Showing 4 results for Asgharzadeh
R. Hajeeboland, N. Asgharzadeh, Z. Mehrfar,
Volume 8, Issue 2 (summer 2004)
Abstract
A great number of studies have been conducted on the role of Azotobacter - a free living N2-fixer - in agricultural soils, but our information is lacking on the importance of Azotobacter in pasture soils. This research was conducted to study the relationship between ecological and edaphical factors with the population of the bacteria in soil. Soil samples were taken from two sites in Azarbaidjan (Mishou-dagh and Khadjeh), having different ecology, soils and vegetation types. We investigated also the effect of inoculation of rhizosphere with soil-isolated A. chroococcum on the growth of wheat (Triticum aestivum L. cv. Omid) during 56 days of growth in a pot experiment. The treatments included: 1) inoculation with A. chroococcum (+A), 2) N fertilizer at a rate of 35 mg/Kg as (NH4)2SO4 (+N), 3) +A+N and 4) –A–N as control with four replications. Results showed that the population of Azotobacter chroococcum correlated positively with organic carbon and negatively with soil pH. In soils covered with vegetation the population of bacteria was higher than that in uncovered soils and the highest population of bacteria was found in soil samples collected from the rhizosphere of grass species and the lowest in that of legume species. In inoculation experiment, shoot and, particularly root growth, increased in the order of +N, +A and +A+N in comparison with control (–A–N) plants. These treatments also stimulate uptake and transport of K into shoot. Interestingly, the effect of +A treatment was significantly higher than that of +N and +A+N treatments. The same results were obtained for nitrogen. A higher uptake and particularly transport of K into shoot was attributed to low molecular weight organic molecules produced in inoculated roots and transport K into shoot. Results showed that inoculation with Azotobacter not only enhanced growth and chlorophyll content, but also stimulated uptake and translocation of ions into shoot. The stimulatory impact of inoculation is most likely a general effect that could also be important in micronutrients translocation into shoot.
S. Mashhadi Asghari, N. Aliasgharzadeh,
Volume 8, Issue 4 (winter 2005)
Abstract
Peat is the best known and the most widely used rhizobial carrier, but unfortunately, it lacks of sufficient sources in Iran. This research aimed at using some inexpensive materials as carrier instead of peat for producing the rhizobial inoculant for alfalfa. For this purpose, the physical and chemical properties of some materials to be used as carriers were determined and the viability of Sinorhizobium meliloti on these carriers during 6 months at +4 ºC was evaluated. The selected carriers were 1) Peat (control) 2) Vermicompost 3) Bilogical Filter Waste (BFW) 4) Vermiculite+Vermicompost (1:1w/w), and 5) Vermiculite+BFW (1:1w/w). Also to determine the suitable moisture content of carriers on prolongation of bacterial survival, two matric potential levels including –10 and –30 kpa were applied on the carriers. The results showed that vermiculite+BFW (1:1w/w) not only maintained a standard number of bacteria compared to the other treatment, but also caused good nodulation on alfalf seedling at the end of the 6th month. Although BFW carrier maintained a high number of bacteria after six months storage, it can not be recommended as a suitable carrier because of its negative effect on nodulation. In this study, higher number of bacteria was maintained in the matric potential of –30 kpa than –10kpa.
L. Rasipour, N. Aliasgharzadeh,
Volume 11, Issue 40 (summer 2007)
Abstract
Certain microorganisms in soil have phosphate solubilizing ability. Phosphorus has an important role in plant nutrition and N2 fixation in legumes. The interactive effect of three phosphate solubilizing bacteria (PSB) and Bradyrhizobium japonicum on yield and N, P, K uptake and nodulation of soybean root (Glycin max L. CV. Harcor) was studied under greenhouse conditions. In greenhouse experiment treatments consisted of a factorial combination of four levels of PSB (without PSB M0 ,Pseudomonas putida M1 , Aeromonas hydrophila M2 , Pseudomonas fluorescens M3) and two levels of B.japonicum (without bacterium B0 and with bacterium B1) and three levels of P(P0 = 0 , P1=29, P2 = 58 mg triple superphosphate/Kg soil) in a randomized complete block design with four replications. At harvest, shoot dry weight, seed weight, nodule number, dry and fresh weight of nodules and concentrations of N, P, K in shoot dry matter were measured. PSB significantly increased shoot dry weight, N, P, K concentrations in shoot, fresh and dry weight and number of root nodules. B.japonicum had positive significant effect on these parameters as well as on seed weight. Dual inoculation of plants with PSB and B.japonicum had significant effect on shoot dry weight, P and N concentrations in shoot. Increasing phosphorus levels significantly increased plant dry weight, shoot P concentration and seed weight. Highest P concentration in shoot was obtained at P2 level but in plants inoculated with P.putida, dry weight at P1 level was not significantly different from P2 level.
E. Karimi, A. Lakzian, K. Khavazi, A. Asgharzadeh, G.h. Haghnia,
Volume 11, Issue 42 (winter 2008)
Abstract
It is important to investigate the genetic diversity and evaluate symbiotic effectiveness of the indigenous rhizobial population. It helps understand the responses of indigenous isolates to different rhizobial inoculants. In spite of the importance of bacterial diversity, there are a few scientific reports about it in Iranian soils. Genetic diversity of 150 isolates of Sinorhizobium isolated from Hamadan soils was studied by using PCR / RFLP 16S-23S rDNA technique. The results showed that all isolates clustered in three different groups. Group (I) formed 122 isolates and they were quite similar to Sinorhizobium meliloti from viewpoint of genetic characteristics. Twenty five isolates were clustered in Group (II) and they belonged to Sinorhizobium medicae. Group (III) had two isolates and they were new species and quite different from the other groups. Shannon diversity index was different within eleven different land units (Medium gradient mountains, Level lands, Plateau, Foot slopes, Depressions and Composite land) and there was a correlation between Shannon index and some soil properties. Difference in Similarity index showed that Sinorhizobium groups in each land unit were different.
