نشریه روابط خاک و گیاه
پیاپی 27 (پاییز 1395)

Due to wasteful use of low-quality irrigation water, many agricultural lands in arid and semi-arid regions of Iran are confronted with salinity phenomenon. Salinity decreases growth and yield of plants, therefore, ways to combat deleterious effects of soil salinity on plant growth should be sought. One of these strategies is physiological prevention of salt accumulation in plants and increasing their resistance to salinity. In this greenhouse study, the main objective was to investigate the interaction effects of potassium (K) and boron (B) on yield and uptake of some micronutrients by roots and shoots of radish under salinity conditions. The experiment was carried out as factorial, based on completely randomized design with three replications, at 3 levels of K (1, 4 and 8 mM), 3 levels of B (0.1, 0.2 and 0.3 mg/L) and 3 levels of salinity (1, 4 and 8 dS/m) in quartz sand culture medium. Results showed that interaction of K and B on fresh and dry weight of shoots, fresh weight of roots and uptake of B, Fe, Cu, Zn and Mn was significant at different levels of salinity. Maximum fresh and dry weight of roots and shoots was observed in 8 mM K treatment. Also, maximum B, Fe and Mn uptake in shoots, and maximum B, Fe and Cu uptake by roots was observed at 4 mM K level. Uptake of B, Fe, Mn and Cu in roots was higher at salinity of 4 dS/m than 8 dS/m. At 4 dS/m salinity, maximum shoot yield and B uptake in roots, Zn uptake in shoots, and Mn uptake in roots and shoots, was observed at 8 mM K and 0.3 mg/L B. At salinity level of 8 dS/m, maximum B and Mn uptake in shoots and B and Fe uptake in roots was observed at 4 mM K and 0.3 mg/L B. According to the results this study, different levels of salinity and concentration of K and B, due to the interaction of these two elements, affect yield and uptake of plant micronutrients.

One of the main anxieties in application of wastewater and compost in agricultural lands is their salinity and uptake of heavy metals by plants. To envestigate the effects of wastewater and compost on yield and accumulation of lead and nickel in the basil shoots, as well as electrical conductivity (EC) and pH in soil profile and its leachate, a factorial test was conducted, based on completely randomized design with three replications, in 48 lysimeters. The factors included four types of watering [raw wastewater (W1), treated wastewater (W2), combination of 50% raw wastewater and fresh water (W3) and fresh water (W4)] and four compost levels [0 (C1), 40 (C2), 80 (C3) and 120 (C4) ton/ha]. Totally, 11 waterings were applied during the growing season. Basil plants were harvested at three stages. After the third harvest, soil samples were taken from 10, 20, 40, 65, 85 and 105 cm depth in the lysimeters. Results showed that application of wastewater and compost, compared to the control treatment, significantly increased (p≤ 0.05) fresh and dry weights, concentration of lead and nickel in the shoots of basil, as well as EC of the soil, relative to type of irrigation water and level of compost. But, wastewater and compost application significantly decreased (p

This study was performed to evaluate the role of ethylene stress, ethylene inhibitors and action treatments on longevity of potted-carnation flowers. For this purpose, first, potted-carnation flowers were pretreated with different concentrations of amino-oxyacetic acid (AOA), benzyladenine (BA) and 1-methylcyclopropene (1-MCP). Then, ethephon (as stress treatment) was sprayed on the pretreated flowers. Results showed that the lowest longevity of carnation flowers (5 and 6 days, respectively) in both studied cultivars (‘Silver pink’ and ‘Lilac on purple’) was related to 30 mg/L ethephon. Maximum flower longevity (11.5 days) was related to ‘Lilac on purple’ cultivar. The 0.6 µL/L of 1-MCP treatment, in both cultivars, was the most effective treatment in inhibition of ethephon on reduction of flowers longevity. Also, the lowest amount of ethylene production and the highest enzyme activity was observed when the flowers were pretreated by 0.6 µL/L of 1-MCP before the stress is applied. The highest proline accumulation was related to 30 mg/L ethephon treatment. Maximum α-amylase activity occurred in 30 mg/L ethephon, 10 and 20 mg/L BA and 50 mg/L AOA pretreatments.

