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Engagement of polyamines, abscisic acid and anti-oxidative enzymes in version of Blue Panicgrass ( Panicum antidotale Retz. ) to saline environments

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A aquicultural experiment was conducted to measure the possible engagement of polyamines ( PAs ) , abscisic acid ( ABA ) and anti-oxidative enzymes such as superoxide dismutase ( SOD ) , peroxidase ( POD ) and catalase ( CAT ) in version of six populations of Panicum antidotale Retz. to selection force per unit area ( soil salt ) of a broad scope of home grounds. Plants of six populations were collected from six different home grounds with ECe runing from 3.39 to 19.23 darmstadtiums m?1and pH from 7.65 to 5.86. Young tillers from 6-month-old workss were transplanted in fictile containers each incorporating 10 cubic decimeter of half strength Hoagland ‘s alimentary solution entirely or with 150 mol m?3 NaCl. After 42 yearss growing, contents of polyamines ( Put, Spd and Spm ) and ABA, and the activities of anti-oxidative enzymes ( SOD, POD and CAT ) of all populations by and large increased under salt emphasis. The populations collected from extremely saline home grounds showed a greater accretion of polyamines and ABA and the activities of anti-oxidative enzymes as compared to those from mild or non-saline home grounds. Furthermore, Spm/Spd and Put/ ( Spd + Spm ) ratios by and large increased under salt emphasis. However, the populations from extremely saline environments had significantly higher Spm/Spd and Put/ ( Spd + Spm ) ratios as compared to those from mild or non-saline environments. Similarly, the populations adapted to high salt accumulated less Na+ and Cl? in culm and foliages, and showed less lessening in leaf K+ and Ca2+ under salt emphasis. Higher activities of anti-oxidative enzymes and accretion of polyamines and ABA, and increased Spm/Spd and Put/ ( Spm + Spd ) ratios were found to be extremely correlated with the grade of adaptability of Panicum to saline environment.

Keywords: Bluegrass ; Adoptability ; Evolution ; Soil salt ; Selection force per unit area

Article Outline

1. Introduction

2. Materials and methods

3. Consequences

3.1. Growth attributes

3.2. Activities of antioxidant enzymes

3.3. Polyamines and ABA

3.4. Ion accretion

4. Discussion

5. Decision

Mentions

1. Introduction

Soil salt is one of the major modification factors for harvest and eatage production in the waterless and semi-arid parts of the universe including Pakistan. Although, the recent technological promotion has brought about novel and effectual techniques to get the better of this job, their high cost makes them non-practicable for hapless husbandmans peculiarly populating in countries inflicted with terrible abiotic emphasiss. In this state of affairs, geographic expedition and cultivation of salt tolerant species offer a practical solution for effectual use of stress-affected dirts ( [ Wu, 1981 ] , [ Amtmann et al. , 2005 ] , [ Ashraf and Harris, 2005 ] and [ Liang et al. , 2008 ] ) . For illustration, the species that are found entirely on saline home grounds possess familial fluctuation necessary to let the development of salt-tolerant populations in response to the choice force per unit area of the home grounds ( Ashraf et al. , 1989 ) . Undoubtedly, the development of any peculiar character depends on two major determiners running analogue for a sufficient length of clip ; i.e. , the being of appropriate familial fluctuation, and the happening of appropriate natural choice force per unit area ( [ Noble et al. , 1984 ] , [ Ashraf et al. , 1986 ] , [ Ashraf et al. , 2005 ] , [ Ashraf and McNeilly, 1990 ] , [ Al-Khatib et al. , 1992 ] and [ Ashraf, 2005 ] ) . Although during the recent old ages, a figure of advanced techniques including familial profiling and molecular sweetenings have been tried for enhanced emphasis tolerance, genetically based fluctuation found in natural populations of workss has been seldom attempted, although the possible value of such familial resources has late been emphasized in modern research plans ( [ Rogers and Noble, 1992 ] , [ Munns, 2002 ] , [ Ashraf, 2004 ] and [ Hameed and Ashraf, 2008 ] ) .

