جستجوی مقالات مرتبط با کلیدواژه "salt tolerant" در نشریات گروه "آب و خاک"

Soil salinity is the main factor in reducing crop yield, especially in arid areas. The availability of Phosphorous (P), is low in salt-affected soils. The purpose of this study was to isolate and identify the phosphate solubilizing fungi from saline-sodic soils and also to investigate phosphate solubilization in the presence of different salt concentrations. For this purpose, twenty soil samples were collected from the rhizosphere of Salicornia persica. Isolation of phosphate solubilizing fungi was done by plate culture technique on National Botanical Research Institute’s phosphate growth medium- Bromo Phenol Blue (NBRIP-BPB) solid media. Phosphate solubilization was tested in the presence of 0, 50, 100, 200, 400, 600, 800, and 1000 mM NaCl during 15 days of incubation on solid media. Thereafter, the phosphate solubilizing potential of isolates was tested in 6-day experiments in broth, and the phosphate solubilizing capability was evaluated in the presence of different concentrations of NaCl. The results showed that all strains produced halo zone until NaCl concentration reached to 200 mM, but with increasing salinity, only KARFUN 1 and KARFUN 2 could solubilize phosphate. Results of the 6-day experiment in broth culture were showed that KARFUN 1 had the highest phosphate solubilization potential, so it was selected for further investigation. Molecular identification indicated that KARFUN 1 isolate had a similarity of 100% with Aspergillus. niger and A. tubingensis species. The results showed that with increasing NaCl concentration, the phosphate solubilization increased and pH decreased. The lowest and the highest phosphorous concentration was observed in 1000 and 0 mM NaCl, respectively. Irrespective of NaCl concentration, results showed that there was an increase in phosphorous solubilization during the incubation time. The maximum phosphate solubilization was achieved (549 mgL-1) after 12 days of incubation and pH reached to 1.19. However, the KARFUN1 strain was able to solubilize inorganic phosphate in different NaClconcentrations as it could release 224 mgL-1 phosphorus at 1000 mM NaCl in broth medium.

To investigate drought tolerant isolates of rhizobial symbioant of lentil (Lens culinaris L.), 12 soil samples were collected from cultivated and non-cultivated area of Golestan, Chaharmahal-O-Bakhtiari and Isfahan provinces. Local cultivars of lentil including Binam Dorosht, Ghazvini and Faridani were planted in each soil sample. After 10 weeks, a total of 324 rhizobial isolates were recovered from root nodules of the lentil plants. Evaluation of the ability of the isolates to grow at different concentration of salt showed that all isolates grew normally on 200 mM NaCl and only 20% was determined as salt tolerant isolats(>400mM). Among the isolates RL249 was classified as superior salt tolerant strain due to growing on 600 mM salt. The drought tolerance of the isolates was also examined, using PEG6000. In general, the salt tolerant isolates were also drought tolerant, however their tolerance to salinity and drought is not related to their geographical origin. In a randomized split factorial design with three replications, the effectiveness of tolerant isolates(RL249 and RL211) and a sensitive strain (RL 77) was compared on two cultivars of lentil (Binam Dorosht and Faridani) under water stress treatments with the consumptions of 50, 75,90 and 98% of soil available water. Although nodulation rate was reduced in both cultivars as the consequence of drought stresses, plants of Binam Dorosht cultivar showed high nodulation rate due to the increased fresh weight of the roots. Despite the fact that RL249 was identified as a superior nodulating and salt/drought isolate, however nodulation efficiency was decreased significantly under water stress treatments with more than 50 % of soil available water.