h. dashti

Soil compactibility can be quantified using different indices such as maximum dry bulk density (BDmax) and critical water content (θcritical) in a compaction test. The objective of this study was to determine soil properties influencing soil compactibility by evaluate pedotranfer functions (PTFs) with respect to their accuracy and usefulness for the prediction of BDmax and θcritical using linear regression and ANN methods. 100 soil samples were collected from arable and virgin lands in southeast Iran. Primary particle size distribution, CaSO4, CaCO3, organic matter (OM) contents and natural bulk density were used as predictors. Two PTFs were developed using linear multiple stepwise regression: a PTF that estimates BDmax using clay and sand contents and natural bulk density as predictors (R2 = 0.45), the other one for the estimation of θcritical using clay and CaSO4 contents as predictors (R2 = 0.51). Furthermore, an attempt was made to construct PTFs for the prediction of the BDmax and θcritical using ANNs. High prediction efficiencies were achieved using the ANN models. Generally, when all of the easily-available soil properties were included as predictors, much more accurate estimates were obtained by the ANN models for the θcritical and BDmax as compared with the linear regression method. Sensitivity analysis showed that the most important variable in BDmax prediction using ANNs is the BDnatural followed by sand and clay, CaCO3 and CaSO4 contents. The θcritical had the highest sensitivity to clay content and the lowest sensitivity to OM content in the studied soils.

Enzymes play a crucial role in plant-pathogen interactions and are very important to manage plant diseases. Take-all is a disease (Gaeumannomyces graminis var. tritici) affecting the crowns and roots in wheat. So far, the resistance mechanism of this disease has not been identified; therefore, this research was performed to identify the components of resistance to this disease in a number of wheat genotypes. In this study, 8 bread wheat genotypes were cultured, and the changes in “peroxidase, Polyphenol Oxidase (PPO), Phenylalanine Ammonia-Lyase (PAL), and total protein” was assessed in 0, 4, 7, 9, and 12 days after inoculation. The results showed that different genotypes of wheat had different pathogenicity reactions to the take-all disease. Based on the average disease intensity, the genotypes were divided into three groups: resistant, moderately resistant, and susceptible. The results indicated that the level of polyphenol oxidase and phenylalanine ammonia-lyase, and the total protein increased in the resistant and moderately resistant groups. Cluster analysis by K-means was performed to produce three clusters. Polyphenol oxidase activity, phenylalanine ammonia-lyase activity, and total protein content in the second (resistant) and third (moderately resistant) clusters were higher than the first cluster (susceptible). Multivariate analysis indicated that peroxidase enzyme might indirectly influence the resistance. The results have clarified the role of polyphenol oxidase enzymes and total protein in enhancing resistance to take-all disease.

In order to investigate the effects of supplementary calcium chloride and potassium nitrate on proline, protein content, chlorophyll and growth of Ammi (Carum copticum L.) under different salinity levels and nutrient solutions (NS), a RCBD design with factorial arrangement was conducted at the Agriculture Research Field, Vali-e-Asr University of Rafsanjan, during September 2009. The treatments were three levels of salinity (0, 50 and 100 mMol) and five different nutrition solutions including: Control: Hoagland solution only (N1); Hoagland solution plus 20 mM CaCl2 in nutrition solution (N2); Hoagland solution plus 20 mM CaCl2 as spray (N3); Hoagland solution plus 20 mM KNO3 in nutrition solution (N4) and Hoagland solution plus 20 mM KNO3 as spray (N5). Results showed that proline content was significantly affected by salinity and the type of nutrient solution and their interactions. Increasing salinity, especially at 100 Mmol NaCl, significantly reduced chlorophyll a,b and total chlorophyll. Chlorophyll a, b and total chlorophyll content were not significantly affected by the type of nutrition solution. The highest and lowest protein content were observed by control and 100 Mm NaCl treatments respectively. The type of nutrient solution also influenced protein content. The highest and lowest protein contents were related to N3 and N5, respectively. Total dry weight and stem dry weight were significantly reduced by salinity while root dry weight was not affected by salinity. The highest leaf area was achieved on control and nutrition solution N5. Generally, it is concluded that Ammi could tolerate salinity up to 50 mMol NaCl and leaf spraying of Ca and K would be better to ameliorate salinity rather than using in nutrition solution.

