Morpho-agronomical response of rice (Oryza sativa L.) to foliar iron

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1 1229 Bulgrin Journl of Agriculturl Science, 21 (No 6) 215, Agriculturl Acdemy Morpho-gronomicl response of rice (Oryz stiv L.) to folir iron M. A. Dehghi 1, K. Aghi 1, D. Tlei 2 nd M. Seddighi 1 1 Shhed University, Deprtment of Agronomy, Fculty of Agriculture, Tehrn, Irn 2 Shhed University, Medicinl Plnts Reserch Center, Tehrn , Irn Astrct Dehghi, M. A., K. Aghi, D. Tlei nd M. Seddighi, 215. Morpho-gronomicl response of rice (Oryz stiv L.) to folir iron. Bulg. J. Agric. Sci., 21: Rice (Oryz stiv L.) is crop set to e in high demnd of mrket. Among the nutrients, iron is n essentil element in plnts phenologicl cycles. Assessment of this element effects could led to improving the plnt growth s well s the quntity nd qulity of yield. To chieve this, the effect of folir ppliction of iron ws exmined on yield nd components of rice. The experiment wsconducted sed onrndomized lockdesign with three replictes. The morphologic nd gronomic feedcks of the rice were nlyzed y exposing the rice seedlings to different concentrtions of Fe solution (, 5, 1 nd 15 mgl -1 ). It ws reveled tht sprying Fe hd significnt effecton grin yield (GY), grins per plnt (GP) nd grin length (GL). Estimtion of Correltion coefficients showed tht, GY ws positively correlted with GL nd GP, while it ws negtively correlted with unfilled grins (UG). According to multiple regression nlysis using the stepwise method, it ws concluded tht incresing in thegy ws minly due to increse of GP nd lso reduction of UG mount. Consequently, the results suggest tht, sprying Fe could e considered s suitle technique to increserice grin yield. Key words: chemicl fertilizers, micro-nutrients, iron concentrtion, rice Arevitions: Fe - Iron folir; FG - numer of filled grins; GL - grin length; GP - grins per plnt; GY - grin yield; GW - 1 grins weight; PB - pddy redth; PH - plnt height; PL - pnicle length; UG - numer of unfilled grins Introduction Nowdys, lthough rice (Oryz stiv L.) is n importnt food source of more thn two illion people cross the world, ut mny countries cnnot produce enough rice from lnd nd wter resources. In Irn due to some limittion fctors such s rinfll, rice is usully plnted in northern prts of Irn. Therefore, it hs kept hed of rising demnd. Like other griculturl crops, for the est growth nd yield of rice, dequte mcro nd micronutrients must e ville for the plnt (Colngelo nd Guerinot, 24). Iron (Fe) is one of the most importnt micronutrients, which significntly ffects plnt growth nd yield. Iron promotes the formtion of chlorophyll, enzyme mechnism, which opertes the respirtory system of cells, rections involving cell division nd growth (Colngelo nd Guerinot, 24). Plnts require mcro nd micro elements to grow. In soil, micro nutrients re not lwys present in the solution nd their vilility is limited due to severl fctors, which minly limit their soluility. The min fctors determining the level of solule mcro nd micro nutrients in soil solution re: Oxidtion-reduction rections nd the ph. The soluility of Fe depends on the chnges of ph inside the soil, nd thus ny chnges in soil ph my ffect Fe vilility to the plnt, which covers 3% of griculturl soils in the world (Mori, 1999) nd contining Fe s oxide nd hydroxide compounds with little soluility (Lindsy nd Schw, 1982). In such soils, Fe uptke considerly diminishes nd signs of chlorosis pper on the plnt, resulting in sustntil yield cut (Mrschner, 1995). Thus, sprying Fe on leves my e more effective thn the ppliction of Fe inside the soil. *Corresponding uthor: d.tlei@gmil.com

