Introduction and Objective: The regeneration of trees in forests with a long dry season such as Z... more Introduction and Objective: The regeneration of trees in forests with a long dry season such as Zagros has extreme difficulties. Predicting of water deficit tolerance in the progenies based on the geographic, vegetative and physiologic characteristics such as the performance of photosystem can conducted to increasing the efficiency of plantations. Material and Methods: In this study, the progenies of 40 Persian oak trees derived from 8 populations located in southern Zagros forests were assessed for water deficit tolerance based on their geographic, growth and physiological characteristics such as photosystem II under greenhouse conditions. Also, the percentage of seedling establishment for each mother tree were evaluated by field trial during two years. The corresponding data obtained from these experiments in accompanied by the morphological characteristics of leaves and seeds of mother trees were used to developing of the predictive models of seedling establishment in the field. In this research, greenhouse and forest field experiment was conducted to evaluate the response of Persian oak seedlings to drought stress based on some indicators of stress resistance from photosystem II. Persian oak seedlings from different mother trees were subjected to drought stress by stopping irrigation for one month in the greenhouse conditions. Then, the seedlings were irrigated for one month again and in all stages, the photosystem II, the percentage of leaf yellowing and the percentage of survival of the seedlings were recorded. Also, the establishment of the offspring of mother trees in the forest field was evaluated based on the percentage of survival and the height of the seedlings during two years, and their relationship with the leaf and seed morphological characteristics of the mother trees was investigated. Results: The results showed that there is a positive relationship between the percentage of survival, and stress resistance indicators in greenhouse conditions with the percentage of survival and the height of seedlings in the forest field. Also, seedlings from drier seed origin, lower altitudes and latitudes, had higher drought resistance in greenhouse conditions. However, none of the growth and survival parameters in the field was related to the environmental characteristics of population. The relationship between the leaf and seed morphological characteristics of mother trees with stress resistance and the establishment of seedlings showed that the seedlings grown from wider and heavier seeds had better growth characteristics and survival only in the first year. Also, some leaf morphological characteristics of mother trees, such as petiole length, tooth width and number of veins were affecting traits to seedlings successful establishment in the forest field. Conclusion: The results of this research showed that collecting of larger seeds from mother trees with suitable leaf traits could be effective for reforestation success. In addition, the use of physiological traits in the control condition in greenhouse can help for selecting the resistant progenies from superior populations or mother trees.
It is of crucial importance to assess the performance of the photosystem II efficiency, as the mo... more It is of crucial importance to assess the performance of the photosystem II efficiency, as the most powerful system in light reactions of photosynthesis that is able to provide required electron of system by splitting water. Late frost occurred mostly in growing season and during night in early spring often results in weakness and even death of plants. Therefore, selecting tolerant varieties is one of the most efficient methods to deal with late frost. Due to high diversity and wide dispersal, poplars significantly contribute to the worldwide supply of cellulosic resources. In order to investigate the effect of night late frost on functional component of photosystem II and a number of related physiological traits, seedlings of three clones of black poplar (Populus nigra L.) were exposed to the minimum night temperature of 16, 4, 0 and –20 °C for three nights. To assess the revival potential, seedlings were further maintained in optimum temperature for 14 days. Data were analyzed usi...
The effects of lead (PbCl2) increment, under hydroponic conditions up to 15, 45 and 90 mg/l in pr... more The effects of lead (PbCl2) increment, under hydroponic conditions up to 15, 45 and 90 mg/l in presence of EDTA, on some physiological and biochemical traits of one year old saplings of P. nigra and P. alba, were investigated. Six weeks after establishing in target concentration, the amount of lead, biomass, water, soluble sugars, proline, electrolyte leakage, malondialdehyde, and pigments were assessed in different organs. The results revealed that with increasing lead concentration in culture medium in the studied period, the amount of lead in saplings increased, but no effect was observed on their biomass. In both species the magnitude of lead accumulation in root was higher than leaf. P. nigra had more water and less soluble sugars than P. alba. The concentration of soluble sugars increased up to 1.5 times with lead increment in both species, but proline content increased only in P. nigra up to 2 times and remained constant in P. alba. Elevation of electrolyte leakage in sapling...
To investigate the pivotal physiological processes modulating lead (Pb) tolerance capacities of p... more To investigate the pivotal physiological processes modulating lead (Pb) tolerance capacities of poplars, the saplings of two contrasting poplar species, Populus × canescens with high Pb sensitivity and Populus nigra with relatively low Pb sensitivity, were treated with either 0 or 8 mM Pb for 6 weeks. Lead was absorbed by the roots and accumulated massively in the roots and leaves, leading to overproduction of reactive oxygen species, reduced photosynthesis and biomass in both poplar species. Particularly, the tolerance index of P. × canescens was significantly lower than that of P. nigra. Moreover, the physiological responses including the concentrations of nutrient elements, thiols, organic acids, phytohormones and nonenzymatic antioxidants, and the activities of antioxidative enzymes in the roots and leaves were different between the two poplar species. Notably, the differences in concentrations of nutrient elements, organic acids and phytohormones were remarkable between the two...
Brant oak (Quercusbrantii) is one of the most abundant tree species in Zagros forests but there h... more 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 concent...
