Significant Reduction In Growth Parameters Research Articles

Trifloxystrobin Pretreatment Alleviates Excessive Copper Stress in Wheat (Triticum aestivum L.)

Protective role of Trifloxystrobin pretreatment against excessive copper-related abiotic stress in Triticum aestivum L. was determined in two Turkish wheat cultivars, Sönmez and Gerek 79. Ten-day-old seedlings were pretreated with 20 µM and 80 µM Trifloxystrobin. A group of seedlings was harvested without exposure to Trifloxystrobin as a control. Two days after, seedlings were treated with copper(II) chloride. Seedlings were harvested on the 20th day after sowing. The growth level of the groups was evaluated by measuring the length, fresh weight and shoot dry weight of shoots. Chlorophyll a + b, carotenoid and anthocyanin contents as well as proline levels were assessed. Lipid peroxidation and total activities of superoxide dismutase, peroxidase and glutathione reductase were analyzed to predict the oxidative stress levels. Both cultivars exhibited similar responses to the treatments. Trifloxystrobin doses did not cause damage on plants when applied alone. Seedlings subjected to excessive doses of copper showed significant reductions in growth parameters, as well as chlorophyll and carotenoid pigments. Conversely, copper caused a remarkable increase in anthocyanin, proline and malondialdehyde accumulation. Superoxide dismutase and peroxidase activities increased, while glutathione reductase activity decreased in copper-stressed plants. Trifloxystrobin pretreatment strengthens the antioxidant defense system. All parameters were positively affected by Trifloxystrobin pretreatment. As the dose of Trifloxystrobin increased, the severity of stress decreased in both genotypes. Trifloxystrobin pretreatment is a promising method for reducing copper-induced damage in T. aestivum.

Can deficit irrigations be an optimum solution for increasing water productivity under arid conditions? A case study on wheat plants

Water scarcity is of growing concern in many countries around the world, especially within the arid and semi-arid zones. Accordingly, rationalizing irrigation water has become an obligation to achieve the sustainable developmental goals of these countries. This may take place via using deficit irrigation which is long thought to be an effective strategy to save and improve water productivity. The current study is a trial to evaluate the pros and cons of using 50 and 75 % of the irrigation requirements (IR) of wheat (deficit irrigations) versus 100 %IR, while precisely charting changes in wheat growth parameters, antioxidant enzymes in plant shoots and the overall nutritional status of plants (NPK contents). Accordingly, a field experiment was conducted for two successive seasons, followed a split-plot design in which deficit irrigations (two irrigations to achieve 50 % of the irrigations requirements (IR), three irrigations to attain 75 % IR, and four irrigations to fulfill 100 % IR) were placed in main plots while four different studied wheat cultivars were in subplots. Results obtained herein indicate that deficit irrigations led to significant reductions in growth parameters and productivity of all wheat cultivars, especially when using 50 % IR. It also decreased NPK contents within plant shoots while elevated their contents of proline, peroxidase, and catalase enzymes. On the other hand, this type of irrigation decreased virtual water content (VWC, the amount of water used in production on ton of wheat grains). Stress tolerance index (STI), and financial revenues per unit area were also assessed. The obtained values of grain productivity, STI, VWC and financial revenues were weighted via PCA analyses, and then introduced in a novel model to estimate the efficiency of deficit irrigations (ODEI) whose results specified that the overall efficiency decreased as follows: 50 %IR < 75 %IR < 100 %IR. In conclusion, deficit irrigation is not deemed appropriate for rationalizing irrigation water while growing wheat on arid soils.

Influence of herbicides under biofertilizer application on fennel (Foeniculum vulgare) yield and quality with special reference to herbicide residues

