Response Of Strawberry ‘Selva’ Plants On Foliar Application Of Sodium Nitroprusside (Nitric Oxide Donor) Under Saline Conditions

This study was conducted to evaluate enzymatic and non-enzymatic antioxidant response of ‘Selva’ strawberry plants on exogenous nitric oxide under saline conditions with respect to time of application. Sodium nitroprusside (SNP), as nitric oxide (NO) source, was applied on the leaves by spray before, simultaneously, or after the initiation of saline stress. Results indicated that salinity and/or SNP at concentrations of 50 and 75 μM caused increase in activity of antioxidant enzymes, such as catalase, superoxide dismutase, glutathione reductase, ascorbate peroxidase and peroxidases as well as leaf content of proline, glycine betaine and total phenolics in comparison to control. Time of NO application was important because the highest levels of catalase and ascorbic peroxidase were in plants pre-treated with SNP one week before the initiation of salinity stress. Plants from these combinations had the highest fruit yield among all saline stressed plants. So, it seems that earlier application of SNP is more effective for an optimised protection against deleterious influence of salinity stress, because pre-treated plants had a sufficient time to develop an appropriate antioxidant response. The application of SNP simultaneously or after exposure of plants to stress conditions, was also helpful in increasing plant tolerance but to a lesser extent

Soluble sugars and proline accumulation play a role as effective indices for drought tolerance screening in Persian walnut (

Introduction. Drought stress is the major factor affecting growth, development and production of walnut trees. In Iran, approximately 33 Mha of land is affected by salinization and drought stress. Finding genetic resources tolerant to drought stress at different growth stages is important for such semi-arid regions. Our aim was to understand better the adaptive mechanisms that enable different genotypes of walnut population to survive under drought stress, and to provide some useful clues for walnut tree breeding toward improved drought tolerance with utilization of existing drought-tolerant genetic resources. Materials and methods. To study the mechanism(s) involved in drought tolerance of some Persian walnut genotypes, drought stress was induced using polyethylene glycol-6000 to produce water potentials of 0 Mpa (control), –0.10 MPa, –0.50 MPa, –0.75 MPa, –1.00 MPa, –1.50 MPa and –2.00 MPa. The amount of proline and soluble sugar accumulation in four walnut genotypes (‘Panegine20’, ‘Lara’, ‘Serr’ and ‘Chandler’) were determined after being exposed to the various water potential levels. Results. The rates of seed germination in all genotypes were significantly reduced by low external water potentials. Plants exposed to water stress had a higher amount of soluble sugars in roots and shoots of tolerant genotypes (‘Panegine20’ and ‘Chandler’) and a lower amount of starch in their tissues. These results imply the important roles of soluble sugars as solutes conferring resistance to drought in these genotypes. The free proline levels were also increased in response to drought stress. They were higher in drought-tolerant genotypes than in sensitive ones (‘Lara’ and ‘Serr’). Proline increased more in shoots than in roots. However, the soluble sugar and starch fluctuations were higher in the roots. Conclusion. Our results support a direct correlation between the degree of drought stress and proline content. As a consequence, proline concentrations could be used as a biochemical marker of drought stress level in walnut plants

The ameliorative effects of spermidine and calcium chloride on chilling injury in pomegranate fruits after long-term storage

Introduction. Pomegranate fruits (Punica granatum L.) are chilling-sensitive crops. Materials and methods. Pomegranate fruits were treated with calcium chloride and spermidine, alone or in combination, by normal dip and vacuum infiltration methods. The treated fruits were stored at 2 °C for 4 months. At the end of the storage period, samples were held for 3 days at 20 °C, then the qualitative constituents were evaluated. Results and discussion. Treated fruits exhibited less weight loss and higher juice content than control fruits. Non-treated fruits developed chilling injury manifested as an increase in K+ leakage and polyphenol oxidase activity. Calcium chloride and spermidine treatments resulted in lower soluble solid content, but some fruits showed higher titratable acidity. All treatments significantly increased ascorbic acid content. The pH of aril juice in treated fruits was lower than that of non-treated fruits, probably due to higher titratable acidity. Total antioxidant activity and total phenolic content increased in treated fruits. In our study, a correlation was observed between total phenolic content and total antioxidant activity. Conclusion. The treatments applied in our experiments maintained overall quality of pomegranate fruits during long-term storage. Postharvest application of calcium and spermidine either alone or in combination could ameliorate adverse effects of low temperature on pomegranate fruit quality during cold storage. Vacuum infiltration was as effective as the normal dip method. However, normal dip is a simpler and faster treatment method

