EFFECT OF NUTRIENT CATIONS TO IMPROVING SALINITY- TOLERANCE RESPONSES IN SORGHUM BICOLOR L. ABSTRACT

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1 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 EFFECT OF NUTRIENT CATIONS TO IMPROVING SALINITY- TOLERANCE RESPONSES IN SORGHUM BICOLOR L. OMAR ABDUALLAH AL-AMOUDI* AND AFAF ABDUALLAH RASHED Biology Deprtment, Fculty of Applied Sciences, Umm Al-Qur University, Mkkh, Sudi Arbi. ABSTRACT Seedling of Sorghum bicolor L. were grown hydroponiclly in growth units, filled with continuously erted hlf strength of Hoglnd-nutrient solution. Different tretments were mnipulted to determine the combined effect of three NCl levels (30, 60 nd 90 mm) with combined levels of C 2 : K : Mg 2 (10:12:3 mm) on seedling growth. Seedling length, lef sp osmollity, totl chlorophyll, soluble protein, proline, phosphpenolpyruvte crboxylse (PEPC) ndsucrose phosphte synthse (SPS) were used s rection criteri. Severl ions (N, K, C 2 nd Mg 2 ) were nlysed in seedling mteril. Sline tretments decresed the growth, which ws prtly restored with the ction rtio tretment. A significnt reltion ws observed between the electric conductivity of the nutrient solution nd the osmollity of leves using independent tretment (slinity or ction rtio). Slinity t ll concentrtions used in this work were reduced the totl chlorophyll nd soluble protein yield compred with tht obtined t 0 mmncl. However, there ws n increse, of previous criteri, s consequence of the ppliction of ction rtio tretments in ech sline concentrtion. Higher concentrtions of proline in shoot were obtined with incresing slinity concentrtions. PEPC enzyme ctivity in roots ws considerbly higher thn shoot under slt medium s well s with ction tretments. Both shoot nd root SPS ctivities were slightly higher in root thn in shoot subjected to slt nd ction tretments. At high NCl concentrtion, the rtio N/C nd N/Mg decresed s consequence of ction tretments. Therefore, the ction combintion tretments were pplied in the nutrient solution could be importnt fctors in the hydroponic culture of sorghum grown under sline conditions. Key words:sorghum, slinity, C 2, K, nd Mg 2 ctions, reltive shoot growth rte, slt stress, totl chlorophyll INTRODUCTION Slinity is mjor problem in se-irrigted griculture. Millions of tons of slt re nnully dumped onto the soil from the se-wter irrigtion (Hsegw et l., 2000 nd Zhu, 2001). The growth of plnts my be reduced under slt stress becuse of () n osmotic stress due to lowering of the externl wter potentil, or (b) effects of specific ions on metbolic processes rnging from the bsorption of nutrients to enzyme ctivtion or inhibition (Crvjl et l., 2000). Moreover, ion regultion nd osmoregultion re subjects of intensive reserch into possible mechnisms of slt tolernce (Krley et l., 2000 nd Ver-Estrell et l., 2004). In grin Sorghum (Sorghum bicolor L.) nd in vrious orgns of other species, the primry effects of slt stress re to reduce growth rte, lef emergence rte, nd overll shoot development (Neves-Piestun nd Bernstein, 2001). In mny, but not ll, slt sensitive L-77 Botny