In order to evaluate the salinity and priming effects on vegetative growth and some physiological traits of safflower, cv. Goldasht, a factorial experiment, with completely randomized blocks design and 4 replications, was conducted in Research Greenhouse of Vali-e-Asr University of Rafsanjan in 2009. Treatments included seed priming at 4 levels (no prime as control, priming with distilled water, priming with NaCl and priming with 20 Mm Ca(NO3)2 for 24 hours) and salinity at 4 levels (0, 8, 16 and 24 dS/m). Results indicated that dry weight of aerial parts, root dry weight, stem length, leaf area and head dry weight were decreased with increasing salinity. Salinity affected significantly the dry matter partitioning. As in higher salinities, more dry matter was translocated to stem and head, which was accompanied with less dry matter translocation to roots and leaves. The root/shoot ratio was significantly decreased with increasing salinity due to higher dry matter translocation to stems. Though, higher salinities decreased significantly the root dry weight. At salinity level of 24 dS/m, this safflower cultivar translocated more dry matter to shoots as compared to roots and leaves. Comparison of means showed that chlorophyll content and Spad index were decreased at higher salinity levels. Leaf area and plant height were significantly reduced only at salinities higher than 16 dS/m. The results of this experiment showed that in general, the Goldasht cultivar of safflower could tolerate salinity stress up to 16 dS/m in the vegetative stage with prominent decrease in stem and root dry weight, which could be due to some resistance mechanisms to salinity. This result must be accurately evaluated in a field experiment.

In order to investigate the effects of supplementary calcium chloride and potassium nitrate on plant growth of Ammi (Carum copticum L.) in different salinity levels and nutrient solutions (NS), an experiment based on randomized complete block design (RCBD) with factorial arrangement was conducted under greenhouse condition in the faculty of agriculture, Vali-e-Asr university of Rafsanjan, during September to December 2009. The treatments were three levels of salinity levels (0, 5 and 100 mmol) and five different nutrition solution including: Control: Hoagland solution only (N1); Hoagland solution plus 40 mM CaCl2 in nutrition solution (N2); Hoagland solution plus 40 mM CaCl2 as spray (N3); (4) Nutrient solution plus 40 mM KNO3 in nutrition solution (N4) and Hoagland solution plus 40 mM KNO3 as spray (N5). Results showed that relative water content of leaf did not affected by salinity, type of nutrient solutions and the interaction of salinity and nutrient solution. The lowest and the highest sodium content were observed in the control and 100 Mm NaCl treatments, respectively. K, Ca and Mg content significantly reduced in Ammi shoot with increasing salinity. Salinity increased soluble sugars in plant while type of nutrient solution and interaction of salinity and nutrient solution were not significantly affected soluble sugars. The Highest and lowest protein content of plant organs were observed in the control and 100 Mm NaCl, respectively. Type of nutrient solution also influenced protein content. The highest protein content related to N3 and the lowest related to N5.

To study the effect of nitrogen, salinity and organic matter on growth and root morphology of pistachio (Cv. Badami), a greenhouse experiment was conducted. Treatments consisted of four nitrogen (N) levels (0, 60, 120 and 180 mg kg-1 soil as urea), four salinity levels (0, 800, 1600 and 2400 mg NaCl kg-1 soil) and three organic matter (OM) levels (0, 2 and 4% soil as farmyard manure). Treatments were arranged in a factorial manner in a completely randomized design with three replications. As the salinity levels increased, leaf, stem and root dry weights and root density, were significantly reduced. Addition of N up to 120 mg kg-1 soil, had no significant effect on growth, but the highest N level (180 mg kg-1), due to nutrient imbalance, reduced abovementioned plant parameters. In low salinity levels, N application improved the growth of pistachio seedlings, but at the highest salinity level, N addition didn’t suppress the adverse effects of soil salinity. Due to useful physical and nutritional properties of soil organic matter, addition of OM significantly increased leaf, stem and root dry weights, stem height, shoot/root ratio and root density.