PLANT ECOPHYSIOLOGY (ARSANJAN BRANCH)
Year:2010 | Volume:1 | Issue:3|Papers Count:10

In order to evaluate the effect of elimination of one or two irrigation circuits on yield and yield components of wheat cultivars at the end of growth season and to select the best cultivars for optimal production, an expriment was conducted in 2008-2009 in the field of educatioal center of Jahad-Keshavarzi –Fars province, (Pasargad city). The study was conducted as a split plot in randomized complete blocks design with three replications. Irrigation treatments within three levels as the main plots which included: complete irrigation (control), elimination of the latest irrigation (ripening stage of seed), and elimination of two latest irrigations (flowering stage) and wheat cultivars [Bahar, Pishtaz, Chamran, and Shiraz] were used as subplots. The results showed that irrigation treatments had significant effects on grain yield, 1000 seed weight, biological yield, harvest index, so there was a highly significant difference between the elimination of two latest irrigation treatments and the two other irrigation treatments which caused significant reduction in grain yield, 1000 seed weight, biological yield, and harvest index. Grain yield and other traits were higher for control treatment of irrigation. There were significant differences for all traits between wheat cultivars and the highest values for grain yield, 1000 seed weight, biological yield, harvest index, the number of spikelets per m2, belong to Chamran and Pishtaz cultivars. Evaluation of resistance or sensitivity of wheat cultivars to drought stress at the end of growth season showed that elimination of one latest irrigation for Pishtaz cultivar and of two latest irrigation for Chamran cultivar may be possible and these cultivars were the most resistant cultivars and Shiraz and Bahar cultivar were the most sensitive cultivars.

In order to evaluate the effect of drought stress on yield, yield components and ion contents of four wheat cultivars (Roshan, Shiraz, Falat and Chamran) a split plot experiment was used in Research Station of Eghlid- Azad- University in which drought treatments [four water supply treatments (irrigating after the soil water potential reached -.0.5 bar (control), 1.5 bar, -3 and -5 bar were arranged as main plots and genotypes as subplots, based on a randomized complete block design with three replications. The measured parameters were yield and its components and leaves ion contents. The present study demonstrated that the number of spike and grain per plot were reduced significantly by stress. Grain weight was less sensitive to stress. Biological and grain yields were decreased by stress. Among the cultivars Roshan had the lowest and Chamran the highest grain and biological yields. Biological yield differences were related to lower plant height and tillers per plant and the grain yield differences were related to the reduction of ear per plant and grain per ear. Grain protein content was influenced by drought stress. Drought stress caused decrease in ion contents except Na and Cl. In general the Roshan cultivar showed lowest yield, yield component and ion content while Chamran cultivar showed opposite results.

In order to determine the effect of different amounts of nitrogen application in different sowing dates on phonological, characterictics and grain yield of canola (Hyola 401), the experiment, a randomized complete block design, arranged in a split-plot with four replications in Biekola Agriculture Research Station in Neka city during 2007-2008. Five sowing dates including 29 October, 8, 18, 28 November and 8 December were considered as main plots and four levels of nitrogen urea fertilizer application including 150, 200, 250 and 300 kg/ha urea were considered as sub plots. Results revealed significant differences of sowing date and nitrogen for number of days to flowering, number of days to end of flowering, number of days to maturity, 1000 seed weight, biological yield and grain yield. The nitrogen effect was significant on each studied trait except duration of flowering and harvest index. The interaction between sowing date and nitrogen application were not significant for all studied traits except the number of days to maturity and 1000-seed weight. Significant positive correlation was observed between seed yield and each phenological trait, indicating in the first and second sowing dates and also high amount of nitrogen levels make increasing amount of phenological traits and seed yield.In the first sowing date the seed yield related to four nitrogen application levels were 2864, 3026, 3276 and 3707 kg/ha respectively. For fifth sowing date seed yields were 1754, 1835, 1973 and 2268 kg/ha respectively. Therefore one of the effective ways of compensating for decreasing yield components and seed yield due to late planting date is increasing the amount of nitrogen application.

To evaluate the effect of different levels of wheat residue and N fertilizer (urea) on rapeseed yield (Talayeh cv.) a study was conducted in Aliabad Kamin Agricultural Education Center located in Pasargad in 2009-2010. The study was carried out as a factorial design in a randomized-complete blocks with three repeats, the first factor was 3 levels of N fertilizer (175, 225, 300 kg/ha) and the second one was four levels of wheat residues (0, 25, 50 and 75%). The results of treatments with wheat residue levels of 25 and 50 %, and high levels of N fertilizer showed that the number grin in pod, the grain yield, harvest index and biological yield increased. The application of 0 and 75% level wheat residue with low N fertilizer level also caused reducing of the number grin in pod, the grain yield, harvest index and biological yield. The result illustrated that the application of organic residue and N fertilizer must be used in optimum range. Treatments of wheat residue and N fertilizer had not significant effect on the weight of 1000 grains.