2 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 species, elevted clcium (C 2 ) concentrtions in the root medi meliorte prt of the growth reduction cused by the stress. Severl investigtions hve been crried out to study the possible role of vrious kinds of chemicl tretment to improve the irrigtion medium nd growth in sline environments (Crvjl et l., 2000). In literture, there re conflicting reports concerning the effects of clcium (C 2 ), potssium (K ) nd mgnesium (Mg 2 ) on slt tolernce in plnts (Lopez nd Stti, 1996). In contrst, ddition of clcium to slinized medi hs been reported to effectively enhnce slt tolernce in ben (Younis et l., 1993), citrus (Bnuls et l., 1991), rice (Shh et l., 1987) nd mung ben (Nkmr et l., 1990). In plnt cells, mintining cytosolic potssium (K ) in n environment with high sodium (N ) concentrtion is key fctor in determining the bility to tolerte slinity (Mthuis nd Amtmnn, 1999). Typiclly involved in these responses re sugrs, sugr lcohols, nd mny others molecules such s mino cids, orgnic cids, or inorgnic ions (Munns, 2005). The effect of soil slinity on biomss nd grin yield in mny vrieties of Sorghum hs been tested (Begdullyev et l., 2007). It should be noted tht the principl of mesuring the ctivtes of enzymes due to tht been reported (Huber nd Huber, 1991), under slt stress could regulte the ctivity of sucrosephosphte synthse (SPS), wheres phosphoenolpyruvtecrboxylse (PEPC) could be sensitive to inorgnic slts (Osmond, 1972). In previous studies (Rshed, 2008) three levels of combined ctions C 2 K Mg 2 (in mm rtio of 4:6:1, 7:9:2 nd 10:12:3) been tested on sorghum exposed to slinity, nd growth yield exhibited positive results. In the sme wy, the ction rtio C 2 : K : Mg 2 (10:12:3 mm) gve increse in growth biomss nd greter production in sline treted. In the present study we, therefore, re-evlute previous findings by performing full ssessment of the effect of slinity nd ction rtio C 2 : K : Mg 2 (10:12:3 mm) into Sorghum, under controlled slinity conditions. In ddition to compring these prmeters s reltive osmollity of lef cell sp, plnt length, root/shoot rtio, totl chlorophyll concentrtion, soluble protein nd proline contents. The ctivities of both enzymes (PEPC) nd (SPS), s well s the concentrtions of N, K, C 2, Mg 2 within nd cross tretments were nlysed in seedling mteril. L-78 MATERIALS AND METHODS Growth conditions nd experimentl design Grins of (Sorghumbicolor L.), were obtined from Fiff est of Gzn, south west of Sudi Arbi. Grins were sterilized by 10% sodium hypochlorite solution for 10 min nd rinsed severl time with distilled wter nd soked in wter for 24 h, then trnsferred to rectngulr pltes covered by two lyers of sheth cloth. The grins were lso covered with lyer of wetted sheth cloth, irrigted with distilled wter nd left t growth room temperture (30 C) for germintion. Seedling of one week (shoot lengths reched bout 2 cm) old were trnsferred to the growth units nd subjected to different slinity levels : 0, 30, 60 nd 90 mmncl, which correspond to 1.98, 4.82, 7.82 nd 12.2 dsm -1 slinity levels. Different levels of ctions C 2 : K : Mg 2 (10:12:3 mm) were dded to the nutrient solution, which correspond to 6.74, 9.21 nd 14.8 dsm -1 slinity levels. Seedlings were grown for 3 weeks hydroponiclly in growth units consists of 4 polyethylene tubes with dimensions: 5 cm dimeter, 51 cm length. Ech tube hs n out nd inlet in order to pore the nutrient solution. The cpcity of ech tube is 1500 ml with 31 pores (8 mm) were mde in ech tube distributed in two lterntion lines, where the seedlings should be settled. The plstic tips of micropipettes (Eppendorf), were used to support the seedlings during growth nd when they were hrvested. An ir pump terminl with pressure (200 ml/min), which llows continues ertion to the nutrient solution, were used. The growth units were plced in growth room with photosynthetic photon flux density ws 800 µmol m -2 s -1 with dy/night temperture (32/28 C), nd the surfce wter temperture reches to bout 30 C, with reltive humidity mens vlue ws 65%. Mesurement of plnt length nd root nd shoot rtio Plnt length of ech plnt ws mesured with ruler prior to hrvest, with precision of ~ 1 mm. After hrvesting, shoots nd roots were frozen in liquid nitrogen, lyophilized, weighed, ground to powder, nd kept in freezer (-20 C ) for further nlyses. Botny