2 123 Along with ctivtion, stomtl sornce my e importnt in the folir ppliction of nutrients, since most of the spryed nutrients re sored through the stomt. Eichert nd Burkhrdt (21) reported model showing tht stomtl pthwy is for lrge nions such s urnine nd for smll ctions such s Fe 3+. This my further prove the ffectivity of folir Fe on rice growth nd yield. In ddition, the physicochemicl properties of compound my lso e determining fctor in folir ppliction. Besides their role in producing orgnic molecules, it is found tht mcro- nd micro-nutrients my ct s signl molecules in plnt, regulting plnt functions (Coruzzi nd Bush, 21). Reserchers hve indicted tht different plnt species hve dissimilr strtegy to iron uptke. Non-grminceous plnts in encounter to low concentrtion of Fe ct three different functions; (ii) production of H + into the rhizosphere y H + -ATPse, resulting in decresed soil ph nd higher Fe 3+ uptke ((Romheld, 1987; Colngelo nd Guerinot, 24), (ii) reducing Fe 3+ to Fe 2+ ecuse of the ferric chelte reductse ction of FRO2 (Roinson et l., 1999), nd (iii) trnsport of Fe 2+ into the plnt y IRT1, the min root trnsporter of iron (Eide et l., 1996; Vert et l., 22). The grsses (Tkgi et l., 1984), cteri nd fungi (Guerinot, 1994), use the second strtegy to iron uptke, chelting Fe rther thn cutting it, with excreting phytosiderophores, from mugineic cid fmily, into the soil nd thus chelting Fe 3+, which is lter incorported into plnt orgnic molecules using specil trnsporters (Colngelo nd Guerinot, 24; Ogo et l., 26). Appliction of cid nd Fe-fortified orgnic mterils hs een developed over the pst ten yers due to (i) the cidifying property of the mteril with Fe, (ii) the chelting property with Fe, nd (iii) the crrying property of cidifiers. To reduce Fe deficiency the following solutions my e suggested (Wllce, 1991) proper soil mngement, right lnce of nutrients such s P nd micronutrients, using Fe cheltes, use of ferrous mterils for spry ppliction, or ure-cid sulfte- Fe, or grdully-relesed Fe cheltes especilly t seeding. Due to this issue, the present study ws imed to investigte the effects of folir iron on rice (Oryz stiv L.) considering yield nd its relted trits. Despite this, the growth qulity nd yield of the rice under folir iron on the pddy fields should e sujected to further investigtions in the future s this cse hs not een scrutinized yet. Mterils nd Methods Germintion nd growth condition The rice seeds were provided from the Rice Reserch Institute of Irn, Rsht, Irn. The seeds were germinted in M. A. Dehghi, K. Aghi, D. Tlei nd M. Seddighi greenhouse to provide nursery. After one month of germintion, the seedlings were cultivted in the frmers fields t the Morke region of Isfhn province, Irn. Three nd five weeks fter cultivtion, 272 kg.h -1 (125 N kg.h -1 ) of ure ws pplied in the greenhouse. After 45 dys of germintion, the seedlings were cultivted in the frmers fields t the Morke region of Isfhn province, Irn. After plnting the seedlings, ure nd mmonium phosphte were pplied t 16 nd 3 kg.h -1 in the min field, respectively. The field ws irrigted nd weeds, pests, nd diseses were, controlled, chemiclly nd mechniclly. Experimentl design We crried out n experiment sed on rndomized complete lock design (RCBD) with five concentrtion of iron (, 5, 1, nd 15 mgl -1 ) nd three replictes during Mrch 21 - April 211. In this study, the Fe solule in wter with free mino cids (Trde Corp Compny, Spin) s io-nutrient with functionl L--mino cids ws used. After two months the Fe solutions were spryed onto the rice plnts t the stem producing stge. The experimentl unit foe ech tretment ws 3 3 meter with 2 2 cm 2 spce for ech seedling. At the physiologicl mturity, the plnts were hrvested from surfce of 1m 2 (including plnts in ech plot). Ten plnts from ech plot rndomly were selected nd dt on grins per plnt (GP), pnicle length (PL cm), plnt height (PH cm), numer of filled (FG), nd unfilled (UG) per 1 grins, pddy redth (PB mm), grin redth (GB mm), grin length (GL