نشریه روابط خاک و گیاه
پیاپی 14 (تابستان 1392)

Whenever good quality water is scarce، treated municipal wastewater will be considered for using in agriculture. In this research، raw and treated wastewater from Serkan Wastewater Treatment Plant، Hamadan province، Iran، were used to determine the transfer coefficient of Fe، Ni and Mn from soil to plant and some soil properties in potato cultivation under lysimetric conditions. Irrigation treatments were: raw wastewater، treated wastewater، tap water، combination of 50% raw wastewater and 50% tap water and combination of 50% treated wastewater and 50% tap water. Results showed that the effect of irrigation water quality on pH and EC was significant (P<0. 01). The effect of soil depth on EC and pH was significant (P<0. 01) and non-significant، respectively. The interaction on these parameters was not significant. pH was decreased and EC was decreased as soil depth increased. Maximum amounts of EC and pH of soil belonged to raw wastewater and tap water treatments، respectively. Higher EC in raw wastewater and pH in tap water was the reason for these high values in soil. The effect of treatments on transfer coefficient of Mn and Fe from soil to shoots was significant. In potato tubers، this effect was significant only for Mn. Maximum transfer coefficients from soil to potato shoots and tubers belonged to Ni، Fe and Mn، respectively. Also، coefficients of heavy metals transfer from soil to shoots were more than tubers.

In order to improve quantitative and qualitative properties and vase life of rose cv. Dolcvita، an experiment was conducted in a randomized complete blocks design with ten treatments and three replications in a hydroponic greenhouse adjacent to Yasouj city، Iran. Treatments included control، spermidine (0. 5، 1 and 1. 5 mM)، calcium sulfate (2. 5 and 5 mM)، spermidine 0. 5 mM+ calcium sulfate 2. 5 mM، spermidine 0. 5 mM + calcium sulfate 5 mM، spermidine 1 mM + calcium sulfate 2. 5 mM and spermidine 1 mM + calcium sulfate 5 mM. Traits such as length of flower stalk، stem diameter، flower bud diameter، fresh weight of stem، chlorophyll content and vase life were measured. Results showed that effect of spermidine and calcium sulfate on all traits، except chlorophyll content، was significant (P<0. 05). The highest and lowest length of flower stalk، stem diameter and fresh weight of stem was obtained in the 1. 5 mM spermidine and control treatments، respectively. The highest diameter of flower bud was observed in the 0. 5 mM spermidine and 2. 5 mM calcium sulfate treatments. Flower vase life in the 0. 5 mM spermidine + 5 mM calcium sulfate treatment was higher than that in the other treatments. Therefore، application of 1. 5 mM spermidine is recommended for improving quantitative properties and combination of 0. 5 mM spermidine with 5 mM calcium sulfate for increasing vase life of rose، cultivar Dolcvita، in hydroponic system.

In order to investigate the effects of different forms of nitrogen in nutrient solution on photosynthesis rate and quantitative properties of rose cv. Dolcvita، an experiment was conducted in a randomized complete blocks design with seven ratios of urea: NH4+: NO3- (0-100-0، 0-50-50، 0-0-100، 50-0-50، 25-25-50، 15-15-70 and 0-0-100) and three replications، in a hydroponic greenhouse which grows rose flower. The rooted plants of rose cv. Dolcvita were potted filled with perlite and cocopeat (50:50) substrates. Then، quantitative properties such as plant stalk height، bud length، diameter of bud and stem، leaf area index، vase life، fresh weight of stalk، leaf greenness and photosynthesis parameters were measured. The results showed that increasing the ammonium in nutrient solution reduced the photosynthesis rate، water use efficiency and leaf mesophyll efficiency. The highest stalk height was obtained from 25-25-50 and 0-0-100 treatments (88. 3 cm and 86. 9 cm)، respectively. The highest fresh weight of stalk was obtained in 0-0-100 treatment. Application of 50-0-50 treatment increased leaf greenness as compared to other treatments. When ammonium was increased in nutrition solution، the vase life was reduced. The highest and lowest vase lives were obtained from 25-25-50 and 100-0-0 treatments (17. 6 and 11. 1 days)، respectively.