3 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 The rest of the plnt mteril ws weighed fter drying in forced ir circultion oven t 80 C for 72 h. Roots nd shoots rtio were recorded ccording to Kingsbury et l. (1984). Soluble protein nd proline nlysis Soluble proteins were extrcted from lyophilized shoot of treted seedlings. Smple of 0.20 g powder ws homogenized in 3 ml Tris-HCl buffer (0.1 M, ph 7.5) contining 1 mmphenylmethnesulfonylfloride (PMSF), t 4 C. The homogente ws centrifuged t x g for 30 min. Protein in the superntnt ws mesured by the method of Lowry et l., (1951) using bovine lbumin to estblish stndrd curve.extrction nd determintion of proline ws mesured spectrophotometricllyccording to Btes et l. (1973). Chlorophyll content Chlorophyll content ws mesured from Lyophilized shoot powder. Smple of 0.1 g ws extrcted with 5ml of 80% (v/v) cetone nd filtered. Absorbencies of spectrophotometer were clculted t 645 nd 663 nm. Chlorophyll content (mg g-1 fw lef) ws estimted by equtions of Lichtenthler (1987). Cell sp osmollity Smples of shoot sp were obtined using Scholnder pressure chmber ccording to the method of Jchett et l. (1986). Osmollity of cell Sp (mosmol/kg) ws directly mesured, ccording to mnul stndrd method (Osmette A, S TM model 2004). Determintion of phosphpenolpyruvte crboxylse (pepc) PEPC ws ssyed in extrcts of lyophilized mteril. Shoot nd root powders were homogenized in morter nd pestle with 4ml of ice-cold extrction buffer (0.1 M Tris/HCl buffer, ph 7.8, 1 mm MgSO 4 nd 0.5 mm EDTA). The extrct ws centrifuged in cooling centrifuge (Beckmn centrifuge, Model J2 21) for 25 min t rpm. The enzyme ctivity ws ssyed t 30 C in totl of one ml s finl volume of the following rection medium (50 µm HEPES/NOH (ph 8.57), 10 µm MgCl 2, 10 µm NHCO 3 ), nd 50 µl PEP, 50 µl NADH, 10 µl MDH. The rection rte ws mesured by the decrese in L-79 bsorbnce t 340 nm of NADH (oxidtion of NADH) using Shimtzu multipurpose recording Spectrophotometer (Cecil CE 7200 split bem spectrophotometer) ccording to Tietz nd Wild(1991). Determintion of sucrose phosphte synthse (sps) SPS ws ssyed in extrcts of lyophilized mteril. Shoot nd root powders were homogenized in morter nd pestle with 4ml of ice-cold extrction buffer (50 mm HEPES / KOH buffer, ph 7.4), nd bsorbnce ws mesured t 620 nm using spectrophotometer (model UV 200 RS), nd flow the method described by Vssey (1988). Ion nlysis For ech smple nlysed, 10 mg of dry seedling mteril ws digested with 3ml of concentrtedultrpure HNO 3 nd 2ml of H 2 SO 4. The smples were plced overnight in microwve t 90 C. After digestion t 270 C for 6 hours ccording to the method described by Netondo et l., (2004). The mount of N, K, C 2 nd Mg 2 in the smple ws then determined with Atomic Absorption Spectrophotometer (Model do dlme). Ion concentrtions were expressed s mmol per g of dry weight. Sttistics Sttisticl nlyses were done with ANOVA by SigmStt. RESULTS AND DISCUSSION The Effect of tretments on cell sp osmollity nd growth prmeters Sorghum bicolor L. ws exposed for 3 weeks to nutrient medium supplemented with different concentrtion of NCl levels : 0, 30, 60 nd 90 mmncl, which correspond to 1.98, 4.82, 7.82 nd 12.2 dsm -1 slinity levels nd in combintion with ction rtio of C 2 : K : Mg 2 (10:12:3 mm). Song nd Fujyim, (1996) stte tht ction rtio support N ction. Positive liner reltionship is estblished between electric conductivity (EC) nd ction-n combintion in the nutrient solution (Tble1). Plnt grown in sline medi ccumultes high levels of slt Botny

