Scholarly article on topic 'Protective role of α-tocopherol on two Vicia faba cultivars against seawater-induced lipid peroxidation by enhancing capacity of anti-oxidative system'

Protective role of α-tocopherol on two Vicia faba cultivars against seawater-induced lipid peroxidation by enhancing capacity of anti-oxidative system Academic research paper on "Biological sciences"

CC BY-NC-ND
0
0
Share paper
Keywords
{"Antioxidant enzymes" / "Faba bean" / "Ion content" / MDA / Proline / Yield / α-Tocopherol}

Abstract of research paper on Biological sciences, author of scientific article — Salwa A. Orabi, Magdi T. Abdelhamid

Abstract To examine the effect of seawater stress on growth, yield, physiological and antioxidant responses of faba bean plant and whether the exogenous application with vitamin E could mitigate the adverse effect of salinity stress or not, a pot experiment was carried out during 2011/12 winter season under green house of the National Research Centre, Dokki, Cairo, Egypt. Two faba bean cultivars (Giza 3 and Giza 843) irrigated with diluted seawater (Tap water, 3.13 or 6.25dSm−1) and α-tocopherol (0, 50 or 100mgL−1) were used. At 75days after sowing, growth sample was taken for vegetative growth measurement, proline, carotenoids, antioxidant enzyme activities (SOD, CAT, POX and PAL), lipid peroxidation, and inorganic ions as well as seed yield and yield attributes were determined. The results revealed that seawater triggered significant inhibitory effects on faba bean growth and yield especially for Giza 3 cultivar with obvious increments in MDA and Na+ ion contents. Foliar application with α-tocopherol at rate of 100mgL−1 followed by 50mgL−1 on faba bean plants exerted certain alleviative effects on these indices in particular on Giza 843. α-Tocopherol could play an important role in alleviation of injury of faba bean irrigated with diluted seawater through the enhancement of the protective parameters such as antioxidant enzymes, proline, carotenoids, and inorganic ions (K+ and Ca2+) to be effective in decreasing MDA content, lessening the harmful effect of salinity, and improving faba bean growth, seed yield and seed yield quality.

Academic research paper on topic "Protective role of α-tocopherol on two Vicia faba cultivars against seawater-induced lipid peroxidation by enhancing capacity of anti-oxidative system"

Accepted Manuscript

Protective role of a-tocopherol on two Vicia Faba cultivars against seawater-induced lipid peroxidation by enhancing capacity of anti-oxidative system

Journal of the Saudi Society of Agricultural Sciences

PII: DOI:

Reference:

Salwa A. Orabi, Magdi T. Abdelhamid

S1658-077X(14)00055-1 http://dx.doi.Org/10.1016/j.jssas.2014.09.001 JSSAS 132

To appear in:

Journal of the Saudi Society of Agricultural Sciences

Received Date: 7 May 2014

Revised Date: 1 September 2014

Accepted Date: 2 September 2014

Please cite this article as: Orabi, S.A., Abdelhamid, M.T., Protective role of a-tocopherol on two Vicia Faba cultivars against seawater-induced lipid peroxidation by enhancing capacity of anti-oxidative system, Journal of the Saudi Society of Agricultural Sciences (2014), doi: http://dx.doi.org/10.1016/jjssas.2014.09.001

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Protective role of a-tocopherol on two Vicia Faba cultivars against seawater-induced lipid peroxidation by enhancing capacity of anti-oxidative system

Salwa A. Orabi, Magdi T. Abdelhamid*

Botany Department, National Research Centre, 33 Al Behoos Street, Dokki, Cairo, Egypt Corresponding authors. Tel.: +201004145751 - E-mail address: magdi. abdelhamid @ yahoo.com

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Protective role of a-tocopherol on two Vicia Faba cultivars against seawater-induced lipid peroxidation by enhancing capacity of anti-oxidative system

Abstract

To examine the effect of seawater stress on growth, yield, physiological and antioxidant responses of faba bean plant and whether the exogenous application with vitamin E could mitigate the adverse effect of salt stress or not, a pot experiment was carried out during 2011/12 winter season under green house of the National Research Centre, Dokki, Giza, Egypt. Two faba bean cultivars (Giza 3 and Giza 843) and irrigation with diluted seawater (Tap water, 3.13 or 6.25 dS m-1) and a-tocopherol (0, 50 or 100 mg L-1) were used. At 75 days after sowing, growth sample was taken for vegetative growth measurement, proline, carotenoids, antioxidant enzyme activities (SOD, CAT, POX and PAL), lipid peroxidation, inorganic ions as well as seed yield and yield attributes were determined. The results revealed that seawater triggered significant inhibitory effects on faba bean growth and yield especially for Giza 3 cultivar with obvious increments in MDA and Na+ ions contents. Foliar application with a-tocopherol at rate of 100 mg L-1 followed by 50 mg L-1 on faba bean plants exerted certain alleviative effects on these indices in particular on Giza 843. a-tocopherol could play an important role in alleviation of injury of faba bean irrigated with diluted seawater through the enhancement of the protective parameters such as antioxidant enzymes, proline, carotenoids, inorganic ions (K+ and Ca2+) to be effective in decreasing MDA content, lessening the harmful effect of salinity, and improving faba bean growth, seed yield and seed yield quality.

Key words Antioxidant enzymes; Carotenoids; Faba bean; Ion content; MDA; Proline, Yield; a-tocopherol.

1. Introduction

Salt tolerance in plants is a complex trait, which varies widely among closely related species and between different varieties (Ashraf, 2002). Differences between closely related plants are particularly interesting to identify a small number of factors responsible for salt tolerance (Gehlot et al., 2005). Salinity stress has been studied in relation to regulatory mechanisms of osmotic and ionic homeostasis (Ashraf and Harris, 2004). The response of plants to a salinity stress may vary with the genotype, nevertheless some general reactions occur in all genotypes. Salinity can affect plant physiological processes resulting in reduced growth and yield (Yamaguchi and Blumwald, 2005). Increased tolerance to salinity stress in crop plants is necessary in order to increase productivity with limited water supplies and high salinity.

Salinity stress is known to trigger oxidative stress in plant tissues through the increase in reactive oxygen species (Apel and Hirt, 2004). Chloroplasts are the major organelles producing the reactive

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

oxygen species (ROS) such as, the superoxide radical (O2'~), hydrogen peroxide (H2O2) and singlet oxygen (O'O during photosynthesis (Asada, 1992). The production of ROS can be particularly high, when plants are exposed to salinity stress (Ashraf, 2009). ROS cause chlorophyll degradation and membrane lipid peroxidation. So, malondialdehyde (MDA) accumulation is an oxidative stress indicator that is a tested tool for determining salt tolerance in plants (Yildirim et al., 2008).

