Bellevue, Quebec Published online: 09 Mar 2011.

Transcription

1 This rticle ws downloded y: [McGill University Lirry] On: 11 August 214, At: 11:15 Pulisher: Tylor & Frncis Inform Ltd Registered in Englnd nd Wles Registered Numer: Registered office: Mortimer House, Mortimer Street, London W1T 3JH, UK Act Agriculture Scndinvic, Section B Soil & Plnt Science Puliction detils, including instructions for uthors nd suscription informtion: Effect of Nod fctor sprys on soyen growth nd productivity under field conditions Jun J. Almrz, Fzli Mood, Xiomin Zhou, Alfred Souleimnov & Donld L. Smith Progrm de Edfologí, Colegio de Postgrdudos, Montecillo, Estdo de Mexico, Mexico Deprtment of Plnt Science, Mcdonld Cmpus, McGill University, Ste Anne de Bellevue, Queec Pulished online: 9 Mr 211. To cite this rticle: Jun J. Almrz, Fzli Mood, Xiomin Zhou, Alfred Souleimnov & Donld L. Smith (211) Effect of Nod fctor sprys on soyen growth nd productivity under field conditions, Act Agriculture Scndinvic, Section B Soil & Plnt Science, 61:3, , DOI: 1.18/ To link to this rticle: PLEASE SCROLL DOWN FOR ARTICLE Tylor & Frncis mkes every effort to ensure the ccurcy of ll the informtion (the Content ) contined in the pulictions on our pltform. However, Tylor & Frncis, our gents, nd our licensors mke no representtions or wrrnties whtsoever s to the ccurcy, completeness, or suitility for ny purpose of the Content. Any opinions nd views expressed in this puliction re the opinions nd views of the uthors, nd re not the views of or endorsed y Tylor & Frncis. The ccurcy of the Content should not e relied upon nd should e independently verified with primry sources of informtion. Tylor nd Frncis shll not e lile for ny losses, ctions, clims, proceedings, demnds, costs, expenses, dmges, nd other liilities whtsoever or howsoever cused rising directly or indirectly in connection with, in reltion to or rising out of the use of the Content. This rticle my e used for reserch, teching, nd privte study purposes. Any sustntil or systemtic reproduction, redistriution, reselling, lon, su-licensing, systemtic supply, or distriution in ny form to nyone is expressly foridden. Terms & Conditions of ccess nd use cn e found t

2 Act Agriculture Scndinvic Section B Soil nd Plnt Science, 211; 61: ORIGINAL ARTICLE Effect of Nod fctor sprys on soyen growth nd productivity under field conditions JUAN J. ALMARAZ 1, FAZLI MABOOD 2, XIAOMIN ZHOU 2, ALFRED SOULEIMANOV 2 & DONALD L. SMITH 2 Downloded y [McGill University Lirry] t 11:15 11 August Progrm de Edfologí, Colegio de Postgrdudos, Montecillo, Estdo de Mexico, Mexico, 2 Deprtment of Plnt Science, Mcdonld Cmpus, McGill University, Ste Anne de Bellevue, Queec Astrct A field experiment ws conducted t Ste. Anne de Bellevue, Queec during the growing sesons of 22 nd 23, to study the effect of Nod fctor tretments, pplied t specific growth stges, on photosynthesis nd iomss ccumultion y soyen grown under two tillge systems (conventionl tillge, no-tillge). Spry ppliction of Nod fctors incresed photosynthesis t the four fully expnded trifolite leves nd full loom growth stges under no-tillge nd conventionl tillge; they incresed plnt iomss t the eginning seed filling stge. Nod fctor tretment did not ffect yield in 22, due to severe drought during the reproductive period. In 23, Nod fctor ppliction incresed yield under conventionl tillge ut not under no-tillge, nd this my hve een due to the negtive effect of no-tillge on plnt growth on the clylom soil t the experimentl site. This study indicted tht responses to Nod fctors re ffected y environmentl conditions, nd tht Nod fctors my e useful when pplied to soyen grown under conventionl tillge. Keywords: Biomss, Nod fctors, photosynthesis, soyen, tillge systems, yield. Introduction Nod fctors re molecules produced y rhizoi s prt of signl exchnge with legumes tht leds to symiotic infection nd susequent formtion of N fixing root nodules (Spink et l., 1991; Schultze, et l., 1992; Long, 1996; Schultze & Kondorosi, 1998). At low concentrtions Nod fctors induce series of physiologicl nd morphologicl responses in the host plnt, such s depolriztion of the root corticl cell plsm memrnes, clcium spiking, root hir deformtion, formtion of