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Showing 2 results for Fayyaz
Payam Fayyaz, Seyedeh Saba Nabavi Goldeh, Masoud Dehdari,
Volume 1, Issue 1 (9-2014)
Brant oak(Quercusbrantii) is one of the most abundant tree species in Zagros forests but there have been scantefforts to its propagation via shoot cuttings approach. Any achievement in its asexual reproduction shall accelerate the breeding improvements. For this purpose, under growing twigs of Brant oak with and without apical bud were cultured in different culture mediums of half MS and WPM adopting in vitro conditions. In order to study of the explants' sterilization, four kinds of sterilizing reagent consist of ethanol, mercury chloride, sodium and calcium hypochlorite with and without Tween as a surfactant in different concentrations were tested and the rate of contamination, phenolic leakage and browning of explants were recorded. The effect of different treatments of ascorbic acid, acetic acid, PVP, activated charcoal and darkness on phenolic leakage and browning of explants were evaluated. The ratio of proliferation and callus formation with different NAA and BAP concentrations were investigated. Finally the rooting vigor of explants by four auxin combinations (control, 0.4 mg L-1 NAA, 0.4 mg L-1 IBA and a mixture of NAA and IBA with amount of 0.1 and 0.3 mg L-1) and three cytokinin concentration (0, 0.4 and 1 mg L-1 ) were assessed. The results revealed that the best suitable condition to establish and proliferate of under growing twigs of Brant oak was sterilizing the explants using mercuric chloride 0.1% (w/v) and transferring to WPM medium containing 0.5 mg L-1 PVP or activated charcoal. Increasing BAP and NAA concentrations up to 1 and 0.1 mg L-1 respectively had no significant effect on proliferation rate of explants. None of the rooting treatments were conducted to root formation in explants.
Somayeh Homayounfar , Roghaiyeh Zolfaghari , Payam Fayyaz ,
Volume 3, Issue 2 (3-2017)
Background and objectives: Plant species with wide geographic ranges, exhibit high tolerance to cold stress. Trees in temperate regions must cope with freezing temperatures, especially in late autumn and winter. One of the mechanisms to tolerate cold stress is through decreasing photoperiod and temperature during acclimation. In addition, provenance of a species could be one of the main factors contributing to cold resistance. Therefore, in the present study, the effect of cold stress on physiological responses of Pistacia atlantica seedlings from three provenances was investigated in southern Zagros to select the most cold-resistant provenance.
Material and methods: Seeds of three provenances, namely Margon, Noor Abad and Yasuj, from southern Zagros, were collected and planted in pots. After germination of seeds, induction of acclimation was carried out at two stages for four weeks. This was accomplished through the simulation of temperature and photoperiod of Yasuj region from September to November. Following that, the indexes of photosystem efficiency and chlorophyll content were measured. After each acclimation stage, leaves and stems of seedlings were exposed to three levels of temperature, +4°C (control), -20°C for one hour, and -20 for two hours. Then, relative water content (RWC) and electrolyte leakage (EL) of stems and leaves were measured. This study was conducted as a factorial with three factors of provenance (three levels), cold treatments (three levels) and acclimation (two levels), adopting a completely random design.
Results: The results showed that EL increased with decreases in temperature and this increase was the highest in the case of the Noor Abad provenance. In addition, the stem RWC of Yasuj and Margoon provenances decreased in the second cold acclimation stage. Chlorophyll content, photosystem efficiency and electron transport rate were lower in Noor Abad provenance, compared with other two provenances. Moreover, except the electron transport rate, all fluorescence parameters significantly decreased during the cold acclimation.
Conclusion: The results showed that measuring EL and fluorescence parameters could be a useful indicator for identifying cold-tolerant provenances. The seedlings of Noor Abad provenance exhibited the least and Margoon provenance showed the highest resistance to cold stress. This could be due to high altitude and cold climate of Margoon provenance.