Removing of the toxic oxygen radicals rapidly is of prime importance in any defense mech Plants protect cells and sub-cellular systems from the cytotoxic effects of these active oxygen radicals with both non-enzymatic and enzymatic antioxidant system such as carotenoids, ascorbic acid, a-tocopherol, proline, SOD, peroxidase (POX) and catalase (CAT) (Munne-Bosch and Alegre, 2000; Sairam and Srivastava, 2001; Mishra et al., 2009). There are several reports underline the intimate relationship between antioxidant enzyme activities and increased tolerance to environmental stress (Abd El-Motty and Orabi, 3013; Orabi et al., 2013). Differences in the accumulation patterns of Na+ and K+ were found under salinity stress. The salt tolerant plants maintained a high K+ content and higher K+:Na+ ratio compared with the salt sensitivity plants (Azooz et al., 2004). High K+:Na+ ratio is

more important for many species than simply maintaining a low concentration of Na+ (Cuin et al., 20°3)-

food wit

aocxci acc

Faba beans (Vicia faba L.) are popular legume food with high yield capacity and high protein content (30% of their dry weight) which contain most of the necessary anino acids for human and animal nutrition and low sulphur amino acids concentrations (Gaber et al., 2000). In recent years, the importance of carotenoids and tocopherols has been increasingly recognized due to the emerging knowledge of their health benefits. Because humans can synthesize neither carotenoids nor tocopherols, they rely on their uptake through diet for the production of vitamin A and the supply with vitamin E (Fraser and Bramley, 2004). Tocopherols are a group of compounds synthesized only by photosynthetic organisms and are involved in the quenching and scavenging of 1O2 (Neely et al., 1988) and act as highly efficient recyclable chain reaction terminators for the removal of polyunsaturated fatty acid (PUFA) radical species generated during Lipid per oxidation (Munne-Bosch and Falk, 2004). Furthermore, tocopherols contribute to membrane stability by influencing its fluidity and permeability (Fryer, 1999) and might participate in protection of the D1 protein against high light (Trebst et al., 2002). Tocopherols are believed to protect chloroplast membranes in plants from photo ation and help to provide an optimal environment for the pholosynthetic machinery, their accumulations also occurs as a response to variety of abiotic stress including high light, drought, salt and cold and may provide an additional line of protection from oxidative damage (Munne-Bosch and Algere, 2002). The major tocochromanol in leave is a-tocopherol, whereas seeds accumulate higher leves of tocotrienols (Grusak and Dellapenna, 1999).

Comparing the response among genotypes of the same species to salinity provides a convenient and useful tool for un-veiling basic mechanisms involved in salt tolerance. The mechanism of salt tolerance is still not fully understood (Ghars et al., 2008). Therefore, this work was conducted to

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

compare the effect of salt stress on growth, yield parameters, physiological and antioxidant responses of two faba bean (Vicia faba L.) genotypes differing in salt tolerance and whether exogenous application with vitamin E could mitigate the adverse effect of salt stress.

lea DA

2. Materials and Methods

2.1. Experimental procedures A pot experiment was conducted at the green house of the National Research Centre, Dokki, Giza, Egypt during the winter season of 2011/12 to study the effect of foliar spray of a-tocopherol (Vitamin E) on faba bean grown under salinity conditions. Daytime temperatures ranged from 14.5 to 30.2°C with an average of 23.2 ± 3.8°C whereas temperatures at night were 12.4 + 1.8°C, with minimum and maximum of 8.0 and 17.0°C respectively. Daily relative humidity averaged 57.7±9.6% in a range between from 38.1 to 78.7%.

Two Faba bean (Vicia faba L.) cultivars were used in this experiment, namely Giza 3 (G3, Orobanche-susceptible) and Giza 843 (G843, Orobanche-tolerant) were obtained from Agricultural Research Centre, Ministry of Agriculture and Land Reclamation, Egypt. Faba bean seeds were selected for uniformity by choosing those of equal size and with the same colour. The selected seeds were washed with distilled water, sterilized with 1% sodium hypochlorite solution for about 2 min and thoroughly washed again with distilled water. Ten seeds were sown on November 22, 2011 along a centre row in each pot at 30-mm depth in plastic pots, each filled with about 7.0 Kg clay soil mixed with sandy soil in a proportion of 3:1 (V:V) respectively in order to reduce compaction and improve drainage. Saline water was prepared by mixing fresh water (0.23 dS m-1) with seawater (51.2 dS m-1). Concentration of EC, pH, cations and anions of irrigation water and soils used on the pot experiment are shown on Table 1. At sowing, a granular commercial rhizobia was incorporated into the top 30-mm of the soil in each pot with the seeds. Granular ammonium sulfate 20.5% N at a rate of 40 Kg N ha-1, and single super phosphate (15% P2O5) a rate of 60 Kg P2O5 ha-1 were added to each pot. The N and P fertilizers were mixed thoroughly into the soil of each pot immediately before sowing. The experiment was laid out in factorial design using three factors (cultivars, seawater, and a-tocopherol) with five replications. Seedlings were thinned after 10 days after sowing (DAS) to ve four seedlings per pot till harvest and irrigated with equal volumes of tap water until 15 DAS. Starting from 16th day, all pots were irrigated either with tap water (S0) or different diluted seawater namely 3.13 or 6.25 dS m-1 which considered as S1, and S2, respectively. Faba bean plants were sprayed with three levels of a-tocopherol at the rate of 0, 50, or 100 mg L-1 twice at 45 and 60 DAS. The a-tocopherol levels of 0, 50, or 100 mg L-1 were considered as Toc0, Toc1, or Toc2, respectively. Faba bean plant growth sample was taken at 75 DAS, for determining some growth traits (shoot height and shoot dry weight) and some biochemical

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

measurements in leaves. At harvest time (140 DAS), pods were collected from each replicate and some yield criteria such as seed weight, seed numbers and seed index were determined.

2.2. Measurements

Extraction of the antioxidant enzymes superoxide Dismutase (SOD), catalase (CAT), and peroxidase (POX) were determined as 5g of frozen leaves tissues were homogenized in pre-chilled mortar in presence of 10 ml of 59 mM potassium phosphate buffer (pH7) with 1% (W/V) insoluble polyvinyl pyrolidone (PVP) and 0.1 mM EDTA. The extraction procedures were repeated twice and supernatants were pooled, raised to a certain volume, referred as crude enzyme extract, all operations were carried out at 4C for further analysis. The activity? of SOD (EC 1.15.1.1) was determined following Dhindsa et al. (1981). One unit of SOD was defined as the amount of enzyme that inhibits by 50% the rate of NADH oxidation observed in blank. The activity of CAT (EC 1.11.1.6) was determined according to Aebi (1983). The activity of catalase was estimated by the decrease of absorbance at 240 nm for 1min as a consequence of H2O2 consumption. The activity of peroxidase (POX, EC 1.11.1.7) was determined according to Nakano and Asada (1981). The activity of peroxidase was estimated by the increase of absorbance due to formation of tetraguaiacol at 470 nm due to the oxidation of guaiacol in the presence of H2O2. The activity of phenylalanine ammonia lyase (PAL, EC 4.3.1.5) extracted and assayed according to the method adopted by Beaudoin-Egan and Thorpe (1985). The activity of PAL is defined as the amount of enzyme forming 1m mol of trans-cinnamic acid from the substrate phenylalanine per min. Lipid peroxidation was determined by estimating the malondialdehyde (MDA) content as described by Dhindsa et al. (1982). Proline concentration was determined by the method of Bates et al. (1973). Carotenoid content was determined according to Jensen (1978). Mineral ions content was measuring in dry samples according to the method described by Chapman and Pratt (1978).

uGsoi usi

2.3. Statistical analysis of the data

All data were subjected to an analysis of variance (ANOVA) for a factorial design, after testing for the homogeneity of error variances according to the procedure outlined by Gomez and mez (1984). Statistically significant differences between means were compared at P < 0.05 using Least Significant Difference (LSD) test.