Bluegrass offers an first-class beginning of analyzing adaptability in response to choice force per unit area as it can defy multiple emphasiss including salt, drouth, fire, etc. Its colonisation on extremely saline ( [ Rasul et al. , 1994 ] , [ Tomar et al. , 2003 ] and [ Ashraf et al. , 2006 ] ) , alkaline ( Ryan et al. , 1975 ) , drought-hit ( [ Cope, 1982 ] , [ Bokhari et al. , 1987 ] and [ Chaudhary, 1989 ] ) , and waterlogged ( Ashraf, 2004 ) soils shows its version to a broad scope of environmental conditions. However, survey of the familial footing of adaptability is instead hard because emphasis tolerance has been shown to be a complex multigenic trait ( [ Ashraf, 1994 ] , [ Niknam and Mccomb, 2000 ] and [ Ashraf and Harris, 2004 ] ) affecting multiple mechanisms which makes it more hard to analyze the heritage of emphasis tolerance. In this state of affairs, physiological and biochemical alterations under nerve-racking conditions might offer any easy attack to analyze heritage of emphasis tolerance ( Niknam and Mccomb, 2000 ) .

Polyamines ( PAs ) , spermidine ( Spd ) , spermine ( Spm ) and their diamine obligate precursor putrescine ( Put ) , are little aliphatic aminoalkanes that are omnipresent in all works cells. They play a function as regulators of cell proliferation and distinction ( Bouchereau et al. , 1999 ) . Similarly, ABA by and large referred to as a emphasis endocrine, is known to intercede a assortment of emphasis responses that help last workss under different emphasiss ( [ Barry et al. , 2003 ] , [ Zhang et al. , 2006 ] , [ Khadri et al. , 2007 ] , [ Maggio et al. , 2007 ] and [ S & A ; aacute ; nchez-D & A ; iacute ; az et al. , 2008 ] ) . In add-on, anti-oxidative enzymes ( SOD, POD and CAT ) have been reported to play a cardinal function in tolerance to environmental emphasiss in a figure of works species ( [ Fadrzilla et al. , 1997 ] and [ Raza et al. , 2007 ] ) . The degrees of all these bio-molecules are reported to increase shortly after exposure to emphasize conditions and are believed to intercede a assortment of responses under nerve-racking conditions ( [ Iqbal et al. , 2006 ] , [ Iqbal and Ashraf, 2006 ] and [ Iqbal and Ashraf, 2007 ] ) . However, whether their addition under stress status is an adaptative response is still ill-defined.

In position of the critical function of polyamines, ABA and anti-oxidative enzymes in emphasis tolerance, we hypothesized that these bio-molecules could be used as a possible standard for know aparting the otherwise adapted populations of blue grass for their salt-tolerance potency. Since Panicum antidotale has been found turning on a assortment of home grounds ( Ashraf, 2003 ) , there would be a just opportunity of development of emphasis tolerance in populations from diverse home grounds. Therefore, the chief aim of the present survey was to measure whether polyamines, ABA and anti-oxidative enzymes have played a function in the adaptability of P. antidotale populations to saline home grounds.

2. Materials and methods

The possible function of polyamines, ABA and anti-oxidative enzymes in version of Blue Panicgrass [ Panicum antidotale Retz. ] to saline environments was assessed in a aquicultural experiment conducted during 2006. The experiment was laid out in a wholly randomized design with four reproductions. Six populations of P. antidotale Retz. were collected from six different sites with a broad fluctuation in ECe and pH. These populations were collected from ( 1 ) salt-affected country of Pakka Anna, Faisalabad ( P1 ) [ dirt ECe = 19.23 darmstadtium m?1 ; pH 6.75 ; co-ordinates = 31 & A ; deg ; 19?26.20?N, 72 & A ; deg ; 45?38.49?E ] ; the bank of disposal H2O channel, Rajawala, University of Agriculture Faisalabad ( P2 ) [ dirt ECe = 14.87 darmstadtium m?1 ; pH 6.45 ; co-ordinates = 31 & A ; deg ; 25?30.61?N, 73 & A ; deg ; 03?53.84?E ] ; the bare country of Punjab Wild Life Research Institute ( PWRI ) , Faisalabad ( P3 ) [ ECe = 9.31 darmstadtium m?1 ; dirt pH 7.65 ; co-ordinates = 31 & A ; deg ; 28?51.27?N, 73 & A ; deg ; 12?46.78?E ] ; the bank of canal ( PWRI ) , Faisalabad ( P4 ) [ ECe = 7.19 darmstadtium m?1 ; dirt pH 6.68 ; co-ordinates = 31 & A ; deg ; 28?26.21?N, 73 & A ; deg ; 12?13.78?E ] ; Botanical Garden Research Area, University of Agriculture, Faisalabad ( P5 ) [ dirt ECe = 4.83 darmstadtium m?1 ; pH 6.10 ; co-ordinates = 31 & A ; deg ; 25?43.96?N, 73 & A ; deg ; 04?17.40E ] and forest plantation ( Eucalyptusspp. ) PWRI, Faisalabad ( P6 ) [ ECe = 3.39 darmstadtium m?1 ; dirt pH 5.86 ; co-ordinates = 31 & A ; deg ; 28?36.00?N, 73 & A ; deg ; 12?38.51E ] . The climatic conditions of Faisalabad are: altitude = 213 m ; minimal temperature = 2 & A ; deg ; C ; maximal temperature = 47 & A ; deg ; C ; mean temperature 24 & A ; deg ; C ; mean rainfall 300 millimeter [ Climatological Data Processing Centre, Pakistan Meteorological Department, Karachi, Pakistan ; hypertext transfer protocol: //www.met.gov.pk/cdpc/home.htm ] .