BackgroundWeed occurrence and fertilization are considered two of the most factors influencing fennel yield. A two season’s field study was undertaken to investigate the response of fennel crop to two different herbicides under the application of biofertilizers. The two herbicides are pendimethalin (at reduced rate), fluazifop-p butyl and a combination of sequential application of both of them. The biofertilizers were used in 3 rates of 1:1:1, 2:1:1 and 1:1:2 (v/v/v) from atmospheric nitrogen-fixating, phosphorous-dissolving and potassium-solubilizing bacterial strains.ResultsThe results indicated that under all rates of the biofertilizers, the two herbicides applied individually caused significant reduction in growth parameters of the fennel plant estimated. Hand weeding (untreated check) increased fruit yield by 63% and oil yield by 78% compared to unweeded control, while sequential application of pendimethalin + fluazifop increased fruit yield by 45% and oil yield by 83% under biofertilizers at the rate of 2:1:1. Slight decrease in protein content using pendimethalin + fluazifop (12.94, and 12.96%) compared to 13.56% for hand weeding was observed. However, fluazifop alone showed no significant differences (13.63 and 13.13%) during both seasons under the biofertilizer rate of 2:1:1. No detectable residues of pendimethalin and fluazifop applied alone or sequentially were found in the analyzed dry seeds.ConclusionThe obtained results concluded that using proper level of biofertilizer combined with herbicides would increase the seed yield and oil content of fennel. Nevertheless, further investigation is needed to search for safer and effective weed control methods in medicinal plants.

Heat shock proteins gene expression and physiological responses in durum wheat (Triticum durum) under salt stress.

Salt stress is a major abiotic stress causing adverse effects on plant growth and development. The aim of this study was to investigate the effect of NaCl stress on growth, stress indicator parameters (lipid peroxidation, chlorophyll content and proline content), yield, and the expression of heat shock proteins genes (Hsp17.8, Hsp26.3, Hsp70 and Hsp101) of five Jordanian durum wheat (Triticum durum) landraces. Plants were irrigated with tap water as control or 200mM NaCl. Significant differences among the 5 Triticum durum landraces in terms of growth parameters,stress indicator parameters, and expression of heat shock proteins genes were observed. Salt stressed landraces demonstrated decreased growth, increased levels of stress indicator parameters, and upregulation in Hsp17.8, Hsp26.3, Hsp70 and Hsp101 expression. Landraces T11 and M23 showed the highest growth, lowest levels of stress indicator parameters, and high expression of heat shock protein genes under NaCl stress. Whereas, J2 and A8 landraces showed the lowest growth, highest levels of stress indicator parameters and low expression of heat shock protein genes under NaCl stress. In conclusion, NaCl stress caused significant reduction in growth parameters, increased level of lipid peroxidation and proline content and upregulation in heat shock proteins gene expression levels. Growth, stress indicator parameters and gene expression results suggest that T11 and M23 landraces are the most NaCl stress tolerant landraces and could be used to enhance the gene pool in wheat breeding programs.

Inducing Salinity Tolerance in Mango (Mangifera indica L.) Cv. “El-Gahrawey” by Sodium Silicate Pentahydrate and Glycine Betaine تعزیز تحمل شتلات المانجو صنف ̋ الجحراوى ̏ للملوحة بواسطة سلیکات الصودیوم والجلیسین بیتین.

The investigation was done to study the effect of Sodium Silicate Pentahydrate (Si) and Glycine betaine (GB) on enhancing salt tolerance of Mango seedlings “El-Gahrawey” cultivar grown under salinity stress. The results indicated that the application of sodium chloride (NaCl) induced a significant reduction in growth parameters and plant development, increasing salinity levels decreased plant leaf number, stem diameter, and stem length as well as fresh and dry weight of leaves. Also, a reduction of chlorophyll was observed in salt-affected plants. Besides, salt stress lead to an accumulation of sodium Na+ and a decrease in N, P, K+, Ca2+, and Mg2+ concentrations in mango leaves. However, Combinations of Si and GB sprays was the most effective treatment in alleviating the negative impacts of salt stress in mango, this treatment increased significantly most of the tested parameters under salt stress.

Ocimum basilicum Leaf Extract Induces Salinity Stress Tolerance in Faba Bean Plants

THE PRESENT work investigated the possible protective role of aqueous Ocimum basilicum leaves extract (OLE) on Vicia faba plants irrigated with different leves of salinity (0.0, 50, 100 or 150 mM NaCl). The toxic effects of salinity on Vicia faba plants were assessed by determining oxidative stress such as lipid peroxidation. Furthermore, growth parameters, antioxidant enzymes activity [catalase (CAT), peroxidase (POD) and ascrobate peroxidase (APX)], organic solutes (soluble sugars, soluble proteins and proline) and ions content (Na+, K+, Ca2 and Mg2+) on Vicia faba plants grown under salinity stress in the presence or absence of aqueous extract of O. basilicum leaves were also measured. The obtained results revealed that salinity stress resulted in a significant increase in the activity of antioxidant enzymes, organic solutes, lipid peroxidation and ions content, which were associated with a significant reduction in growth parameters compared with control plants. OLE significantly alleviated the harmful effect of salinity on Vicia faba plants and increased the activity of antioxidant enzymes activity, osmolytes (soluble sugar and soluble protein), and ions content (K+, Ca2+ and Mg2+), which could be an induced defensive mechanism against salinity stress.

