Root system architecture (RSA) is an important agronomic trait with vital roles in plant producti... more Root system architecture (RSA) is an important agronomic trait with vital roles in plant productivity under water stress conditions. A deep and branched root system may help plants to avoid water stress by enabling them to acquire more water and nutrient resources. Nevertheless, our knowledge of the genetics and molecular control mechanisms of RSA is still relatively limited. In this study, we analyzed the transcriptome response of root tips to water stress in two well-known genotypes of rice: IR64, a high-yielding lowland genotype, which represents a drought-susceptible and shallow-rooting genotype; and Azucena, a traditional, upland, drought-tolerant and deep-rooting genotype. We collected samples from three zones (Z) of root tip: two consecutive 5 mm sections (Z1 and Z2) and the following next 10 mm section (Z3), which mainly includes meristematic and maturation regions. Our results showed that Z1 of Azucena was enriched for genes involved in cell cycle and division and root grow...
In spite of rapid progress in plant biotechnology, somatic embryogenesis has been used as one of ... more In spite of rapid progress in plant biotechnology, somatic embryogenesis has been used as one of the most applicable techniques for micropropagation and plant regeneration, lack of comprehensive and systematic studies associated with the somatic embryogenesis still persists up to now. In this review paper, general aspects of <em>in vitro</em> somatic embryogenesis such as terminology, factors which are involved in somatic embryogenesis in different species and induction and development stages in the gymnosperm, dicots (globular, heart-shaped and torpedo) and monocots (globular, scuetellar, and coleoptilar stages) have been explained. Plant growth regulators functions, physiological condition of mother plants, application of somatic embryogenesis for transgenic crop production, genetically approaches such as gene expression pattern involved in somatic embryogenesis and finally molecular and physiological markers to distinguish the embryogenic competence cells have been di...
One of the most effective ways to propagate Lilium is by using tissue culture techniques, prefera... more One of the most effective ways to propagate Lilium is by using tissue culture techniques, preferably through bulblet production. In addition to the surviving percentage of Lilium bulbs after transplantation, the small size of in vitro bulblets compared to commercial bulbs and bulblets‟ dormancy are the most important constraints to commercializing Lilium micropropagation. Different concentrations of sucrose or sorbitol as carbohydrate sources were investigated as maturation and enlargement factors on in vitro bulblets of Lilium longiflorum cv. „Ceb-dazzle‟. Five concentrations of gibberellic acid and 4°C cold treatment for 6, 7, 8, 9, 10 and 11 weeks in the greenhouse were studied in relation to the dormancy breaking of three in vitro Lilium bulblets cultivars: „Simplon‟, „Navona‟ and „Ceb-dazzle‟, which belong to the Oriental, Asiatic and LA hybrids. The results showed that 3% of sucrose and two weeks of culture significantly increased the bulblet maturation and enlargement of „Ceb...
A cytogenetic and morphometric study was performed on 5 M4 gamma irradiated tetraploid cotton cul... more A cytogenetic and morphometric study was performed on 5 M4 gamma irradiated tetraploid cotton cultivars (Gossypium hirsutum L.). The mutant lines varied significantly in their meiotic characteristics. Meiotic abnormalities including cytomixis, formation of laggard chromosome, stickiness as well as disorganised chromosomes may be responsible for the reduction in pollen fertility and abnormal pollen grain formation in cotton cultivars studied. The cultivars studied differed significantly in their morphometric characteristics indicating their genomic differences.
Enhancement of in vitro micro corm production in Gladiolus as an alternative commercial method ha... more Enhancement of in vitro micro corm production in Gladiolus as an alternative commercial method has been focus of attention. With respet to the position of Gladiolus in Iran's ornamental plants market and in order to provide the proper protocol for the proliferation of glycol corms by tissue culture method, the effect of different concentrations of naphthalene acetic acid (NAA) and benzyl aminopurine (BAP) in two explants and production of shoot and roots of two commercial gladiolus cultivars were investigated. In the next experiment the role of different concentrations of sucrose (in Murashige and Skoog plant growth liquid medium) in production of corms was studied and finally cold treatment in 3 times were used to break dormancy of propagated cormlets. All of the main experiments were conducted as factorial based on completely randomized design with 3 replications. The highest number of shoots (14) and roots (12) was observed in White cultivar with the treatments of 2mg/L BAP a...