mm), nd 1-grin weight (GW g), seed moisture were mesured. Sttisticl nlysis At first, the rw dt were tested for normlity distriution y using the SAS softwre No. 9 nd the min dt were nlyzed for mesured trits using nlysis of vrince nd the Duncn s multiple rnge test (P.1). Anlysis of vrince nd men comprison were done using Proc GLM of SAS softwre. Results Anlysis of vrince showed tht sprying Fe on leves significntly ffected GY, PH, GL, PB nd GP (Tle 1).The vrition due to yer ws significnt for GY, PH, PL, FG, UG, PB nd GP (Tle 1). The coefficient of vrition ws vried from 1.13 for GL to for UG. The interction yer nd Fe hd no significnt effect on studied trits (Tle 1). In generl, trits such s GY, PH, PL, FG, GL, PB nd GP were higher in the first yer of experiment; while the mount

3 Morpho-Agronomicl Response of Rice (Oryz Stiv L.) to Folir Iron 1231 of UG ws lower (Tle 2). During two yers nd sed on comined dt, ppliction of folir Fe improved yield nd some importnt yield components such s GW nd GP (Figure 1). The highest yield nd its components were otined t 15 mgl -1 of Fe concentrtion. There ws no significnt difference mong nd 5 mgl -1 concentrtions on GY nd GP t. Grin yield mens were 71.92, 72.67, nd gm -2 t, 5, 1 nd 15 mgl -1 concentrtions respectively, showing grdul rise concurrent with increse of Fe concentrtion. The mximum rise for GY with 11.6% or gm -2 elonged to 15 mgl -1 concentrtion. According to these results, there ws significnt positive liner regression etween GY nd different level of Fe concentrtions (Tle 3). The corresponding regression model fitted for grin yield Tle 1 Comine nlysis of dt derived from the experiment of folir Fe on studied morphologicl trits in rice S.O.V df Men Squre GY GW PH PL FG UG GB GL GP Y n.s n.s Fe n.s n.s n.s.24 n.s.3 n.s Fe Y n.s.7 n.s 2.81 n.s.47 n.s 7.45 n.s.58 n.s.1 n.s.8 n.s n.s Error C.V, % Men ** nd * men tht the corresponding F vlue is significnt t the.1 nd.5 levels, respectively Y: yer, Fe: Iron folir, R: repliction, CV: coefficient of vrition, GY: grin yield (g.m -2 ), GW: 1 grins weight (g), PH: plnt height (cm), PL: pnicle length (cm), FG: numer of filled grins, UG: numer of unfilled grins, GL: grin length (mm), PB: pddy redth (mm), GP: grins per plnt Tle 2 Men comprison of rice morphologicl trits under impct of yer fctor Mens Yer GY PH PL FG UG GL GP GY: grin yield (g.m -2 ), GW: 1 grins weight (g), PH: plnt height (cm), PL: pnicle length (cm), FG: numer of filled grins, UG: numer of unfilled grins, GL: grin length (mm), PB: pddy redth (mm) nd GP: grins per plnt Tle 3 Correltions coefficients etween rice morphologicl trits under effect of different concentrtions of folir Fe GY GW PH PL FG UG GB GL GP GY 1 GW PH.665 **.541 ** 1 PL.669 ** * 1 FG ** 1 UG * GB ** GL.551 ** GP.946 ** **.655 ** ** ** 1 ** nd * men tht correltion is significnt t the.1 nd.5 levels, respectively (2-tiled). GY: grin yield (g.m -2 ), GW: 1 grins weight (g), PH: plnt height (cm), PL: pnicle length (cm), FG: numer of filled grins, UG: numer of unfilled grins, GL: grin length (mm), PB: pddy redth (mm), GP: grins per plnt

4 1232 M. A. Dehghi, K. Aghi, D. Tlei nd M. Seddighi ws GY= F with R 2 =.946,which shows suitle goodness of fit which is of importnt in terms of estimting the expected grin yield for given Fe concentrtion (Figure 1). Similrly, GP s one of the importnt yield components showed n increse y 8.3% (or grins per plnt) t 15 mgl -1 concentrtion in comprison with control. The corresponding vlues for GP were equl to , , nd , respectively showing reltive reduction t second Fe concentrtion level (5 mgl -1 ) followed y grdul rise t1 nd 15 mgl -1 levels. Also GW s one of the other importnt yield components showed rise equl to 5.15% (or 1.15 g). Also, sprying Fe incresed the GL. The mximum rise in GL vlues (.17 mm) oserved t 15 mgl -1 of