INFLUENCE OF SALINITY ON GROWTH AND ORGANIC COMPOUNDS CONTENT OF CARROT (Daucus carota L.)

Carrot production of valuable carotenes, carbohydrate and protein are hindered by elevated salinity levels in many parts of the world. To assess this problem, germination and growth of two carrot cultivars (Daucus carota cvs Jordan and Napoli) were studied in vivo and in vitro under different salt stress concentrations (0, 75, and 150 mM NaCl). Seeds were directly or gradually exposed to these salt concentrations. With elevated salinity levels, significant reductions in growth parameters (dry shoot weight, fresh shoot weight, shoot length, root length, and root number) were observed. Also, significant difference in germination percentage was observed at 150 mM NaCl in both cultivars when compared with control treatment (90% germination percentage in Napoli and 71% in Jordan cultivar). Growth rate, tolerant index, and relative water content (RWC) declined as salinity increased. The 150 mM NaCl salinity treatment significantly reduced the shoot chlorophyll and protein content, but increased carbohydrate content. Lesser impairment by the gradual exposure of seedling to salinity provides an opportunity to study the acquirement of salt tolerance.

NUTRIENT UPTAKE, PROLINE CONTENT AND ANTIOXIDANT ENZYMES ACTIVITY OF PEPPER (Capsicum annuum L.) UNDER HIGHER ELECTRICAL CONDUCTIVITY OF NUTRIENT SOLUTION CREATED BY NITRATE OR CHLORIDE SALTS OF POTASSIUM AND CALCIUM

This study was conducted to evaluate effects of higher conductivity of nutrient solution created by nitrate or chloride salts of potassium and calcium on growth characteristics of pepper plants (Capsicum annuum var annuum) during four months of growth period. Two EC5 and EC8 dS/m of Hoagland nutrient solution were prepared using various salt combinations, namely; KCl + CaCl2, KNO3 + CaNO3, and KNO3 + CaNO3 + NaCl. Hoagland nutrient solution with EC 1.8 dS/m was served as control. Higher conductivity treatments had different effects on pepper plant growth. The most significant reduction in growth parameters of plant height, shoot fresh weight, fruit yield and nutrients uptake were in plants treated with KCl + CaCl2 particularly at EC8. Application of KNO3 + CaNO3 particularly at EC5 showed no difference with control regarding many growth parameters. Application of KNO3 + CaNO3 at EC5 resulted in higher shoot fresh weight compared to control. All salinity treatments except KNO3 + CaNO3 at EC5 reduced fruit yield compared to control. Treatments of KCl + CaCl2 and KNO3 + CaNO3 + NaCl particularly at EC8 of nutrient solution resulted in higher leaf proline concentration, catalase and peroxidase enzymes activity compared to control. Other conductivity treatments showed no difference in catalase or peroxidase enzymes activity. The significant lowest amount of leaf N, K, Mg and Ca was in KCl + CaCl2 at EC8. On the other hand, the highest leaf macronutrient concentrations were in KNO3 + CaNO3 at EC5 and/or EC8 that showed only higher leaf N and Ca values compared to control. Leaf micronutrient concentrations were highest in KNO3 + CaNO3 at EC5 that generally showed no difference with control plants. However, application of KCl + CaCl2 particularly at EC8 and to less extent KNO3 + CaNO3 + NaCl at EC8 reduced leaf micronutrient concentrations. Application of KNO3 + CaNO3 at EC5 increased and KCl + CaCl2 or KNO3 + CaNO3 + NaCl at EC8 decreased the leaf Fe concentration compared to control plants.

Toxicity assessment of anatase (TiO2) nanoparticles: A pilot study on stress response alterations and DNA damage studies in Lens culinaris Medik

The research was targeted to investigate the effect of nano-TiO2 (anatase) on germination, vigour index, stress enzymes and mitotic cell cycle profile in lentils (Lens culinaris Medik.). Seed germination results indicated that TiO2 NP (Nanoparticle) at lowest concentration promotes seed germination, vigour index and biomass; however, at higher concentrations, they showed significant reduction in growth parameters and photosynthetic pigments in concentration-dependent manner. NP treatments triggered an excessive formation of reactive oxygen species (ROS) which was evident from increased production of stress enzymes, lipid peroxidation, augmented DNA damage and aberrant mitotic cell division. The results exhibit a dose-dependent modification of NP- mediated oxidative stress and genotoxicity in lentil.