Based on their taxonomic characters, six species of genus Rosa were collected from ten provinces ... more Based on their taxonomic characters, six species of genus Rosa were collected from ten provinces of Iran (33 populations). In each population, five plants were randomly selected, and some branches were harvested in spring and autumn to study their vegetative and floral characteristics. Fifty-five qualitative and quantitative characters were grouped using the most suitable method of cluster analysis (Ward), and an ordination diagram was drawn based on the most variable factors for each species and section. Cluster analysis of quantitative and qualitative characters showed significant differences between characters. According to the flora of Iran, there are two main subgenera within the genus Rosa. The first branch separates subgenus Hulthemia from subgenus Rosa. The second group consists of sections Pimpinellifoliae, Caninae and Cinnamomeae. The latter two are very close to each other, and crosspollination between them could be one of the reasons for these close relationships. The results showed that the effect of ecological factors such as altitude of the species habitat influenced intraspecies variation. The results of classification of four species from section Pimpinellifoliae and two species from section Cinnamomeae confirmed previous classification. In this study, three new natural hybrids, Rosa pulverulenta × Rosa boissieri, Rosa elimatica × Rosa iberica and Rosa pimpinellifolia × R. iberica, were reported from Iran for the first time. The results of this study can help us to choose parental hybrids appropriately. Using natural hybrids in breeding programs improves appropriate transfer of character to modern rose species.
Among the genetically modified (GM) crops that are being approved for commercialization, herbicid... more Among the genetically modified (GM) crops that are being approved for commercialization, herbicide resistant crops, especially those harboring cp4-epsps, have a considerable contribution. Gene-specific methods can be used to screen the presence of GMOs. To establish an effective qualitative and quantitative screening method, a set of primers were designed considering the cp4-epsps sequence. The specificity, the limit of detection, the efficiency, and the ability to quantify the GMO content were tested in GM cotton, soybean, and canola events. The results demonstrated that the primers can specifically detect cp4-epsps GM crops. The limit of detection was found to be 0.4 ng/μl DNA per PCR reaction with the ability to detect 1-16 copies of the haploid genome of each GM event. The efficiency of this screening method (which was 94-110% with an R2 higher than 0.96) indicated that these new primers can be applied to the screening of GM samples that contain the cp4-epsps gene. Also, the gene-specific real-time PCR screening method could be successfully developed for qualification of different types of GM cotton, soybean and canola events with the construction of a serial dilution ranging from 10% to 1%.
The taxonomy of polycystine radiolarians is important for biostratigraphic, paleoecological and p... more The taxonomy of polycystine radiolarians is important for biostratigraphic, paleoecological and paleoceanographical reconstructions. In this study we describe four morphogroups of Actinomma boreale from the North Atlantic and Arctic Oceans. We distinguish them from two other four-shelled Actinomma species from the Southern Ocean and North Pacific, namely Sphaeropyle langii and Prunopyle antarctica, which are both moved to genus Actinomma. As A. antarcticum is an already occupied name, P. antarctica is renamed to A. friedrichdreyeri nomen novum. Quantitative and qualitative intraspecific morphological variation was studied by examining 922 specimens (8599 photographs) from 49 samples, of which 45 are from the surface sediment, two are from deeper sediments, and two are plankton samples. We found significant differences in shell diameters between North Atlantic and Arctic Atlantic samples, and between Recent and downcore samples within A. boreale. We also found significant differences between populations of A. friedrichdreyeri and A. langii from the Southern Ocean versus the North Pacific. We do not recommend naming of extant polycystine radiolarian species based on continuous characters without supporting phylogenetic information. Therefore, with this study we have provided directions for phylogenetic investigations on A. boreale, A. friedrichdreyeri and A. langii.