Fe, compred with control. At the different level of Fe concentrtions (, 5, 1 nd 15 mgl -1 ) grin length men were equl to 6.11, 6.3, 6.11 nd 6.28 mm, respectively showing tht the vrition trend ws similr to GP. The re- Plnt height (cm) () grin height (mm) () 75 Fe concentrtion (mgl -1 ) 5.5 Fe concentrtion (mgl -1 ) grin per pnicle (c) c c Fe concentrtion (mgl -1 ) 1 grin weight (g) (d) Fe concentrtion (mgl -1 ) grin yield (gm -2 ) (e) y = x c c 65 Fe concentrtion (mgl -1 ) Fig. 1. Effect of different levels of folir Fe concentrtion on plnt height (), grin height (), grin per pnicle (c), 1 grin weight (d) nd grin yield (e) in rice. Men vlues ± S.E re from three independent replictes nd vlues superscripted y different letters re significntly different y Duncn s multiple rnge test (p.1)

5 Morpho-Agronomicl Response of Rice (Oryz Stiv L.) to Folir Iron 1233 sults suggested tht increse of Fe concentrtion from 5 to 15 mgl -1 hd slightly negtive effect on GW (Figure 1). Estimtion of correltion coefficients etween studied trits showed, under impct of folir Fe, GY ws positively correlted with GL, GP, PL nd PH while ws negtively correlted with UG. Also some positive nd significnt correltions were found etween GW-PH, GP-PH, PL-FG, PL, GP, FG-GB, nd GL-GP while the correltion etween UG nd GP ws negtive (Figure 2). Stepwise liner regression (SLR) nlysis showed tht GY ws positively regressed with GP, GW nd ws negtively regressed with PH. Stndrdized coefficients showed tht GP hd the highest impct on GY. The corresponding regression model fitted for grin yield ws GY = GP GW.314 PH with R 2 =.99. Discussion Fig. 2. Correltions coefficients etween 12 morphologicl trits in rice under effect of different concentrtions of folir Fe. The strength nd direction of the correltions mong the different trits re indicted y the color (red indictes positive correltions, while lue indictes negtive correltions, nd the shding represents the strength of the correltion) According to the results, the interction of yer Fe ws not significnt showing tht effect of folir Fe on improvement of quntity of yield nd its components ws independent from the impct of yer. The reduction of GY oserved in second yer ws minly due to the significnt rise in the mount of UG nd lso significnt decrese of GP. Folir ppliction of nutrients especilly micronutrients such s iron my e n efficient wy to provide the crops with needed nutrients, especilly t regions where soil ph is limiting fctor for nutrient soluility nd uptke. Mrschner nd Crowley (1998) found tht folir ppliction of Fe could provide the rley stressed plnts with dequte Fe. According to Eichert nd Burkhrdt (21) most prts of the solutes spryed onto the leves re sored through the stomtl pthwy. The results of this study suggested tht sprying folir Fe fertilizer hd positive effect to improve rice grin yield. Also, ppliction of Fe t 15 mgl -1 ws the proper concentrtion to increse rice grin yield in the field. This method my e economiclly importnt compred to the soil fertiliztion of Fe. The folir Fe my highly e sored through the plnt stomt, while soil fertiliztion my not e efficient since Fe compounds re much sujected to precipittion. Therefore highly reduced uptke especilly in clcreous soils (Eichert nd Burkhrdt, 21). This study showed tht folir Fe could significntly increse GY, GP nd GL. With regrd to the strong nd significnt correltion oserved etween GY-GP (.946, P.1) nd considering SLR results, increse of GP ws the min responsile of increse in GY. In fct, ppliction of folir Fe incresed the GP, which led to increse in GY. The increse in GP ws due to increse in the mount of leves chlorophyll nd thus efficiency of photosynthesis process. The SLR results showed significnt ut poor negtive effect of PH (-.2) on GY indicting competition etween vegettive trits (which re enhnced