3. Results and discussions

3.1. Growth and yield

The data presented in Tables 2 indicated that plant height and shoot dry weight (shoot DW) of both cultivars G3 and G843 were significantly decreased at all levels of seawater especially at 6.25 dS m-1. Foliar application with a-tocopherol at concentrations of 50 or 100 mg L-1 recorded

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

significant increments in growth parameters compared with control. Although seawater salinity stress reduced the growth traits of the two faba bean cultivars, there were major differences in their reduction, which was judged with the ability of G843 to enhance its tissue water contents, whereas the opposite was appeared in G3. Accordingly, plant salt tolerance is determined by genotypes and biochemical pathways that facilitate retention of water and synthesis of osmotically active metaboliles (Sarwat and El-Sherif, 2007). Since salt stress limits plant growth by adversely affecting various physiological and biochemical processes including photosynthesis, antioxidant capacity and homeostasis (Ashraf, 2004) resulting in damaging growth cells so that they can't perform their functions (Chen and Murata, 2000). The reduction in growth parameters under seawater salinity conditions were obtained in several other plant species (Dogan, 2011; Abd El-Samad et al., 2011; Orabi et al., 2013). a-tocopherol foliar application at 50 or 100 mg L-1 improved growth parameters even at higher level of seawater of 6.25 dS m-1. Supporting these results, Sakr and El-Metwally (2009) reported that a-tocopherol significantly increased dry matter accumulation in stem and leaves of wheat plants compared with untreated plants in the soil salt areas, where it could counteract the harmful effect of high

ition, a-toc

soil salt stress level on growth of wheat plants. In addition, a-tocopherol at 50 and 100 mg L-1 significantly increased all tested morphological parameters (plant height, number of branches, leaves/plant, fresh cut of shoots and roots) of hibiscus rosa sinenses L. plants grown under new reclaimed lands of Noubaria and the highest values were obtained at 100 mg L-1 application compared with those obtained by low level and untreated plants (El Quesni et al., 2009).

Seawater salinity caused significant decreases in seed weight, seed number and seed index especially those of sensitive G3 compared with G843 (Table 2). These results are in agreement with those reported by Abdelhamide et al. (2010), kumar et al. (2012), El Lethy et al. (2013), and Orabi et al. (2013) on different plant species. These decreases in yield and yield components might be attributed to the decreases in plant growth, photosynthetic pigments and disturbance in the nutrients balance. On the other hand, a-tocopherol at rate of 50 or 100 mg L-1 caused marked increases in yield of the two faba bean cultivars either irrigated with tap water or seawater saline solution compared with the corresponding controls. The enhancement effects of a-tocopherol on faba bean yield were proved earlier by other researchers on different plant ecies (Sakr and El Metwally, 2009; Soltani et al., 2012; Sadak and Dawood, 2014).

3.2. Total carbohydrates and total crude proteins

Tables 3 shows that seawater salinity caused significant decreases in total carbohydrate and total crude protein contents of seeds of the two faba bean cultivars compared with controls. The reduction in the biosynthesis of carbohydrates might be due to the inhibitory effect of salinity on chlorophyll synthesis (Sadak and Dawood, 2014). The reduction in protein content under seawater salinity stress might be due to the disturbance in nitrogen metabolism or inhibition of

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

nitrate absorption as reported by El Zeiny et al. (2007). Meanwhile, foliar application of a-tocopherol at 50 or 100 mg L-1 showed opposite trends to salinity effects mainly at 100 mg L-1, caused significant increases in the two parameters not only relative to corresponding stressed plants but also to the untreated plants irrigated with tap water. However, Sadak et al. (2010) demonstrated that application of a-tocopherol on sunflower plants led to the accumulation of total carbohydrates, stimulation of protein synthesis and delaying senescence of sunflower plant. As for the role of a-tocopherol, it could be concluded that its supplementation could alleviate the harmful effect of ROS caused by salt salinity, through its powerful antioxidant properties (Baghdadi, 2013) and these antioxidant activity of a-tocopherol is mainly due to their ability to donate their phenolic hydrogens to lipid free radicals (Bagheri and Sahori, 2013), involving in both electron transport of PSII and antioxidizing system of chloroplasts and act as membrane stabilizers and multifaceted antioxidant, that scavenge oxygen free radicals, lipid peroxy radicals and singlet oxygen (Diplock et al., 1989), reacting with peroxy radicals formed in the bilayer as they diffuse to the aqueous phase, scavenging cylotoxic H2O2 and reacts non-enzymatically with other ROS: singlet oxygen, superoxide radical and hydroxyl radical and stabilize membrane structures (Blokhina et al., 2003) modulating membrane fluidity in a similar manner to cholesterol and also membrane permeability to small ions and molecules (Foyer, 1992) and decreasing the permeability of digalactosyldiacyl glycerol vesicles for glucose and protons (Berglund et al., 1999).

3.3. Protectants (proline and carotenoids) concentrations 3.3.1. Proline concentration

The effects of a-tocopherol on proline content as one of the osmotic solutes in the leaves of faba bean plants grown under seawater salinity are shown in Table 4. Irrigation of faba bean plants with diluted seawater (3.13 or 6.25 dS m-1) caused significant and gradual increments in proline content in the two studied cultivars especially G843 compared with the corresponding plants irrigated with tap water (So). The response was ascertained after a-tocopherol application at 100 mg L-1 followed by 50 mg L-1, suggesting an excellent mechanism of plants to decrease the osmotic potential. These results support the hypothesis that proline accumulation is a part of siological response of the plant to intense stress (Ain- Lhout et al., 2001). The accumulation proline may be thought an increase in its synthesis constantly with inhibition of its catabolism (Jaleel et al., 2007). In this regard, some researchers have reported that high proline content is a sign of stress (Rai et al., 2003), while others suggest that proline at high concentration acts as a solute for intercellular osmotic adjustment (Silveira et al., 2003). In this regards, higher proline accumulation can be appreciated as a further important factor of adaptation to salinity as reported in number of species (Ashraf and Harris, 2004; Hameed and Ashraf, 2008, Azooz et al., 2011; Taie et al., 2013).

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

3.3.2. Carotenoids concentration

Data in Table 4 shows significant and gradual increase in carotenoids content with increasing seawater levels from 0 to 6.25 dS m-1 and the response was more obvious in G843 (The tolerant cultivar) than in G3 (the susceptible cultivar). In this concern, in chickpea leaves, the carotenoids were measured and effective elevation over control was observed under salinity stress (Mishra et al., 2009). Moreover, Deleterious effects of salinity stress on leaf carotenoids have been reported in several crops such as soybean (Dogan, 2011), peanut (Hossain et al., 2011), maize (Abd El-Samad et al., 2011), common bean (Abdelhamid et al., 2013) and faba bean (Abd El- Samad et al., 2011; Taie et al., 2013). Foliar application of a-tocopherol recorded mostly higher increments in carotenoids content compared with the untreated plants. Parallel to this study, a-tocopherol significantly increased the contents of carotenoids in two wheat genotypes under salt stress (2840 and 6080 mg L-1) compared with the corresponding controls, consequently there was a progressive decline in total chlorophyll:carolenoids ratio, carotenoids might play a role as a free radical scavenger (Sakr and El metwally, 2009). Therefore, increasing of carotenoids in genotypes treated with salinity could enhance their capacity to reduce the damage caused by ROS, which in turn increased chlorophyll content of such plants

imnectr incr

(Azooz, 2009), where carotenoids play a key role in controlling the cellular level of free radicals and peroxides (Apel and Hirt, 2004).

3.4. Antioxidant enzyme activities

The data in Table 5 revealed that the salinity tolerant faba bean cultivar G843 showed relatively higher activities of the enzymes superoxide Dismutase (SOD), catalase (CAT), and phenylalanine ammonia lyase (PAL). As salinity level increased, significant increases in the activities of these antioxidant enzymes were obtained. Similar results were obtained by other researchers (Costa et al., 2005; Azooz, 2009; Azooz et al., 2009; Weisany et al., 2012). In the present study, the antioxidant activities were clearly increased after application of a-tocopherol at 100 mg L-1 followed by 50 mg L-1, this may contribute advantages to faba bean plants especially Cv. G843 and helped Cv. G3 to perform better in various aspects of growth and tabolism as they defend against the harmful effect of salinity stress through mainly the increase in activities of SOD, CAT, PAL, and peroxidase (POX) enzymes together with the increase of some antioxidant substances. Salt provokes a dose-dependent increase in SOD activity, which could represent a defense mechanism against salt-induced O.-2 generation. SOD catalyses the conversion of the super oxide anion to H2O2. It was clear that G843 cultivar has a higher dismutating capacity under moderate and high doses of seawater salinity. These results are in a good agreement with those reported by Wang et al. (2009), and Wang and Han (2009), who found higher constitutive and induced level of SOD in tolerant alfalfa cultivar under salt