pre-infection threds nd induction of nodule primordi (Heidstr & Bisseling, 1996; Long, 1996; Downie & Wlker, 1999). Nod fctors re essentil in estlishment of rhizoilegume symioses nd induce responses in the specific host plnts, resulting in nodule formtion. However, hormone-like responses to Nod fctors hve een found in non-legume plnts, in oth somtic tissue culture systems nd whole plnts. In crrot mutnts nd Norwy spruce, Nod fctors restore or promote cell division nd somtic emryo formtion (De Jong et l., 1993; Dychok et l., 2, 22). Norwy spruce emryogenic cultures contin Nod fctor-like molecules, nd the suppression of the development of pro-emryogenic msses y depletion of uxin in the medium is relieved y incresing the concentrtion of endogenous or externl Nod fctor-like molecules (Dychok et l., 22). Accelerted seed germintion nd plnt growth, s well s incresed photosynthetic rte in severl plnt species, including soyen, hve een oserved when they were treted with sumolr concentrtions of Nod fctors (Smith et l., 22; Souleimnov et l., 22; Prithivirj et l., 23; Almrz et l., 27; Khn et l., 28). Prithivirj et l. (23) found tht, under field conditions, erly stges of plnt growth cn e ccelerted y Nod fctor spryings; however, there is no informtion out the effect of Nod fctor sprys on photosynthesis, on enhncement of plnt iomss t vrious growth stges nd on finl Correspondence: D.L. Smith, Deprtment of Plnt Science, Mcdonld Cmpus, McGill University, Lkeshore Rod, Ste Anne de Bellevue, Queec. H9X 3V9. Fx: (514) E-mil: Donld.Smith@McGill.C (Received 3 Mrch 29; revised 18 Ferury 21; ccepted 24 Ferury 21) ISSN print/issn online # 211 Tylor & Frncis DOI: 1.18/

3 Downloded y [McGill University Lirry] t 11:15 11 August 214 iomss nd seed yield under field conditions. Technologies tht increse iomss production in order to increse food supply lso llow more removl of CO 2 from the tmosphere, incresing iomss stocks ville for iofuel production nd hrvest residues for enhncing soil orgnic cron (Grten & Wullschleger, 1999; Kiniry et l., 1999). Since Nod fctors hve the potentil to increse plnt growth nd iomss they my e useful technology for mitigting greenhouse gs emissions. Our ojective ws to study soyen responses to Nod fctors sprys t severl growth stges, under two tillge systems, nd over two growing sesons. Mterils nd methods Experimentl site nd seeding This reserch ws conducted t the Lods Agronomy Reserch Center of the Mcdonld Cmpus of McGill University, Ste. Anne de Bellevue, Queec, in 22 nd 23. The soil of the experimentl site ws Chteuguy cly lom (fine, mixed, noncid, frigid, Hpludlf), nd the previous crop on the site ws corn. Plots were plnted with soyen vriety OAC Byfield on 22 My 22 nd 23 My 23 t density of 45, plnts h 1 in rows 2 cm prt using seven-row no-till seeder (Fro Enterprise Ltd, Swift Current, SK). Seeds were inoculted with pet-sed commercil inoculnt (Affix, Bios- Agriculture, Inc., QC), t rte of 1 7 cells seed 1, efore sowing. Tretments nd experimentl design Soyen ws estlished t the experimentl site under two tillge systems: conventionl (CT) nd no-tillge (NT). The experimentl site ws cropped to corn in the previous yer (21) nd fter hrvest the crop residues were incorported in CT plots nd left on surfce in NT plots. The CT plots were moldord plowed in the fll of 21 nd 22, while the NT plots were not tilled. The CT plots were offset disked prior to soyen seeding in My of 22 nd 23, nd the NT plots were mintined without tilling. The Nod fctor tretments were pplied to soyen grown under the two tillge systems t three soyen growth stges: V4, R2 nd R4 (Fehr & Cviness, 1977). Two levels of Nod fctor were included: mg L 1 nd control without Nod fctor. The solution ws mde y dissolving Nod fctor in 5 ml of distillted wter nd then diluting this to otin the required concentrtion. The Nod fctor solution ws prepred in 2 L continers, nd efore sprying Tween-2 (Fisher Scientific, PA, Effect of Nod fctor sprys on soyen growth 229 USA) ws dded (.5%) s surfctnt. The control consisted of wter without Nod fctor, nd with Tween-2 (.5%). The Nod fctor used in this study ws Nod Bj (C18:1, MeFuc), isolted from Brdyrhizoium jponicum strin 532C (the method used to isolte this Nod fctor ws previously