Plants were collected in four replicates from their parent home grounds along with dirt samples ( 500 g at a deepness of 30 centimeter from the surface ) that were used for the finding of dirt ECe and pH. All the workss were established in pots incorporating normal dirt and allowed to turn for 6 months under natural conditions. The freshly grown tillers of comparable size of each population were transplanted equidistant in fictile containers each incorporating 10 fifty half strength Hoagland ‘s alimentary solution and they were allowed to set up for 21 yearss. These populations were exposed to 0 ( normal ) or 150 mol m?3 ( saline ) NaCl for a period of 42 yearss. The coveted salt degree was obtained by an increase of 50 mol m?3 NaCl on alternate yearss. The solution was continuously aerated for 6 h day-to-day during the whole experiment period and renewed on a regular basis after 1 hebdomad. During the class of experiment, the mean twenty-four hours and dark temperatures were 37 ± 3 and 24 ± 3 & A ; deg ; C, severally, and photoperiod from 11 to 12 h. The comparative humidness ranged from 45.9 to 58.6 % .

After 42 yearss, excised culms and roots were washed with distilled H2O, oven dried at 65 & A ; deg ; C for 7 yearss and their dry weights recorded. Superoxide dismutase ( SOD ) activity was assayed by nitroblue tetrazolium ( NBT ) method following Giannopolitis and Ries ( 1977 ) , whereas, catalase ( CAT ) andperoxidase ( POD ) activities were measured following the method of Chance and Maehly ( 1955 ) with some alterations as reported by Raza et Al. ( 2007 ) . The activity of each enzyme was expressed on protein footing measured by the method of Bradford ( 1976 ) .

The extraction, purification and quantification of polyamines were done from fresh foliages by benzoylation method as described by Flores and Galston ( 1982 ) with some alterations as reported by Iqbal et Al. ( 2006 ) . ABA contents were besides determined from fresh foliages ( 3rd foliage from top ) following the methods of Guinn et Al. ( 1986 ) with some alterations as reported by Iqbal and Ashraf ( 2006 ) . Both polyamines and ABA were determined utilizing HPLC ( Sykam GmbH, Kleinostheim, Germany ) equipped with a S-1121 double Piston dissolver bringing system, S-3210 UV-vis sensor and equipped with a Hypersil ODS reverse-phase ( C18 ) column ( 4.6 mm – 250 millimeter, 5-?m atom size: Thermo Hypersil GmbH, Germany ) . The peak countries for polyamines and ABA were recorded and calculated by a computing machine bundle [ SRI PeakNT version 2.66 [ MS ] chromatography informations acquisition and integrating package ( SRI Instruments, Torrance, CA, USA ] . The values were compared with the reliable criterions run through for the whole process and the concentrations of PAs and ABA calculated.

