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.
Adel Jalili; Kian Najafi Tireh Shabankareh
Volume 19, Issue 3 , December 2012, , Pages 406-420
Abstract
Due to uncontrollable natural regeneration of invasive and non-native species of Prosopis juliflora in the coastal areas in south of the country, effects of the species on soil properties under canopy cover were investigated. This study was conducted in Hormozgan province, in different sites including ...
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Due to uncontrollable natural regeneration of invasive and non-native species of Prosopis juliflora in the coastal areas in south of the country, effects of the species on soil properties under canopy cover were investigated. This study was conducted in Hormozgan province, in different sites including Bandar Abbas, Ghaleghazi, Minab and Sirik. In each region, the species were randomly selected in one hectare of land and then the soil under and outside the canopy cover were sampled from two depths, 0-15 and 15-30 cm. pH, EC, saturation percentage, soluble calcium and magnesium, chlorine, HCO3-, SO42-, potassium, organic carbon, total nitrogen and available phosphorus phosphorus were measured in laboratory. Results of this research showed that there were significant differences in some soil properties such as pH, EC, and organic carbon in depth of 0-15 centimeter. It is worth noting that changes in soil properties under canopy cover were not similar in all regions. This may be due to the establishment period of the species in different regions, habitat conditions, the occurrence of rainy and drought periods and the density and diversity of native species. Some soil properties did not differ statistically beneath and outside the canopy of this species but it seems that the trend of these changes has not been stable. It is emphasized that the role of Prosopis juliflora in connection with the change in density and diversity of natural vegetation beneath the canopy cover could not conclusively be attributed only to changes in soil.