INFLUENCE OF SALT STRESS ON GROWTH AND ANTIOXIDANT RESPONSES OF TWO MALUS SPECIES AT CALLUS AND PLANTLET STAGES

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1 Pk. J. Bot., 45(2): , 213. INFLUENCE OF SALT STRESS ON GROWTH AND ANTIOXIDANT RESPONSES OF TWO MALUS SPECIES AT CALLUS AND PLANTLET STAGES KAI WANG 1, LIXIN ZHANG 1*, MEI GAO 1, LIXIA LV 2, YONGGUI ZHAO 1, LINSEN ZHANG 3, BINZHI LI 3, MINGYU HAN 3 AND ASHOK K. ALVA 4 1 Collg o Li Sins, Northwst A&F Univrsity, 7121, Yngling, Shnxi, P.R. Chin 2 Collg o Forstry, Northwst A&F Univrsity, 7121, Yngling, Shnxi, P.R. Chin 3 Collg o Hortiultur, Northwst A&F Univrsity, 7121, Yngling, Shnxi, P.R. Chin 4 USDA-ARS-Vgtl n Forg Crops Rsrh Unit, 9935, Prossr, WA, USA * Corrsponing uthor s -mil rss: zhnglixinyngling88@yhoo.om.n Astrt Soil sliniztion hs om mjor thrt to ppl (Mlus omsti L.) proution in som rgions o Chin. In this stuy, w invstigt th ts o slt strss i.. 15 mm NCl on growth n ntioxint rsponss o 15- ol llus n plntlts o two Mlus spis i.., rootstok Mlus roust Rh (Rh) n sion Mlus omsti Borkh. v. () grown on Murshig n Skoog (MS) mium. Slt strss inu n inrs in tivitis o suproxi ismuts (SOD), proxis (POD) n glutthion ruts (GR) in two Mlus spis, whil rs in tls (CAT) tivity in n unhng pttrn in tht in Rh spis rsptivly t llus n plntlts stgs. Aitionlly, slt strss l to n inrs in hyrogn proxi (H 2 O 2 ) n suproxi rils (O 2 ) ontnts, long with n nhn umultion o mlonilhy (MDA) rsulting in rs in rltiv growth rt (RGR) o oth spis. Th tivitis o SOD, POD, CAT n GR o oth spis t plntlts stg wr grtr whil H 2 O 2, O 2 n MDA ontnts lowr thn thos t llus stg. Th two Mlus spis show similr umultion o MDA n RGR t oth irntition stgs, lthough thy show irnt pttrns o H 2 O 2 n O 2 umultion n thir orrsponing svnging pity. Th rsults o this stuy suggst tht llus o oth spis ws mor snsitiv to slt strss thn plntlts. Th rsponss o two Mlus spis to slt strss wr similr t givn irntition stg. Thror, llus stg is mor pproprit or vlution o plnt rsponss to slt strss. Th sion () n mth with rootstok (Rh) to pt to soil slinity strss. Introution Th vsttion o rl ln r u to soil sliniztion hs n inrsing in mny rgions o th worl. Soil slinity strss limits plnt growth n yil o most rops inluing ppl (Mlus omsti L.) (Grttn & Griv, 1998; Zhu, 21; Ashr & Akrm, 29; Ashr t l., 212; Azhr t l., 212). Th Mlus roust Rh n Mlus omsti Borkh. v. r most importnt ommril rootstok n sion rsptivly in Chin. Howvr, th ppl trs with th ov sion/rootstok omintion r snsitiv to slinity strss u to thir ovious growth rtrtion n ruit yil rs in som prts o northrn Chin (M t l., 1992; Du t l., 22). On o th iohmil hngs ourring in plnts sujt to nvironmntl strsss inluing slt strss is th proution o rtiv oxygn spis (ROS), i.. suproxi rils (O 2 ) n hyrogn proxi (H 2 O 2 ), rsulting in oxitiv strss (Hnty, 1994; Zhu, 21; Ashr & Hrris, 24; Pn & Uphyy, 24; Jhn t l., 212). ROS intrt with wi rng o moluls to us multipl mg inluing lipi proxition, mmrn strution, protin nturtion n DNA muttion, whih r trmin y mlonilhy (MDA) umultion (Mittlr, 22). To llvit th ltrious ts o ROS, plnts hv volv