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

stress. Similarly, Koca et al. (2010) reported higher activities of SOD in wild salt-tolerant tomato species than in the cultivated salt sensitive one. Orabi et al. (2013) studied the harmful effect of seawater salinity and recorded higher activities and specific activities of SOD enzymes in the tolerant cultivar Giza 429 of faba bean plants. In the same line, El Lethy et al. (2013) reported significant increases in SOD enzyme activity in wheat plants irrigated with NaCl saline solutions. CAT eliminates H2O2 by breaking it down directly to form water and Oxygen. Thus, this enzyme does not require a reducing power and has a high reaction rate but a low affinity for H2O2 (Willekens et al., 1997). CAT together with SOD considered the most effective antioxidant enzymes in preventing cellular damage (Scandalios, 1993). Increase in the activity of CAT, have been reported in alfalfa (Wang and Han, 2009; Wang et al., 2009) , soybean (Comba et al., 1998), Tobacco (Bueno et al, 1998) and mulberry (China et al, 2001) under salt stress. Significant roles of POX have been suggested in plant development processes (Gaspar et al., 1985). Guaicol peroxidase is among the enzymes that scavenge H2O2 in chloroplasts which is produced through dismutation of -O2 catalyzed by SOD. Increased peroxidase (POX), or sometime reffered as POD activity has been reported in salt-tolerant and sensitive species of alfalfa (Wang et al., 2009; Wang and Han, 2009), tomato (Koca et al., 2006) and rice (Dionisio-Sese and Tobita, 1998). Increased POX in salt sensitive cultivar G3 and relatively in salttolerant faba bean G843 may be attributed to increased activity of POX encoding genes or

tran inte

increased activation of already existing enzymes as suggested by Dionisio-Sese and Tobita (1998) who reported an increase in peroxidase activity in salt sensitive rice varieties, Hitomebore and IR28, in response to salt stress and showed an increase in lipid peroxidation and electrolyte leakage as well as Na+ accumulation in the leaves under saline conditions. In this regard, in a study occurred by Sadak et al. (2010) on the tolerant faba bean cultivar G843 under salt stress, the tolerance was attained with lowering the level of POX activity. In the same line, Siegal et al. (1982) concluded that change in peroxidase activity level in response to salinity is not a reliable criterion for screening for tolerance in Brassica species. More specifically, guaiacol peroxidase enzyme has been related to the appearance of physiological injuries caused by oxidative stress. Phenylalanine ammonia-lyase (PAL) is considered to be the principal enzyme of the phenylpropanoid pathway (Kacperska, 1993), catalyzing the sformation by deamination of l-Phenylalanine into trans-cinnamic acid, which is the prime intermediary in the biosynthesis of phenolics (Levine et al., 1994). This enzyme is considered by most authors as one of the main lines of cell acclimation against stress (Kacpeska, 1993; Leyva et al., 1995) where plants could accumulate phenolic compounds in response to oxidative stress (Rivero et al., 2001; Ali et al., 2007). a-tocopherol has appeared to play a major role in chloroplaststic antioxidant network of plants. Therefore, it contributes to preservation of an adequate redox station in chloroplasts, and to maintaining thylakoid membrane structure and function during plant development and in plant responses to stress (Munne-Bosch and Alegra,

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

2002; Munne-Bosch, 2005). Similar to our results (Sakr and El-Metwally, 2009) recorded increments in the antioxidant enzymes in response to a-tocopherol application on wheat against oxidative stress.

3.5. Lipid peroxidation

Data in Figure 1 showed that seawater treatments increased gradually MDA contents especially 6.25 dS m-1 which gave the highest significant content of lipid peroxidation. Meanwhile, a-tocopherol treatments decreased significantly MDA content, and the response reached the maximum at 100 mg L-1 with G843. MDA is the decomposition product of poly unsaturated fatty acids of plants membranes under stress. The rate of lipid peroxidation in terms of MDA can therefore be used as an indicator to evaluate plants tolerance to oxidative stress as well as the sensitivity of plants to salt stress (Jain et al., 2001). Increase in lipid peroxidation level in faba bean plants exposed to seawater salinity shows that the enzymes activities might have not been enough to prevent the peroxidation of membrane lipids caused by high concentration of seawater salinity or by other meaning, the increase in MDA level especially in the susceptible cultivar G3 might also be correlated with inadequate activities of the studied antioxidant enzymes (SOD, CAT, POX and PAL) activities to scavenge ROS produced in faba bean leaves. Variations in MDA contents were found in cultivars differing in water deficit stress (Masoumi et al., 2011). On the other hand, decrements have occurred as a result of a-tocopherol application ascertains that plant tolerance would be attained to scavenge ROS produced under salinity.

3.6. Mineral ions content

tolerance

Data in Table 6 showed that mineral ions concentration (K+, and Ca2+) were significantly higher in G843 than G3 cultivar. However, seawater salinity levels (S1 or S2) caused significant and gradual reductions in K+ and Ca+ concentrations, as well as in the K+:Na+ and Ca+2:Na+ ratios, accompanied by gradual and significant increases in Na+ concentrations compared with control plants (So). These results are similar to those results reported by Dogan (2011), Abdelhamide et al. (2010), Abd El-Samad et al. (2011) and El lethy et al. (2013) from different plant species.

awater salinity enhances the content of Na+ as reported by Gunes et al. (2007) and the Excess of Na+ might cause problems with membranes, enzyme inhibition, and disturbance in metabolism which disorganize cell division, elongation and structure (Abo Kassem, 2006). In this connection, Kiarostami et al. (2010) suggested that increased accumulation of sodium (Na+) and chloride (Cl) ions in the tissues inhibits biochemical processes related to photo synthesis through direct toxicity and led to low water potential. The promotion of Na+ uptake by salinity was accompanied by a corresponding decline in K+ concentration, showing an apparent antagonism between K+ and Na+ (Cuin et al., 2009). The selectivity of high K+:Na+ ratio in

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

plants is important content mechanism and selection criterion for salt tolerance (Wenxue et al., 2003; Ashraf and Harris, 2004). Cuin et al. (2003) concluded that high K+:Na+ ratio is more important for many species than simply maintaining a low Na+ concentration. That is reflected in lowering membrane damage and high water content in both genotypes especially under salinity stress (Azooz, 2009). Ashraf and Orooj (2006) reported that the maintenance of higher K+:Na+ ratio in shoot of Trachyspermum ammi L. could be an important component of its salt tolerance. Gharsa et al. (2008) concluded that the better tolerance of plant to salt stress was primarily due to better K+ assimilation, resulting in higher K+:Na+ ratio. Faba bean plants subjected to seawater salinity took up high amounts of Na+, whereas the uptake of K+ and Ca2+ was considerably reduced (Abdelhamid et al. 2010), that low Ca2+:Na+ ratio in a saline medium plays a significant role in growth inhibition in addition to causing significant changes in morphology and anatomy of plants (Cramer et al. 1991). The maintenance of Ca2+ acquisition and transport under salt stress is an important determinant of salinity tolerance. Ca2+ is known to play a crucial role in maintaining the structural and functional integrity of plant membranes in addition to its considerable roles in cell wall stabilization, regulation of ion transport, and selectivity and activation of cell wall enzymes (Marschner, 1995). The reduction in Ca2+ uptak under salt stress conditions might be due to the suppressive effect of Na+ and K+ on this cation or due to reduction of transport of Ca+2 and Mg+2 ions (Asik et al., 2009). On the other hand, plants of both cultivars irrigated either with tap water or saline solution at different levels and exogenously applied with a-tocopherol exhibited decreases in Na+ whereas increments observed in K+ and Ca2+ relative to their corresponding control. Thus, a-tocopherol mostly at 100 mg L-1 followed by 50 mg L-1 partially mitigated the adverse effect of salt stress on minerals content in faba bean leaves. Application of a-tocopherol led to an increase in the contents of ions in the leaf through their role in increasing osmotolerance and/or through regulating various processes including absorption of nutrients from soil solution (Buschmann and Lichtenthaler, 1979; Sadak and Dawood, 2014).