The oven-dried works stuff of roots, culm and foliages was finely land to go through through 2 millimeters sieve. The dried stuff ( 0.1-0.5 g ) was digested in a digestion mixture ( sulfuric acid-hydrogen peroxide ) harmonizing to the method of Wolf ( 1982 ) . Concentrations of Na+ , K+ and Ca2+ in the digests were determined with a fire photometer ( Jenway, PFP7 ) . For Cl? finding, the land stuff ( 0.1-0.5 g ) was extracted in 10 milliliter DW at 80 & A ; deg ; C for 6 H and Cl? concentration determined with a chloride analyser ( Model 926, Sherwood Scientific Ltd. , Cambridge, UK ) .

Analysis of discrepancy ( ANOVA ) of the information was computed utilizing a COSTAT computing machine bundle ( CoHort Software, 2003, Monterey, California ) . The average values were compared with the least significance difference trial following Snedecor and Cochran ( 1980 ) .

3. Consequences

3.1. Growth attributes

Analysis of discrepancy of the information for culm and root dry weights revealed extremely important differences for populations, interventions, and population – intervention interaction footings. Salinity emphasis significantly reduced dry weights of both culm and root in all populations under saline conditions. Both parametric quantities were the highest in population P1 followed by P2 that were collected from countries with ECe = 19.23 and 14.87 darmstadtium m?1, severally. Populations P3 and P4, collected from mild saline dirt [ ECe = 9.31 and 7.19 darmstadtium m?1, severally ] were intermediate in stress tolerance and showed about equal culm and root dry weights. An of import observation in this survey was that populations, P5 and P6 collected from dirts with really low salt, ECe = 4.83 and 3.39 darmstadtium m?1, severally, were unable to defy the applied salt and showed terrible growing suppression at higher degrees of salt emphasis ( Fig. 1a and B ) .

Life-size image ( 68K )

Fig. 1. Growth attributes of six Panicum antidotale populations grown hydroponically for 42 yearss under normal or saline conditions. Vertical lines on bars represent SE values. Means sharing same letters do non differ significantly at 5 % . ***Significant at 0.001 degree. ECe in darmstadtium m?1.

3.2. Activities of antioxidant enzymes

The activities of antioxidant enzymes ( SOD, POD, CAT ) by and large increased in all populations of Panicum antidotale upon exposure to salt emphasis. Statistical analysis of the information for the activities of all three enzymes revealed important differences for populations, interventions and population – intervention interaction footings. The populations from extremely saline home grounds ( P1 and P2 ) showed the highest addition in SOD, POD and CAT upon exposure to salt emphasis. On the other manus, the populations from mild saline home grounds ( P3 and P4 ) showed less addition in the activities of antioxidant enzymes as compared to those from non-saline home grounds ( P1 and P2 ) ( Fig. 2 ) .

Life-size image ( 89K )

Fig. 2. Antioxidative enzymes ( units/mg protein ) of six Panicum antidotale populations grown hydroponically for 42 yearss under normal or saline conditions. Vertical lines on bars represent SE values. Means sharing same letters do non differ significantly at 5 % . ***Significant at 0.001 degree. ECe in darmstadtium m?1.

An of import observation in this survey was that the activities of all three antioxidant enzymes increased up to three-fold in the populations from extremely saline home grounds as compared to those in the populations from mild saline home grounds ( double addition ) . On the other manus, the populations from non-saline home grounds showed a less addition in the enzyme activities upon exposure to salt emphasis. By and large, the addition in SOD activity was greater as compared to those of POD or CAT in the foliages of stressed workss of all populations of P. antidotale ( Fig. 2a-c ) .

3.3. Polyamines and ABA

A important addition in polyamines ( putrescine, spermidine and spermine ) and ABA concentrations was observed in all six P. antidotale populations under salt emphasis. The populations from extremely saline home grounds ( P1 and P2 ) exhibited a greater addition as compared to those from mild saline environments ( P3 and P4 ) . On the other manus, the lowest addition in polyamines was observed in the populations from non-saline environments ( P5 and P6 ) ( Fig. 3a-d ) . A similar tendency was observed for Spm/Spd and Put/ ( Spd + Spm ) ratios which by and large decreased under nerve-racking conditions. The populations from extremely saline home grounds ( P1 and P2 ) exhibited less lessening in both ratios as compared to the populations from mild or non-saline home grounds ( Fig. 3e and degree Fahrenheit ) .