Determination of oil and fatty acids concentration in seeds of coastal halophytic Sueada aegyptica plant

Background: Suaeda aegyptica (S. aegyptica) species belong to the Chenepodiaceae family, the second largest family in the world of plants kingdom. It is indigenous to arid and semi-arid regions of the world and salty coastal zones Persian Gulf of Iran. It is an annual succulent halophyte plant which is characterized by producing oily seeds, high growth rate and large number of biomass. The aim of this study was analysis and determination of oil and fatty acids concentration in the S. aegyptica seed. Material and Methods: The seeds of S. aegyptica were collected form coastal zones of Persian Gulf in Bushehr province, washed and dried. The fatty acids content of the dried seeds were extracted in n-hexane solvent by soxhellet apparatus. The residue of n-hexane in oily phase was evaporated by rotary evaporator and remaining oil was collected for fatty acids analysis. In the presence of potassium hydroxide and BF3 by refluxing for 30 minutes, the methyl ester derivative of fatty acids were produced. Then the resulted derivatives were analyzed by gas chromatography (GC-FID). Results: The seeds of S. aegyptica contains eight fatty acids as: Pelargonic (C9), Capric (C10), Undecylic (C11), Tridecylic (C13), Myristic (C14), Palmitic (C16), Stearic (C18), Linoleic (18:2) and Linolenic (18:3). Average oil content in seeds 014/0 ± 87 / percent. Conclusion: The ratio of unsaturated fatty acids was higher than the saturated ones. Linoleic and Palmitic acids are major unsaturated and saturated fatty acids of S. aegyptica seed respectively

How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels

<div><p>Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH₄NO₃) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in <i>Triticum aestivum</i> plants.</p></div

Determination of fatty acid composition of halophyte plant (Suaeda vermiculata) collected from the shorelines of Persian Gulf region (Bushehr Province).

Background: This study was carried out to determine the oil content and of fatty acids in stem, leave and seed of halophyte plant (Suaeda vermiculata ) locally called &ldquo;Tahma&rdquo; growing along the shorelines of the Persian Gulf in Bushehr Province. Material and Methods: The total oil and fatty acid contents of leaves, stem and root were extracted in n-hexane using Soxhlet and the fatty acid compositions were determined by FID- Gas chromatography. Results: The amount of oil content ranged from 0.68 to 1.74% by dry weight. The lowest present was for in stem and the highest for leave respectively. A total of 11 fatty acids were detected in leave, stem and root of which 8 were saturated and 3 unsaturated. The major saturated fatty acid in leave and stem was palmitic but in the seed was margaric acid. Also, the major unsaturated fatty acids in leave, seed and stem were oleic, linoleic and linolenic respectively. Our results also showed the presence of fatty acids such as plargonic, palmitic and stearic in all of the above organs, which the plargonic was dominant in leave but palmitic, linoleic and stearic in stem. Conclusion: Analysis of results showed that in the seeds of S. vermiculata the major saturated fatty acid is margaric and the major unsaturated fatty acid is linoleic. Also it was shown that the amount of saturated fatty acids in the seed were more than unsaturated fatty acids

Effects of NO and nitrogen sources on GS activity.

<p>Wheat seedlings (cvs Spitfire and Westonia) were grown in glasshouse for two weeks. Then, plants were irrigated with nitrogen-free nutrient solution for a week. Plants treated with different concentrations (left = 4mM and right = 40 mM) and different chemical forms of nitrogen (A = NHCl, B = KNO₃ and C = NH₄NO₃) with 0 (as a control), 20 or 100 μM of SNP for 3 days. Leaf tissues were harvested 24 hours after nitrogen treatments. GS activity was measured on three biological repeats. Different letters meaning significantly different at 5% levels as calculated by Duncan multiple test.</p

List of primers.

<p>List of primers.</p

Effects of NO and nitrogen sources on NO content.

<p>Wheat seedlings (cvs Spitfire and Westonia) were grown in glasshouse for two weeks. Then, plants were irrigated with nitrogen-free nutrient solution for a week. Plants treated with different concentrations (left = 4mM and right = 40 mM) and different chemical forms of nitrogen (A = NHCl, B = KNO₃ and C = NH₄NO₃) with 0 (as a control), 20 or 100 μM of SNP for 3 days. Leaf tissues were harvested 24 hours after nitrogen treatments. NO content was measured on three biological repeats. Different letters meaning significantly different at 5% levels as calculated by Duncan multiple test.</p

Effects of high nitrogen (40 mM) on mRNA expression.

<p>Effects of high nitrogen (40 mM) on mRNA expression.</p