Showing 5 results for Taghavi
S. M. Taghavi, K. Keshavarz,
Volume 6, Issue 4 (winter 2003)
Abstract
During the period from 1997 to 1998, samples of wheat leaves were collected from different wheat farms in Fars and Kohgiluyeh & Boyrahmad provinces to identify the causal agent of wheat leaf blight. On the basis of LOPAT tests and production of fluorescent pigment on KB medium, 181 bacterial isolates were recovered from the samples. Based on biochemical, physiological and pathogenicity tests, the isolates were categorized in five groups. One group was found to be Pseudomonas fluorescens (Pf) and the remaining groups were identified as P. syringae pv. syringae (Pss). The pathogenicity test indicated that Pss strains were the causal agent of bacterial wheat leaf blight in Fars and Kohgiluyeh & Boyrahmad provinces. Whole protein electrophoretic patterns were similar in Pss isolates but only a few showed small variation in some subordinated bands. Pathogenic strains of Pss were also isolated from annual and perennial weeds such as foxtail, hairy vetch, oat grass, barley grass and Cynodon dactylon in some areas including Saadat Shahr and Marvdasht. Among the wheat cultivars tested, Tajan was susceptible to the pathogen but others were immune, resistant, moderately resistant, or moderately susceptible. The results showed that Pss is a seed-born pathogen in wheat kernel perhaps as endophyte in the seeds.
S. M. Taghavi, M. Ziaee,
Volume 7, Issue 1 (spring 2003)
Abstract
In order to compare Pseudomonas syringae pv. syringae (Pss) isolates from cereals, citrus, stone fruits and weeds by phenotypic characteristics, serological properties and pathogenicity, samples were taken during 1998-1999 in Fars Province, Karaj, Fereidan, Aligudarz and Shahrekord regions. From 350 fluorescent isolates, 47 were negative with respect to oxidase, potato soft rot and arginine dihydrolase tests but positive in hypersensitive reaction (HR) on tobacco, pelargonium, or both. In complementary biochemical tests, these isolates were identified as Pss. Based on LOPAT (levan, oxidase, potato soft rot, arginine dihydrolase and HR on tobacco leaves) tests, the isolates were divided into two groups, but based on the results of GATTa tests alone, isolates were divided into nine groups. Isolates from different hosts showed differences in lipolysis, syringomycin production, ice nucleation activity, lecithinase, pathogenicity, serology and protein profiles.
H. Irandoust, G.h. Niknam, A. Ghasemi, S.m. Taghavi, E. Torabi,
Volume 12, Issue 43 (spring 2008)
Abstract
During summer of 2004, tuber and stem samples of potato plants showing wilt symptoms were sampled from different fields of East Azarbaijan, Fars and Karaj provinces. A total of 39 bacterial strians were isolated and based on the morphological, biochemical characters and pathogenicity tests were divided in to two district group. All the strains of East Azarbijan and Karaj provinces were identifeid as race 3 / biovar 2A of Ralstonia solanacearum and strians of Fars province were identified as race 3 / biovar N2 of the bacterium. Distinct differences were observed in utilization of carbon (D-trehalose, D-ribose and tartrate) as well as tyrosinase activity and protein profiling in SDS-PAGE among the two biovars. Based on the results of phenotypic tests, eight strians of biovar 2A were selected and their plasmids were extracted and electrophoresis on 0.7% agarose gel. All the strians had a single plasmid with similar size and no variation was observed among the strains. According to available literature, this is the first report of occurrence of biovar N2 of R. solanacearum in Iran.
A. Taghavi, Gh. Tahmasbi, A. A. Talebi, A. Zarnegar, A. Monfared, H. Nazarian,
Volume 12, Issue 45 (fall 2008)
Abstract
The species diversity of bumblebees was investigated in two provinces, Tehran (Fasham, Zayegan) and Qazvin (Alamut, Wikan) in central Alborz during 2005-2006. Three casts of queen, worker and male bumblebees were collected during spring and summer in six dates in the two mentioned regions. Sampling of adult bees in Wikan was done from 26 July 2006 until 19 September 2006, and in Zayegan from 24 May 2006 to 17 September 2006. In sum, eleven species were collected of which eight species were common in the two regions. Data of different species casts at two regions were analyzed by Excel ver. 6 and Ecological Methodology ver. 6. 1. 2 soft wares. Species diversity of two regions was determined and compared with three indices of Simpson, Shannon-Weiner and Brillion, and evenness was calculated with indices of Simpson, Camargo and Esmit-Willson. Species richness of two regions was compared in research. The obtained results showed species diversity, evenness and species richness were more observable in Wikan compared with Zayegan. Consequently, Wikan in comparison with Zayegan was more sustainable. Similarity of two regions was 0/46, showing many differences in terms of the kinds. Also, there were 8 similar species in the two areas.
A. Abdollahi, M. Norouzi Masir, M. Taghavi, A. Moezzi,
Volume 24, Issue 2 (Summer 2020)
Abstract
Nowadays, one of the ways to confront with the micronutrients deficiency is application of Nano materials to increase the availability of elements such as zinc for plants. Therefore, this study was conducted to investigate the effect of functionalized iron oxide nanoparticles and zinc sulfate chemical fertilizer on the zinc chemical forms in soil solution phase and its correlation with zinc concentrations and uptake in wheat. This study was carried out in a completely randomized design with three replications. Treatment consisted of functionalized iron oxide nanoparticles of Hydroxyl (OH), Carboxyl (COOH) and Amine (NH2), each at three levels (100, 200 and 300 mg.kg-1), ZnSO4 (40 kg.ha-1) and Control (without using iron oxide nanoparticles). At the end of the cultivation period, soil chemical properties such as pH, soil available zinc and dissolved organic carbon and concentrations and the uptake of zinc in plant were measured. The results showed that pH, available zinc and dissolved organic carbon content of soil solution were significantly affected by the treatments. The results obtained from the Visual MINTEQ Geochemical model showed that the highest amount of the free form of zinc (Zn2+) was obtained at the level of 300 mg.kg-1 of carboxyl iron oxide nanoparticles. Also, the experimental treatments significantly influenced the concentration of Zn-DOM species. The positive and significant correlation between Zn+2 and Zn- DOC species with the concentration and total Zn uptake of wheat indicated that these pools of Zn could be liable species in soil. The results of this study, therefore, showed that the application of functionalized iron oxide nanoparticles could help to improve soil conditions in order to increase the zinc availability for plants.