Background The required amounts of chemical fertilizers (NPK) are determined by plant yield, and ... more Background The required amounts of chemical fertilizers (NPK) are determined by plant yield, and product quality is given less consideration. The use of PGPRs is an environmentally friendly approach that, in addition to increasing yield, also improves fruit quality. This study examined the role of specific Streptomyces strains in aiding cucumber plants to 1) use fewer NPK fertilizers in the same quantity 2) improve the quality of cucumber fruit, and 3) promote growth and defense system. Results In this study, the effect of 17 Streptomyces strains on the vegetative traits of cucumber seedlings of the Sultan cultivar was evaluated as the first test. Four strains of Streptomyces with the highest root and shoot dry weight were selected from the strains. This experiment was performed to determine the interaction effect of selected strains and different amounts of NPK on cucumber yield, quality, physiological and biochemical responses of plants. The first experiment’s results revealed tha...
Abstract The possibility of chemical fertilizer residues in cucumber has raised concerns about th... more Abstract The possibility of chemical fertilizer residues in cucumber has raised concerns about the consumption of this beneficial fruit. Although very good studies have been reported on the effect of growth-promoting bacteria on increasing the health of cucumber plants, their performance in commercial greenhouse conditions has been less studied. A two-year study was conducted to evaluate the effect of P. putida strain P3-57 with 100 % or 70 % of the recommended amount of NPK fertilizers on cucumber fruit yield and quality compared to Barvar NPK® commercial biofertilizer under commercial greenhouse conditions. The 30 % reduction in chemical fertilizers reduced yield and overall fruit acceptance score in the sensory evaluation test. Plant treatment with P3-57 or Barvar had no significant effect on yield but when 70 % of chemical fertilizers were used, they increased the quality of cucumber due to the increase in the score of some sensory traits. P3-57-100% had the highest overall acceptance score, which was associated with increased aroma, flavor and fruit juice, and the lowest levels of nitrate, Zn, Mg, Mo, Sr, Ba and Li. Also, the concentration of protein and CAT activity of fruits was higher compared to control-100 % and Barvar-100 %. Evaluation of CAT, APX and POX activity and expression of PR1-1a, GLU, APX, CHIT, LOX and PAL showed that P3-57-100 % and Barvar-100 % stimulate plant immune system through ISR/SAR and SAR pathways respectively. Based on the results of this study, strain P3-57, as a bio-stimulator that increases cucumber quality, has great potential to enter the market.
Plant growth promoting (PGP) effect of Streptomyces on wheat growth in different conditions has b... more Plant growth promoting (PGP) effect of Streptomyces on wheat growth in different conditions has been mostly reported although mechanisms which caused wheat cultivars differently response to a PGP Streptomyces has been less studied. In this study, the effect of two Streptomyces strains, previously reported as PGPR, on the growth of four salt-sensitive commercial wheat cultivars under normal and saline conditions was investigated. Strain C-2012 differently affected the growth of the cultivars in the normal and stress conditions. Cultivars Gonbad with the highest (63%) and Zarin without increased dry biomass upon C-2012 treatments were selected for further study. Salinity significantly decreased seedling fresh and dry weight, K þ and chlorophyll content and glutathione Stransferase activity. Moreover, the stress increased proline and Na þ content and peroxidase (POX) and ascorbate peroxidase (APX) activity in both cultivars. Strain C-2012, generally, ameliorated the negative effect of the stress with increased chlorophyll and carotenoid and reduced Na þ content and APX and SOD activity in both cultivars, however, its effect on biomass was different. Increase in SOD, APX and POX activities in bacterial inoculated-Zarin, but not Gonbad, under normal conditions suggested that this cultivar may recognize strain C-2012 as a gentle stressor and not as a PGPR. These results showed that the responses of the wheat cultivars to a defined PGPR is different in the physiological, phenotypic and molecular level. Based on the results, the evaluation of the effect of a bio-fertilizer on each wheat cultivar is necessary prior to use in a commercial field.