4 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 (Munns, 2002).An osmotic djustment is needed to keep root wter potentil lower thn the externl medium. Such osmotic djustment my led to positively relted to growth reduction (Ottow et l., 2005). As the responses to slinity cell sp osmollity in this work ws incresed by slt stress. Stress effects were bsed on severl mechnisms such s driven uptke of wter, which wsnecessry for the cell enlrgement (Fricke nd Peters 2002). The difference between sline tretment only nd sline with ction ws significnt, except t the concentrtion of 30 mm /21 dy. We found tht slt stress lso ffected cell sp osmollity (Tble 2). Cell sp osmollity ws higher in concentrtion of 90mM/21 dy with ction tretment thn in slt (90 mm) only. Vrious ction hve been reported to contribute to the osmotic djustment, nd s mechnism of mintennce of the cell under sline conditions (Sneok et l., 2001). Mny importnt physiologicl nd morphologicl processes, such s lef enlrgement stomtl opening (Al-Shintinwy, 2000 nd Netondo et l., 2004), nd ssocited lef photosynthesis re directly ffected by the reduction of lef turgor (Ms et l., 1986; Boursier nd Läuchli, 1990), which ccompnies the loss of wter from lef tissue (Jones nd Turner, 1978). They reported tht lthough reltive wter content ws decresed, lef osmollity incresed the slow development of wter deficits resulted not only in osmotic djustment, but lso in decrese in lef tissue elsticity. Similr trends could be seen in the results of other (Çiçek ndçkirlr 2002). Hmd et l. (1992) supposed tht n increse of ion concentrtion in tissues cused n increse in osmollity. Thus, shoot nd root cell-sp osmollity incresed by n increse in slinity concentrtions, reflecting enhnced ion concentrtion in the tissues. A significnt decrese ws observed in seedling length (cm plnt -1 ) when the NCl concentrtion ws incresed from 0 to 90 mm (Tble 2). Menwhile, germintion seeds t ll slinity levels with ction rtio were higher thn tht of slinity ones (result not shown).although seeds hd better efficiency for wter bsorption from growing medi which is obviously due to metbolic ctivities during germintion process. A growth reduction in seedling length of pproximtely (45%) ws found over period (21d) of experiment t 90 mm slt only (Tble 2). It my either be due to reduction in cell size or to inhibition of the mitotic ctivity (Achkzi et l., (2009). No significnt chnges were observed within the two levels (30 nd 60mM) of NCl. Evidence tht slinity (>30mM) inhibited the growth of shoot nd root (Amzllg et l., 1990; Bernstein et l., 1993; Flowers 2004). In mny crops, growth is progressively inhibited by incresing NCl-treted (Erdei nd Tleisnik, 1993; Fricke nd Peters 2002). Crvjl et l. (2000) found tht the growth of tomto ws reduced t high slt concentrtion. Slinity directly ffects the cell wll s well s membrnes (Shlhevet nd Hsio, 1986; Hsegw et l., 2000). In the sme wy, the decreses which ppered in seedling length ws prtil when elevted concentrtion of ction ws supplied to the medium. Furthermore, inhibition of plnt growth by slinity ws ssocited with the ppernce of lef chlorosis or necrosis (Tvkkoli et l. 2011). However, in