Silicon (Si) can protect some plants from biotic and abiotic stresses. In this research, effects of three exogenous Si levels (0, 0.85 and 1.7 mM) on growth, lipid peroxidation, lipoxygenase activity, proline content, H2O2 accumulation, and activity of non-enzymatic and enzymatic antioxidants (catalase and ascorbate peroxidase) under powdery mildew disease stress by Sphaerotheca fuliginea on pumpkin (Cucurbita pepo, var. styriaca), under hydroponic conditions, were investigated. The results revealed that effect of Si in reduction of powdery mildew was significant (P≤ 0.05) and application of 1.7 mM of this element decreased the severity of disease symptoms up to 35%. Increasing the Si concentration in the nutrients solution elevated the amount of this element in roots and shoots of pumpkin plants. The concentration of H2O2, lipid peroxidation and lipoxygenase activity were increased by disease stress. But these parameters were decreased with application of Si. The activity of enzymatic and non-enzymatic antioxidants was significantly enhanced (P≤ 0.05) by the application of Si. Based on the present work, it can be concluded that concentration level of 1.7 mM Si was more effective than the other two treatments in alleviating disease stress, which could be related to the effect of this element on prevention of membrane lipid-oxidation.

This experiment was carried out to investigate the effect of polyamines on growth, flowering and corm production of ‘Golden Wave’ and ‘Blue Sea’ cultivars of freesia. For this purpose, freesia plants were sprayed at 35, 70 and 100 days after planting with concentrations of 0.5 and 1 mM of putrescine, spermidine and spermine and distilled water (control). The factorial experiment was performed in a completely randomized design with 3 replications and 2 pots for each replicate. Results showed that spermine treatment delayed flowering time. But spermidine treatment accelerated flowering and also increased leaf length, flowering stem height, inflorescence height, diameter and length of florets and number of lateral stems in both cultivars. Maximum number of corms was obtained in spermidine treatment. But, plants treated with putrescine had more corm weight and diameter than other treatments and control. Polyamines increased leaves nutrient concentration. The highest nitrogen concentration (2.39 and 2.37 percent) was observed in putrescine and spermine treatments and the highest concentration of phosphorus (0.47 and 0.46 percent), potassium (3.1 and 3.03 percent) and zinc (51.31 and 50.3 mg/L) was obtained in spermidine and putrescine treatments. Almost all polyamines increased magnesium concentration of leaves. The results of this study revealed that polyamines, and especially spermidine and putrescine, could increase yield and improved quality of flower and corm of freesia.

Salinity is a serious problem for expansion of agriculture, especially in arid and semi-arid regions. On the other hand, various benefits of soilless culture have caused the expansion of this system in these areas. In order to investigate the effect of different levels of salicylic acid and salinity stress on vegetative and physiological characteristics of eggplant, a factorial experiment was conducted with two factors, including salicylic acid at three levels (0, 50 and 100 mg/L) and salinity stress at three levels (0, 75 and 150 mM NaCl) with 3 replications. The results showed that the main and interaction effects of different levels of salinity and salicylic acid were significant (except stem diameter, chlorophyll b and calcium concentration) on growth parameters, photosynthetic pigments, soluble sugars, proline and mineral elements. Plant height, number of leaves, leaf area, fresh and dry weight of shoots, fresh and dry weight of roots, photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), soluble sugars and K content were decreased by increasing salinity level. Application of salicylic acid improved these parameters. But, Na and Cl contents were increased under the salinity stress. Application of salicylic acid partially improved this situation. Also, proline content was increased by increasing salinity and salicylic acid levels. Based on the obtained results, and the problem of high salinity level of irrigation water in greenhouses, application of salicylic acid can improve plant growth under saline conditions.