Life-size image ( 167K )

Fig. 3. Polyamine and free ABA in six Panicum antidotale populations grown hydroponically for 42 yearss under normal or saline conditions. Vertical lines on bars represent SE values. Means sharing same letters do non differ significantly at 5 % . ***Significant at 0.001 degree. ECe in darmstadtium m?1.

3.4. Ion accretion

All populations of P. antidotale showed a considerable addition in Na+ contents in different works parts under salt emphasis. The populations from extremely saline home grounds ( P1 and P2 ) accumulated significantly lower Na+ contents in the foliages, roots and culm every bit compared to those from mild saline home grounds ( P3 and P4 ) . In contrast, the populations from non-saline home grounds were the highest of all population in Na+ contents in all works parts ( Fig. 4a-c ) .

Life-size image ( 142K )

Fig. 4. Na+ and K+ contents in root, culm and foliages of six Panicum antidotale populations grown hydroponically for 42 yearss under normal or saline conditions. Vertical lines on bars represent SE values. Means sharing same letters do non differ significantly at 5 % . * , ** , ***Significant at 0.05, 0.01 and 0.001 degrees, severally. ns = non-significant. ECe in darmstadtium m?1.

Although K+ contents in the foliages, roots and culm by and large decreased in all populations of P. antidotale upon exposure to salt emphasis, the populations did non differ significantly for root K+ contents. In contrast, the populations differed significantly for culm or foliage K+ content. Highest K+ contents were observed in the foliages followed by culm and roots. Although all populations collected from diverse home grounds did non demo a big fluctuation in K+ contents in all variety meats studied, the response of the populations from extremely saline home grounds was relatively better as they showed less lessening in K+ contents under salt emphasis as compared to the other populations from mild or non-saline home grounds ( Fig. 4d-f ) .

A general diminishing tendency in Ca2+ content was observed in all variety meats of Panicum populations upon exposure to salt emphasis. The populations from extremely saline home grounds showed a less lessening in Ca2+ contents in all variety meats as compared to those from mild saline home grounds. Highest lessening in Ca2+ contents in all variety meats was observed in the populations from non-saline environments ( Fig. 5a-c ) .

Life-size image ( 149K )

Fig. 5. Ca2+ and Cl? contents in roots, culm and foliages of six Panicum antidotale populations grown hydroponically for 42 yearss under normal or saline conditions. Vertical lines on bars represent SE values. Means sharing same letters do non differ significantly at 5 % . * , ** , ***Significant at 0.05, 0.01 and 0.001 degrees, severally. ns = non-significant. ECe in darmstadtium m?1.

A considerable addition in Cl? content was observed in root, culm and foliages of Panicum populations under salt emphasis. The populations from extremely saline environments showed relatively low Cl? contents as compared to those from mild saline home grounds. In add-on, the populations from non-saline home grounds were the highest of all populations in Cl? contents of all variety meats. Cl? contents were more or less every bit distributed in all variety meats under normal or saline conditions ( Fig. 5d-f ) .

4. Discussion

While mensurating different growing attributes it was apparent that the populations ( P1 and P2 ) collected from extremely saline home grounds had better growing and endurance under saline conditions as compared to those collected from less saline ( P3 and P4, ) or non-saline ( P5, and 6 ) home grounds. The grade of salt tolerance shown by the populations P1 and P2 can be related to the strength of dirt salt ( selection force per unit area ) that may hold been one of the of import determiners responsible for the development of salt tolerance trait in P. antidotale ( [ Ashraf, 2003 ] and [ Hameed et al. , 2008 ] ) .

