Kourosh Behnamfar; Aziz Orsham; Mohamad Hasan Salehe Shoshtari; Mehrzad Tavousi; Abdolreza danaie; jamaladdin Adel
Volume 26, Issue 1 , June 2019, , Pages 49-61
Abstract
The occurrence of below-zero temperatures in recent winters in Khuzestan province has caused the freezing of Prosopis juliflora trees. The aim of this study was to determine the sensitivity of this species to freezing under zero temperatures. In this study, a split split plot was used in a completely ...
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The occurrence of below-zero temperatures in recent winters in Khuzestan province has caused the freezing of Prosopis juliflora trees. The aim of this study was to determine the sensitivity of this species to freezing under zero temperatures. In this study, a split split plot was used in a completely randomized design with six replications. In order to apply the treatments, the branches of elderly trees and two-year old seedlings were considered as main treatment; below-zero temperatures (-1-, -3, -5 and 7 ° C) as the first sub treatment; and different times (1, 2, 3 and 4 hours) as the second sub-treatment. The amount of electrolyte leakage from the membrane of leaf and stem cells was measured and, based on this, LT50 was calculated. The chlorophyll (II) fluorescence and photosynthesis efficiency of the leaves were measured as indicators for determining the damage to frost. The results showed that there was no significant difference for all traits between branches of the old trees and two-year-old seedlings. The percentage of electrolyte leakage from leaf and stem increased significantly with decreasing temperature. The LT50 occurred at -5 ° C after three hours. At -7 ° C, after the first hour, LT50 occurred in the leaves and after the third hour in the stems. After freezing stress, the Fv/Fm decreased significantly. After two hours at -1°C, Fv/Fm did not change significantly but in three hours Fv/Fm decreased from 0.64 (in control) to about 0.48. It reached to 0.15 after applying four hours at -7°C.
Abdolreza danaie; Damon razmjouiee; Shahram yousefi; Somayeh zolfaghari
Volume 24, Issue 2 , July 2017, , Pages 455-463
Abstract
This research was conducted in 2015 in Hallaf (Khozestan province), to locate the potential habitat of Calligonum comosum with the use of GIS and analytic hierarchy. For this purpose, at first, the habitat of the study species was determined in the region and the current position of establishment was ...
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This research was conducted in 2015 in Hallaf (Khozestan province), to locate the potential habitat of Calligonum comosum with the use of GIS and analytic hierarchy. For this purpose, at first, the habitat of the study species was determined in the region and the current position of establishment was determined as the natural environment. Accordingly, the ecological needs of Calligonum were identified and recorded in these areas by GPS. To determine the species soil needs, 30 soil samples were taken from 0-50 cm depth. Soil texture, acidity (pH), and electrical conductivity of soil samples were measured. In the next step, layers of climate, physiographic and soil characteristics maps were prepared and standardized with the help of digital data in GIS. Then by using ARC GIS10 software, all the layers were weighted by AHP method. Eventually, by integrating thelayers in Arc GIS and weighted hierarchical model, the layer of potential habitat for the study species was obtained and presented on the map of the region. On the basis of potential habitat, the resulting map was divided into five classes as follows: very high suitability (38% with an area of 3775 hectares), high suitability (41% with an area of 4149 hectares), suitable (8.6% with an area of 798 hectares), low suitability (11% with an area of 1104 hectares), and very poor suitability (1.4% with an area of 148 hectares).