4. Conclusion

be concluded that faba bean cv Giza843 is more tolerant to salt stress than cv Giza 3. It

It could

ossible that better resistance to salinity of cv Giza 843 was related to its ability to maintain

higher levels of antioxidant enzymes activity, proline and caroteinoids contents resulting in lower H2O2 production and lipid peroxidation associated with diminishing oxidative injury and consequently improved faba bean plant growth and yield. a-tocopherol could play an important role in alleviation of injury of faba bean irrigated with diluted seawater, through the enhancement of the protective parameters such as antioxidant enzymes, proline, carotenoids, inorganic ions (K+, Ca2+) to be effective in decreasing MDA content, lessening the harmful effect of salinity, and improving faba bean growth, seed yield and seed yield quality.

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Acknowledgements

This work was part of the Research Project No. 9050105 supported by the National Research Centre, Cairo, Egypt.

References

Abd El-Motty, E.Z., Orabi, S.A., 2013. The beneficial effects of using zinc, yeast and seler n on yield, fruit quality and antioxidant defense systems in Navel orange trees grown under newly reclaimed sandy soil. J. App. Sci. Res. 9, 6487-6497.

rees grown it of p l ant

Abd El-Sanad, H.M., Shaddad, M.A.K., Barakat, N., 2011. Improvement of p l ants salt tolerance by oxygenous application of amino acids. J. Med. plant Res. 5, 569-5699.

Abdelhamid, M.T, Shokr, M.M.B., Bekheta, M.A., 2010. Growth, root characteristics and leaf nutrients accumulation of four Faba bean (Vicia Faba L.) cultivars differing in their broomrape tolerance and the soil properties in relation to salinity. Commun. Soil Sci. Plant Anal. 41 : 2713-2728.

Abdelhamid, M.T., Rady, M., Osman, A., Abdalla, M.A., 2013. Exogenous application of proline alleviates salt-induced oxidative stress in Phaseolus vulgaris L. plants. J. Hort. Sci.

ress in

Biotech. 88, 439-446.

Abo Kassem, E.E.M., 2006. Effect of salinity: calcium interaction on growth and nucleic acid metabolism in five species of chenopodiaceae. Turk. J. Bot. 31,125-134.

Aebi, H.E., 1983. Catalase. In: Bergmeyer, H.V. (Ed.). Methods of Enzymatic Analysis, velar weinheim, pp. 273-286.

Ain-Lhout, F. Zunzunegui, F.A., Diaz Barradas, M.C., Tirado, R., Clavijio, A., Garcia, N.F., 2001. Comparison of proline accumulation in two Mediterranean shrubs subjected to natural and experimental water deficit. Plant Soil., 230, 175-183.

Ali, M.B., Hahn, E.J., Paek, K.Y., 2007. Methyl Jasmonate and Salicylic acid induced oxidative stress and accumulation of phenolics in panax ginseng Bioreactor root suspension cultures. Molecules, 12, 607-621.

Apel, K., Hirt H., 2004. Reactive oxygen species: metabolism, oxidative stress and signal transduction. Annu. Rev. Plant Biol., 55, 373-399.

Asada, K., 1992. Ascorbate peroxidase-a hydrogen peroxide scavenging enzyme in plants. Physiol. Plant., 85, 235-241.

Ashraf, M., 2002. Salt tolerance of cotton: some new advances. Critical Rev. Plant Sci., 21, 130.

Ashraf, M., 2004. Some important physiological selection criteria for salt tolerance in plants. Flora, 199, 361-376.

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Ashraf, M., 2009. Biotechnological approach of improving plant salt tolerance using antioxidants as markers. Biotech. Adv., 27, 84-93.

Ashraf, M., Harris, P.J.C., 2004. Potential biochemical indicators of salinity tolerance in plants. Plant Sci., 166, 3-16.

Ashraf, M., Orooj, A., 2006. Salt stress effects on growth, ion accumulation and seed oil concentration in an arid zone traditional medicinal plant ajwain (Trachyspermum ammi (L.) Sprague). J. Arid. Environ., 64:209-220.

Asik, B.B., Turan, M.A., Celik, H., Katkat, A.V., 2009. Effects of humic substances on plant growth and mineral nutrients uptake of wheat (Triticum durum cv. Salihli) under conditions of salinity. Asian J. Crop Sci.,1, 87-95.

Azooz, M.M., 2009. Foliar application with riboflavin (Vitamin B2) enhancing the resistance of Hibiscus sabdariffa L. (Deep red sepals variety) to salinity stress. J. Biol. Sci., 9, 109-118.

Azooz, M.M, Ismail, A.M., Abd El Hamid, M.F., 2009. Growth, lipid peroxidation and antioxidant enzyme activities as a selection criterion for the salt tolerance of thee maize cultivars grown under salinity stress. Int. J. Agric. Biol., 11: 21-26.

Azooz, M.M., Shaddad, M.A., Abdel- Latef, A.A., 2004. Leaf growth and K+/Na+ ratio as an indication of the salt tolerance of three sorghum cultivars grown under salinity stress and IAA treatment. Acta Agron. Hungarica, 52, 287-296.

Azooz, M.M., Youssef, A.M., Ahmad, P., 2011. Evaluation of salicylic acid (SA) application on growth, osmotic solutes and antioxidant enzyme activities on broad bean seedlings grown under diluted sea water. Int. J. Plant physiol. Biotech., 3, 253-264.

Bagheri, R., Sahari, M.A., 2013. Comparison between the effects of a-tocopherols and BHT on the Lipid oxidation of kilka fish. World App. Sci. J. 28, 1188-1192.

Bates,L.S., Waldan, R.P., Teare, L.D., 1973. Rapid determination of free praline under water stress studies. Plant Soil, 39, 205-207.

Beaudoin-Egan, L., Thorpe, T., 1985. Tyrosine and phenylalanine ammonialyase activities during shoots inhibition in tobacco callus cultures. Plant Physiol., 78, 438-441.

Berglund, A.H., Nilsson, R., Liljenberg, C., 1999. Permeability of large unilamellar digalactosyl diacylglycerol vesicles for protons and glucose-influence of a-tocopherol, B-carotene, zeaxanthin and cholesterol. Plant physiol. Biochem., 37: 179-186.

Blokhina, O., Virolainen, E., Fagerstedt K.V., 2003. Antioxidants, oxidative damage and oxygen deprivation stress: A review. Ann. Bot., 91, 179-194.

Bughdadi, F.A., 2013. Protective effects of vitamin E against motor nerve conduction beficit in diabetic rats. World App. Sci. J., 27, 28-32.

Buschmann, C., Lichtenthaler, H.K., 1979. The influence of phytohormones on prenyllipid coposition and photosynthetic activities of thylakoids. In: Appelgvist, L.A., Lilj Enberg. C.

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

(Eds.) Advances in Biochemistry and physiology of plant lipids, Elsever, Amsterdam. pp. 145-150.

Chapman, H.D., Pratt, P.F., 1978. Methods of analysis for soils, plant and water. Univ.

