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Effect of salt stress on physiological and antioxidative responses in two species of Salicornia (S. persica and S. europaea

100%

Aghaleh M. , Niknam V. , Ebrahimzadeh H. , Razavi K.

Acta Physiologiae Plantarum

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2011

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tom 33

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nr 4

EN

The effects of salt stress on growth parameters, free proline content, ion accumulation, lipid peroxidation, and several antioxidative enzymes activities were investigated in S. persica and S. europaea. The seedlings were grown for 2 months in half-strength Hoagland solution and treated with different concentrations of NaCl (0, 85, 170, 340, and 510 mM) for 21 days. The fresh and dry weights of both species increased significantly at 85 and 170 mM NaCl and decreased at higher concentrations. Salinity increased proline content in both the species as compared to that of control. Sodium (Na⁺) content in roots and shoots increased, whereas K⁺ and Pi content in both organs decreased. At all NaCl concentrations, the total amounts of Na⁺ and K⁺ were higher in shoots than in roots. Malondialdehyde (MDA) content declined at moderate NaCl concentrations (85 and 170 mM) and increased at higher levels. With increased salinity, superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (GPX) activities also increased gradually in both species. In addition, it seems that GPX, CAT, and SOD activities play an essential protective role in the scavenging reactive oxygen species (ROS) in both species. Native polyacrylamide gel electrophoresis (PAGE) indicated different isoform profiles between S. persica and S. europaea concerning antioxidant enzymes. These results showed that S. persica exhibits a better protection mechanism against oxidative damage and it is more salt-tolerant than S. europaea possibly by maintaining and/or increasing growth parameters, ion accumulation, and antioxidant enzyme activities.

2

Initiation and origin of stigma-like structures [SLS] on ovary and style explants of saffron in tissue culture

88%

Namin M. H. , Ebrahimzadeh H. , Ghareyazie B. , Radjabian T. , Namin H. H.

Acta Biologica Cracoviensia. Series Botanica

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2010

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tom 52

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nr 1

55-60

EN

Saffron, made from the dried stigmas of Crocus sativus L., contains pigments and valuable aromatic compounds, and can be used in medicine and as a spice. Nowadays its production is lower than demand. Tissue culture presents an alternative biochemical tool which can be used to produce stigma-like structure (SLS) in vitro. In this study, the origin and induction of SLS formation was investigated in ovary and style explants of floral buds on MS medium supplemented with 1-naphthalene acetic acid (NAA) and 6-benzlaminopurine (BAP). SLS were directly originated through meristematic cells or indirectly in the form of colorless globular structures from parenchyma tissue. The colorless globular structures initially were conical and pale yellow color at the sharp ends; subsequently they matured into trumpet-like red stigmas with or without finger-like papillae at the margins. Light and electron microscopic observations of ultra- and semithin sections of different developmental stages of SLS showed that these structures possess two kinds of cells: (1) small cells close to parenchyma tissues and (2) large cells oriented towards the peripheral area and apparently originated from the small ones. Our results suggest that the SLS originated from internal parenchyma tissues.

3

The effect of methyl jasmonate on enzyme activities in wheat genotypes infected by the crown and root rot pathogen Fusarium culmorum

88%

Motallebi P. , Niknam V. , Ebrahimzadeh H. , Enferadi S. T. , Hashemi M.

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nr 11

EN

The hemibiotrophic pathogen Fusarium culmorum (Fc) causes crown and root rot (CRR) in wheat. In this study, MeJA treatment was done 6 h after pathogen inoculation (hai) to focus the physiological and biochemical responses in root tissue of the susceptible wheat cv Falat, partially resistant cv Pishtaz and the tolerant cv Sumai3 at the beginning of the necrotrophic stage. The results indicate that treatment with MeJA at 6 hai significantly delayed the necrotic progress in cv Falat, whereas no significant difference was seen in other cultivars. The activities of pathogen responsive defense-related enzymes (SOD, CAT, POX, PPO, LOX and PAL), total phenols and callose contents were higher in Sumai3, while treatment with MeJA significantly increased these enzymes activities and total phenols content in Falat, signifying the most sensitive cultivar which had a weak reaction to the pathogen but a strong response to MeJA treatment. Additionally, MeJA treatment decreased the level of H2O2 and MDA contents particularly in cv Falat. This is the first work reporting the regulation of defense-related enzymes by MeJA treatment at particular time point of 6 hai suggests the possible role of JA in regulating basal resistance in CRR pathogen–wheat interaction. Taken together, our data add new insights into the mechanism of wheat defense including enzymatic events controlling wheat protection against Fc infection.

4

Content of different groups of phenolic compounds in microshoots of Juglans regia cultivars and studies on antioxidant activity

75%

Cheniany M. , Ebrahimzadeh H. , Vahdati K. , Preece J. E. , Masoudinejad A. , Mirmasoumi M.

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nr 02

EN

Phenolic and other compounds were extracted from micropropagated axillary shoots (microshoots) of the walnut (Juglans regia L.) cultivars ‘Chandler’, ‘Howard’, ‘Kerman’, ‘Sunland’, and ‘Z63’. Among cultivars, microshoots showed differences in phenolic compounds, phenolic acids, flavonoids, and proanthocyanidins. All cultivars contained the phenolics acids chlorogenic acid, gallic acid, p-coumaric acid; the naphthoquinone juglone; and the flavonoid quercetin. The phenolic acids syringic acid and vanillin were present only in microshoots of ‘Howard’. Microshoot extracts had different antioxidant activity with ‘Kerman’ the highest and ‘Chandler’ the lowest in each of three antioxidant assays: the phosphomolybdenum assay (PPM), reducing power assay, and 2,2- diphenyl-1-picrylhydrazyl-scavenging effect. There was a strong linear relationship between total phenolic compound content of microshoots and increasing antioxidant activity.