Arsenate disrupts ion balance, sulfur and nitric oxide metabolisms in roots and leaves of pea (Pisum sativum L.) plants

Arsenic (As) pollution is a significant environmental problem worldwide. Although this metalloid affects plant growth and productivity, it is usually associated with oxidative stress which affects a diverse range of metabolic pathways. However, an additional hazard of As is its presence in edible parts of plants which constitutes a potential animal and human health risk. We exposed 20-d-old pea (Pisum sativum L.) plants, which were used as a model due to their agronomic importance, to 50 μM arsenate (AsV). We then analyzed physiological and biochemical parameters in roots and leaves to determine the principal metabolic characteristics of sulfur, reactive oxygen and nitrogen species (ROS and RNS) metabolisms as well as NADPH-regenerating systems. AsV triggered a significant reduction in growth parameters and an increase in oxidative markers (lipid and protein oxidation) in both roots and leaves. In addition, AsV induced a high level of biosynthesis of enriched sulfur compounds such as phytochelatins (PC2 and PC3) in both roots and leaves, with a concomitant decrease in reduced glutathione (GSH) content. These changes were accompanied by alterations in antioxidative enzymes, the NADPH-regenerating system and nitric oxide (NO) metabolism. In roots, these changes were associated with a significant increase in the amino acids proline, glycine, glutamic acid and γ-aminobutyric acid (GABA) content as well as endopeptidase activity. Analysis of AsV-treated 63-d-old pea plants, which had already developed pods, also showed that As is mainly restricted to roots. Although our results indicate that 50 μM AsV causes a differential metabolic response in roots and leaves, the biochemical adaptation of roots to palliate the negative impact of As is more pronounced. This may enable pea plants to survive by restricting As accumulation in roots and by reducing the level of As in the edible parts of the pea plant (fruits).

Effect of Exogenous α-Tocopherol on Sweet Pepper Plants Irrigated by Diluted Sea Water

Capsicum annum is one of the most cultivated summer crops in Egypt which is consider the most susceptible crop to harsh a biotic stresses as Salinity condition. Pots experiment was carried out at Faculty of Agriculture, Fayoum University, Egypt during two successive summer seasons of 2014 and 2015 to study the responsive of Sweet pepper (cv. California wonder) plants irrigated by diluted sea water (EC= 8.0 dSm-1) to foliar applications of 1 mM alpha-Tocopherol (α TOC). Four treatments were arranged in a randomized block design:1) plants irrigated by sea water (SW) and sprayed by tap water (TW), 2) TW for irrigation and α TOC for foliar spray, 3) SW for irrigation and α TOC for foliar spray and 4) the control (TW for irrigation and foliar spray). Pepper plants irrigated by sea water recognized significant reductions in growth parameters (leave number, leaf area, plant dry weight, Fruit number and Fruit yield). Results also showed that, foliar application of pepper plant with αTOC caused a notable upgrading in growth and yield under saline conditions. The maximum increased growth was obtained when plants irrigated by TW and sprayed by 1 mM αTOC. The foliar application of αTOC considerably boosted the activities of Superoxide dismutase (SOD), Catalase (CAT), Ascorbate peroxidase (APX) and Glutathione reductase (GR) of pepper plants contrasted to control treatment. The outcome of present experiment could be recommended for both new reclaimed lands suffering from salt water and regions exposure to salinity hazard in irrigated water.

Biochemical and molecular mechanisms associated with Zn deficiency tolerance and signaling in rice (Oryza sativa L.)

