Payam Fayyaz, Seyedeh Saba Nabavi Goldeh, Masoud Dehdari,
Volume 1, Issue 1 (9-2014)
Abstract
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)
Abstract
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.
Leila Ranjbar, Payam Fayyaz, Ebrahim Adhami, Hamidreza Owliaie, Roghayeh Zolfaghari,
Volume 4, Issue 1 (reserch article 2024)
Abstract
Background and objectives. By accelerating of the intensity and duration of the drought periods in the Zagros forests, the revival of native tree species, including the brant’s oak (Persian oak), is diminished. Despite the knowledge of the importance of phosphorus in increasing drought resistance in different species, there is little information about the role of this element in brant’s oak seedlings in facing drought.
Materials and methods: For this purpose, the main and interactive effects of two factors of soil phosphorus (at five levels of zero, 25, 50, 75 and 100 mg/kg) and soil moisture regime (at three levels of 60, 30 and 10 percent of field capacity) on performance traits of one-year-old brant’s oak seedlings, with six replications, have been examined. The studied traits include morphological traits (root and stem length, number and area of leaves, fresh weight of roots, stems and leaves), physiological traits (relative water content and electrolyte leakage rate in different organs of leaves, stems and roots, and optimum and maximum yield of photosystem II, and chlorophyll index) and nutrition uptake (concentration of potassium and phosphorus elements in leaves).
Results: The results revealed that with the decrease in soil water content, the traits of leaf number, root and leaf fresh weight, relative water content, photosystem II performance, leaf chlorophyll index and leaf potassium and phosphorus content decreased and root length and electrolyte leakage rate increased. The increase of soil phosphorus in the high irrigated seedlings (60 percent of field capacity) caused the development of aerial organs and leaf surface, and in the seedlings that were in water deficit conditions, it caused the maximum performance of photosystem II to be maintained. Increasing soil phosphorus in all water conditions increased phosphorus, potassium and chlorophyll index, in the leaves of brant’s oak, but it had no effect on reducing membrane damage caused by oxidative stress.
Conclusion: In general, application of phosphorus increased the resistance of brant’s oak seedlings to drought stress by improving nutritional status and protecting the photosynthetic apparatus. Implementing higher concentrations of phosphorus is suggested for future research in order to study the possibility of improving water relations and protecting against plasma membrane injury.