under the effect of folir Fe) nd reproductive functions. Compred to the control, GY, GP nd GL were numericlly decresed t 5 mgl -1 concentrtion levels followed y increse t 1 nd 15 mgl -1 levels. In this regrd, Shenker nd Chen (25) noted tht one mjor prolem impiring the success of folir pplictions of Fe is slow penetrting Fe through the lef. High soluility nd low moleculr weight re key fctors governing folir uptke. Thus, this reduction could e due to slow penetrtion long with low concentrtion of Fe. However, the lef poplsmic ph might e decresed y folir Fe ppliction nd therey the lef symplstic Fe uptke would e dvnced (Shenker nd Chen, 25). It seems tht higher concentrtions overcome to the prolem of slow penetrtion of folir Fe. When Fe is deficient, plnt chlorophyll content sustntilly decreses, resulting in the ppernce of chlorotic signs on plnt leves. From this viewpoint, it cn e thought tht Fe sprying on leves led to rise lef chlorophyll content s well s lef re durtion. On the other hnd, rising these

6 1234 two trits led to more photosynthesis nd thus needed crohydrte mterils for grin filling. Therefore, GY long with GP nd GL were incresed (Figure 1). Conclusion The results of this study showed tht sprying folir Fe fertilizer rised GY, GP nd GL. The mximum rise ws oserved t 15 mgl -1 Fe concentrtions, while numericl nd non-significnt reduction ws recorded t 5 mgl -1 level. According to the results of this study, folir spry of Fe could e considered s suitle technique to rise grin yield in rice. References Colngelo, E. P. nd M. L.Guerinot, 24. The essentil sic helix-loop-helix protein FIT1 is required for the iron deficiency response. Plnt Cell, 16: Coruzzi, G. nd D. R. Bush, 21. Nitrogen nd cron nutrient nd metolite signling in plnts. Plnt Physiology, 125: Eichert, T. nd J. Burkhrdt, 21. Quntifiction of stomtl uptke of ionic solutes using new model system. Journl of Experimentl Botny, 52: Eide, D., M. Broderius, J. Fett nd M. L. Guerinot, A novel iron-regulted metl trnsporter from plnts identified y functionl expression in yest. Proceedings of the Ntionl Acdemy of Sciences of the United Sttes of Americ, 93: Guerinot, M. L., Microil iron trnsport. Annul Review of Microiology, 48: M. A. Dehghi, K. Aghi, D. Tlei nd M. Seddighi Lindsy, W. L. nd A. P. Schw, The chemistry of iron in soils nd its vilility to plnts. Journl of Plnt Nutrition, 5: Mrschner, H., Minerl Nutrition of Higher Plnts. Acdemic Press, London, UK. Mrschner, P. nd D. E. Crowley, Phytosiderophores decrese iron stress nd pyoverdine production of Pseudomons fluorescens PF-5 (PVD-INAZ). Soil Biology nd Biochemistry, 3: Mori, S., Iron cquisition y plnts. Current Opinion in Plnt Biology, 2: Ogo, Y., R. N. Iti, H. Nknishi, H. Inoue, T. Koyshi, M. Suzuki, M. Tkhshi, M. S. Mori nd N. K. Nishizw, 26. Isoltion nd chrcteriztion of IRO2, novel iron-regulted HLH trnscription fctor in grminceous plnts. Journl of Experimentl Botny, 57: Roinson, N. J., C. M. Procter, E. L. Connolly nd M. L. Guerinot, A ferric-chelte reductse for iron uptke from soils. Nture, 397: Romheld, V., Different strtegies for iron cquisition in higher plnts. Physiologi Plntrum, 7: Shenker, M. nd Y. Chen, 25. Incresing iron vilility to crops: fertilizers, orgnic-fertilizers, nd iologicl pproches. Soil Science nd Plnt Nutrition, 51: Tkgi, S., K. Nomoto nd T. Tkemoto, Physiologicl spect of mugineic cid, possile phytosiderophore of grminceous plnts. Journl of Plnt Nutrition, 7: Vert, G., N. Grotz, F. Dedldechmp, F. Gymrd, M. L. Guerinot, J. F. Brit nd C. Curie, 22. IRT1, n Aridopsis trnsporter essentil for iron uptke from the soil nd for plnt growth. Plnt Cell, 14: Wllce, A., Rtionl pproches to control of iron deficiency other thn plnt reeding nd choice of resistnt cultivrs. Plnt nd Soil, 13: Received Mrch, 9, 215; ccepted for printing Octoer, 5, 215