spii ntioxitiv mhnisms to svng ROS. Thus, ntioxint nzyms suh s suproxi ismuts (SOD, EC ), tls (CAT, EC ), proxis (POD, EC ) n glutthion ruts (GR, EC ), th ky mmrs o ntioxint prottiv systm, sm to min importnt trminnts o plnt tolrn to slt strss (Vrnov t l., 22; Dlmi & Swhny, 24; Ashr t l., 28, 29). SOD is mjor svngr o O 2 n its nzymti tion rsults in th ormtion o H 2 O 2. POD omposs H 2 O 2, y oxition o o-sustrts, suh s phnoli ompouns n/or ntioxints, whrs CAT rks own H 2 O 2 into wtr n molulr oxygn (Mittlr, 22). Inrsing oy o vin suggsts tht togthr with osmoti justmnt n ion omprtmntliztion, n iint ntioxint systm is lso vitl in mitigting th vrs ts o slinity strss (Ashr, 29). Mny stuis support tht ntioxint rspons ws wll orrlt with NCl tolrn in svrl Mlus spis suh s rootstok Mlus prunioli (Fu t l., 212), MM 16 (Molssiotis t l., 26), EM 9 (Molssiotis t l., 26) n Mlus huphnsis Rh (Du t l., 22) n sion Goln Smooth ppls (Vilpln & Vlntins, 26). Howvr, most o th ov stuis wr rri out using whol plnt slings o rootstok or sion unr pot xprimnts (Ashr t l., 28, 212). As ompr with ll n tissu ultur, th whol plnt ultur stuy lwys xhiits lowr n insnsitiv rsponss n longr gnrtion prio, spilly in tr spis tht hv long rproutiv yls. Th ormr n trt s ttr tool to invstigt th slt tolrn mhnisms (Zhng t l., 24). Thus, th ojtiv o this stuy ws to invstigt th growth n ntioxint systm rsponss to slt strss t llus n plntlt stgs o two Mlus spis, i.. rootstok (Mlus roust Rh) n sion (Mlus omsti Borkh. v. ). Mtrils n Mthos Plnt mtrils, llus inution, rgnrtion n ultur onitions: Th xprimnt ws onut using llus n plntlts o two Mlus spis i.. rootstok (Mlus roust Rh) n sion (Mlus omsti Borkh.

2 376 KAI WANG ET AL., v. ) rom n in vitro ultur. Lvs wr striliz or 3s in 75% thnol n 8 min in.1% HgCl 2, thn wr susquntly wsh with stril wtr iv tims n inlly ut into pis (.5m 1m). Eh xplnt ws ultur in Murshig & Skoog (MS) mium.(murshig & Skoog, 1962) supplmnt with 3gl 1 suros,.2mgl 1 nzylnin (BA), 2mgl 1 2,4-ihlorophnoxyti i (2,4-D) n 2mgl 1 inol ti i (IAA) to inu llus s sri y Li n M (1999). Atr our wks, llus ws sprt rom th xplnt n suultivt to rsh mi tr 25 or urthr prolirtion in growth hmr t 25 ± 2 C n 14 h photoprio (2 lx). Th llus ws mov onto th MS mium ontining 3gl 1 suros, 4mgl 1 BA n.2mgl 1 IAA to inu vntitious us s sri y Yu t l., (25). Th ph o ll growth mi ws just to 5.8 or utolving t 121 C or 2 min, n th mi ws ispns in 25 ml lsks. Avntitious us mrg 3 ltr tr whih tim th xplnts wr inut in rsh mi or 25 in th ormntion onitions or slt trtmnts. Slt strss trtmnts: Th xprimnt ws onut with two trtmnts:. (1) slt strss, MS mium supplmnt with 15 mm soium hlori (NCl) (2), no NCl in mium. Th llus n plntlts wr trnsrr into th ov mi in growth hmr t 25 ± 2 C n 14 h photoprio (2 lx). Clluss n lvs o plntlts wr ollt tr 15 n wsh in istill wtr, thn lott with iltr ppr or ssy. Rltiv growth rt (RGR): Smpls wr wigh t th tim o thir trnsr (Wi) n tr 15 o ulturing (W). Th mn RGR ws lult oring to th rtio, (W-Wi)/Wi. Th RGR in th ontrol ws onsir s 1% n th t o slt strss trtmnt on th growth rt o llus ws otin ollowing Zhng t l., (24). Prprtion o xtrts n ntioxint nzyms tivitis ssy: Th llus n lvs o plntlts wr homogniz in ol mortr n pstl in thr-ol volum o 5 mm phospht ur (ph 6.5) ontining 1. % (m/v) solul polyvinylpyrrollon (PVP). To prpr ru xtrts or th SOD ssy, th plnt mtril ws homogniz in n xtrtion ur onsisting o 5mM Tris (ph 7.8), 1.