Phytophthora drechsleri damping-off is one of the most important diseases of cucumber (Cucumis sa... more Phytophthora drechsleri damping-off is one of the most important diseases of cucumber (Cucumis sativus). Salinity is a serious problem for crop production and affects diversity and activity of soil microorganisms. Application of salt-tolerant biocontrol agents may be beneficial in order to protect plants against pathogenic fungi in saline soils. In this study, a total of 717 Streptomyces isolates were isolated from the rhizosphere of cucumber, out of which two isolates showed more than 70% inhibitory effect against P. drechsleri and had cellulase activity in the presence and absence of NaCl. In a greenhouse experiment, two Streptomyces isolates with the highest antagonistic activity, strains C 201 and C 801, reduced seedling damping-off of cucumber caused by P. drechsleri by 77 and 80%, respectively, in artificially infested soils. Strain C 201 increased dry weight of seedlings up to 21% in greenhouse experiments. Phylogenetic analyses of 16S rRNA gene sequence reveals that strains C 201 and C 801 are closely related to S. rimosus and S. monomycini respectively. Increased activity of polyphenol oxidase (PPO) and peroxidase (POX) enzymes in Streptomyces-treated plants proved the biocontrol-induced systemic resistance (ISR) in cucumber plants against P. drechsleri.
The availability of iron for roots has been demonstrated as a critical factor in plant production... more The availability of iron for roots has been demonstrated as a critical factor in plant production. The addition of synthetic iron chelates to soil is a common practice in agriculture, which is not economically beneficial. Besides, chemical iron fertilizers cause many problems such as food contamination and environmental pollution. Development of natural Ferrioxamine B as an efficient and safe iron source may be the best strategy to overcome plant iron deficiency and prevention of synthetic agent pollution. The present study investigates the ability of a hydroxamate type siderophores
The genus Rosa has a wide variety in Iran and although some natural hybrids have been found in di... more The genus Rosa has a wide variety in Iran and although some natural hybrids have been found in different regions of the country, but no cultivars have been established so far. In order to optimize use of genetic resources in the country and to create varieties with desirable traits, inter-species relationships and identification of diversity, 45 populations from seven species in section Caninae collected from 13 provinces of Iran, were studied. To group the species, 61 qualitative and quantitative characters using the most suitable method of cluster analysis (WARD) were used and their ordination diagram based on the most variable factors for each species and sections were drown. Cluster analysis of quantitative and qualitative characters showed significant differences between characters. The results of classification confirmed previous taxonomy grouping. Factor analysis of R. elymatica populations showed that the hair on pedicels, sepal form, hip length, prickle base and prickle for...
Root system architecture (RSA) is an important agronomic trait with vital roles in plant producti... more Root system architecture (RSA) is an important agronomic trait with vital roles in plant productivity under water stress conditions. A deep and branched root system may help plants to avoid water stress by enabling them to acquire more water and nutrient resources. Nevertheless, our knowledge of the genetics and molecular control mechanisms of RSA is still relatively limited. In this study, we analyzed the transcriptome response of root tips to water stress in two well-known genotypes of rice: IR64, a high-yielding lowland genotype, which represents a drought-susceptible and shallow-rooting genotype; and Azucena, a traditional, upland, drought-tolerant and deep-rooting genotype. We collected samples from three zones (Z) of root tip: two consecutive 5 mm sections (Z1 and Z2) and the following next 10 mm section (Z3), which mainly includes meristematic and maturation regions. Our results showed that Z1 of Azucena was enriched for genes involved in cell cycle and division and root grow...
In spite of rapid progress in plant biotechnology, somatic embryogenesis has been used as one of ... more In spite of rapid progress in plant biotechnology, somatic embryogenesis has been used as one of the most applicable techniques for micropropagation and plant regeneration, lack of comprehensive and systematic studies associated with the somatic embryogenesis still persists up to now. In this review paper, general aspects of <em>in vitro</em> somatic embryogenesis such as terminology, factors which are involved in somatic embryogenesis in different species and induction and development stages in the gymnosperm, dicots (globular, heart-shaped and torpedo) and monocots (globular, scuetellar, and coleoptilar stages) have been explained. Plant growth regulators functions, physiological condition of mother plants, application of somatic embryogenesis for transgenic crop production, genetically approaches such as gene expression pattern involved in somatic embryogenesis and finally molecular and physiological markers to distinguish the embryogenic competence cells have been di...