Production of many cut flowers، such as lilium، is very common in Iran. Flower quality has special importance in lilium flower production process، and proper nutrition is one of the major effective factors. This research was conducted to investigate the effect of different concentrations of potassium silicate، nano-silicon and calcium chloride on concentration of potassium، calcium and magnesium، chlorophyll index and number of florets of Asiatic lily ''Brunello''. The experiment was carried out based on randomized complete blocks design with 9 treatments and 3 replications (each replication included 5 pots)، in Educational/Research Greenhouses of Isfahan University of Technology، Isfahan، Iran. Treatments included drench of potassium silicate at three concentrations (25، 50 and 75 mg/L)، spraying of 25 mg/L potassium silicate، spraying of calcium chloride at two concentrations (25 and 50 mg/L)، spraying of nano-silicon at two concentrations (12. 5 and 25 mg/L) and control (no treatment). Number of florets، chlorophyll index and concentrations of calcium، magnesium and potassium in stem and leaves were measured. Results showed significant differences between treatments in stem and leaf calcium and magnesium، leaf potassium، chlorophyll index at harvest time and number of florets. Drench of 25 mg/L potassium silicate had maximum number of florets per plant (5. 27) and stem magnesium. Spraying 50 mg/L calcium chloride showed maximum leaf calcium، magnesium and potassium، respectively، with 4. 38، 15. 75 and 16. 43 percent increase as compared to control. Spraying of 25 mg/L calcium chloride، with 38. 9 percent increase as compared to control، had maximum stem calcium. Maximum chlorophyll index at harvesting time was related to spraying 25 mg/L potassium silicate. In general، if the goal is production of more florets، then drench of 25 mg/L potassium silicate is an appropriate treatment.

To study the effects of potassium (K) and zinc (Zn) with cadmium (Cd) in roots، stem، leaves and fruits of tomato plants، a greenhouse experiment was conducted as factorial based on complete random blocks design. The first factor was Zn at three levels (88. 8، 177. 6 and 355. 2 μg/L) and the second factor was K at three levels (255، 510 and 1020 mg/L). In this experiment، the basic nutrition solution (Hoagland) contained 20 μM Cd in all the treatments. At the second harvest period، the concentration of Cd، K and Zn was measured in different organs of the plants including roots، stem، leaves and fruits. Results indicated that increasing Zn concentration in nutrition solution had no significant effect on concentration of Cd and K in roots; but، it increased Zn concentration in roots. In stem، application of Zn increased concentration of Cd and Zn; but had no effect on K concentration. In leaves، concentration of K and Cd was increased; but no effect was observed on Zn concentration. In fruits، the concentration of Zn، K and Cd was not affected by increasing Zn concentration in nutrition solution. Increasing K concentration in nutrition solution had no significant effect on concentration of Cd، Zn and K in roots. In stem، only the concentration of Zn was increased. But in leaves، Cd reduced and K increased concentration of K. In fruits، it caused an increase in concentration of Zn. Interaction of K and Zn was significant on concentration of K in roots and Zn in fruits. In general، under the conditions of the present research، in tomato plant، Zn and Cd have synergistic effect and K and Cd have antagonistic effect.

In order to study the effects of different amounts of irrigation and nitrogen levels on physiological reactions of two sorghum (Sorghum bicolor) cultivars، an experiment was performed under greenhouse conditions at Ferdowsi University of Mashhad، in 2011. Treatments were two irrigation regimes (I1، I2، consisting 100 and 40 % of field capacity، respectively)، four nitrogen levels (N1، N2، N3 and N4 consisting 0، 30، 60 and 90 mg N/kg soil، respectively) and two cultivars (Sepideh and M5) arranged in randomized complete block design with three replications. The results showed that water stress significantly decreased chlorophyll a and b and increased carotene contents in sorghum cultivars. Nitrogen application had significant effect on chlorophyll a. Water treatments led to an increase ascorbat and soluble sugars contents. Water stress and nitrogen application increased prolin content of sorghum cultivars. Grain yield was affected by water stress and nitrogen treatments. The highest value of grain yield was obtained by full irrigation and 60 mgN/kg soil. Our result show that in water stress conditions، biochemical changes in sorghum were accrued such as increase activity of antioxidants، reduces the content of free radicals in cells and increase in the amount of carotenes prevents damage to the plant cells. Also in these conditions، with increasing content of osmotic adjustment and water balance of the cells، could prevent severe reduction in leaf relative water content of the cells and causes the stabilization of the cell structure. According to correlation coefficients obtained from the experiments we can conclude that in drought conditions، biochemical factors in maintaining grain yield consist of concentration of soluble carbohydrates and proline، respectively.