In order to evaluate the effect of different levels of benzyladenine, nitrogen and salinity on growth characteristics of pistachio seedlings, cv. Badami Zarand, a factorial experiment with three factors: benzyladenine (0, 250 and 500 mg/L), nitrogen (0 and 100 mg N/kg soil as NH4NO3) and salinity (0 and 2000 mg NaCl/kg soil) was carried out as completely randomized design with three replications for 24 weeks under greenhouse conditions. Results showed that although salinity significantly decreased dry weight of shoots and roots of the seedlings, but application of 500 mg/L benzyladenine increased dry weight of shoots and roots by 125 and 86 percent, respectively. However, simultaneous application of nitrogen and benzyladenine increased dry weight of shoots and roots more than 3 and 2 folds, respectively. Results also showed that salt stress significantly decreased leaf area and length of root system. But simultaneous application of nitrogen and the highest concentration of benzyladenine increased leaf area and length of root system more than 3 and 2.5 folds, respectively. The results of triple effects also showed that although height, leaf number and stem diameter significantly decreased under saline conditions, but simultaneous application of nitrogen and benzyladenine resulted in more prominent increase of these growth characteristics than individual application of these treatments. Finally, it is concluded that simultaneous application of nitrogen and benzyladenine resulted in more effective reduction of harmful effects of salinity on growth characteristics of pistachio seedlings than application of these treatments alone.

To evaluate the effects of different concentrations of iron nanoparticles (10, 100, 1000 and 2000 mg/L) and humic acid (100, 1000 and 2000 mg/L) on growth, flowering and characteristics of cut rose flower, cultivar White Nablus, under hydroponic system, an experiment was conducted based on completely randomized design with factorial arrangement and 5 replications in the Research Greenhouse of Mohaghegh Ardabili University in 2012-2013. Nutrient solution, formulated by Van Zinder and Baker, was used. This nutrient solution was dissolved in the twice-distilled water. Results of the experiment showed that chlorophyll content of leaves was significantly (P≤ 0.05) affected by 1000 mg/L iron nanoparticles and 100 mg/L humic acid, compared to other concentrations. High concentration of iron nanoparticles and humic acid (1000 mg/L) had a significant effect on plant height, chlorophyll fluorescence, cut flower length, total dry weight of cut flower, leaf dry weight and total dry weight, compared to other concentrations. Different treatments of Iron nanoparticles and humic acid did not significantly (P≤ 0.05) affect number of leaves, leaf area and time to flowering. Iron nanoparticles increased flower vase life, whereas humic acid did not significantly (P≤ 0.05) affect the vase life.

To investigate the effect of applying different amounts of municipal solid waste compost (MSWC) and sewage sludge (SS) on yield and concentration of some heavy metals including nickel (Ni), chromium (Cr), cadmium (Cd) and lead (Pb) in organs of green pepper plant, a pot experiment was conducted as a completely randomized design with seven treatments and four replications. Treatments included control, 5% MSWC, 10% MSWC, 5% SS, 10% SS, 5% MSWC SS, and 10% MSWC SS. Results showed that addition of MSWC and SS increased the yield of pepper (fresh and dry weights). The highest amount of fruit fresh weight was in 10% MSWC SS treatment and the highest amount of fruit dry weight was in 5% SS treatment, such that this increase was about 3.5 times in fresh weight and about 3 times in dry weight, as compared to the control. The shoot yield showed significant increase in fresh and dry weight, too. Application of these fertilizers increased plant height as compared to control. The highest increase was about 28% in 5% SS, as compared to control. Also, adding MSWC and SS caused significant increase in concentration of heavy metals in fruits, leaves, shoots and roots of pepper plant. Increasing the level of fertilizers caused an increase in concentration of heavy metals in the plants. Concentration of Ni of fruits was maximum in all the treatments, except in control and 5% MSWC, and concentration of Cd exceeded the critical level for human in all the treatments, except in control, 10% MSWC and 5% SS. Calculation of transfer index showed that accumulation of heavy metals in pepper plants is mainly in roots and not in the shoots. Cadmium, with transfer index of 0.52, has more mobility in plants, as compared to Pb (index of 0.44) and Ni (index of 0.14).