% (m/v) PVP n 1 mm EDTA. Th homognts wr ntriug (1g or 2 min t 4 C) n th suprntnts us or nzym ssys. Protin ontnt ws trmin y th mtho o Bror (1976), using ovin srum lumin s th protin stnr. SOD tivity ws stimt y roring rs in sorn t 56nm o suproxi-nitrolu ttrzolium omplx y th nzym. On unit o SOD ws onsir to th mount o nzym rquir to inhiit ttrzolium (NBT) rution y 5% (Buhmp & Friovih, 1971). Proxis (POD) tivity ws ssy s sri y Ngo & Lnho (198). POD tivity spiilly with guiol t 47 nm n on unit o nzym tivity ws tkn s th rt o guiol whih ws oxiiz in thr min. Ctls (CAT) tivity ws ssy y msuring th rsiul H 2 O 2 y th tris-hcl rgnt oring to Wng (1995). Asorn ws ror immitly t 24 nm vry our min n on unit o nzym trmin th mount nssry to ompos 1μmol o H 2 O 2 pr min t 25 C. Glutthion ruts (GR) tivity ws msur s sri y Gr & Logn (1996). Th rtion ws strt y th ition o.5 mm NADPH. Th rt o nonspii NADPH oxis tivity ws sutrt. A molr xtintion oiint o 62 m -1 ws us to lult GR tivity. Dtrmintion o H 2 O 2, O 2 n MDA ontnts: Th H 2 O 2 ontnt ws stimt oring to Pzzioh- Czohr n Winsk (22). Frsh l tissu (1. g h smpl) ws groun in ol ton (1 ml) n ntriug t 3 g or 1 min. On ml o th suprntnt ws mix with.1ml titnium rgnt n.2ml o 17 M mmoni solution n thn it ws ntriug t 3g or 1 min. Th pripitt ws wsh 5 tims with ton y rsuspnsion, rin, n issolv in 3 ml o 1 M H 2 SO 4. Th sorn o th solution ws msur t 41 nm ginst lnks, whih h n prpr similrly ut without plnt tissu. Th O 2 ontnt ws nlyz using th mtho o Elstnr n Hupl (1976). On ml o th nzym xtrt s sri ov or SOD ws mix with 1 ml o 1 mm hyroxylmmonium hlrori, n thn inut or 3 min t 3 C. On ml o th inut solution ws thn to 1 ml o 17 mm 3-minonznsuloni i n 1 ml o 7 mm 1-nphthylmin, n thn urthr inut or 2 min t 3 C. Th sorn o th solution ws monitor t 53 nm. Mlonlhy (MDA) ws xtrt with 1% trihloroti i n sorn msur t 45, 532 n 6 nm with.6% thiorituri i s sri y Hth n Pkr (1968). All sptrophotomtri nlyss wr onut with Shimzu UV-17 sptroluorimtr (Shimzu, Kyoto, Jpn) Sttistil nlysis: Eh trtmnt inlu 4 rplitions (lsks). Anlysis o vrin ws lult using th SPSS-11 sttistil sotwr n th signiin mong mn vlus ws trmin t 95 % onin limit. Rsults Anlysis o vrin or rspons prmtrs: Anlysis o vrin show tht th ts o slt strss (Ss), irntition stg (D), n spis (Sp) wr signiint on most prmtrs msur, xpt th ts o Sp on RGR n ontnts o O 2 n MDA. Two-wy intrtions wr lso signiint or: (1) Ss D or RGR, H 2 O 2 n MDA ontnts n GR tivity; (2) Ss Sp or MDA ontnt, tivitis o SOD, POD n GR; (3) D Sp or RGR, H 2 O 2 ontnt n tivitis o CAT, POD n GR. Th mgnitu o F vlus or most o th prmtrs wr in th orr: D > Ss > Sp, xpt th orr o Ss > D > Sp or RGR. This stuy show tht hoi o spis n irntition lvl r importnt to ovrom th vrs ts o slt strss in trms o plnt growth n ntioxint rsponss (Tl 1).