All Panicum populations showed multi-fold addition in anti-oxidative enzymes ( superoxide dismutase, peroxidase and catalase ) upon exposure to salt emphasis. It is now widely accepted that reactive O species ( ROS ) are produced under salt emphasis, which can destruct the normal metamorphosis through oxidative harm of lipoids, proteins and nucleic acids ( McCord, 2000 ) thereby finally damaging cell construction ( [ Mittler, 2002 ] and [ Vranov & A ; aacute ; et al. , 2002 ] ) . Therefore, ROS must be scavenged by enzymatic and/or non-enzymatic antioxidant systems for the care of normal growing in nerve-racking environments. In position of different research workers, salt tolerance is frequently correlated good with a more efficient anti-oxidative system ( [ Sreenivasulu et al. , 2000 ] , [ Ashraf and Harris, 2004 ] , [ Demiral and Turkan, 2004 ] , [ Juan et al. , 2005 ] , [ Demiral and T & A ; uuml ; rkan, 2005 ] , [ de Azevedo Neto et al. , 2006 ] , [ L & A ; oacute ; pez-G & A ; oacute ; mez et al. , 2007 ] , [ Masood et al. , 2006 ] , [ Yazici et al. , 2007 ] , [ Tuna et al. , 2008 ] and [ Ashraf, 2009 ] ) . In the present survey, superoxide dismutase ( SOD ) , catalase ( CAT ) and peroxidase ( POD ) activities were increased in the foliages of stressed workss of all populations. Activities of all three anti-oxidative enzymes were greater in the populations from home grounds with high salt as compared to those from low saline or non-saline environments. These findings show that familial variableness was present in different Panicum populations that had been triggered in populations as a effect of exposure to high choice force per unit area.

Increased degrees of polyamines under nerve-racking environments play an of import function in stress tolerance of harvest workss ( [ Iqbal and Ashraf, 2006 ] , [ Iqbal and Ashraf, 2007 ] , [ Iqbal et al. , 2006 ] and [ Mutlu and Bozcuk, 2007 ] ) . Most widely accepted and by experimentation proven point of view is that PAs exert their protective action on bio-molecules due to their chemical construction as organic polycations ( Kuznetsov et al. , 2006 ) . In add-on, their maps include stabilisation of construction and map of membranes particularly that of thylakoid, DNA stabilisation, ordinance of enzyme activity, care of cell division/cycle and elongation, buffering of cellular pH, hold in aging, map as 2nd couriers and ordinance of other multiple cellular responses ( [ Krishnamurthy and Bhagwat, 1989 ] , [ Galston et al. , 1997 ] , [ Bouchereau et al. , 1999 ] , [ Kakkar and Sawney, 2002 ] , [ Alcazar et al. , 2006 ] , [ Kuznetsov et al. , 2006 ] and [ Xiong et al. , 2006 ] ) . Therefore, it can be postulated that hyper-production of Put in combination with Spd and Spm regulated growing and development of tolerant populations under nerve-racking conditions and are cardinal physiological determiners of salt tolerance in P. antidotale.

An interesting observation in this survey was that Spm/Spd ratio by and large decreased under salt emphasis. The population P1 exhibited the highest Spm/Spd ratios followed by P2, P3 and P4, severally. In contrast, the populations P5 and P6 showed the lowest Spm/Spd ratio. It is now good established that Spm and Spd have a common biosynthetic tract ( [ Friedman et al. , 1989 ] , [ Bortolotti et al. , 2004 ] and [ Kuznetsov et al. , 2006 ] ) . Therefore, the greater addition in Spm/Spd ratio in the populations from extremely saline environment under salt emphasis indicated that the biosynthetic tract might hold been more directed towards spermine biogenesis.

Similarly, Put/ ( Spm + Spd ) ratio was the highest in P1 and P2 as compared to all the other populations that showed about equal Put/ ( Spm + Spd ) ratio ( Fig. 3e and degree Fahrenheit ) . Furthermore, an addition in this ratio was greater in the populations from extremely saline environments [ P1 and P2 ] as compared to those from mild or non-saline environments which had about equal addition in Put/ ( Spd + Spm ) ratio. These consequences support that tolerance to salt-stress was associated with a rise in Put and an evident damage in the capacity to synthesise Spd from Put. Consequently, the Put accretion observed in the stress-tolerant workss in response to emphasis might hold resulted from an sweetening of Put synthesis or, instead, from an suppression of the activity of the enzyme SAM decarboxylase, therefore leting Put to roll up in works tissues ( [ Santa-Gruz et al. , 1997 ] and [ Bouchereau et al. , 1999 ] ) .