California, Div. Agric. Sci. publ. 4034. pp. 162-165. Chen, T.H.H., Murata, N., 2000. Enhancement of tolerance of abiotic stress by metaboli

engineering of betaines and other compalible solutes. Curr. Opin. Plant Biol., 5, 250-257. Comba, M.E., Benavides, M.P., Gallego, S.M., Tomaro M.L., 1998. Relationship between nitrogen fixation and oxidative stress induction in nodules of salt-treated soybean plants. Phyton-Int. J. Exp. Bot., 60,115-126. Costa, P.H., Azevedo-Neto, A.D., Bezerra, M.A., Prisco J.T., Gomes-Filho, E., 2005. Antioxidant-enzymatic system of two sorghum genotypes differing in salt tolerance. Braz. J. Plant Physiol., 17, 353-361. Cramer, G.R., Epstein, E., Lauchli, A. 1991. Effects of sodium, potassium and calcium on salt-

stressed barley II. Elemental analysis, Physiol. Plant. 81, 197-202. Cuin, T.A, Miller, A.G., Laurie, S.A., Leigh, R.A., 2003. Potassium activities in cell

compartments of salt-grown barley leaves. J. Exp. Bot. 54, 657-661. Cuin, T.A., Tian, Y., Betts, S.A., Chalmandrier, R., Shabala, S., 2009. Ionic relations and osmotic adjustment in durum and bread wheat under saline conditions. Funct Plant Biol 36: 1110-1119.

Dhindsa, R.S., Plumb-Dhindsa, P., Reid, D.M., 1982. Leaf Senescence and lipid peroxidation Effects of some phytohormones and scavengers of free radicals and singlet oxygen. Physiol. Plant., 56, 453-457.

Dhindsa, R.S., Plumb-Dhindsa, P., Thorpe, T. A. 1981. Leaf Senescence: Correlated with increased levels of membrane permeability and lipid peroxidation and decreased level of superoxide dismutase. J. Exp. Bot., 32: 93-101. Dionisio-sese, M.L., Tobita, S. 1998. Antioxidant responses of rice seedlings to salinity stress. Plant Sci., 135, 1-9.

Diplock, A.T., Machlin, L.J., Packer L., Pryor, W.A., 1989. Vitamin E: Biochemistry and health lications. Ann. New York Acad. Sci., pp: 570. an, M., 2011. Antioxidative and proline potentials as a protective mechanism in soybean plants under salinity stress. Afr. J. Biotechnol. 10, 5972-5978.

Diplock, imp

El-Lethy, S.R., Abdelhamid, M.T., Reda F. 2013. Effect of potassium application on wheat (Triticum aestivum L.) cultivars grown under salinity stress. World App. Sci. J. 26, 840850.

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

El-Quesni, F.E.M, Abd El-Aziz, N.G., Kandil, M.M., 2009. Some studies on the effect of ascorbic acid and a-tocopherol on the growth and some chemical composition of Hibiscus rosa sineses L. at Nubaria. Ozean J. App. Sci. 2, 159-167.

El-zeiny, H.A., Abou, L.B., Gaballah, M.S., Khalil, S., 2007. Antitranspirant application to sesame plant for salinity stress Augmentation. Res. J. Agric. Biologic. Sci., 3, 950-959.

Foyer, M.J., 1992. The antioxidant effects of thylakoid vitamin E (a-tocopherol). Plant Environ., 15, 381-392.

Fraser, P.D., Bramley, P.M., 2004. The biosynthesis and nutritional uses of carotenoids. Prog lipid Res., 43, 228-265.

Fryer, M.J., 1999. The antioxidant effects of thylakoid vitamin E (a-tocopherol). Plant cell Environ, 15: 381-92.

Gaber, A.M., Mostafa H.A.M., Ramadan, A.A., 2000. Effect of gamma irradiation of Faba beans (Vicia Faba) plant on its chemical composition, Favism causative agent and hormonal levels. Egypt. J. Physiol. Sci., 24, 1-16.

Gaspar, T., Penel C., Castillo F.J., Greppin H., 1985. A two step control of basic and acid peroxidases and its significance for growth and development. Plant physiol., 64, 418-423.

Gehlot, H.S., Purohit, A., Shakhawat, N.S., 2005. Metabolic changes and protein patterns associated with adaptation to salinity in Sesamum indicum cultivars. J. Cell Mol. Biol., 4, 31-39.

Gharsa, M.A., Parre, E., Debez, A., Bordenava, M., Richard, L., Leport, L., Bouchereau, A., Savoure, A., Abdelly, C., 2008. Comparative salt tolerance analysis between Arabidopsis thaliana and the llungiella halophila, with special emphasis on K+/Na+ selectivity and proline accumulation. J. plant physiol., 165, 588-599.

Gomez, K.A., Gomez, A.A., 1984. Statistical Procedures for Agricultural Research. John Wiley & Sons Inc., Singapore.

Grusak, M.A., Dellapenna, D., 1999. Improving the nutrient composition of plants to enhance human nutrition and health. Annu. Rev. Plant Physiol. Mol. Biol., 15, 133-61.

Gunes, A., Anal, A., Al paslan, M., Eraslan, F., Bagci, E.G., Cick, N., 2007. Salicylic acid ced changes on some physiological parameters symptomatic for oxidative stress and mineral nutrition in maize (Zea mays L.) grown under salinity. J. Plant Physiol., 164, 728736.

Hameed, M., Ashraf, M., 2008. Physiological and biochemical adaptations of Cynodon dactylon (L.) pers, from the salt range (Pakistan) to salinity stress. Flora, 203, 683-694.

Hossain, M.A., Ashrafuzzaman, M., Ismail, M.R., 2011. Salinity triggers proline synthesis in peanut leaves. Maejo Int. J. Sci. Tech., 5, 159-168.

Gunes, A induc

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Jain, M., Mathur, G., Koul, S., Sarin, N.B., 2001. Ameliorative effects of proline on salt stress induced lipid peroxidation in cell lines of groundnut (Arachis hypogea L.). Plant Cell Rep., 20, 463-8.

Jaleel, C.A., Manivannan, P., Kishore Kumar, A., Sankar, B., Panneerselvam, R., 2007. Calcium Chloride effects on salinity induced oxidative stress, proline metabolism and indol alkaloid accumulation in catharanthus roseus. Comptes Rendus Biol., 330, 674-683.

Jensen, A., 1978. Chlorophylland carotenoids. In: Hallebust, J.A., Craigie, J.S. (Eds.), Hand book of Physiochemical and Biochemical Methods Cambridge Univ. press. Cambridge, UK,

Kacperska, A., 1993. Water potential alteration A prerequisite or a triggering stimulus for the development of freezing tolerance in over wintering herbaceous plants?. In: Li, P.H., Christerson, L., (Eds.), Advances in plant cold Hardiness, CRC press, Boca Raton. Pp.7391.

Kiarostami, K.H., Mohseni, R., Saboora, A., 2010. Biochemical changes of Rosmarinus officinalis under salt stress. J. stress physiol. Biochem., 6, 114-122.

Koca, H., Ozdemir, F., Turkan, I., 2006. Effect of salt stress on lipid peroxidation and superoxide dismutase and peroxidase activities of Lycopersicon esculentum and L. pennellii. Biol. Plant., 50, 745-748.

Kumar, S., Singh, R., Nayyar, H., 2012. a-tocopherol application modulates the response of wheat (Triticum aestivum L.) seedlings to elevated temperatures by mitigation of stress injury and enhancement of anitioxidants. J. Plant growth Regul., 32, 307-314.

Levine, A., Tenhaken, R., Dixon, R., Lamb, C., 1994. H2O2 from the oxidative burst orchestrates the plant hypersensitive disease resistance response. Cell, 79, 583-93.

Leyva, A., Jarrillo, J.A., Salinas, J., Martinez-Zapater M., 1995. Low temperature induces the accumulation of phenylalanine ammonia-lyase and chalcone synthase mRNA of Arabidopsis thaliana in light-dependent manner. Plant physiol., 108, 39-46.

Marschner, H., 1995. Mineral nutrition of higher plants. Academic press, London.