descried y Souleimnov et l., 22 nd Prithivirj et l., 23). The Nod fctor tretments (including the control) were spryed directly onto the soyen plnts using 13.6 L spryer pump. This ws done t three growth stges during the seson: V4, R2 nd R4. The Fehr nd Cviness (1977) growth stge system for soyen ws used to indicte the growth stges in our study. In this system, soyen development is divided into vegettive (V) nd reproductive (R) stges. The vegettive stges re numered ccording to how mny fully developed trifolite leves re present on the min stem; leves on the rnches re not considered. Thus, the vegettive stges re: V1 (first trifolite), V2 (second trifolite), V3 (third trifolite), V4 (four trifolite), V5 (five trifolite), V6 (six trifolite). The reproductive stges re numered to indicte flowering, pod nd seed development nd plnt mturtion. The reproductive stges re: R1 (eginning flowering, first flower), R2 (full flowering, flowers in top 2 nodes), R3 (eginning pod development, 5 mm pods on the top 4 nodes), R4 (full-sized pods, 19 mm pods on the top 4 nodes), R5 (eginning seed filling, 3 mm seeds on the top 4 nodes), R6 (fully filled seeds on t lest one of the top 4 nodes), R7 (eginning mturity, t lest one mture pod), nd R8 (full mturity, 95% of pods on the plnt re mture). The tretments were rrnged in split plot experimentl design with four replictes, where the min plot ws tillge system nd the su-plot ws Nod fctors. All plots received 5 kg P 2 O 5 equivlent h 1 nd 5 kg K 2 O equivlent h 1 t plnting sed on soil test. Weeds were controlled using post-emergent hericide or mnully; ll plots were spryed with.4 L h 1 Venture (Syngent Crop protection, Inc., Ontrio) plus 2 L h 1 Bsgrn (BASF Cnd, Inc., Ontrio), nd, when necessry, hnd control ws lso used. Precipittion nd soil moisture Records of dily precipittion nd ir temperture were otined from the Dorvl wether sttion locted 2 km from the experimentl site. Moisture ws mesured in ech plot, in the top 2 cm of the soil, with field scout TDR soil moisture meter, model 3 (Spectrum Technologies, Inc., Plinfield, IL). A totl of four mesurements were tken per

4 Downloded y [McGill University Lirry] t 11:15 11 August J.J. Almrz et l. plot, two etween rows nd two within rows. These were verged to produce plot vlue. Photosynthesis, lef re nd dry weight A portle gs exchnge system (LI-64, Li-Cor Inc., Lincoln, NE) ws used to mesure photosynthetic rte. The photosynthetic photon flux density (PPFD) nd the concentrtion of CO 2 flowing into the chmer were 8 mmol m 2 s 1 nd 5 mmol mol 1, respectively, nd the temperture 24 to 28 8C. The mesurements were tken on nerly expended lef during the second dy fter sprying the Nod fctors. This ws done ech time Nod fctors were spryed on the plnts (t V4, R2 nd R4 stges). Plnts smples were collected t three growth stges during the seson: R1, R3, R5; leves were seprted from the shoots nd lef re ws mesured using lef re meter (Delt-T Devices Ltd, Cmridge). Plnt mteril ws dried t 7 8C for 72 h to determine dry weight. Yield nd iomss Soyen ws hrvested t the R8 stge (physiologicl mturity) to determine yield nd iomss. Smples of 1 plnts were hrvested from ech soyen plot; shoots nd grin were seprted, nd su-smple ws tken nd dried t 7 8C for 72 h nd weighed, in order to estimte moisture content nd stem dry weight. In ddition, n re of 4.5 m 2 in ech soyen plot ws hrvested with smll plot comine (Winterstieger, Slt Lke City, UT) in order to determine yield per unit re. Sttisticl nlysis Dt were nlysed with the Sttisticl Anlysis System (SAS Institute,1985) y nlysis of vrince (ANOVA) nd when ANOVA showed significnt (p 5.5) tretment effect the mens of tretments were compred with n LSD test (p5.5) (Steel & Torrie, 198). Results nd discussion Precipittion nd soil moisture The two growing sesons hd very different temperture nd rinfll profiles nd this ffected soyen development nd growth. In 22 My nd June were cooler thn the norm while in 23 these months were wrmer thn the norm. In oth sesons the wrmest months were July nd August with tempertures ove or equl to C. My precipittion ws greter thn the long-term norm nd July temperture ws lower thn the long-term norm in oth yers. The 22 growing seson hd less precipittion thn 23, nd ws