نشریه اکوفیزیولوژی گیاهی
پیاپی 5 (تابستان 1389)

Drought stress is of the most significant factors reducing crop yield. Using plant growth regulators such as Brassinosteroids is a practical solution to reduce the losses. Brassinosteroids are steroidal plant compounds with broad biological activities that are able to increase plant performance through changes in plant metabolism and protect them against environmental stress. In a greenhouse study, vocational city center Arsanjan, the impact of three levels of irrigation in field capacity (FC), mild stress (FC2/3) and severe stress (FC1/3) and four concentrations of plant growth regulators Article 28- Homobrassinolid zero, M 10-10, 10-8 M and 10-6 M digits on some savory characters S. Bachtiarica was investigated. The results showed that reducing irrigation had a significant effect on the reduction of growth parameters, including length and root dry weight, stem diameter, branch number, plant height, shoot yield and total yield. Concentration of 10-8 M 28- Homobrassinolid significantly increased root dry weight, stem diameter, branch number, plant height, total yield and essence performance. Oil Percentage by reducing irrigation, increased significantly at 1% so that showed 36 % oil In full irrigation to 87.% In severe stress and use of hormone 10-8 M were recorded. Essential oil yield at 5% level under the influence of irrigation and use of hormones was most essential functions related to irrigation andusing 10-8 M 28-Homobrassinolid and value 32/29 kg/ha respectively. The relationship of these hormone levels in the full irrigation, mild and severe stress significantly increased respectively 59, 30 and 24 percent oil yield than the control plants were. Generally, the results show that the use of 28- Homobrassinolid through increased stimulation of growth parameters and dry matter yield increased performance savory essence of this plant and an appropriate policy to deal with water stress.

In order to evaluate the effect of halopriming on seed germination and seedling growth of canola (cv OKP) under salinity conditions, laboratory experiment was performed as a factorial experiment based on completely randomized design with four replications. Experimental factors included 3 priming treatments (NaCl 1%, KNO3 3% and non-priming as control) and five salinity solutions using 2:1 molar ratio of NaCl and CaCl2 included 0, 50, 100, 150 and 200 mM (EC equal to 0, 3.1, 7.9, 12.3 and 19.4 dSm-1, respectively). Result showed that seed halopriming increased final germination percentage (FGP), germination index (GI) and seedling fresh and dry weight (SFW and SDW) compared to non-primed treatment. Although KNO3 3% and NaCl 1% had similar effects on these traits, seed priming with KNO3 resulted maximum FGP (68%), GI (41.3), SFW (18.6 mg) and SDW (3.5 mg). At low levels of salinity, there were no significant differences between primed and non-primedseeds for the FGP and GI, but with increasing salinity levels, primed seeds showed better performance than non-primed seeds. Halopriming of the canola seeds significantly improved radicle length and radicle to primary shoot ratio in salinity conditions when compared to the control. These results indicated that halopriming treatments significantly improved seed performance under salinity conditions.

In this research the effect of nitrogen (0, 13, 27, 41, 55, 69 and 83 mg concentration) studied on Datura stramonium alkaloid content. Leaf and root Hyoscyamine and hyoscin levels were assayed 12, 18 and 22 weeks after culturing, under different nitrogen fertilizer treatments, using TLC and HPLC. The results showed that root, stem and leaf fresh and dry weights in treatment plants were higher than the control ones. Nitrogen caused hyocyamine and hyoscin levels to increase compared with the control. Hyoscyamine and hyoscin levels were higher in roots than leaves. The plant hyoscin content was higher than hyocyamine.

In order to study the effect of nitrogen and sulphur consumption on quantity and quality of wheat production, this research consisting of seven treatments was conducted as a Randomized Completely Block Design with three replications in Baiza region of Fars province during the year 2008- 2009.Each treatment composed of a nitrogen fertilizer source and its time of application. The treatments were as follows: 1- 135 kg/ha nitrogen from urea (in planting time) 2- 135 kg/ha nitrogen (1/3 from urea in planting time + 1/3 from urea as foliar application for two times in tillering stage + 1/3 from ammonium sulfate as foliar application in stemming stage for two times equal to 25 kg S) 3- 135 kg/ha nitrogen (1/3 from urea in planting time + 1/3 from ammonium sulfate as foliar application for two times equal to 25 kg S in tiller stage + 1/3 from ammonium sulfate as foliar application in stemming stage for two times equal to 25 kg S) 4- 135 kg/ha nitrogen from Sulphur Coated Urea in planting time 5- 135 kg/ha nitrogen (2/3 from SCU in planting time + 1/3 from ammonium sulfate as foliar application for two times equal to 25 kg S in stemming stage) 6- 135 kg/ha nitrogen (1/3 from SCU in planting time + 1/3 from ammonium sulfate as foliar application for two times equal to 25 kg S in tiller stage + 1/3 from ammonium sulfate as foliar application in stemming stage for two times equal to 25 kg S) 7- control (without usage of nitrogen and sulfur).The results showed that the effect of treatments on seed sulfur concentration and seed nitrogen concentration were significant. The treatments No. 6 and No.3 with 7.257 and 6.29 kg/ha had the highest sulfur uptake respectively while the control with 4.35 kg/ha was the lowest. The treatments No. 6, No. 2 and No. 3 with 97.13, 92.74 and 90.05 kg/ha respectively had the highest nitrogen uptake and the control with 65.27 kg/ha had the lowest nitrogen uptake. For one thousand seed weight the treatments No. 6, No. 3 and No. 2 with 39.92, 39.78 and 38.78 g respectively were the highest while control with 34.94 g was the lowest. The effect of different treatments on yield was highly significant (p<0.01 % level). Also mean yield comparison using Duncan's multiple range test showed that treatment No.6, No. 2 and No. 3 with 5500, 5342 and 5275 kg/ha had the highest yield and control with 3933 kg/ha had the lowest yield.

