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51.
Water deficit stress is the main limiting factor in corn production in different regions of Iran. Choosing appropriate corn hybrids and well-managed irrigation practices will result in significant water savings (WS) and good outcomes. Therefore, a randomized complete block design arranged in split plots with four replications was used to evaluate the effect of irrigation regimes on some agronomic traits of corn hybrids. Three different irrigation regimes (irrigation after depleting 60%, 70%, and 80% of field capacity (FC) as water deficit stress, mild water deficit stress and well-irrigated treatment, respectively) were allocated to main plots and four grain corn hybrids (KSC 500, KSC 647, KSC 700, and KSC 704) were randomized in subplots. The results indicated that grain yield (GY), harvest index (HI), and relative water content (RWC) decreased, whereas water use efficiency (WUE), WS, and irrigation efficiency (IE) increased, with increasing water deficit stress intensity. Irrigation after depleting 70% of FC caused the highest economic WUE (1.01 kg grain m?3). In addition, late maturing hybrids (KSC 700 and KSC 704) showed higher values of all measured traits, except for HI, compared to mid-maturing hybrids (KSC 647 and KSC 500). 相似文献
52.
The oak decline is known as one of the most destructive complex diseases causing high economic losses around the world, especially in Iran. The main objective of the present study was to investigate the possible role of bacteria as causative agents of oak decline in the Zagros forests of Iran. To do this, stem, root and leaf samples were taken from symptomatic Persian oak trees (Quercus brantii) in different zones of Zagros forests (Ilam Province, Iran). From 150 bacterial isolates, 20 showed pathogenicity against Geranium seedlings. Among 20 hypersensitivity test positive strains, four strains showed pathogenicity against oak saplings. Based on morphological and 16S rRNA gene sequence analysis, three strains were identified as Bacillus pumilus and one strain as non‐sporulating Gram‐negative Stenotrophomonas maltophilia. Pathogenicity studies of different B. pumilus and S. maltophilia strains revealed that they have potential to cause the disease in oak saplings and symptoms of disorder in Persian oak trees. To our knowledge, there are no previous records of B. pumilus and S. maltophilia causing decline on Fagaceous trees like Q. brantii. More detailed field and molecular studies are required to confirm the absolute role of such bacteria in occurrence of oak decline in Zagros forests. 相似文献
53.
Abbas Shali Seyedhadi Ghasemi Gholamreza Ahmadian Gholamali Ranjbar Ali Dehestani Naeimeh Khalesi Ebrahim Motallebi Majid Vahed 《Phytoparasitica》2010,38(2):141-147
The possible role of chitinase in in vitro growth inhibition of the wheat pathogens Fusarium graminearum and Bipolaris sorokiniana by Bacillus pumilus SG2 was investigated. B. pumilus SG2, a chitinolytic bacterium producing two different chitinases, was previously isolated from the saline deserts of Iran.
When grown in Spizizen salts medium with colloidal chitin, B. pumilus SG2 secreted two chitinases into the medium, resulting in growth inhibition of F. graminearum and abortion of hyphal elongation of B. sorokiniana. In contrast, when glucose was used as the carbon source, the chitinases were not expressed and antifungal activity of the
B. pumilus SG2 was completely abolished. These results confirmed that expression of the B. pumilus SG2 chitinases is under the control of two types of regulation, special regulation by chitin and global regulation by glucose.
We demonstrated that chitinases are the main components that caused hyphal inhibition activity of B. pumilus SG2. Hyphal inhibition of F. graminearum and B. sorokiniana was stable in agar for a minimum of 14 days. 相似文献
54.