This research was conducted to study the effect of three nutrient solutions on potato (Solanum tuberosum) minituber production in hydroponic system under greenhouse conditions. The basic experimental design was factorial with randomized complete blocks with four replications. The first factor was nutrient solution at three levels (Hoagland and Snyder, Imma and Angel, Novella et al.) and the second factor was potato cultivar at two levels (Agria and Kaiser). The plant seedlings were obtained from tissue culture. Results showed that the main effect of nutrient solutions and interaction between nutrient solutions and potato cultivars were significant on plant height, stem diameter, roots and shoots dry weight, yield and number of minitubers per plant. Plants grown from Agria cultivar in Imma and Angel solution produced the greatest plant height (96.8 cm), shoots dry matter (92.22 g), roots dry matter (20.08 g) and yield (195.66 g per plant). Kaiser cultivar had the highest number of minitubers (9.1 per plant). Maximum minituber weight was obtained from Novella et al. solution (21.93 g) and in Agria cultivar (28.78 g). Results also showed that the greatest starch content (9.57%) and nitrate content (728.72 mg/kg dry weight) were observed in Agria cultivar and Imma and Angel solution and Hoagland and Snyder solution, respectively. Maximum phosphorus content of minituber (0.33%) belonged to Imma and Angel solution and the highest potassium content (2.62%) was measured in Agria cultivar.

Organic fertilizers preserve food cycle, reduce pollution and remediation of soil physicochemical properties and stabilization of plants in soil. To investigate the effect of organic fertilizer (vermicompost, compost and manure) on physiological characteristics of Petunia hybrida, a factorial greenhouse experiment was conducted based on completely randomized design with three replications at Ferdowsi University of Mashhad. Treatments consisted of three irrigation levels (irrigation based on 100% of field capacity (FC), equivalent to 360 ml of water (D1), 50% of field capacity, equivalent to 180 ml water (D2), and 25% of field capacity, equivalent to 90 ml water (D3), in each 2-kg pot) and four fertilizer treatments (control, compost, vermicompost and manure). The measured morphophysiologic traits were plant height, number of lateral branches, number of leaves, number of flowers, volume of roots, dry weight of leaf, root, stem and flower, electrolyte leakage, stomatal conductance and photosynthetic pigments. Results showed that irrigation levels and fertilizer types were significant for all measured traits. The interaction of irrigation and fertilizer treatments showed that the highest amount of leaf dry weight, stem dry weight, plant height, number of flowers and stomatal conductance was obtained in the 100% FC and manure fertilizer. In 25% FC treatment, 10-flower weight was increased by 38, 29 and 61% in compost, manure and vermicompost, respectively, compared to control. Among the fertilizer treatments, the highest level of chlorophyll a was measured in control. However, the highest chlorophyll b, total chlorophyll and carotenoid content was observed in vermicompost treatment. Generally, manure and vermicompost had better effects in improving the performance and number of flowers of petunia under deficit irrigation.

In recent decades, due to the negative effects of conventional farming on human health and the environment, the organic farming is taken into consideration in order to produce healthy food materials. The aim of the present study was to assess the greenhouse owners’ knowledge, attitude, and practice with respect to healthy cucumber and tomato production in greenhouse farming systems in Isfahan county, Iran. Required data was collected on a sample of 110 farmers through face-to-face interviews based on a comprehensive structured questionnaire. Behavioral analysis of farmers’ decision making is based on “knowledge, attitude and practice” (KAP) survey using structural equation modeling. Research findings showed that despite the positive attitude of most greenhouse owners toward production of healthy crops, there is no proper use of pesticides and fertilizers in greenhouse farming. Although most farmers believe that overuse of pesticides and chemical fertilizers endangers human health and environment, but they don’t adhere to proper usage principles and amount of pesticides and chemical fertilizers. Also, small-scale greenhouses, weak farm economy, low literacy level, and lack of adequate awareness, have led to select the least risky and fastest way to combat the pests. Therefore, it is very important to improve greenhouse owner's knowledge in fertilizer selection and pest management, and strengthening the marketing system of healthy products.