3 INFLUENCE OF SALT STRESS ON GROWH OF TWO MALUS SPECIES 377 Tl 1. F vlus or th ts o slt strss (Ss), irntition stg (D) n spis (Sp) n thir intrtions on irnt growth n ntioxint prmtrs o th llus n plntlts o two Mlus spis. Sour o Slt strss Dirntition Spis vrition (Ss) lvl (D) (Sp) Ss D Ss Sp D Sp Ss D Sp RGR *** *** ** * H 2 O 2 ontnt *** *** *** *** ***.5 O 2 ontnt *** *** MDA ontnt *** *** *** 5.11 * SOD tivity *** *** ** *** CAT tivity *** *** **.47 POD tivity *** *** *** * *.85 GR tivity *** *** ** *** ** *** *, **, *** signiin t 5%, 1% n.1 % lvl o signiin, rsptivly. CAT, tls; GR, glutthion ruts; H 2 O 2, hyrogn proxi; MDA, mlonilhy; POD, proxis; RGR, rltiv growth rt; SOD, suproxi ismuts; O 2, suproxi rils RGR: Th RGR o llus n plntlts in oth Rh n spis ws rs unr slt strss ov th ontrol. Th ov ngtiv ts wr grtr on llus s ompr to thos on plntlts in oth spis. Th two Mlus spis show similr vlus o RGR t oth irntition stgs (Fig. 1). RGR ( % ) Cllus Plntlts Cllus Plntlts Rh Slt strss Fig. 1. Rltiv growth rt (RGR) o llus n plntlts o two Mlus spis grown or 15 ys in Murshig n Skoog (SM) mium with (ontrol) n 15 mm NCl. Vlus r mns ± S.E. (n=4). At th top o ll rs, irnt lttrs init signiint irns mong th mn vlus (p<.5). Antioxint nzyms tivitis: By omprison with ontrol onitions, slt strss inrs SOD tivitis in llus n plntlts o Rh y 156% n 76%, n in thos o y 81% n 25%, rsptivly. Th SOD tivitis in plntlts wr grtr thn thos in llus o oth spis. Th SOD tivitis in llus or plntlts wr grtr or Rh thn thos or (Fig. 2A). Slt strss rs tivitis o CAT in llus n plntlts o y 2% n 14% rsptivly ov th ontrol. Th CAT tivitis in llus n plntlts o Rh wr not signiintly inlun y slt strss. Th CAT tivitis o oth spis wr grtr in plntlts s ompr to thos in llus. Th CAT tivitis in llus wr grtr or s ompr to thos or Rh (Fig. 2B). Th POD tivitis wr inrs y 15% in llus n 53% in plntlts o rsptivly un slt strss ov th ontrol. Whil th ts o slt strss on POD tivitis o Rh wr signiint ut only in plntlts. mintin highr lvl o POD tivitis thn Rh with th sm irntition stg. Th POD tivitis in llus wr grtr thn thos in plntlts o oth spis (Fig. 3A). Slt strss inrs GR tivitis o Rh n in llus y 55% n 175%, n thos in plntlt y 59% n 224%, rsptivly, s ompri with ontrol onitions. Th GR tivitis in plntlts wr grtr thn thos in llus o oth spis. GR tivitis o Rh wr grtr thn thos o t plntlt stg rgrlss o slt strss trtmnts, whil th rvrs ws tru t llus stg (Fig. 3B). Contnts o H 2 O 2 n O 2 : Slt strss inrs H 2 O 2 ontnts o Rh n t llus stg y 95% n 63% rsptivly, n O 2 ontnts o thos t th sm stg y 4% n 63% rsptivly ov th ontrol. Th orrsponing inrs rts o Rh n t plntlts stg wr 5% n 53% or H 2 O 2 n 21% n 15% or O 2 rsptivly. Th H 2 O 2 n O 2 ontnts in llus wr grtr thn thos in plntlts o oth spis. H 2 O 2 ontnts o wr grtr thn thos o Rh, whil th onvrs ws tru or O 2 ontnts ut only t llus stg (Fig. 4A & B). Lipi proxition: Slt strss inrs MDA ontnts in llus o Rh n Fuj y 55 n 49 %, n in plntlt o thos y 28% n 38%, rsptivly. Th grtr MDA ontnt ws ror in llus thn in plntlts o oth spis. At givn irntition stg, th MDA multion ws similr in two Mlus spis (Fig. 5). Disussion Slinity strss inhiits vgttiv n rproutiv growth o mny rops y inuing svr physiologil ysuntions n using irt n inirt hrmul ts (Ashr t l., 28, 212; Ashr & Ali, 28; Iqr t l., 212). Th vlution o slt strss on growth rsponss wr onut in som plnts t irnt irntition lvls suh s llus o Hlinthus nnuus n Niotin tum (Erison & Alinito, 1984;