The first step for permanent management of jungles is to have some information about principles of jungles upgrowth and their natural structure. Without being aware of upgrowth principles and degree of sensitivity, ecological balance will be in serious danger. So the purpose of this research is to indicate the status of the natural structure cumulus of Oak stability to estimate the upgrowth stage (seriate trend), the number and the changes in jungles dynamism and to indicate the the proper methods of management. For this purpose the an area which is the only one include Oak jungle was studied at Shazand city (in Markazi province). To study the vegetal cover in respect to some factors such as very great genetic and supportive value and the necessity of the high processor in our study to indicate the trend of ecological changes and seriate trend, we used complete statistical method and some qualities such as tree figuration, format, height and the number of buds, the average of canopy diameter, and tree situation. The study of variance diagram of diameter levels showed that the area had a nonevent-aged decreasing structure and it consisted of duble hump distribution. The study of number of variance diagram in altitudinal ranks showed that this curve is in a near normal and toward right with a little slope status. But the study of ecological changes and seriate structure of Oak stability in accordance to horizontal and perpendicular structure of area, dried trees reproduction also the attention to the development cycle of natural area showed this area is in an optimal stage and is going to an ageing one. For this reasons in the jungle area with the same upgrowth situation, the correct and suitable methods should be chosen before getting this level of upgrowth. To do this we should indicate and clarify the phases observed in an upgrowth cycle, through the cartography.Then we should analyze every bole in every specific phase to indicate the length of every phase to finally be able to indicate the time limit, area and the amount of intensity of our interference in every part of jungle.

In this research, to evaluate vegetation cover percentage an to determine optimum vegetation indexes for multivariate regression modeling in the Ab-Mahi subbasin of Doorodzan dam watershed basin with the area of 15, 800 ha, usimg spectral reflection detected by ETM+ sensor of landsat satellite in the year 2002. In the first step, after primitive image processing, including radiometric and geometric correction using optimum index factor (OIF), false color composite map with band combination: RGB=741 were prepared for field studies. Then, by doing field studies, considering false color composite map 63 plots (1m *1 m) were randomly selected at the region area. The percentage of canopy cover were estimated in the field studies. In this regard the coordinates of each point was determined using GPS. These information were used in order to construct the vegetation cover incorporated with ETM+ imagery data. To obtain a reliable vegetation map six main bands of ETM+ and 26 artificial imagery were applied to training data set in ILWIS software. Finally the overall accuracy of prediction was calculated by coefficient of determination (r2) and root means of square error (RMSE). The constructed vegetation canopy map was used in land qualitative evaluation of rangeland for the study area. At last, It was shown that it is possible to model and determine the vegetative land cover percentage with an acceptable accuracy using satellite images (ETM+) and implementing appropriate digital analysis.

Rangelands are natural ecosystems containing great genetic resources and plant species diversity having profound effects on stability of the rangelands. Species richness and biological diversity have been declined throughout the world as a result of human activities. National parks and protected areas are an attempt to conserve the remaining species. Measuring species richness is important to understand resource condition but heterogeneity in plant distribution make inventories difficult. This study aimed to compare two methods of measuring species richness (Whittaker and Modified Whittaker plot) for the Poshtah Mayvaleh in Ilam, Iran.This study was carried out in two grassland and shrubland vegetation using six replicates. A total of 154 plant species was found belong to 121 genus and 35 plant families. Among them Asteraceae were abundant. The result of this study shows that there is a significant difference between two methods in measuring species richness for both vegetation types. Also the Modified Whittaker plot showed better estimating of species richness by plot area according to the result of regression analysis.

Nowadays climate changes as one of the six major environmental subjects has been put forward as the most important challenge in sustainable development and poverty elimination that in most researchers beliefs result in increasing the concentration of green house gases 100 years ago. Mean while, carbon is considered as the most important component of these gases. Carbon sequestration during the photosynthesis process via plant biomass is the extent of this atmospheric gas. Artemisia sieberi Besser is known as one of the most principal elements of vegetarian societies of Iran, that should be known as the view point of carbon sequestration potential. So the key area of Rudshur- Saveh that is considered as Artemisia sieberi Besser society was selected and 25 stocks of species out of site were chosen randomly and aerial phytomass (including leaf, twig, stem) and underground phytomass (root) and the existing litter were cut, weighted and collected and finally transferred to the laboratory and coefficient of conversion of carbon sequestration of each plant organ was separately determined by ash-method. Results showed that the amount of carbon sequestration of Artemisia sieberi Besser species at the past uring region in comparison with the exclusion site was significantly different. Also carbon sequestration among the aerial phytomass (leaf, twig, stem), underground phytomass (root) and litter has been significantly different at two sites.