In order to determine the best nutrient solution and potato cultivar for minituber production in aeroponics and comparison with classic hydroponics، a factorial experiment with three factors of culture system (aeroponics and hydroponics)، nutrient solution (Chang et al.، APCoAB and commercial nutrient solution of Isfahan)، and different potato cultivars (Marfona، Santana and Moren) was carried out. The results showed that fresh weight of shoot and roots، and potato plant height was significantly higher in aeroponics compared to classic hydroponics. The highest shoot and root fresh weight in aeroponics was observed in Moren cultivar، nourished with commercial nutrient solution of Isfahan. Plant height was the highest in Moren cultivar، APCoAB nutrient solution and aeroponic system. The lowest shoot and root fresh weight and plant height were observed in Marfona cultivar. Yield and number of minitubers per plant in aeroponics increased 58. 08 and 277. 2 percent compared to hydroponics، respectively. The highest yield and number of minitubers was obtained in aeroponics system، APCoAB nutrient solution and Marfona cultivar. Therefore، it was concluded that in minituber production، the aeroponics system is superior to classic hydroponics and the best potato cultivar for cultivation in this system is Marfona and the best nutrient solutions are APCoAB and Chang et al. solutions.

In order to study the effects of foliar spraying of Pseudomonas fluorescens bacteria on quantitative characteristics، yield and yield components of two rice cultivars، a factorial experiment، based on completely randomized design with three replications، was conducted in Rice Research Institute of Rasht، Guilan province، Iran. In this experiment، two rice cultivars (Khazar and Hashemi) were sprayed with eight levels (strains) of P. fluorescens bacteria. The control treatment was not sprayed. Studied characteristics consisted of: stem diameter، plant height، length of panicle، length and width of flag leaf، number of fertile tillers، 100-seed weight، number of seeds per panicle، number of seeds per plant and yield per plant. The results indicated that foliar spraying by different strains of Pseudomonas had significant effect on stem diameter. The highest length of flag leaf and plant height was observed in Pseudomonas fluorescens strain 136 and the lowest of these characteristics was caused by Pseudomonas fluorescens strain 177. The highest and least number of seeds per panicle was observed in treatments sprayed by Pseudomonas fluorescens strains 4 and 177. The highest and lowest number of seeds per plant was related to strains 4 and 168 and 169، respectively. At the end of the experiment، it was found that P. fluorescens strain 4، P. fluorescens strain 136 and P. fluorescens strain 168 increased yield and yield components more than other strains. In general، foliar spraying of growth promoting bacteria had positive effects and enhanced plant growth.

Extensive use of chemical pesticides to control pests in developed and developing countries has led to the increase in crop production and decrease in post-harvest losses، which has caused harmful effects on human health. When the amount of pesticides exceeds permissible limits، some measures should be undertaken to reduce their application. In order to control cucumber pests in greenhouse، farmers use pesticides extensively، which their residues threaten human health in the society. Due to the importance of this problem، the residue and pre-harvest period of the Imidacloprid insecticide in some of the greenhouses of Varamin region، Tehran province، Iran was measured. In order to determine the pre-harvest period، spraying of Imidacloprid pesticide was done in a completely randomized block design with three replications، and two treatments of Imidacloprid and control (no insecticide). Sampling was done 1، 2، 3، 5، 7، 10 and 14 days after spraying. Samples were then transferred to the laboratory and preserved in freezer until the extraction and purification were performed and the amount of pesticide residues was measured. Based on the results، Imidacloprid residue reached below the maximum residue level (MRL) of 1 mg/kg two days after spraying. But for more confidence، the third day after spraying was considered as the pre-harvest period. Sampling for determination of Imidacloprid residue was performed in four greenhouses of Varamin region. The results showed that mean Imidacloprid residue levels were above the MRL value in these greenhouses.