4 378 KAI WANG ET AL., Silvn t l., 23) n plntlts o Pinus virginin (Wi & Nwton, 25). Zhng t l. (24) rport tht th mximum RGR o llus inu rom Populus uphrti ws osrv t low onntrtion o NCl (5 mm), whrs signiint growth inhiition t highr onntrtions o NCl (15 n 25 mm). In th prsnt stuy, th llus surviv in mium ontining 15 mm NCl ovr 15. Chrin & Ry (23) stt tht growth o th llus ulturs o Su nuilor Moq ws signiintly inhiit t 5, 1, 15 n 2mM NCl. Wtn t l., (2) show tht th growth o Populus uphrti plntlts slightly rs unr slt strss (5 mm NCl). Howvr, th rson or irnt rsponss to slt strss twn llus n plntlt rmins unlr. Our rsults show tht slt strss i.. 15 mm NCl signiintly inhiit th growth o llus n plntlts o Rh n. Th RGR t plntlt stg ws grtr thn tht t llus stg or oth Mlus spis unr slt strss. Th RGR o oth spis ws similr t givn irntition stg (Fig. 1). It is onlu tht th llus growth ws mor snsitiv to slt strss thn plntlt growth o two Mlus spis, n th sion () oul mth with rootstok (Rh) to pt to soil slinity. SOD tivity(u mg -1 protin) (A) Slt strss CAT tivity(u mg -1 protin) (B) 1 1. Cllus Plntlts Cllus Plntlts. Cllus Plntlts Cllus Plntlts Rh Rh Fig. 2 Suproxi ismuts (SOD) (A) n tls (CAT) tivity (B) in llus n plntlts o two Mlus spis grown or 15 ys in Murshig n Skoog (SM) with (ontrol) n15 mm NCl. Vlus r mns ± S.E. (n=4). At th top o ll rs, irnt lttrs init signiint irns mong th mn vlus (p<.5). POD tivity (U mg protin -1 ) (A) Slt strss Cllus Plntlts Cllus Plntlts GR tivity (U mg -1 protin) (B) Cllus Plntlts Cllus Plntlts Rh Rh Fig. 3 Proxis (POD) tivity (A) n glutthion ruts (GR) tivity (B) in llus n plntlts o two Mlus spis grown or 15 y in Murshig n Skoog (SM) mium with (ontrol) n 15 mm NCl. Vlus r mns ± S.E. (n=4). At th top o ll rs, irnt lttrs init signiint irns mong th mn vlus (p<.5).

5 INFLUENCE OF SALT STRESS ON GROWH OF TWO MALUS SPECIES 379 H 2O 2 ontnt (μ mol g -1 DW) (A) Slt strss O 2 ontnt (μ mol g -1 DW min -1 ) (B).2. Cllus Plntlts Cllus Plntlts Cllus Plntlts Cllus Plntlts Rh Rh Fig. 4. Hyrogn proxi (H 2 O 2 ) (A) n suproxi rils (O 2 ) (B) ontnts in llus n plntlts o two Mlus spis grown or 15 y in Murshig n Skoog (SM) mium with (ontrol) n 15 mm NCl. Vlus r mns ± S.E. (n=4). At th top o ll rs, irnt lttrs init signiint irns mong th mn vlus (p<.5). MDA ontnt (μ mol g -1 DW) Cllus Plntlts Cllus Plntlts Rh Slt strss Fig. 5. Mlonilhy (MDA) ontnt in llus n plntlts o two Mlus spis grown or 15 ys in Murshig n Skoog (SM) mium with (ontrol) n 15 mm NCl. Vlus r mn ± S.E. (n=4). At th top o ll rs, irnt lttrs init signiint irns mong th mn vlus (p<.5). Plnts xpos to slinity strss gnrlly show nhn gnrtion o ROS inluing O 2 n H 2 O 2 in plnt lls, whih us onsirl mg to ll mmrns u to lipi proxition (Blokhin t l., 23). Th lvl o MDA is onsir s goo initor o gr o lipi