the current work, the seedling remined helthy for the durtion of experiment nd the shoots showed no sign of senescence or slt injury. When shoot nd root dry weight s reltive shoot nd root growth rte (RGR) ws clculted, it incresed when slinity ws pplied with ction (result not shown).results lso reveled tht root /shoot rtios re significntly incresed by receiving high concentrtion of pplied slts (Tble 2). A mximum increse for root shoot rtio (0.50) is recorded in the highest level of slt (90 mm) combining with ction rtio. The results nd dt presented in this investigtion confirm this view other erlier reports did (e.g. Bengum et l., 1992; Mühling nd Läuchli, 2002 nd Begdullyevet l., 2007). Growth reduction reflects the incresed metbolic energy cost nd reduced crbon gin, which re ssocited with slt dpttion (Netondo et l., 2004). It is known tht roots llow plnt to bsorb nutrients from the surrounding medium, nd helthy root system is key to helthy plnt. Plnt grown with vrious wys by which plnts cn keep endogenous levels of ions low hs been reported (Zhu, 2001). An increse in root: shoot rtio could be n indiction of helthier plnt, provided tht the increse comes from greter root size nd not from decrese in shoot weight (Aishhet l., 2011). L-80 Botny

5 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 Tble 1. Electric conductivity of ction tretment t ech sline level NCl C : K : Mg 10 : 12 : 3 0 mm - 30 mm - 60 mm - 90 mm - EC (ds m -1 ) Tble 2. Effect of NCl concentrtion (0, 30, 60 nd 90 mm) nd ction (C 2 : K : Mg 2 ) rtio (10:13:3) on cell sp osmollity (mosmol Kg -1 ), plnt length (cm), nd root/shoot rtio of Sorghum. Ction rtio NCl (mm) Growth prmeter/ plnt ge * Cell Sp Osmollity Plnt Root/ Cell Sp Plnt Root/ Cell Sp Plnt length Shoot osmollity length Shoot osmollity length Root/ Shoot ± ±0.9 b ± ± ±66 b 32.7± b ± ± b 2450± ± ± ± c ± ±2.2 b ± ±0.6 b ± ± ± ± ± ±1.6 c ± ±1.2 c ± ± b 1520± ± b 1688± ± b ± ± b 1850± ± c 20900± ± ± ± ± ±0.7 b 0.35 b 2260± ± b ± ±0.3 b ± ±2.4 b ± ±0.7 * Ction rtio =(C2 K Mg2; 10:12:3 in mm). Dt re men ±SE (4=n). Different letters indicte significntly different vlues t probbility levels of P = Reltionship between chlorophyll content cross tretments Slinity cused decreses in chlorophyll content nd ffect the synthesis of chlorophyll (Netondo et l., 2004), or ccelerte its degrdtion (Reddy nd Vor, 1986). Totl chlorophyll content declined significntly during the whole experimentl period with incresed slinity (Tble 3). It is more relevnt t high slinity inhibiting photosynthesis nd biomss production (Netondo, et l., 2004). The strongest effect of slt occurred bout L-81 Botny

6 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 (74%) s loss in chlorophyll content, with plnts grown under 90mM NCl(21d). Treted with ction rtio, it recovered the totl chlorophyll contents nd loss could be ccounted by bout 13% only through the experimentl period. A smll drop occurred in the chlorophyll totl (20%) t 60mM NCl (14d) with ction correction, but then it ws restored. However, the drop in the chlorophyll totl ws nerly liner. The reduction in the chlorophyll totl content is expected to be under stress conditions. Its stbility depends on membrne stbility, which - under sline condition hrdly remins intct (Crpici et l., 2009). The chlorophyll totl of plnts my be tken s n indictor of improving new genotypes for slt stress depending on the present or other findings. Reltionship between soluble protein nd proline content cross tretments Slinity cused decreses in soluble protein. Slt stress