ABSTRACTIn this study, zinc (Zn) deficiency caused a significant reduction in growth parameters and tissue Zn concentrations in BRRI 33 (sensitive) but not in Pokkali (tolerant). The increase of proton extrusion in both genotypes under high pH suggests that it gets triggered as a common consequence of reducing pH and solubilization of Zn. Real-time PCR showed pronounced upregulation of OsZIP4, OsDMAS1, OsNAS2 and OsPCS1 in Zn-deficient roots of Pokkali, and to a lesser extent in BRRI 33 only for OsZIP4 and OsPCS1. This suggests that OsDMAS1, OsNAS2 and OsPCS1 functions as secondary consequences leading to higher chelation and uptake of Zn under Zn deficiency in Pokkali. Further, a major increase in CAT, POD, SOD, GR and key metabolites suggests that high antioxidant defense plays a critical role in Zn deficiency tolerance in Pokkali. Further, Pokkali self-grafts and plants having Pokkali rootstock combined with BRRI 33 scion showed no significant decline in plant height, root dry matter and Zn concentration along with upregulation of Zn transporters (OsZIP4 and OsIRT1) under Zn deficiency, suggesting that signal driving mechanisms for Zn deficiency tolerance mechanisms are generated in the root and Zn-inefficient BRRI 33 is not capable of producing signals or sensing them.

Biochemical and molecular responses underlying differential arsenic tolerance in rice (Oryza sativa L.)

The arsenic (As) is a toxic element causing major health concern worldwide. Arsenate stress caused no significant reduction in growth parameters and shoot electrolyte leakage but showed increased root arsenate reductase activity along with relatively lower root As content and shoot translocation rate in As-tolerant BRRI 33 than in As-sensitive BRRI 51. It indicates that As inhibition and tolerance mechanisms are driven by root responses. Interestingly, As stress showed consistent decrease in phosphate content and expression of phosphate transporters (OsPT8, OsPT4, OsPHO1;2) under both high and low phosphate conditions in roots of BRRI 33, suggesting that limiting phosphate transport mainly mediated by OsPHO1;2 directs less As accumulation in BRRI 33. Further, BRRI 33 showed simultaneous increase in OsPCS1 (phytochelatin synthase) expression and phytochelatins (PCs) content in roots under As exposure supporting the hypothesis that root As sequestration acts as ‘firewall system’ in limiting As translocation in shoots. Furthermore, increased CAT, POD, SOD, GR, along with elevated glutathione, methionine, cysteine and proline suggests that strong antioxidant defense plays integral part to As tolerance in BRRI 33. Again, BRRI 33 self-grafts and plants having BRRI 33 rootstock combined with BRRI 51 scion had no adverse effect on morphological parameters but showed reduced As translocation rate, increased root arsenate reductase activity, shoot PC synthesis and root OsPHO1;2 expression due to As stress. It confirms that signal driving As tolerance mechanisms is generated in the roots. These findings can be implemented for As detoxification and As-free transgenic rice production for health safety.

Influence of elevated carbon dioxide and ammonium nutrition on growth and nitrogen metabolism in wheat (Triticum aestivum)

Growth under elevated CO2 (EC) conditions inhibits nitrate (NO3-) assimilation in crop plants, hence ammonium (NH4+) nutrition is beneficial compared to NO3– nutrition under EC conditions. In the present study, an attempt was made to compare the suitability NH4 + vs mixed NH4 + + NO3 – nutrition in wheat (Triticum aestivum L.). Wheat seedlings supplied with NH4+ alone or with both NH4+ + NO3– as nitrogen (N) source and grown under ambient (380 μl/l, AC) or elevated (600±50 μl/l, EC) CO2 conditions were analyzed for growth and biochemical parameters. Plants receiving only NH4+ as N source showed significant reduction in growth parameters. The negative effects of NH4+ nutrition were manifested in form of reduced root length, root surface area and thinner leaves under EC. Negative effects of NH4+ nutrition were ameliorated in plants receiving mixed NH4 + + NO3 – nutrition. Supplementing NO3 – -N with NH4+ -N led to the enhancement of various morphological and biochemical parameters in EC grown plants. Activity and gene expression of the enzymes, nitrate reductase and glutamine synthetase was significantly higher in plants supplied with both NH4+ + NO3– ions and grown in EC, as compared to plants grown in AC, resulting in lesser reduction in N content of the EC grown plants. Our study indicates that mixed NH4+ + NO3– nutrition will be more suitable for wheat cultivation under high CO2 conditions in future.