dry during the mid-seson, with the lowest rinfll recorded in August: only 1 mm (Tle I). Tillge ffected soil moisture only during 23. Averge soil moisture for the 23 growing seson ws greter for NT thn CT, ut during the July August dry period of this yer there ws no difference etween tillge systems for soil moisture (Tle II). Photosynthetic rte In 22, the first Nod fctor spry (soyen growth stge V4) did not increse photosynthetic rte under oth NT nd CT. After the second Nod fctor spry, t R2, lrger increse on photosynthetic rte ws oserved nd ws detected for oth NT nd CT. There ws no chnge in photosynthetic rte following the third Nod fctor spry (R4) (Figure 1A). Nod fctor sprys incresed soyen stomtl conductnce t the R2 growth stge (Figure 1B). In 23, the first Nod fctor spry (V4) incresed photosynthetic rte under NT ut not under CT. After the second Nod fctor spry (R2) photosynthetic rte lso ws incresed, nd lthough the increse ws smller thn following the previous spry, there ws detectle increse for oth tillge systems. There ws no effect on photosynthesis following the third spry (R4) (Figure 1C). For stomtl conductnce significnt effects were oserved Tle I. Temperture nd precipittion during the growing sesons of 22 nd 23 t the experimentl site. Air temperture (8C) Precipittion (mm) Month My June July August Septemer Averge

5 Downloded y [McGill University Lirry] t 11:15 11 August 214 Tle II. Averge soil moisture (% soil wter content SWC) in the growing seson (MyAugust) nd in the period JulyAugust, for soyen grown under two tillge systems. Growing seson JulyAugust 22 CT NT CT NT CT Conventionl tillge, NT No-tillge. Ech men is the verge of four plots. Mens ssocited with the sme letter re not different (p5.5) y Lest Significnt Difference (LSD) test. The comprisons re for the tretments within ech yer. only t the R2 stge for the CT tretment nd t V4 nd R2 for the NT tretment (Figure 1 D). Soyen photosynthetic rte ws incresed y Nod fctor sprys in oth tillge systems in oth growing sesons; however, the effects were oserved only t the V4 or R2 growth stges, nd not t R4. The photosynthetic rte ws generlly greter in 23 thn in 22 (Figure 1A nd 1C); the sme trend ws oserved for stomtl conductnce (Figure 1B nd 1D). Reports indicte tht photosynthesis is positively ssocited with lef re, lef mss nd lef nitrogen content (Del Pozo & Dennett, 1999; Oski et l., 21), reching higher vlues round the time of pod filling (Surhmnym, µ mol CO 2 m 2 s c c A 22) when sink demnd is gretest. However, we did not find the highest photosynthetic rtes t R4 (pod setting nd erly pod filling); insted we oserved the highest rte t R2. Our findings suggest tht the non-response of photosynthetic rte to Nod fctor nd reltively lower vlues of photosynthetic rte nd stomtl conductnce t R4, prticulrly in 22, were due to wter stress (Tle I nd II), which proly ffected totl grin production t the end of the seson. The summer of 22 ws drier thn 23, with longer period without precipittion. Low soil moisture levels during the JulyAugust period (Tle II) lso indicted tht the plnts were wter stressed during the middle of their reproductive development. In fct, loss of lef re ws oserved t the R5 stge, which resulted in similr or lower LAI thn t the R3 stge, prticulrly under the NT system (Figure 2). Soyen LAI, iomss nd yield Soyen plnts were generlly hrvested one growth stge fter Nod fctor ws pplied (7 to 1 dys fter ech spry), in oth growing sesons. In 22, Nod fctor incresed LAI under oth tillge systems t R3. However the effect of Nod fctor ws oserved only under CT t R5, due to erly loss of some lef re, cused y drought (Figure 2A). Numericl increses in soyen iomss were oserved t the µ mol CO 2 m 2 s Effect of Nod fctor sprys on soyen growth C mol m 2 s c c B mol m 2 s D V4 R2 R4 V4 R2 R4 Figure 1. Photosynthetic rte (A nd C) nd stomtl conductnce (B nd D) in soyen t three growth stges (V4, R2, R4) in 22 nd 23 growing sesons. NT No-tillge, CT Conventionl tillge, S Control without Nod fctor sprys, S Nod fctor sprys. Ech histogrm r represents the men of four locks (4 oservtions per lock, 16 per tretment). Brs ssocited with the sme letter re not different (p5.5) within ech growth stge y lest significnt difference (LSD) test.