reduces protein synthesis, increses protein hydrolytic enzyme ctivity, decreses mino cid synthesis nd interferes with enzyme structures leding to decreses in soluble protein content (Bvei et l., 2011). However, s one result of this study, slinity stress with ction did not detect tht decreses in protein content of leves. Perhps this is relted to gene expression (Bvei et l., 2011). The mesurement of proline ccumultion is lso n importnt criterion for determining plnt tolernce to slt stress (Çiçek ndçkirlr 2002). However, there were gret differences in the incresed proline contents in slt stress medium (Tble 3). It is generlly ssumed tht proline is cting s comptible solute in osmotic djustment nd the increse of proline in slt stress is more pprent in sensitive genotypes thn in tolernt ones (Khn et l., 2009). Furthermore, it ws shown tht the cpbility of number of crop plnts to ccumulte proline in response to slt or other stresses ws highly vrible within species (Ashrf et l., 2004). Tble 3. Effect of NCl concentrtion (0, 30, 60 nd 90 mm) nd ction (C 2 : K : Mg 2 ) rtio (10:13:3) on plnt chlorophyll content (mg g -1 lef fresh weight), soluble protein (mg g -1 ) nd proline content (µmol g -1 ) of Sorghum. Ction rtio dded to medium * NCl (mm) Chlo. content Growth prmeter/ plnt ge Soluble Proline Chlo. Soluble Proline Chlo. Soluble protein content content protein content content protein Proline content ± ±1.4 b 0.069±0.01 c 1.94±0.72 8±1.5 b 1.2± ±0.81 9±0.8 b 2.1± ± ±0.8 b 1.3± ± ±0.6 b 0.86± ± ± ±0. 1 b ±0.41 9±1.1 b 0.56± ± ± ± ± ±1.6 b 0.82±0.03 b ±0.42 8±0.7 b 0.63± ± ± ± ±0.04 b 6.2±0.5 b 0.91±0.07 b ±0.2 b 14.2± ± ± ± ± ± ±1.3 b 1.5± ±0.03 b 13.3± ± ±0.23 b 16.5± ±0.1 b 1.84± ± ± ±0.3 b 15.5± ± ±0.1 b 13.5± ± ± ± ± ± ± ± ±0.02 b 12.5± ± ± ±1.1 b 0.65±0.04 * Ction rtio =(C 2 K Mg 2 ; 10:12:3 in mm).dt re men ±SE (4=n). Different letters indicte significntly different vlues t probbility levels of P =0.05. Reltionship between PEPC ndsps ctivities ndsps ctivities were nlyzed in both shoot nd cross tretments : The effects of slt concentrtion root seedling. PEPC enzyme ctivity in roots were nd ction rtio on the contribution of PEPC considerbly higher thn shoot under slt medium s L-82 Botny

7 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 well s with ction tretments. Both shoot nd root SPS ws lest ffected under slinity tretments, however, the ctivities were slightly higher in root thn in shoot subjected to slt nd ction tretments (Tble 4). The finding for both enzymes cn be interesting becuse the observtions on slinity with ction hs not been recognized by other works. Obviously, the results confirm tht both enzymes root ws highly ffected by slinity levels thn shoot, nd this might be considered to ply n importnt role in such tretments. The induction of PEPCse under sline tretment only ws reported in leves plnt (Yen et l., 1995). Guerrier (1988) lso reported tht the levels of PEPCse ctivity could be used s biochemicl indictor of slt tolernce. On the other hnd, Notton nd Blnke (1992) recorded n increse in pprent Km of PEPCse ctivity in Avocdo fruit under slinity. In generl Vernon et l., (1988) recorded de novo synthesis of PEPCse in stressed Mesembrynthemumcrystllinum. PEPCse hs unusul properties when compred to PEPC from C 4 plnts (Jio et l., 1991). Tietz nd Wild (1991) reported tht PEPCse ctivity could be tken s biochemicl indictor of dmge tissues, nd this could be reflect the effect of slt by disrupting lipid-protein ssocitions. PEPCse is expected to contribute the control of crbon flux