Effects of Short or Long-Term Exposure of Dithiopyr on Certaine Blood, Growth and Tissue Biochemical Parameters in Catfish (Clarias garipinus)

In the current study the effects of acute or chronic exposure of dithiopyr herbicide (weed controllers) in Catfish (Clarias garipinus) was studied. LC50 was determined, and recorded as 460 μgl-1. Acute and chronic effects on certain blood, growth and tissue biochemical parameters were studied as a function of exposure time. Exposure of Clarias garipinus to acute or chronic toxicity of the herbicide resulted in significant increase in glucose, total cholesterol, creatinine, uric acid and Lactate dehydrogenase (LDH) in the herbicide-treated group, while aspartate aminotransferase (AST) and alanine aminotransferase (ALT) showed a fluctuating activities in both exposures. In contrast, there was significantly (P&lt;0.01) lower values for liver and muscle glycogen in acute toxicity as compared with the control group. Also, in herbicide exposed fish a significant reduction in growth parameters was recorded. These alterations could be attributed to the changes in the metabolic pathways of the studied fish that meight be takes place as a secondary response in the fish to provide energy for the "fight-or-flight" reaction and to compensate the high energy demand. This study implies the importance of previous knowledge about the susceptibility of cultured fish species before using herbicides.Int J Appl Sci Biotechnol, Vol 3(2): 314-321 DOI: http://dx.doi.org/10.3126/ijasbt.v3i2.12686

Evaluation of photosynthetic performance of wheat cultivars exposed to boron toxicity by the JIP fluorescence test

The changes in growth and photosynthetic performance of two wheat (Triticum aestivum L.) cultivars (Bolal-2973 and Atay-85) differing in their sensitivity to boron (B) toxicity were investigated under toxic B conditions. Eight-day old seedlings were exposed to highly toxic B concentrations (5, 7.5, and 10 mM H3BO3) for 5 and 9 days. Fast chlorophyll a fluorescence kinetics was determined and analysed using JIP test. Growth parameters, tissue B contents, and membrane damage were measured at two stress durations. The photochemical performance of PSII was hindered more in the sensitive cultivar (Atay-85) than that of the tolerant one (Bolal-2973) under B toxicity. The increase in the B concentration and stress duration caused membrane leakage in both cultivars. However, higher membrane damage was observed in Atay-85 compared to Bolal-2973. Additionally, significant reduction of growth parameters was observed in both cultivars at toxic B concentrations. The accumulation of B was higher in shoots than in roots of both cultivars. Nevertheless, Atay-85 translocated more B from roots to leaves compared to Bolal-2973. The advantages of certain JIP test parameters were demonstrated for evaluation of PSII activity in plants exposed to B stress. Evaluation of photosynthetic performance by JIP test as well as assessment of growth and tissue B content might be used to determine the effects of B toxicity in wheat. The results indicated lesser sensitivity to B toxicity in Bolal-2973 compared to Atay-85.

The changes induced in the physiological, biochemical and anatomical characteristics of Vicia faba by the exogenous application of proline under seawater stress

The depletion of fresh water resources leads to the utilisation of various alternative sources of water, such as seawater. In this regard, the foliar application of proline is one of the alternative shotgun approaches to increase plant stress tolerance. A pot experiment was conducted in the wire house of the National Research Centre, Dokki, Cairo, Egypt, during the winter season of 2010–2011. The experiment consisted of three concentrations of proline (0, 25 and 50mM) and two concentrations of diluted seawater (3.13 and 6.25dSm−1), whereas control plants were irrigated with tap water (0.23dSm−1). Diluted seawater caused significant reductions in growth parameters, photosynthetic pigments, some mineral contents (P, K, Ca+2), the K+:Na+ ratio and the level of total carbohydrates. In contrast, N, Na+, and Cl− contents, osmoprotectants (soluble carbohydrates, total phenolic concentrations, free amino acids, proline), and activities of antioxidant enzymes (peroxidase and polyphenol oxidase) significantly increased with an increasing salinity level compared with control plants. The foliar application of 25mM proline caused significant increases in growth parameters, photosynthetic pigments, N, P, K+, and Ca+2 %, the K+:Na+ ratio, total carbohydrates, and soluble carbohydrates, accompanied by significant decreases in Na+, Cl−, phenolic contents, free amino acids, proline, and the activities of antioxidant enzymes compared with the control. In addition, 25mM proline minimised the deleterious effect of salinity on the anatomical structure of the faba bean stem and leaf. The proline treatment at 50mM was as essentially toxic to faba bean plants as to that of salinity stress. This toxicity was apparent by the reduction of growth parameters, photosynthetic pigments, N, P, K+, and Ca+2, K+:Na+ ratio and significant increases in Na+ and Cl− concentrations. Therefore, the exogenous application of proline at a concentration of 25mM partially alleviated the toxicity of diluted seawater on faba bean plants, whereas the 50mM proline treatment was toxic.