Introduction and Objective: The regeneration of trees in forests with a long dry season such as Z... more Introduction and Objective: The regeneration of trees in forests with a long dry season such as Zagros has extreme difficulties. Predicting of water deficit tolerance in the progenies based on the geographic, vegetative and physiologic characteristics such as the performance of photosystem can conducted to increasing the efficiency of plantations. Material and Methods: In this study, the progenies of 40 Persian oak trees derived from 8 populations located in southern Zagros forests were assessed for water deficit tolerance based on their geographic, growth and physiological characteristics such as photosystem II under greenhouse conditions. Also, the percentage of seedling establishment for each mother tree were evaluated by field trial during two years. The corresponding data obtained from these experiments in accompanied by the morphological characteristics of leaves and seeds of mother trees were used to developing of the predictive models of seedling establishment in the field. In this research, greenhouse and forest field experiment was conducted to evaluate the response of Persian oak seedlings to drought stress based on some indicators of stress resistance from photosystem II. Persian oak seedlings from different mother trees were subjected to drought stress by stopping irrigation for one month in the greenhouse conditions. Then, the seedlings were irrigated for one month again and in all stages, the photosystem II, the percentage of leaf yellowing and the percentage of survival of the seedlings were recorded. Also, the establishment of the offspring of mother trees in the forest field was evaluated based on the percentage of survival and the height of the seedlings during two years, and their relationship with the leaf and seed morphological characteristics of the mother trees was investigated. Results: The results showed that there is a positive relationship between the percentage of survival, and stress resistance indicators in greenhouse conditions with the percentage of survival and the height of seedlings in the forest field. Also, seedlings from drier seed origin, lower altitudes and latitudes, had higher drought resistance in greenhouse conditions. However, none of the growth and survival parameters in the field was related to the environmental characteristics of population. The relationship between the leaf and seed morphological characteristics of mother trees with stress resistance and the establishment of seedlings showed that the seedlings grown from wider and heavier seeds had better growth characteristics and survival only in the first year. Also, some leaf morphological characteristics of mother trees, such as petiole length, tooth width and number of veins were affecting traits to seedlings successful establishment in the forest field. Conclusion: The results of this research showed that collecting of larger seeds from mother trees with suitable leaf traits could be effective for reforestation success. In addition, the use of physiological traits in the control condition in greenhouse can help for selecting the resistant progenies from superior populations or mother trees.
It is of crucial importance to assess the performance of the photosystem II efficiency, as the mo... more It is of crucial importance to assess the performance of the photosystem II efficiency, as the most powerful system in light reactions of photosynthesis that is able to provide required electron of system by splitting water. Late frost occurred mostly in growing season and during night in early spring often results in weakness and even death of plants. Therefore, selecting tolerant varieties is one of the most efficient methods to deal with late frost. Due to high diversity and wide dispersal, poplars significantly contribute to the worldwide supply of cellulosic resources. In order to investigate the effect of night late frost on functional component of photosystem II and a number of related physiological traits, seedlings of three clones of black poplar (Populus nigra L.) were exposed to the minimum night temperature of 16, 4, 0 and –20 °C for three nights. To assess the revival potential, seedlings were further maintained in optimum temperature for 14 days. Data were analyzed usi...
The effects of lead (PbCl2) increment, under hydroponic conditions up to 15, 45 and 90 mg/l in pr... more The effects of lead (PbCl2) increment, under hydroponic conditions up to 15, 45 and 90 mg/l in presence of EDTA, on some physiological and biochemical traits of one year old saplings of P. nigra and P. alba, were investigated. Six weeks after establishing in target concentration, the amount of lead, biomass, water, soluble sugars, proline, electrolyte leakage, malondialdehyde, and pigments were assessed in different organs. The results revealed that with increasing lead concentration in culture medium in the studied period, the amount of lead in saplings increased, but no effect was observed on their biomass. In both species the magnitude of lead accumulation in root was higher than leaf. P. nigra had more water and less soluble sugars than P. alba. The concentration of soluble sugars increased up to 1.5 times with lead increment in both species, but proline content increased only in P. nigra up to 2 times and remained constant in P. alba. Elevation of electrolyte leakage in sapling...
To investigate the pivotal physiological processes modulating lead (Pb) tolerance capacities of p... more To investigate the pivotal physiological processes modulating lead (Pb) tolerance capacities of poplars, the saplings of two contrasting poplar species, Populus × canescens with high Pb sensitivity and Populus nigra with relatively low Pb sensitivity, were treated with either 0 or 8 mM Pb for 6 weeks. Lead was absorbed by the roots and accumulated massively in the roots and leaves, leading to overproduction of reactive oxygen species, reduced photosynthesis and biomass in both poplar species. Particularly, the tolerance index of P. × canescens was significantly lower than that of P. nigra. Moreover, the physiological responses including the concentrations of nutrient elements, thiols, organic acids, phytohormones and nonenzymatic antioxidants, and the activities of antioxidative enzymes in the roots and leaves were different between the two poplar species. Notably, the differences in concentrations of nutrient elements, organic acids and phytohormones were remarkable between the two...
Brant oak (Quercusbrantii) is one of the most abundant tree species in Zagros forests but there h... more 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 concent...
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