One of the most effective ways to propagate Lilium is by using tissue culture techniques, prefera... more One of the most effective ways to propagate Lilium is by using tissue culture techniques, preferably through bulblet production. In addition to the surviving percentage of Lilium bulbs after transplantation, the small size of in vitro bulblets compared to commercial bulbs and bulblets‟ dormancy are the most important constraints to commercializing Lilium micropropagation. Different concentrations of sucrose or sorbitol as carbohydrate sources were investigated as maturation and enlargement factors on in vitro bulblets of Lilium longiflorum cv. „Ceb-dazzle‟. Five concentrations of gibberellic acid and 4°C cold treatment for 6, 7, 8, 9, 10 and 11 weeks in the greenhouse were studied in relation to the dormancy breaking of three in vitro Lilium bulblets cultivars: „Simplon‟, „Navona‟ and „Ceb-dazzle‟, which belong to the Oriental, Asiatic and LA hybrids. The results showed that 3% of sucrose and two weeks of culture significantly increased the bulblet maturation and enlargement of „Ceb...
A cytogenetic and morphometric study was performed on 5 M4 gamma irradiated tetraploid cotton cul... more A cytogenetic and morphometric study was performed on 5 M4 gamma irradiated tetraploid cotton cultivars (Gossypium hirsutum L.). The mutant lines varied significantly in their meiotic characteristics. Meiotic abnormalities including cytomixis, formation of laggard chromosome, stickiness as well as disorganised chromosomes may be responsible for the reduction in pollen fertility and abnormal pollen grain formation in cotton cultivars studied. The cultivars studied differed significantly in their morphometric characteristics indicating their genomic differences.
Enhancement of in vitro micro corm production in Gladiolus as an alternative commercial method ha... more Enhancement of in vitro micro corm production in Gladiolus as an alternative commercial method has been focus of attention. With respet to the position of Gladiolus in Iran's ornamental plants market and in order to provide the proper protocol for the proliferation of glycol corms by tissue culture method, the effect of different concentrations of naphthalene acetic acid (NAA) and benzyl aminopurine (BAP) in two explants and production of shoot and roots of two commercial gladiolus cultivars were investigated. In the next experiment the role of different concentrations of sucrose (in Murashige and Skoog plant growth liquid medium) in production of corms was studied and finally cold treatment in 3 times were used to break dormancy of propagated cormlets. All of the main experiments were conducted as factorial based on completely randomized design with 3 replications. The highest number of shoots (14) and roots (12) was observed in White cultivar with the treatments of 2mg/L BAP a...
Based on their taxonomic characters, six species of genus Rosa were collected from ten provinces ... more Based on their taxonomic characters, six species of genus Rosa were collected from ten provinces of Iran (33 populations). In each population, five plants were randomly selected, and some branches were harvested in spring and autumn to study their vegetative and floral characteristics. Fifty-five qualitative and quantitative characters were grouped using the most suitable method of cluster analysis (Ward), and an ordination diagram was drawn based on the most variable factors for each species and section. Cluster analysis of quantitative and qualitative characters showed significant differences between characters. According to the flora of Iran, there are two main subgenera within the genus Rosa. The first branch separates subgenus Hulthemia from subgenus Rosa. The second group consists of sections Pimpinellifoliae, Caninae and Cinnamomeae. The latter two are very close to each other, and crosspollination between them could be one of the reasons for these close relationships. The results showed that the effect of ecological factors such as altitude of the species habitat influenced intraspecies variation. The results of classification of four species from section Pimpinellifoliae and two species from section Cinnamomeae confirmed previous classification. In this study, three new natural hybrids, Rosa pulverulenta × Rosa boissieri, Rosa elimatica × Rosa iberica and Rosa pimpinellifolia × R. iberica, were reported from Iran for the first time. The results of this study can help us to choose parental hybrids appropriately. Using natural hybrids in breeding programs improves appropriate transfer of character to modern rose species.
Among the genetically modified (GM) crops that are being approved for commercialization, herbicid... more Among the genetically modified (GM) crops that are being approved for commercialization, herbicide resistant crops, especially those harboring cp4-epsps, have a considerable contribution. Gene-specific methods can be used to screen the presence of GMOs. To establish an effective qualitative and quantitative screening method, a set of primers were designed considering the cp4-epsps sequence. The specificity, the limit of detection, the efficiency, and the ability to quantify the GMO content were tested in GM cotton, soybean, and canola events. The results demonstrated that the primers can specifically detect cp4-epsps GM crops. The limit of detection was found to be 0.4 ng/μl DNA per PCR reaction with the ability to detect 1-16 copies of the haploid genome of each GM event. The efficiency of this screening method (which was 94-110% with an R2 higher than 0.96) indicated that these new primers can be applied to the screening of GM samples that contain the cp4-epsps gene. Also, the gene-specific real-time PCR screening method could be successfully developed for qualification of different types of GM cotton, soybean and canola events with the construction of a serial dilution ranging from 10% to 1%.