in the photosynthetic pthwy under slin condition (Soussiet l., 1999). Bsed on the dt reported by Grci-Muriňo et l. ( 2003), it cn be hypothesized tht both enzymes PEPCse nd SPS my hve positive impct on osmotic djustment. Different lines of evidence suggest tht PEPCse enzyme contribute to the regultion of tmospheric CO 2 uptke, wheres SPS enzyme contribute to the control of sucrose production in leves. There were some evidence tht these enzymes chnges my be relted to the degree of mny fctors such s cell composition, the pttern of ction distribution, growth condition nd certinly the ge of the tissue is likely to be n importnt fctor, lthough the photoperiod, temperture, slinity nd nutritionl sttus were widely pprecited (Huber nd Huber, 1992). In this investigtion, the ctivities of both enzymes in slt stressed seedlings were pproximtely greed with the dt from other vrieties of sorghum (Huber nd Huber, 1992). Tble 4. Effect of NCl concentrtion (0, 30, 60 nd 90 mm) nd ction (C 2 : K : Mg 2 ) rtio (10:13:3) on the contribution of PEPC ndsps ctivities in Sorghum. Ction rtio dded to medium * NCl (mm) Phosphpenolpyruvte crboxylse ctivity (µmol NADH g -1 h -1 ) Sucrose phosphte synthse ctivity (mg sucrose g -1 h -1 ) shoot root shoot root ± 0.08 b 0.44 ± ±0.007 b 0.29 ± ± ± ±0.01 b 0.42 ± ± ± ±0.002 b 0.62 ± ± ± ±0.002 b 0.86 ± ± ± ±0.003 c 0.04 ±0.008 b ± ± ±0.002 b ±0.002 b ± ± ±0.006 b ±0.03 b ± ± ±0.005 b ±0.003 b * Ction rtio =(C 2 K Mg 2 ; 10:12:3 in mm).dt re men ±SE (4=n). Different letters indicte significntly different vlues t probbility levels of P =0.05. N mong ction of K,C, nd Mg 2 Chemicl composition ws nlyzed in the seedling. Aprt from the chnges in the concentrtion of N nd Cl -, the only differences produced by the tretments were in the concentrtions of K,C, nd Mg 2. As the concentrtion of N incresed, L-83 higher concentrtion of NCl ws dded to the nutrient solution (Figure 1 A) s the toxic effect of N or Cl - ws still present (Crvjl et l., 2000). However, t both levels of NCl (60 nd 90 mm), nd when the ction blnce ws incresed, the concentrtion of N decresed significntly. Botny

8 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 Potssium (Figure 1 B) ws decresed fter the ppliction of the concentrtions of NCl, but n increse ws observed t 0 mmncl when the ction blnce ws incresed. Concentrtions of both Mg nd C (Figure 1 C nd D) did not chnge with ction tretments t 0 mmncl, but significnt decrese occurred t 30, 60 nd 90 mmncl, which ws prtly restored by ction ppliction. Moreover, in the study by Kml Uddin et l. (2011) shoot K: N rtio reduced in different slt stress mong species Psplumvgintum. The concentrtion of Cl - ws lwys incresed proportionlly fter incresing the NCl concentrtion in the nutrient solution (dt not shown). Figure 1. Ction concentrtion of sodium =(A); potssium =(B); mgnesium = (C) nd clcium = (D) in mmol per g of dry weight of seedling treted with ction rtio (C 2 K Mg 2 : 10:12:3 mm) nd three sline levels (30,60 nd 90 mm). Treted ( ), sline only ( ).Dt re men ±SE (4=n). The rtio mong ction ws clculted in seedling plnt. It cn be noticed (see Figure 1 A-D) tht t high NCl concentrtion, the rtios N/C nd N/Mg decresed s consequence of ction tretments. Lrge mounts of NCl decresed the concentrtions of K, C, nd Mg 2, giving high vlues of the rtios of N / C nd N / Mg 2 (Zimmermnn 1978). However, in our work, the rtio N/K did not chnge much with the tretment. L-84 CONCLUSION To summrize, we cn conclude tht the concentrtion of ction in plnts grown under sline conditions could be n importnt fctor in sorghum production using hydroponic systems. When sline is vilble, with concentrtions of the rtio C 2 : K : Mg 2 (10:12:3 mm) incresed in number of growth prmeters, lthough the toxic effect of N or Cl - ws still present. Further improvement of Botny