6 232 J.J. Almrz et l. m 2 m A 22 c m 2 m C 23 c c B 8 6 D c c Downloded y [McGill University Lirry] t 11:15 11 August 214 g m R3 growth stge, fter the second spry. At the R5 stge Nod fctor tretment incresed soyen iomss under CT ut not under NT (Figure 2B). During the 23 seson Nod fctor tretment cused increses in LAI t R1 nd R3 only in NT; while increse in LAI t R5 stge ws oserved only in CT. At this stge there ws some loss of lef re due to drought (Figure 2C). Nod fctor spry incresed plnt iomss under the CT system t R5 only. In ddition, t this stge iomss ws lower under NT thn CT (Figure 2D). Soyen yield ws lower in 22 thn in 23. In 22, seed yield nd stem iomss were not ffected y Nod fctor tretment. In 23 seed yield ws g m R1 R3 R5 R1 R3 R5 Figure 2. Lef re (A nd C) nd ccumulted soyen iomss (B nd D) t three growth stges (R1, R3, R5) in 22 nd 23 growing sesons. NT No-tillge, CT Conventionl tillge, S Control without Nod fctor sprys, S Nod fctor sprys. Ech histogrm r represents the men of four locks (1 plnts per lock, 4 per tretment). Brs ssocited with the sme letter re not different (p5.5) within ech growth stge y lest significnt difference (LSD) test. incresed (p5.5) under the CT system ut not under NT. Stem iomss ws not different under oth tillge systems. Seed yield ws lower under NT thn CT with or without Nod fctor tretment (Tle III). Nod fctor spryed on soyen plots incresed plnt iomss only under CT conditions t R5 (Figure 2B nd 2D). These effects re proly the result of lrger LAI due to Nod fctor tretment (Figure 2A nd 2C) tht my hve resulted in higher photosynthetic rtes. It is known tht most of the sugrs produced y photosynthesis re llocted to seeds during the pod filling stge, so tht n increse in photosynthesis per unit lef re or dely in lef Tle III. Soyen grin yield nd stlk iomss production in two tillge systems with two levels of Nod fctor (sesons of 22 nd 23). 22 th 1 23 Tillge system NF level Yield Stlk iomss Yield Stlk iomss NT c 2.2 NT c 2.26 CT CT NT No-tillge, CT Conventionl tillge. NF Nod fctor, Control without Nod fctor spry, 1 Nod fctor (141.6 mg L 1 ) spryed three times during the growing seson on soyen folige. Ech men is the verge of four plots. Mens ssocited with the sme letter re not different (p.5) y Lest Significnt Difference (LSD) test.