The taxonomy of polycystine radiolarians is important for biostratigraphic, paleoecological and p... more The taxonomy of polycystine radiolarians is important for biostratigraphic, paleoecological and paleoceanographical reconstructions. In this study we describe four morphogroups of Actinomma boreale from the North Atlantic and Arctic Oceans. We distinguish them from two other four-shelled Actinomma species from the Southern Ocean and North Pacific, namely Sphaeropyle langii and Prunopyle antarctica, which are both moved to genus Actinomma. As A. antarcticum is an already occupied name, P. antarctica is renamed to A. friedrichdreyeri nomen novum. Quantitative and qualitative intraspecific morphological variation was studied by examining 922 specimens (8599 photographs) from 49 samples, of which 45 are from the surface sediment, two are from deeper sediments, and two are plankton samples. We found significant differences in shell diameters between North Atlantic and Arctic Atlantic samples, and between Recent and downcore samples within A. boreale. We also found significant differences between populations of A. friedrichdreyeri and A. langii from the Southern Ocean versus the North Pacific. We do not recommend naming of extant polycystine radiolarian species based on continuous characters without supporting phylogenetic information. Therefore, with this study we have provided directions for phylogenetic investigations on A. boreale, A. friedrichdreyeri and A. langii.
Background The required amounts of chemical fertilizers (NPK) are determined by plant yield, and ... more Background The required amounts of chemical fertilizers (NPK) are determined by plant yield, and product quality is given less consideration. The use of PGPRs is an environmentally friendly approach that, in addition to increasing yield, also improves fruit quality. This study examined the role of specific Streptomyces strains in aiding cucumber plants to 1) use fewer NPK fertilizers in the same quantity 2) improve the quality of cucumber fruit, and 3) promote growth and defense system. Results In this study, the effect of 17 Streptomyces strains on the vegetative traits of cucumber seedlings of the Sultan cultivar was evaluated as the first test. Four strains of Streptomyces with the highest root and shoot dry weight were selected from the strains. This experiment was performed to determine the interaction effect of selected strains and different amounts of NPK on cucumber yield, quality, physiological and biochemical responses of plants. The first experiment’s results revealed tha...
Abstract The possibility of chemical fertilizer residues in cucumber has raised concerns about th... more Abstract The possibility of chemical fertilizer residues in cucumber has raised concerns about the consumption of this beneficial fruit. Although very good studies have been reported on the effect of growth-promoting bacteria on increasing the health of cucumber plants, their performance in commercial greenhouse conditions has been less studied. A two-year study was conducted to evaluate the effect of P. putida strain P3-57 with 100 % or 70 % of the recommended amount of NPK fertilizers on cucumber fruit yield and quality compared to Barvar NPK® commercial biofertilizer under commercial greenhouse conditions. The 30 % reduction in chemical fertilizers reduced yield and overall fruit acceptance score in the sensory evaluation test. Plant treatment with P3-57 or Barvar had no significant effect on yield but when 70 % of chemical fertilizers were used, they increased the quality of cucumber due to the increase in the score of some sensory traits. P3-57-100% had the highest overall acceptance score, which was associated with increased aroma, flavor and fruit juice, and the lowest levels of nitrate, Zn, Mg, Mo, Sr, Ba and Li. Also, the concentration of protein and CAT activity of fruits was higher compared to control-100 % and Barvar-100 %. Evaluation of CAT, APX and POX activity and expression of PR1-1a, GLU, APX, CHIT, LOX and PAL showed that P3-57-100 % and Barvar-100 % stimulate plant immune system through ISR/SAR and SAR pathways respectively. Based on the results of this study, strain P3-57, as a bio-stimulator that increases cucumber quality, has great potential to enter the market.