Masoumi, H., Darvish, F., Daneshian, J., Nourmohammadi, G., Habibi, D., 2011. Chemical and chemical responses of soybean (Glycine max L.) cultivars to water deficit sress. Aust. J. rop Sci., 5, 544-553.

Mishra, M., Mishra, P.K., Kumar, U., Prakash, V., 2009. NaCl phytotoxicity induces oxidative stress and response of antioxidant system in Cicer arietinum L.cv. Abrodbi. Bot. Res. Int., 2, 74-82.

Munne- Bosch, S., 2005. The role of a-tocopherols in plant stress tolerance. J. Plant physiol., 162, 743-748.

bioc Cro

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Munne-Bosch, S., Alegre, L., 2000. The significance of B-carotene, a-tocopherol and the xanthophyll cycle in droughted Melissa officinalis plants. Aust. J. Plant Physiol., 27, 13946.

Munne-Bosch, S., Alegre, L., 2002. The function of tocopherols and tocotrienols in plants. Crit. Rev. Plant Sci., 21, 31-57.

Munne-Bosch, S., Alegre, L., 2000. Changes in carotenoids, tocopherols and diterpenes during drought and recovery, and the biological significance of chlorophyll loss in Rosmarinus officinalis plants. Planta, 210, 925-31.

Munne-Bosche, S., Falk, J., 2004. New insights into the function of tocopherols in plants. Planta, 218, 323-6.

Nakano, Y., Asada K., 1981. Hydrogen peroxide is scavenged by ascorbate specific peroxidase in spinach chloroplasts. Plant Cell Physiol., 22, 867-880.

Neely, W.C., Martin, J.M., Barker, S.A., 1988. Products and relative reaction rates of the oxidation of tocopherols with singlet molecular oxygen. Photochem. Photobiol., 48, 423-8.

Orabi, S.A., Mekki, B.B., Sharara F.A., 2013. Alleviation of adverse effects of salt stress on faba bean (Vicia faba L.) plants by exogenous application of salicylic acid. World App. Sci. J., 27, 418-427.

Rai, S.P., Luthra, R., Kumar, S., 2003. Salt-tolerant mutants in glycophytic salinity response (GRS) genes in Catharanthus roseus .Theor. Appl. Genet., 106, 221-230.

Rivero, R.M., Ruiz, J.M., Garcia, P.C., Lopez-Lefebre, L.R., Sanchez, E., Romero, L., 2001). Resistance to cold and heat stress: accumulation of phenolic compounds in tomato and watermelon plants. Plant Sci., 160, 315-321.

Sadak, M. Sh., Dawood, M.G., 2014. Role of ascorbic acid and a-tocopherol in alleviating salinity stress on flax plant (Linum usitatissimum L.) J. Stress Physiol. Biochem., 10, 93111.

Sadak, M.Sh., Rady, M.M., Badr, N.M., Gaballah, M.S., 2010. Increasing sun flower salt tolerance using nicotinamide and a-tocopherol. Int. J. Acad. Res., 2, 263-270.

Sairam R. K., Srivastava, G.C., 2001. Water stress tolerance of wheat Triticum aestivum L.: Variation in hydrogen peroxide accumulation and antioxidant activity in tolerant and susceptible genotype. J. Agron. Crop Sci., 186, 63-70.

Sakr, M.T., El-Metwally, M.A., 2009. Alleviation of the harmful effects of soil salt stress on growth, yield and endogenous antioxidant content of wheat plant by application of antioxidants. Pak. J. Biol. Sci., 12, 624-630.

Sarwat, M.I., El-Sherif, M.H., 2007. Increasing salt tolerance in some barley genotypes (Hordeum vulgare) by using kinetin and benzyladenin. World J. Agric. Sci., 3, 617-629.

Scandalios, J.G., 1993. Oxygen stress and superoxide dismutase. Plant physiol., 101, 7-12.

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Siegal, S.M., Chen, J. Kottenmeier, W. Clark, K., Siegel, B.Z., Change, H., 1982. Reduction in peroxidase in Cucumis, Brassica and other seedlings cultured in saline waters, Phytochem., 21, 539-542.

Silveira, J.A., Viegas, R., Da Rocha, I.M., Moreira, A.C., Moreira, R., Oliveira, J.T., 2003. Proline accumulation and glutamine synthetase activity are increased by salt-induced proteolysis in cashew leaves. J. Plant physiol., 160, 115-123.

Soltani, Y. Saffari, V.R., Moud, A.A.M., Mehrabani, M., 2012. Effect of foliar application of a-tocopherol and pyridoxine on vegetative growth, flowering and some biochemical constituents of calendula officinalis L. plants. Afri. J. Biotechnol., 11, 11931-11935.

Taie, H., Abdelhamid, M.T., Dawood, M.G., Nassar, R.M., 2013. Pre-sowing seed treatment with proline improves some physiological, biochemical and anatomical attributes of faba bean plants under sea water stress.. J. App. Sci. Res., 9, 2853-2867.

Trebst A., Depka, B., Hollander-Czytko, H., 2002. A specific role for tocopherol and of chemical singlet oxygen quenchers in the maintenance of photosystem II structure and function in Chlamydomonas reinhardtii. FEBS Lett, 516, 156-160.

Wang, X.S., Han, J.G., 2009. Changes of proline content, activity and active isoforms of antioxidative enzymes in two alfalfa cultivars under salt stress. Agric. Sci. China, 8, 431440.

Wang, W.B., Kim, Y.H., Lee, H.S., Kim, K.Y., Deng, X.P., Kwak, S.S., 2009. Analysis of antioxidant enzyme activity during germination of alfalfa under salt and drought stresses. Plant Physiol. Biochem. 47:570-577.

Weisany, W. Yousef, S., Gholamreza, H., Adel, S., Kazem, G., 2012. Changes in antioxidant enzymes activity and plant performance by salinity stress and zinc application in soybean (Glycin max L.) plant. Osmics J., 5, 60-67.

Wenxue, W., Bilsborrow, P.E., Hooley, P., Fincham, D.A., Lombi, E., Forster, B.P., 2003. Salinity induced differences in growth, ion distribution and partitioning in barley between the cultivar Maythorpe and its derived mutant Golden promise. Plant Soil, 250, 183-191.

Yamaguchi, T., Blumwald E., 2005. Developing salt-tolerant crop plants: challengers and

opportunities. Trends Plant Sci., 12, 615-620. Yildrimi

imin, B., Yaser, F., Ozpay, T., Ozpay, D.T., Turkozu, D., Terziodlu, O., Tamkoc, A., 2008. Variations in response to salt stress among field pea genotypes (Pisum sativum sp. Orvense L.). J. Amin. Veter. Adv., 7, 907-910.

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Fig. 1. Effect of a-tocopherol on malondialdehyde (MDA) in the leaves of two faba bean cultivars grown under seawater saline conditions. The vertical bars with different letters are significantly different from each other at P < 0.05 according to Least Significant Difference (LSD) test. S0 (tap water); S1 (3.13 dS m-1); S2 (6.25 dS m-1); Toc0 (0 mg L-1); Toc1 (50 mg L-1); Toc2 (100 mg L-1). Measurements were made at 75 d after sowing (DAS). Cultivars of faba bean used were Giza 3(G3) and Giza 843 (G843).