The ABA contents in all Panicum populations by and large increased significantly under salt emphasis. The populations P1 and P2 had significantly higher addition in ABA contents under salt emphasis as compared to P3 and P4. The lowest addition in ABA content was found in the populations P5 and P6 which were collected from the home grounds with low dirt salt ( Fig. 3d ) . ABA is now good known to quickly roll up in response to emphasiss and is involved in the mediation of many emphasis responses that help works endurance under nerve-racking environments ( [ Pierce and Raschke, 1980 ] , [ Jia and Zhang, 2000 ] , [ Jia et al. , 2001 ] , [ Jia et al. , 2002a ] , [ Jia et al. , 2002b ] , [ Mills et al. , 2001 ] and [ Zhang et al. , 2006 ] ) . This is known to happen in a figure of monocot workss including wheat ( [ Mumtaz et al. , 1997 ] , [ Naqvi et al. , 1997 ] , [ Aldesuquy and Ibrahim, 2001 ] and [ Iqbal et al. , 2006b ] ) , rice ( [ Henson, 1984 ] , [ Kishor, 1989 ] , [ Bohra et al. , 1995 ] and [ Moons et al. , 1995 ] ) , barley ( [ Stewart and Voetberg, 1985 ] , [ Kefu et al. , 1991 ] and [ G & A ; oacute ; mez-Cadenas et al. , 2003 ] ) , sorghum ( [ Amzallag et al. , 1998 ] and [ Saneoka et al. , 2001 ] ) , and maize ( [ Benson et al. , 1988 ] and [ Liu et al. , 2005 ] ) . A significant grounds suggests that increased ABA degrees limit H2O loss by stomatous closing and therefore it plays a important function in works version to emphasiss. ABA has been reported to modulate the procedure of version in two interacting stairss. First, ABA acts via differential signal transduction tracts on cells under imposed emphasiss. Second, ABA may modulate through some genes/gene merchandises, which control the look ( up-regulation or down-regulation ) of emphasis adaptative-specific cistrons ( [ Zeevaart and Creelman, 1988 ] , [ Bray, 1991 ] and [ Hetherington and Quatrano, 1991 ] ) , thereby ensuing in overall synthesis of genomic merchandises which may play a function in works endurance under different environmental conditions ( [ Mundy and Chua, 1988 ] , [ El-Enany, 2000 ] , [ Chandler and Robertson, 1994 ] , [ Barry et al. , 2003 ] , [ Khadri et al. , 2007 ] and [ Maggio et al. , 2007 ] ) . Therefore, the higher production of ABA in the populations ( P1 and P2 ) from extremely saline countries may propose its function in adaptability and development of salt-tolerance trait in these populations. On the other manus, the populations from the home grounds with mild dirt salt ( P3 and P4 ) accumulated less ABA and therefore were less adaptative to salt emphasis. Populations form non-saline environment ( P1 and P3 ) that had the lowest ABA content did non demo any version to salt emphasis.

The consumption and accretion of ions in workss is one of the possible indexs of salt tolerance, because they are genetically regulated, though besides affected by the environment ( selection force per unit area ) ( Chaubey and Senadhira, 1994 ) . In this survey, Na+ and Cl? contents by and large increased in all works parts studied of all populations, whereas, K+ and Ca2+ contents decreased significantly. The populations from extremely saline home grounds showed a less addition in Na+ and Cl? contents and a less lessening in K+ and Ca2+ contents thereby keeping high K+/Na+ and Ca2+/Na+ ratios as compared to those from home grounds with mild or normal salt degrees ( Graifenberg et al. , 1995 ) . On the other manus, the comparing among populations revealed that the tolerant populations accumulated less Na+ as compared to the sensitive 1s. Therefore, it can be concluded that ion exclusion mechanism might hold been the prime adaptative constituent of salt tolerance in Panicum populations.

5. Decision

Our consequences clearly show that strength of choice force per unit area ( soil salt ) played a cardinal function in the version of Panicum populations to salt emphasis. Overall, all polyamines ( Put, Spm and Spd ) , ABA and anti-oxidative enzymes increased under salt emphasis in all populations. Similarly, the populations adapted to high salt accumulated less Na+ and Cl? in culm and foliages, and showed a less lessening in leaf K+ and Ca2+ under salt emphasis. The populations from extremely saline countries accumulated more polyamines, ABA and showed higher activities of anti-oxidative enzymes as compared to those from mild or non-saline home grounds. Increased Spm/Spd ratio in the populations from extremely saline home grounds indicated the efficiency of Spm biosynthetic tract while increased Put/ ( Spm + Spd ) ratio indicated the efficiency of Put biosynthetic tract. Therefore, both polyamines may hold played a function in P. antidotale to digest salt emphasis.

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