Plant growth promoting (PGP) effect of Streptomyces on wheat growth in different conditions has b... more Plant growth promoting (PGP) effect of Streptomyces on wheat growth in different conditions has been mostly reported although mechanisms which caused wheat cultivars differently response to a PGP Streptomyces has been less studied. In this study, the effect of two Streptomyces strains, previously reported as PGPR, on the growth of four salt-sensitive commercial wheat cultivars under normal and saline conditions was investigated. Strain C-2012 differently affected the growth of the cultivars in the normal and stress conditions. Cultivars Gonbad with the highest (63%) and Zarin without increased dry biomass upon C-2012 treatments were selected for further study. Salinity significantly decreased seedling fresh and dry weight, K þ and chlorophyll content and glutathione Stransferase activity. Moreover, the stress increased proline and Na þ content and peroxidase (POX) and ascorbate peroxidase (APX) activity in both cultivars. Strain C-2012, generally, ameliorated the negative effect of the stress with increased chlorophyll and carotenoid and reduced Na þ content and APX and SOD activity in both cultivars, however, its effect on biomass was different. Increase in SOD, APX and POX activities in bacterial inoculated-Zarin, but not Gonbad, under normal conditions suggested that this cultivar may recognize strain C-2012 as a gentle stressor and not as a PGPR. These results showed that the responses of the wheat cultivars to a defined PGPR is different in the physiological, phenotypic and molecular level. Based on the results, the evaluation of the effect of a bio-fertilizer on each wheat cultivar is necessary prior to use in a commercial field.
Phytophthora drechsleri damping-off is one of the most important diseases of cucumber (Cucumis sa... more Phytophthora drechsleri damping-off is one of the most important diseases of cucumber (Cucumis sativus). Salinity is a serious problem for crop production and affects diversity and activity of soil microorganisms. Application of salt-tolerant biocontrol agents may be beneficial in order to protect plants against pathogenic fungi in saline soils. In this study, a total of 717 Streptomyces isolates were isolated from the rhizosphere of cucumber, out of which two isolates showed more than 70% inhibitory effect against P. drechsleri and had cellulase activity in the presence and absence of NaCl. In a greenhouse experiment, two Streptomyces isolates with the highest antagonistic activity, strains C 201 and C 801, reduced seedling damping-off of cucumber caused by P. drechsleri by 77 and 80%, respectively, in artificially infested soils. Strain C 201 increased dry weight of seedlings up to 21% in greenhouse experiments. Phylogenetic analyses of 16S rRNA gene sequence reveals that strains C 201 and C 801 are closely related to S. rimosus and S. monomycini respectively. Increased activity of polyphenol oxidase (PPO) and peroxidase (POX) enzymes in Streptomyces-treated plants proved the biocontrol-induced systemic resistance (ISR) in cucumber plants against P. drechsleri.
The availability of iron for roots has been demonstrated as a critical factor in plant production... more The availability of iron for roots has been demonstrated as a critical factor in plant production. The addition of synthetic iron chelates to soil is a common practice in agriculture, which is not economically beneficial. Besides, chemical iron fertilizers cause many problems such as food contamination and environmental pollution. Development of natural Ferrioxamine B as an efficient and safe iron source may be the best strategy to overcome plant iron deficiency and prevention of synthetic agent pollution. The present study investigates the ability of a hydroxamate type siderophores
The genus Rosa has a wide variety in Iran and although some natural hybrids have been found in di... more The genus Rosa has a wide variety in Iran and although some natural hybrids have been found in different regions of the country, but no cultivars have been established so far. In order to optimize use of genetic resources in the country and to create varieties with desirable traits, inter-species relationships and identification of diversity, 45 populations from seven species in section Caninae collected from 13 provinces of Iran, were studied. To group the species, 61 qualitative and quantitative characters using the most suitable method of cluster analysis (WARD) were used and their ordination diagram based on the most variable factors for each species and sections were drown. Cluster analysis of quantitative and qualitative characters showed significant differences between characters. The results of classification confirmed previous taxonomy grouping. Factor analysis of R. elymatica populations showed that the hair on pedicels, sepal form, hip length, prickle base and prickle for...
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