Redox and nitric oxide homeostasis are affected in tomato (Solanum lycopersicum) roots under salinity-induced oxidative stress

The nicotinamide adenine dinucleotide phosphate (NADPH) and reduced glutathione (GSH) molecules play important roles in the redox homeostasis of plant cells. Using tomato (Solanum lycopersicum) plants grown with 120mM NaCl, we studied the redox state of NADPH and GSH as well as ascorbate, nitric oxide (NO) and S-nitrosoglutathione (GSNO) content and the activity of the principal enzymes involved in the metabolism of these molecules in roots. Salinity caused a significant reduction in growth parameters and an increase in oxidative parameters such as lipid peroxidation and protein oxidation. Salinity also led to an overall decrease in the content of these redox molecules and in the enzymatic activities of the main NADPH-generating dehydrogenases, S-nitrosoglutathione reductase and catalase. However, NO content as well as gluthahione reductase and glutathione peroxidase activity increased under salinity stress. These findings indicate that salinity drastically affects redox and NO homeostasis in tomato roots. In our view, these molecules, which show the interaction between ROS and RNS metabolisms, could be excellent parameters for evaluating the physiological conditions of plants under adverse stress conditions.

ASCORBIC ACID FOLIIAR SPRAY COUNTERACTING EFFECT OF SALINITY ON GROWTH, NUTRIENTS CONCENTRATIONS, PHOTOSYNTHESIS, ANTIOXIDANT ACTIVITIES AND LIPID PEROXIDATION OF BEAN (&lt;i&gt;PHASEULUS VULGARIS&lt;/i&gt; L.) CULTIVARS

A water culture experiment was carried out in the Department of Fertilization Technology at National Research Centre, Cairo, Egypt, to investigate the effect of Ascorbic Acid (AsA) foliar application and salinity stress (100 ppm and 100 mmoL NaCl) on growth, nutrients concentration and some biochemical parameters of two kidney bean (Phaseulus Vulgaris L.) cultivars. Salinity caused significant reduction in growth parameters (leaves and root dry weights) and some of biochemical parameters (nutrients concentration, photosynthesis pigment, Carbonic Anhydrase Activity (CAA), antioxidant enzyme activity Peroxidase (POD) and lipid peroxidation). The reduction effect on Paulista cultivar was higher than Nebraska cultivar at 100 mM NaCl salinity stress. Meanwhile, POD activity was increased under salt stress conditions. Lipid Peroxidation (LP) under 100 mmoL NaCl salinity was significantly increased. The two cultivars showed an increase in MDA content with NaCl salinity stress, but the increase in sensitive cultivars Paulista was higher than that in salt-tolerant Nebraska cultivar. Application of (AsA) not only mitigated the inhibitory effect of salt stress in both kidney bean cultivars, but also in some cases induced a stimulatory effect greater than that estimated in the control plants on growth parameters which were accompanied by marked increases in nutrients concentration and photosynthetic system (pigments and carbonic anhydrase activity). Ascorbic Acid (AsA) has been shown to be an essential antioxidant; agent may act as a scavenger of ROS for mitigating the injury on bio-membranes under salt stress. Therefore, this study suggested that (AsA) application may induce an adaptive response in kidney bean through stimulation of the antioxidant enzymes activities, photosynthesis processes and lower lipid peroxidation, in Nebraska relative to Paulista may contribute to salt tolerance mechanism in Nebraska.

Initial Population Density its Effect on the Pathogenic Potential and Population Growth of Rotylenchulus reniformis on Cowpea (Vigna unguiculata L.)

Initial Population Density its Effect on the Pathogenic Potential and Population Growth of Rotylenchulus reniformis on Cowpea (Vigna unguiculata L.) A glasshouse experiment was conducted to assess the potential of Rotylenchulus reniformis population of Delhi on cowpea (Vigna unguiculata) cultivar Pusa komal. In the present study, different inoculums levels viz., 10, 100, 1000 and 10000 with immature females and equal number of males were inoculated in the rhizosphere of ten day old cowpea plants. Significant reduction in growth parameters were recorded at 1,000 and 10,000 females/ plants.