7 Downloded y [McGill University Lirry] t 11:15 11 August 214 Effect of Nod fctor sprys on soyen growth 233 senescence re likely to increse finl iomss nd grin yield (Hyti et l., 1995), however, the opposite cn lso e true in tht ny stress t this stge is likely to reduce finl iomss nd yield. We oserved tht soyen yield ws incresed y Nod fctor under CT ut not NTnd only in 23 (Tle III). Our results indicte tht photosynthesis nd LAI were negtively ffected y drought, nd the impct ws greter in 22 thn 23; this ws proly the cuse of lower yield nd lower yield responses to Nod fctor sprys in 22. Yield ws lower under NT thn CT with or without Nod fctor tretment, prticulrly in 23 (Tle III). This could e ttriuted to negtive effect(s) of NT on soyen growth under southwestern Queec conditions. It hs een reported tht NT in cold climtes my decrese erly seson soil temperture, especilly in hevy soils, which could result in slower germintion nd delyed crop estlishment (Hyhoe et l., 1996; Vyn et l., 1998; Drury et l., 1999). Although these conditions do not lwys result in lower yield, in hevy soils of Estern Cnd NT delyed soyen growth nd reduced yield due to higher wter contents in the seeded, nd greter penetrometer resistnce hve een reported (Drury et l., 1999). The soil t our experimentl site ws cly lom, so tht some of these fctors, comined with the effect of drought, my hve cused the lck of response to Nod fctors under NT. Generlly, the effects of Nod fctor sprys on plnt iomss nd seed yield were not lrge; however, they were consistent in cusing increses during oth vegettive nd reproductive stges. The gretest photosynthetic response to Nod fctor ws oserved t R2 (Figure 1), nd the gretest iomss increse ws t R5 (Figure 2). Similr trends or etter effects would hve een expected t the finl growth stge (mturity) if drought hd not occurred. The drought of 22 ws prticulrly severe, with devstting impcts on wide rnge of crops cross Cnd (Wheton et l., 25). Even under such extreme conditions we oserved some numericl increses in soyen yield. Our results suggest tht Nod fctors should e spryed on soyen grown under CT to increse yield. Also these results indicte tht responses to Nod fctor sprys in soyen re ffected y environmentl fctors. Nod fctors my constitute new griculturl technology tht increses soyen yield, contriuting to incresed iomss production, for incresed world food supply, which lso llows for more removl of the greenhouse gs CO 2 from the tmosphere. In conclusion, Nod fctor spryed onto soyen grown under field conditions incresed photosynthetic rtes t growth stges V4 nd R2, nd iomss t the R5 stge. There ws no effect of Nod fctor on finl iomss nd yield in 22 due to severe drought during the reproductive period. Yield ws incresed y Nod fctor tretment under CT, ut not NT, in 23. Our results indicte tht Nod fctor sprys could e used most efficciously on soyen plnts grown under CT, ecuse the negtive effect of NT on soyen reduces response to Nod fctors. References Almrz, J. J., Zhou, X., Souleimnov, A., & Smith, D. (27). Gs exchnge chrcteristics nd dry mtter ccumultion of soyen treted with Nod fctors. Journl of Plnt Physiology, 164, De Jong, A. J., Heidstr, K., Spink, H. P., Hrtog, M. V., Meijer, E. A., Hendriks, Lo Schivo, T. F., Terzi, M., Bisseling, T., Vn Kmmen, A., & De Vries, S. C. (1993). Rhizoium lipooligoscchrides rescue crrot somtic emryo mutnt. Plnt Cell, 5, Del Pozo, A., & Dennett, M. D. (1999). Anlysis of the distriution of light, lef nitrogen, nd photosynthesis within the cnopy of Vici f L. t two contrsting plnt densities. Austrlin Journl of Agriculturl Reserch, 5, Downie, J. A., & Wlker, S. A. (1999). Plnt responses to nodultion fctors. Current Opinion in Plnt Biology, 2, Drury, C. F., Tn, C. S., Welcky, T. W., Oloy, T. O., Hmill, A. S., & Wever, S. E. (1999). Red clover nd tillge influence on soil temperture, wter content, nd corn