This study had been conducted in order to investigate and examine the consumption time and type of micronutrients on penology and the yield of soybean function in Galikesh, Golestan province at 1388. The experimental design was randomized complete blocks with three replications. The consumption time of micro fertilizer as the main factor (main plot) is in 3 levels and the type of micro fertilizer as the subplot is in 4 levels. We investigated different characteristics such as: The leaf surface of harvest index, the number of sharps in a sheath, the seed in sheath. The obtained data shows that there are significant differences between them in terms of function and case study characteristics. So the highest function of seed when fertilizers were used in 10 foliar level and sheath formation and the lowest function of seed is when it blossoms. It seems that according to the environmental conditions of Golestan province and also the shortage of micronutrients in the region's soil, the consumption of micronutrients may improve the production of Soybean in the region.

In order to evaluate the effect of sub-soiling on the soil physical properties and wheat yield in dryland conditions, this research was conducted in Mamassani area in the province of Fars for one year in 1388. The research was performed in the form of a complete blocks design with four replications. Treatments were 1) conventional tillage without using subsoiler (Control) 2) using subsoiler with the shank space of 40 cm (shank space equal to the subsoiling depth) 3) using subsoiler with the shank space of 60 cm (shank space equal to 1.5 times of the sub-soiling depth) and 4) using subsoiler with the shank space of 80 cm (shank space equal to 2 times of the sub-soiling depth). Sub-soiling depth was set on 40 cm which was the lower limit of the hard pan depth in the soil. Results showed that sub-soiling decreased the soil bulk density and cone index, and increased water retention in the soil. Results also revealed that applying subsoiler increased wheat yield and yield components in dryland conditions because sub-soiling improved soil physical conditions andincreased wheat yield. Results of this study also showed that sub-soiling with the shank space of 40 and 60 cm had better performance compared to the shank space of 80 cm. On the other hand, shank space of 40 cm reduces the subsoiler effective working width and effective field capacity. Therefore, shank space of 60 cm is recommended for subsoiler in the dryland conditions.

Agricultural ecosystems are widely related to economical and social condition in the world. The major aim of agricultural ecosystems management is maximizing energy flow and human service materials. Input and output energy have been calculated in different agricultural ecosystems in different locations of the world. In this study, energy flow at agricultural ecosystem of wheat under rainfed farming was evaluated by using statistics and information about wheat farmers (preparation of questionnaire from province farmers). The data of inputs and outputs changed into equivalent values of input and output energy and calculated energy efficiency. Energy value of this type of cultivation was 3467 thousands kcal ha-1 and outputs (production) energy value of wheat grain and straw yield were 2422 and 1949 thousands kcal ha-1 respectively. Also, energy efficiency value (input: output ration) was 1.23 and energy efficiency value of grain and straw were 0.68 and 0.54, respectively. Results showed that the most energy consumer in wheat cultivation of Boushehr province were nitrogen fertilizer, machinery and Gasoline fuel, and the lowest were human and herbicide energy probably, due to climatic conditions topography, population and culture.

In order to investigate the effect of grazing intensity on ecological indicators using qualitative rangeland health model, we selected Chaharbagh semi steppe rangelands. Then, three functional attributes (soil/site stability, hydrologic function and biotic integrity) of rangeland health were evaluated using rangeland health model. In this study 17 ecological indicators were used. Increasing grazing intensity resulted in variation of ecological indicators and also three functional attributes of rangeland health in key area evaluated as healthy category in comparison to reference area. Grazing intensity in critical area resulted in soil degradation between basal areas(inter patches) and also affected on plant structure characteristics e.g. dominance and perennial plants composition. Results showed that three functional attributes of rangeland health can be at risk in critical area in comparison with reference area.