Tree-Temperature Monitoring for Frost Protection of Orchards in Semi-Arid Regions Using Sprinkler Irrigation 总被引：1，自引：0，他引：1
Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran （a 0.17 ha peach orchard and a 0.24 ha orange orchard） to protect peach blossoms and orange trees leaves and fruits from low temperature damage. The experiment used a system that monitored the trees and air temperatures using two thermistors. The water application rate by the irrigation system was determined by an energy balance as implemented by the software FROSTPRO, In the peach orchard, the system was tested during three frost events during the spring of 2003 and three other events during the spring of 2004. The system successfully kept peach flowers above the critical temperature, i.e., -4.0℃ in spring 2004 （control block -4.12℃, and sprinkled block ＋0.5℃） during all events. Similar results were obtained in the orange orchard during three frost events in the winter of 2004, during which the tree temperatures were at least 2.5℃ above the critical temperature. Results from field tests show that the system can effectively protect the peach blossoms from damage. Determination done after the frost events showed a 12% blossom kill in the sprinkled blocks while in the unsprinkled control block a 41.5% blossom kill. Calculations indicated that when using variable application rates, the amount of water used can be reduced by 54.3%. Spatial distribution of minimum temperatures during the three frosts was also studied in Jahrom, Iran. Results showed a significant temperature control in the experimental block, especially in the central part of the orchard, but the block margins （about 3.6% of the total area） were at the risk of low temperature due to the wind drift effects. 相似文献
55.
OBJECTIVE: To characterise 18 isolates of Haemophilus paragallinarum isolated from chickens in Indonesia. PROCEDURE: The isolates were identified to species level by traditional phenotypic methods. Six of the isolates were also identified by a species-specific polymerase chain reaction. Fourteen of the isolates were examined for resistance to a panel of seven antimicrobial agents using a disc diffusion method. All 18 isolates were serotyped according to the Page scheme using reference antisera in a haemagglutination inhibition test. RESULTS: Four of the 18 isolates were obtained from indigenous (kampung) chickens, with the remainder being from typical intensive poultry production systems. The 18 isolates were obtained from 11 outbreaks that showed the typical clinical signs of infectious coryza and 11 of the isolates were obtained from chickens that had been vaccinated with infectious coryza vaccines. All 18 isolates were confirmed as H paragallinarum by biochemical testing and six isolates were also identified as H paragallinarum by the polymerase chain reaction test. Eleven isolates were resistant to erythromycin and streptomycin, 10 to neomycin, eight to oxytetracycline, five isolates to doxycycline, three to sulphamethoxazoltrimethoprim but only one to ampicillin. Seven isolates were Page serovar A, four were Page serovar B and seven were Page serovar C. CONCLUSION: The presence of all three Page serovars (A, B and C) has been confirmed for the first time in Indonesian chickens. As the majority of the infectious coryza vaccines in use in Indonesia contain only serovar A and C, the presence of serovar B in chickens indicates that the protection by these bivalent vaccines would be reduced. The use of trivalent infectious coryza vaccines that contain serovars A, B and C is recommended for use in Indonesia. 相似文献
56.
Weria Weisany Gholamreza Heidari Adel Siosemardeh Hedieh Badakhshan 《Journal of plant nutrition》2014,37(14):2255-2269
The purpose of the present work was to evaluate effects of zinc application on growth and uptake and distribution of mineral nutrients under salinity stress [0, 33, 66, and 99 mM sodium chloride (NaCl)] in soybean plants. Results showed that, salinity levels caused a significant decrease in shoot dry and fresh weight in non-zinc application plants. Whereas, zinc application on plants exposed to salinity stress improved the shoot dry and fresh weight. Potassium (K) concentration, K/sodium (Na) and calcium (Ca)/Na ratios significantly decreased, while sodium (Na) concentration increased in root, shoot, and seed as soil salinity increased. Phosphorus (P) concentration significantly decreased in shoot under salinity stress. Moreover, calcium (Ca) significantly decreased in root, but increased in seed with increased salinization. Iron (Fe) concentration significantly decreased in all organs of plant (root, shoot, and seed) in response to salinity levels. Zinc (Zn) concentration of plant was not significantly affected by salinity stress. Copper (Cu) concentration significantly decreased by salinity in root. Nonetheless, manganese (Mn) concentration of root, shoot, and seed was not affected by experimental treatments. Zinc application increased Ca/Na (shoot and seed) ratio and K (shoot and seed), P (shoot), Ca (root and seed), Zn (root, shoot, and seed) and Fe (root and shoot) concentration in soybean plants under salinity stress. Zinc application decreased Na concentration in shoot tissue. 相似文献