9 Reserch Article ISSN Vol 2/Issue 2/Apr-Jun 2012 sorghum yield will require further reserch into the effect of plnt minerl nutrition on the regultion of seeds number nd size s well s the regultion of wter reltions of the plnts nd enzymes involved in nitrogen metbolism nd trnsport within sorghum plnts. ACKNOWLEDGEMENT This reserch wsprtly supported by theking Abdulziz City for Science nd Technology (KACST) nd by Umm Al-Qur University, which mde the studies possible.we re grteful to Dr. In Dodd for his comments.we lso cknowledge the ssistnce of LEC technicin stff member t Lncster University. REFERENCES 1. AchkziAK,Kyni SA nd Hnif A. Root nd shoot growth response of sunflowerunder slt stress. Cderno de PesquisSér Bio. 2009; 21 (1): Aishh S, Sberi HAR, Hlim RA nd Zhrh AR. Yield responses of forge sorghums to slinity nd irrigtion frequency. Afr JBiotechnol. 2011; 10 (20): Al-Shintinwy F. Photosynthesis in two whet cultivrs on differing in slt susceptibility. Photosynthetic. 2000; 38: Amzllg GN, Lerner HR ndpoljkoff-myber A. Induction of incresed slt tolernce in Sorghum bicolor by NCl pretretment. J Exp Bot. 1990; 41: Ashrf M, Mukhtr N, Rehmn S, Rh ES. Sltinduced chnges in photosynthetic ctivitynd growth in potentil plnt bishops weed (AmmoleimjusL.). Photosynt. 2004; 42: Bnuls J, Legz F nd Primo-Millo E. Slinity clcium interctionson growth nd ionic concentrtion of citrus plnts. Plnt nd Soil. 1991; 133: Btes LS, Wldren RP nd Tere ID. Rpid determintion of proline for wter stress studies. Plnt nd Soil. 1973; 39: Bvei V, Shirn B, Khodmbshi M nd Rnjbr A. Protein electrophoretic profiles nd physiochemicl indictors of slinity tolernce in Sorghum bicolorl.afr J Biotechnol. 2011; 10 (14): Begdullyev T, Kienzler K, Kn E, Ibrgimov N nd Lmers J. Response of Sorghum (Bicolor vrieties) to soil slinity nd feed production in Krklpkstn, Uzbekistn. Irri Drin Sys. 2007; 21: L Bengum F, Krmoker J L, Ftth Q A nd Mniruzzmn AF. The effect of slinity on germintion nd its correltion with K, N, Cl 11. ccumultion in germinting seeds of Triticmestivum L. Cv. Akbr. Plnt Cell Physiol. 1992; 33: Bernstein N, Läuchli A nd Silk WK. Kinetics nd dynmics of sorghum (Sorghum bicolor L.) lef development t vrious N/C slinities: I. Elongtion growth. Plnt Physiol. 1993; 103: BoursierP ndläuchli A. Growth responses nd minerl nutrient reltions of slt stressed Sorghum. Crop Sci. 1990; 30: Crpici EB, Celik N, ByrmG. Effects of slt stress on germintion of some mize (Ze mys L.) Cultivrs. Afr JBiotechnol. 2009; 8 (19): Crvjl M, Cerdá A nd Mrtinez V. Modifiction of the response of sline stressed tomto plnts by the correction of ction disorders. Plnt Growth Regultion, 2000; 30: Çiçek N, Çkirlr H. The effect of slinity on some physiologicl Prmeters in TwoMize Cultivrs. Bulg J Plnt Physiol. 2002; 28 (1-2): ErdeiL ndtleisnik E. Chnges in wter reltion prmeters under osmotic nd slt stress in mize nd sorghum. Physiol Plnt. 1993; 89: Flowers T J. Improving crop slt tolernce. J Exp Bot. 2004; 55 (396): Fricke W nd Peters W S. The Biophysics of lef growth in slt-stressed brley. Plnt Physiol. 2002; 129 (1): Grci-Muriňo S, Monrel J, Alvrez R, Vidl J nd Echevrri C. Chrcteriztion of slt stress-enhnced phosphoenolpyruvte Botny

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