshahr.Soil samples were collected from different horizons of the studied profiles and seven samples with a wide range of gypsum content were selected. Gypsum content of the soil samples were determined by methods of acetone, sodium carbonate, resin, calcium and magnesium difference, diluted extracted sulfate, ammonium carbonate, sodium citrate and hydrochloric acid. To calculate the recovery percentage of the methods, after adding a certain amount of gypsum with known purity percentage to the soil samples, gypsum content was determined again by above mentioned eight methods. To evaluate the suitability of the methods, in addition to the recovery percentage of the methods, coefficient of variability and extent of proximity of the regression line to the 1:1 line were used. The results revealed that among the used methods, the method of sodium carbonate is the most accurate one. Resin method is ranked as the second best method and can be used in non-saline soils as another accurate method for determination of gypsum content. Sodium citrate and hydrochloric acid methods for different amounts of gypsum and ammonium carbonate method for gypsum content up to 30% are third in rank as far as their accuracy is concerned. Acetone, calcium magnesium difference and diluted extracted sulfate methods are not sufficiently accurate, because of low solubility of gypsum in water which is used as an extractant. In general, the most important determinant of accuracy of the methods is extractants of the gypsum among which the sodium carbonate has the highest efficiency.

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An experiment was conducted in order to evaluate the effects of increased concentration of potassium and calcium in hydroponic nutrient solution on the response of safflower to salinity. The experiment was carried out in a glasshouse using a completely randomized design. Four saline treatments (Johnson solution containing 100 mM of NaCl, Johnson solution containing 100 mM of NaCl + 10 mM potassium, Johnson solution containing 100 mM of NaCl + 5 mM calcium, Johnson solution containing 100 mM of NaCl + 10 mM potassium + 5 mM calcium) and Johnson solution without any addition of salt as control. Leaf area per plant, shoot and root dry matter was decreased in saline treatments. The concentration of potassium and calcium in the plants were decreased but those of sodium were increased at salinity. The extent of shoot and root dry mater reduction with salinity was less in saline treatment with additional calcium alone. The addition of potassium into the nutrient solution could not mitigate the negative effects of salt stress on the plants. Increasing the concentration of both potassium and calcium in saline nutrient solution resulted in a greater reduction of shoot dry matter. The results showed that the negative effects of salinity may be alleviated by increasing the concentration of calcium in nutrient solution.

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The reclamation of salt-affected soils which occur on 831×106 ha can be effective in increasing agricultural production. Cultivation of plant species which are resistant to salinity can improve the soil by increasing the solubility of calcite and releasing the calcium in soil solution. This study was conducted as a column experiment with a saline-sodic soil (SAR = 23.8, EC= 12.88 dS m-1, pH= 7.7, CaCO3= 15.15 %). Three plant treatments including Sesbania acuelata, Cyanodon dactylon and Rubia tinctorum, and three chemical treatments including gypsum in two levels (50% and 100% gypsum requirement) and sulfuric acid with a control were arranged. All treatments were replicated 3 times. The soil columns were similarly leached by 41 liters of tap water during 30 days in 8 stages. After leaching, SAR and EC in soil, the amounts of sodium in leachate and total amount of sodium in plants shoot were determined. Results showed that the SAR was decreased compared to control by the plant treatments and the chemical amendments by about 59% and 65%, respectively. Moreover, two plants of Cyanodon dactylon and Rubia tinctorum had maximum amount of leachate sodium, which shows an impressive role of these plants in dissolution and leaching of exchangeable or sediment sodium in comparison with the other treatments. According to salient performance of phytoremediation in improvement of physicochemical properties of soil compared to chemical amendments, phytoremediation can be recommended as a profitable low-cost and effective method for remediation of saline-sodic soils.

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Rill erosion is the detachment and transport of soil particles by concentrated flow of runoff. It is the most common form of water erosion in the hill slopes. Rill erodibility is the rate at which soil particle is detached and transported by shear force of the concentrated flow. The study was conducted to determine the rill erodibility in different soil textures in Zanjan province using a rainfall simulator. To this end, samples of eight soil textures consisting of clay, clay loam, silty loam, sandy clay loam, sandy loam, loamy sand, and sandy were collected from land surface and transported to small plots (120 cm  100 cm) on a sloped uniform land (10%). The plots were exposed to five simulated rainfalls with a constant intensity of 60 mm h-1 for one hour. Based on the results, there was a significant difference among the soil textures in the rill erodibility (p< 0.01). Rill erodibility of the soils significantly correlated with mineral fraction (sand, clay, gravel) and exchangeable sodium percentage (ESP). With an increase in sand and gravel percentage, soil infiltration rate strongly increased and consequently production of the concentrated flow steadily decreased. Multiple regression analysis indicated that the rill erodibility in the soils was remarkably related to ESP (R2= 0.85, P< 0.01). Clay soil showed to have the highest rill erodibility among the soil textures due to higher exchangeable sodium percentage (ESP= 13).