emergence. Agronomy Journl, 91, Dychok, J. V., Toin, A. E., Price, N. P. J., & von Arnold, S. (2). Rhizoil Nod fctors stimulte somtic emryo development in Pice ies. Plnt Cell Reports, 19, Dychok, J. V., Wiweger, M., Kenne, L., & von Arnold, S. (22). Endogenous Nod-fctor-like signl molecules promote erly somtic emryo development in Norwy spruce. Plnt Physiology, 128, Fehr, W. R., & Cviness, C. E. (1977). Stges of soyen development. Specil Report 8. Ames: Iow Coopertive Extension Service. Grten, C. T., & Wullschleger, S. D. (1999). Soil cron inventories under ioenergy crop (switchgrss): mesurement limittions. Journl of Environmentl Qulity, 28, Hyti, R., Egli, D. B., & Crfts-Brndnen, S. J. (1995). Cron nd nitrogen supply during seed filling nd lef senescence in soyen. Crop Science, 35, Hyhoe, H. N., Dwyer, L. M., Stewrt, D. W., White, R. P., & Culley, J. L. B. (1996). Tillge, hyrid nd therml fctors in corn estlishment in cool soils. Soil nd Tillge Reserch, 4, Heidstr, R., & Bisseling, T. (1996). Nod fctor-induced host responses nd mechnisms of Nod fctor perception. New Phytologist, 133, Khn, W., Prithivirj, B., & Smith, D. (28). Nod fctor [Nod Bj V (C(18:1), MeFuc)] nd lumichrome enhnce photosynthesis nd growth of corn nd soyen. Journl of Plnt Physiology, 165, Kiniry, J. R., Tischler, C. R., & Vn Esroeck, G. A. (1999). Rdition use efficiency nd lef CO2 exchnge for diverse C-4 grsses. Biomss nd Bioenergy, 17,

8 Downloded y [McGill University Lirry] t 11:15 11 August J.J. Almrz et l. Long, S. R. (1996). Rhizoium symiosis: Nod fctors in perspective. Plnt Cell, 8, Oski, M., Shinno, T., Kned, T., Llmed, S., & Nkmur, T. (21). Ontogenetic chnges of photosynthetic nd drk respirtion rtes in reltion to nitrogen content in individul leves of field crops. Photosynthetic, 39, Prithivirj, B., Zhou, X., Souleimnov, A., Khn, W., & Smith, D. L. (23). A host-specific cteri-to-plnt signl molecule (Nod fctor) enhnces germintion nd erly growth of diverse crop plnts. Plnt, 216, SAS Institute (1985). SAS user s guide: Sttistics (5th Edn). Cry: SAS Institute. Schultze, M., Quiclet-Sire, B., Kondorosi, E., Virelizier, H., Glushk, J. N., Endre, G., Gero, S. D., & Kondorosi, A. (1992). Rhizoium meliloti produces fmily of sulfted lipooligoscchrides exhiiting different degrees of plnt host specificity. Proceedings of the Ntionl Acdemy of Sciences USA, 89, Schultze, M., & Kondorosi, A. (1998). Regultion of symiotic root nodule development. Annul Review of Genetics, 32, Smith, D. L., Prithivirj, B., & Zhng, F. (22). Rhizoil signls nd control of plnt growth. In T. M. Finn, M. R. O Brin, D. B. Lyzell, K. Vessey nd W. E. Newton (Eds.), Nitrogen fixtion: glol perspectives, pp Wllingford: CABI Pulishing. Souleimnov, A., Prithivirj, B., & Smith, D. L. (22). The mjor Nod fctor of Brdyrhizoium jponicum promotes erly growth of soyen nd corn. Journl of Experimentl Botny, 53, Spink,H.P.,Sheeley,D.M.,vnBrussel,A.A.N.,Glushk,J., York,W.S.,Tk,T.,Geiger,O.,Kennedy,E.P.,Reinhold,V.N., & Lugtenerg, B. J. J. (1991). A novel highly unsturted ftty cid moiety of lipooligoscchride signls determines host specificity of Rhizoium. Nture, 354, Steel, R. G. D., & Torrie, J. H. (198). Principles nd procedures of sttistics: iometricl pproch. McGrw-Hill, New York. Surhmnym, D. (22). Interreltionship etween lef gsexchnge chrcteristics, re lef mss, nd yield in soyen (Glycine mx L. Merr.) genotypes. Photosynthetic, 4, Vyn, T. J., Opoku, G., & Swnton, C. J. (1998). Residue mngement nd minimum tillge systems for soyen following whet. Agronomy Journl, 9, Wheton, E., Wittrock, V., Kulshreshth, S., Koshid, G., Grnt, C., Chipnshi, A., Bonsl, B., Adkins, P., Bell, G., Brown, G., Howrd, A., & McGregor, R. (25). Lessons lerned from the Cndin drought yers 21 nd 22: Synthesis report. Prepred for Agriculture nd Agri-Food Cnd. Ssktchewn Reserch Council (SRC) Puliction No E3. Ssktoon, Ssktchewn.