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Table 1. EC, pH, and concentration of cations and anions of irrigation water and soil used in the pot experiment

EC pH Cations meq l-1 Anions meq l-1

dS m-1 Ca2+ Mg2+ Na+ K+ HCO3- CO32- SO42- Cl-

Water:

Tap water 230. 7.35 1.00 0.50 2.40 0.20 0.10 0.00 1.30 2.70

Sea water 51.2 7.76 43.20 15.12 454.57 1.51 6.05 0.00 76.36 432.00

Sandy 0.14 8.11 2.60 2.40 1.31 0.21 1.13 0.00 4.22 0.70

Clay 1.40 7.59 5.60 1.90 5.90 0.37 1.50 0.00 6.77 5.50

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Table 2. Effect of a-tocopherol on plant height, shoot dry weight (shoot DW), seed yield per plant, seed number per plant and weight per seed (seed index) in two faba bean cultivars grown under seawater saline conditions*

Treatments

Growth and yield traits

Cv Seawater Toc Plant height (cm) Shoot (g plai

G3 S0 Toc0 66.5 2.23

Tocl 68.0 2.80

Toc2 70.7 3.10

S1 Toc0 62.2 2.01

Toc1 65.8 2.56

Toc2 67.5 2.70

S2 Toc0 60.5 1.62

Toc1 63.7 2.05

Toc2 64.5 2.16

G843 S0 Toc0 64.8 3.04

Toc1 66.0 3.45

Toc2 68.8 3.80

S1 Toc0 59.5 2.36

Toc1 63.3 3.01

Toc2 64.2 3.30

S2 Toc0 58.0 1.91

Toc1 61.0 2.41

Toc2 62.5 2.55

LSD 0.05 1.6 0.15

Seed yield

(g plant-1)

Seed No. Plant-1

Seed Index (g)

4.20 5.70 6.30 3.60 4.81 5.33 2.30 3.63 3.91

6.55 89.5

1 .61 5.05 5.48 0.42

6.7 7.7 8.2 5.7 7.0

7.7 4.

5.8 6.2

9.0 10.7 11.3 7.7 9.7 10.3 6.0 7.7

8.1 0.7

0.63 0.75 0.77 0.64 0.69 0.70 0.58 0.63 0.63 0.73 0.80 0.80 0.73 0.75 0.79 0.60 0.66 0.68 0.08

#S0 (tap water); S1 (3.13 dS m-1); S2 (6.25 dS m-1); Toc0 (0 mg L-1); Tocl (50 mg L-1); Toc2 (100 mg L-1). Measurements (plant height and shoot DW) were made at 75 d after sowing (DAS), while seed yield, seed number and seed index were made at harvest. Cultivars of faba bean used were Giza 3(G3) and Giza 843 (G843).

ieed index

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Table 3. Effect of a-tocopherol on in total carbohydrate (TC), and total crude protein (TCP) in seed yield of two faba bean cultivars grown under seawater saline conditions*

Treatments Seed traits

Cv Seawater Toc TCP TC

G3 S0 Toc0 25.0 49.9

Toc1 27.0 53.2

Toc2 29.0 57.6

S1 Toc0 22.3 42.8

Toc1 23.3 45.0

Toc2 23.7 46.2

S2 Toc0 21.0 39.1

Toc1 22.7 41.8

Toc2 23.3 42.6

G843 S0 Toc0 25.5 51.0

Toc1 27.5 54.3

Toc2 29.6 58.8

S1 Toc0 22.8 43.7

Toc1 23.8 45.9

Toc2 24.1 47.2

S2 Toc0 21.4 39.9

Toc1 23.1 42.7

Toc2 23.8 43.5

LSD 0.05 1.5 1.9

*S0 (tap water); S1 (3.13 dS m-1); S2 (6.25 d mg L-1). Measurements were made at harvest. 843 (G843).

oc0 (0 mg L-1); Tocl (50 mg L-1); Toc2 (100 vars of faba bean used were Giza 3(G3) and Giza

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Table 4. Effect of a-tocopherol on proline and carotenoids in the leaves of two faba bean cultivars grown under seawater saline conditions*

Treatments Protectant concentrations

Cv Seawater Toc Proline (^ mole g-1 FW) Caroteniods (mg g-1 FW)

G3 S0 Toc0 8.9 0.187

Tocl 9.5 0.197

Toc2 11.1 0.217

S1 Toc0 9.7 0.220

Toc1 12.1 0.253

Toc2 13.4 0.263

S2 Toc0 10.5 0.207

Toc1 13.0 0.227

Toc2 14.9 0.240

G843 S0 Toc0 10.7 0.227

Toc1 11.3 0.250

Toc2 12.2 0.267

S1 Toc0 11.6 0.250

Toc1 14.0 0.287

Toc2 15.6 0.330

S2 Toc0 12.9 0.257

Toc1 15.0 0.297

LSD 0.05 Toc2 17.1 0.7 0.337 N.S

*S0 (tap water); S1 (3.13 dS m-1); S2 (6.25 d: mg L-1). Measurements were made at 75 d a:

3(G3) and Giza 843 (G843).

c0 (0 mg L-1); Tocl (50 mg L-1); Toc2 (100 ing (DAS). Cultivars of faba bean used were Giza

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Table 5. Effect of a-tocopherol on superoxide dismutases (SOD), catalases (CAT), phenylalanine ammonia lyase (PAL), and peroxidases (POX) enzymes activities in the leaves of two faba bean cultivars grown under seawater saline conditions*

Treatments Enzymes activities

Cv Seawater Toc SOD CAT PAL POX

(^ mole g-1 FW)

Toc0 Toc1 Toc2 Toc0 Toc1 Toc2 Toc0 Toc1 Toc2 Toc0 Toc1 Toc2 Toc0 Toc1 Toc2 Toc0 Toc1 Toc2

LSD 0.05

68.6 74.8 72.7

73.3 91.2

85.7 79.6

80.4 86.0

140.6 3.9

*S0 (tap water); S1 (3.13 dS m-1); S2 (6.25 mg L-1). Measurements were made at 75 d after

3(G3) and Giza 843 (G843).

71.0 72.6

83.1 74.5

88.2 90.8

78.4 80.3

93.3 95.3 90.8 108.0 112.1 _5_5

23.9 26.0 29.0 31.7 38.0 41.6 36. 41.

33.0 35.9

6.4 8.1

44.6 48.9 45.5 50.9 55.1 1.9

12 .2 13.3 15.2 6.1 6.9 7.0 9.6 10.7 12.1 11.7 12.5 14.0 1.9

; Toc0 (0 mg L-1); Toc1 (50 mg L-1); Toc2 (100 ing (DAS). Cultivars of faba bean used were Giza

Journal of the Saudi Society of Agricultural Sciences (2014) xx, xx-xx

Table 6. Effect of a-tocopherol on ion concentrations (K+, Ca2+ and Na+) and K+:Na+ and Ca+2:Na" ratios in the leaves of two faba bean cultivars grown under seawater saline conditions*

Treatments K Ca Na K+:Na+ Ca+2:Na+

Cv Seawater Toc (%) Ratio

Toc0 Tocl Toc2 Toc0 Tocl Toc2 Toc0 Toc1 Toc2 Toc0 Toc1 Toc2 Toc0 Toc1 Toc2 Toc0 Toc1 Toc2

LSD 0.05

1.74 1.91 2.02 1.29

1.38 1.54 1.18 1.27

1.32 1.83 2.01 2.12 1.35 1.45 1.62 1.24

1.39 0.18

2.33 2.45 2.56 2.01

2.17 2.32 1.82 1.91 1.99 2.76 2.93 3.06

2.41 2.60 2.78

2.18 2.29

2.42 0.17

*S0 (tap water); S1 (3.13 dS m-1); S2 (6.25 d mg L-1). Measurements were made at 75 d a: 3(G3) and Giza 843 (G843).

0.31 0.28 0.25 0.42 0.39 0.37 0.52 0.49 0.48 0.24 0.20 0.21 0.33 0.31 0.30 0. 0.

5.68 6.86 8.08 3.09 3.58

2.26 2.61 2.77 7.57 10.25

.92 3.44 3.75 0.95

7.56 8.80 10.25 4.83 5.64 6.36

1.39 15.02 14.98 7.38 8.41 9.44 5.14 5.92 6.53 1.25

oc0 (0 mg L-1); Toc1 (50 mg L-1); Toc2 (100 ng (DAS). Cultivars of faba bean used were Giza