proxition in strss plnts (Dhins t l., 1981; Msi, 23; Apl & Hirt 24). Molssiotis t l., (26) rport proution o H 2 O 2 n O 2 n MDA umultion wr inrs in ppl rootstok MM 16 unr slt strss. Our rsults show tht slt strss inu similr inrss in ontnts o H 2 O 2 n O 2 n MDA o sion n rootstok Rh t givn irntition stg (Figs. 4-5). Th slt-inu hrmul ts n llvit y tivting ntioxint nzyms suh s SOD, POD, CAT n GR, whih n tivly svng ROS (Dlmi & Swhny, 24; Ashr t l., 28). O ths ntioxint nzyms, SOD untions s th irst lin o ns ginst oxition t th mmrn ounris. POD togthr with CAT r liv to two iint H 2 O 2 svnging systms whih ilitt rpi rmovl o H 2 O 2 in lls o plnts inluing Mlus (Mittlr, 22; Blokhin t l., 23). Antioxint ns systm in plnts, is hrtriz y ROS (H 2 O 2 n O 2 ) umultion n nhn tivitis o ntioxint nzyms, whih trmin lipi proxition i.. xtnt o umultion o MDA (Gosstt t l., 1994; Ashr, 22; Dlmi & Swhny, 24; Shn t l., 26; Ashr & Ali, 28; Ashr t l., 212). Th rsults o our stuy monstrt tht slt strss inu inrss in tivitis o SOD, POD n GR, n rs in tht o CAT. Th inrs H 2 O 2 n O 2 ontnts rsult in nhn MDA umultion in llus n plntlts o oth Mlus spis (Figs. 2-5). Th H 2 O 2 n O 2 proution in llus o oth spis ws grtr, whil tivitis o SOD, CAT n GR (xpt

6 38 KAI WANG ET AL., tht o POD) wr lowr s ompr with thos in plntlts, rsulting in grtr MDA umultion unr slt strss. POD tivity ws grtr in s ompr to tht in Rh unr slt strss. Th rvrs ws tru or SOD n GR tivitis. Th CAT tivity ws grtr in thn tht in Rh ut only t llus stg. Th H 2 O 2 ontnts o wr grtr thn thos o Rh whil th rvrs ws tru or O 2 ontnts t llus stg unr slt strss. In slt-strss plnts, th MDA umultion n plnts growth prormn r trmin y th tivitis n hng pttrns o ntioxint nzyms to rmov ROS (Dlmi & Swhny, 24; Ashr t l., 28). Although tivitis n hng pttrns o ths ntioxint nzyms n ontnts o H 2 O 2 n O 2 wr pnnt on nzyms typ, Mlus spis n irntition lvl. MDA umultion n RGR o llus n plntlts h no signiint irn twn two Mlus spis unr slt strss (Figs. 1-5). Our rsults show tht umultion o MDA ws grtr whil RGR ws lowr t llus stg s ompr to plntlts stg o oth spis unr slt strss. Th two Mlus spis show similr MDA multion n RGR t givn irntition stg (Figs. 1 & 5). Ths inings suggst tht th irntition stg o plnt tissu might t th slinity tolrn u to vrition in gn xprssion ross irnt irntition stgs (Jmil t l., 211). Th plnt tissu t llus stg ws mor snsitiv to slt strss thn tht t plntlts stg. Thror, llus might rgr n pproprit irntition stg or vluting plnt rsponss to slinity strss. Th sion () n rootstok (Rh) hol similr growth n lipi proxition rsponss t givn irntition stg. Conlusion In onlusion, th ngtiv ts o slt strss wr similr in two Mlus spis. Th llus stg o oth spis ws mor snsitiv to slt strss s ompr to th plntlt stg s vint rom grtr proution o H 2 O 2 n O 2 n lowr untioning o th ntioxint nzym systm, whih rsult in grtr MDA umultion n lowr RGR in th ormr s ompr to thos in th lttr. Th llus ultur stuy n mor usul to vlut growth n ntioxitiv rsponss to slt strss or Mlus spis u to its rltivly st n snsitiv rsponss, short gnrtion tim, n ontroll nvironmnt. Th sion () n mth with rootstok (Rh) to pt to soil slinity. Aknowlgmnts This rsrh ws support y Spil Fun or Agro-sintii Rsrh in th Puli Intrst (213314) n Wst Light Fountion o CAS ( ), Progrm or Agriulturl Si-Th Innovtion o Shnxi Provin (211NXC1-18), Environmnt Prottion Progrm (212-47) n Si-th Co-orinting Innovtiv Enginring Projts o Shnxi Provin (211KTZB2-2-5). Rrns Apl, K. n H. Hirt. 24. Rtiv oxygn spis: Mtolism, oxitiv strss n signl trnsution. Annu. Rv. Plnt Biol., 55: Ashr, M. 22. Slt tolrn o otton: som nw vns. Crit. Rv. Plnt Si., 21: 1-3. Ashr, M. 29. Biothnologil pproh o improving plnt slt tolrn using ntioxints s mrkrs. Biothnol. Av., 27: Ashr, M. n N.A. Akrm. 29. Improving slinity tolrn o plnts through onvntionl ring n gnti nginring. Biothnol. Av., 27: Ashr, M. n P.J.C. Hrris. 24. Potntil iohmil initors o slinity tolrn in plnts. Plnt Si., 166: Ashr, M. n Q. Ali. 28. Rltiv mmrn prmility n tivitis o som ntioxint nzyms s th ky trminnts o slt tolrn in nol (Brssi npus L.). Environ. Exp. Bot., 63: Ashr, M., H.R. Athr, P.J.C. Hrris n T.R. Kwon. 28. Som prosptiv strtgis or improving rop slt tolrn. Av. Agron., 97: Ashr, M., N.A. Akrm, Mhoo-Ur-Rhmn n M.R. Fool Mrkr-ssist sltion in plnt ring or slinity tolrn. Mthos Mol. Biol., 913: Azhr, S.S., S.H. Shn, H. Ahm, Z.A. Swti, F.M. Asi, Frhtullh n A.H. Shn Apttion to polythyln strss mintins totipotny o ll lins o oryz stiv L. CV. Swt-1 or longr prio. Pk. J. Bot., 44(1): Buhmp, B. n I. Friovih Suproxi ismuts: improv ssys n pplil to rylmi gls. Anl. Biohm., 44: Blokhin, O., E. Virolinn n K.V. Fgrstt. 23. Antioxints, oxitiv mg n oxygn privtion strss: rviw. Ann. Bot., 91: Bror, M.M A rpi n snsitiv mtho or th quntittion o mirogrm quntitis o protin utilizing th prinipl o protin-y ining. Anl. Biohm., 72: Chrin, S. n M.P. Ry. 23. Evlution o NCl tolrn in th llus ulturs o Su nuilor Moq. Biol. Plnt., 46: Dlmi, A. n V. Swhny. 24. Antioxint ns mhnism unr rought strss in wht slings. Physiol. Mol. Biol. Plnts, 1: Dhins, R.S., P.P. Dhins n T.A. Thorp L snsn: Corrlt with inrs lvls o mmrn prmility n lipi proxition, n rs lvls o suproxi ismuts n tls. J. Exp. Bot., 32: Du, Z.J., H. Zhi, X.S. Luo, S.H. Chng n Z.Y. Pn. 22. Slt-tolrn intiition on ppl rootstoks. J. Fruit Si., 19: 4-7. Elstnr, E.F. n A. Hupl Inhiition o nitrit ormtion rom hyroxyl lmmoniumhlori: simpl ssy or suproxi ismuts. Anl. Biohm., 7: Erison, M.C. n S.H. Alinito Protins prou uring slt strss in too ll ultur. Plnt Physiol., 74: Fu, M.Y., C. Li n F.W. M Physiologil rsponss n tolrn to NCl strss in irnt iotyps o Mlus prunioli. Euphyti, /s Gosstt, D.R., E.P. Millhollon, M.C. Lus, S.W. Bnks n M.M. Mrny Th ts o NCl on ntioxint nzym tivitis in llus tissu o slt-tolrnt n sltsnsitiv otton ultivrs (Gossypium hirsutum L.). Plnt Cll Rp., 13:

7 INFLUENCE OF SALT STRESS ON GROWH OF TWO MALUS SPECIES 381 Gr, S.C. n B.A. Logn Alimtion o olir ntioxint systms to growth irrin in thr rolv vrgrn spis. Plnt Physiol., 112: Grttn, S.R. n C.M. Griv Slinity-minrl nutrint rltions in hortiulturl rops. Sinti. Hort., 78: Hth, R.L. n L. Pkr Photoproxition in isolt hloroplsts I. Kintis n stoihiomtry o tty i proxition. Arh.Biohm. Biophys., 125: Hnry, G.A.F Oxygn n nvironmntl strss in plnts: n volutionry ontxt. Pro. Roy So., Einurgh 12B: Iqr, Z., M.S.A. Ahm, M. Hm, T. Nwz n A. Trtl Comprtiv slinity tolrn o imristylis ihotom (L.) vhl n shonopltus junois (Rox.) pll, th nit sgs or rhilittion o slin wtlns. Pk. J. Bot., 44: 1-6. Jmil, A., M. Ashr n M.R. Fool Gn xprssion proiling o plnts unr slt strss. Cri. Rv. Plnt Si., 3: Jhn, B., M.J. Khn, M. Shi, M.A. Khn n M. Shri Et o slinity n ABA pplition on prolin proution n yil in wht gnotyps. Pk. J. Bot., 44(3): Li, Y.H. n B.K. M Stuis on th ormtion n lssiition o M26 l xplnts riv rom llus. J. Fruit Si., 16(4): M, R.C., S.Y. Hn n Y.F. Li Erly high ultivtion thniqus o ppl in ostl slin rgion. Chin Fruits, 2: Msi, A. 23. Physiologil ts o oxitiv strss in rltion to thyln in post-hrvst prou. Post Hrvst Oxitiv Strss in Hortiulturl Crops Foo Prouts Prss, Nw York. Mittlr, R. 22. Oxitiv strss, ntioxints n strss tolrn nginring: An nlytil omprison. Trns Plnt Si., 7: Molssiotis, A., T. Sotiropoulos, G. Tnou, G. Dimntiis n I. Thrios. 26. Boron-inu oxitiv mg n ntioxint n nulolyti rsponss in shoot tips ultur o th ppl rootstok EM 9 (Mlus omsti Borkh). Environ. Exp. Bot., 56: Molssiotis, A., T. Sotiropoulos, G. Tnou, G. Koiis, G. Dimntiis n I. Thrios. 26. Antioxint n ntomil rsponss in shoot ultur o th ppl rootstok MM 16 trt with NCl, KCl, mnnitol or soritol. Biol. Plnt., 5(3): Murshig, T. n F. Skoog A rvis mium or rpi growth n iossy with too tissu ultur. Physiol. Plnt, 15: Ngo, Τ.Τ. n H.M. Lnho A snsitiv n vrstil hromogni ssy or proxis n proxis-oupl rtions. Anl. Biohm., 15: Pn, S.K. n R.K. Uphyy. 24. Slt strss injury inus oxitiv ltrtions n ntioxitiv n in th roots o Lmn minor. Biol. Plnt., 48: Pzzioh-Czohr, M. n A. Winsk. 22. Sptroluorimtri trmintion o hyrogn proxi svnging tivity. Anl. him. At., 452: Shn, L., S.Y. Zho n G.M. Xi. 26. Rsrh progrss on th intiition o slt tolrn rlt gns n molulr mhnism on slt tolrn in highr plnts. Mol. Plnt Br., 4: Silvn, B.D., M.G. Susn, P.B. Mrí n L.T. Mrí. 23. Bhviour o ntioxint ns systm in th ptiv rspons to slt strss in Hlinthus nnuus L. lls. Plnt Growth Rgul., 4: Vilpln, R. n M.C. Vlntins. 26. Antioxint potntil n proxitiv stt o Goln Smooth ppls trt wth 1-Mthylylopropn. Amr. So. Hort. Si., 131: Vrnov, E., D. Inz n B.F. Vn. 22. Signl trnsution uring oxitiv strss. J. Exp. Bot., 53: Wng, C.Y Et o tmprtur pronitioning on tls, proxis n suproxi ismuts in hill zuhini sqush. Posthrvst Biol. Thnol., 5: Wtn, S., K. Kojim, Y. I n S. Sski. 2. Ets o slin n osmoti strss on prolin n sugr umultion in Populus uphrti in vitro. Plnt Cll Tiss. Orgn Cult., 63: Wi, T. n R.J. Nwton. 25. Polymins ru slt-inu oxitiv mg y inrsing th tivitis o ntioxint nzyms n rsing lipi proxition in Virgini pin. Plnt Growth Rgul., 46: Yu, Y.L., Z.H. Wng, B. Zhou, n Z.X. Sun. 25. Rsrh o ultur mtho o two-stp rgnrtion systm rom ppl's l. Diuous Fruit Trs, 19: 4-7. Zhng, F., Y.L. Yng, W.L. H, X. Zho n L.X. Zhng. 24. Ets o slinity on growth n omptil soluts o llus inu rom Populus uphrti. In Vitro Cll Dv- Pl., 4: Zhu, J.K. 21. Plnt slt tolrn. Trns Plnt Si., 6: (Riv or pulition 9 Jun 211)