Salinity is a limiting factor in agricultural production that inflicts great damages on agricultural products. In order to decrease or stop salinity stress, numerous methods are proposed by different researchers. One of the methods to reduce the damages of salinity stress is cultivating tolerant plants to salinity. In this research, resistance of three radish cultivars to salinity stress was investigated, from physiological points of view, and the best resistant cultivar was introduced. This factorial experiment was carried out in Research Greenhouse of Ferdowsi University of Mashhad, Iran, based on complete randomized design, with three replications. Treatments included three commercial cultivars of radish (Cherry belle, Sparkler and Scarlett Cincinnati) as the first factor and four levels of salinity (control, 33, 66 and 99 mM NaCl) as the second factor. Salinity levels, as soluble form in irrigation water, were applied at the four-leaf stage of the plants. Results showed that salinity decreased the amount of soluble sugars and potassium content of aerial parts and tubers, and also increased stomatal conductance, anthocyanin content of tubers and sodium content of aerial parts and tubers. The highest tolerance of different radish cultivars to salinity stress was observed at 66 mM salinity level and the 33 mM salinity level had no significant difference, compared to control, in most physiological characteristics. Under salinity stress conditions, sodium accumulation in aerial parts was more than tubers. The highest amount of tuber anthocyanin was measured at 66 mM salinity level in Scarlett Cincinnati cultivar. Among the radish cultivars, the highest salinity tolerance and salt accumulation was obtained from Scarlett Cincinnati cultivar. Considering that the apparent shape of this cultivar (stretched appearance with red color) is very different from Cherry belle and Sparkler cultivars, and more water is stored in its tissues, thus, this trait has caused high resistance to salinity stress.

Nowadays, phenolic compounds and plant growth regulators such as salicylic acid has been prescribed to reduce the adverse effects of different stresses. This greenhouse experiment was conducted in 2013, as a factorial randomized complete block design with 3 replications, to examine the effects of lead and salicylic acid on basil (Ocimum basilicum) plant, cv. Keshkeni Luvelou. Factors included 4 levels of lead [0 (control), 100, 200 and 300 mg/kg of soil] and foliar application of salicylic acid at 3 levels [0 (control), 50 and 100 ml/L]. Results showed that addition of lead significantly reduced leaf area, number of leaves, plant hight, fluorescence and chlorophyll content of the plants and increased proline, soluble carbohydrates and guaiacol and ascorbate peroxidase enzymes. In addition, salicilic acid spraying had significant (P≤0.01) influence on all traits. Spraying salysilic acid at concentration of 100 ml/L at the fourth level of lead (300 mg/kg soil) decreased guaiacol, ascorbate peroxidase and soluble carbohydrates by 78.6, 73.8 and 24.3%, respectively, compared to the control. In this study, the interaction between salicylic acid and lead on leaf area, plant height, leaf chlorophyll content, fluorescence, proline, soluble carbohydrates, guaiacol and ascorbate peroxidase was significant. In general, the results of this experiment suggested that salicilic acid plays a moderating role, reducing the negative effects of lead toxicity on the studied traits of basil.

Blossom-end rot (BER) is one of the physiological disorders related to calcium (Ca) deficiency in the fruit which reduces yield and fruit quality of bell pepper (Capsicum annuum L.). Every year, occurrence of BER in bell pepper of Shahreza greenhouses causes a loss to farmers of this vegetable. This experiment was conducted to elucidate the effects of foliar application of calcium sources and rates on the nutrients concentration and blossom-end rot of bell pepper fruit under greenhouse conditions in Shahreza region during 2013. A factorial experiment using completely randomized blocks design was carried out with three factors of Ca fertilizer type, Ca concentration and pepper cultivars, and three replications. Calcium fertilizers were calcium chloride (CaCl2.2H2O) and calcium nano-chelate that were sprayed at Ca concentration levels of 0 (foliar application of distilled water), 0.9 and 1.8 g/L. The three pepper cultivars were Inspiration (red), Arenkia (orange) and Toranto (yellow). Results indicated that foliar application of calcium chloride significantly decreased BER of bell pepper fruit, compared with the control. In this treatment, BER incidence was from 30.3 to 44.9 percent, compared with 65.5% in the control. Also, BER severity was from 1.3 to 1.6, compared with 2.1 in the control. This was due to increased Ca concentration and decreased N/Ca, K/Ca and Mg/Ca ratios in the fruits. While, foliar application of Ca nano-chelate had not significant effect on the incidence and severity of BER in pepper fruit. Based on the results of this research, it is suggested that direct spray of fruits with Ca (1.8 g/L from CaCl2.2H2O source) is recommendable to decrease BER of bell pepper fruit under similar conditions of this research.