SHORT COMMUNICATION Timing of prtil defolition ffects crohydrte concentrtion of vegettive tissues nd concentrtion of phenolics in erries of potted De Chunc (Vitis sp.) grpevines Justine E. Vnden Heuvel 1, Jessic L. Roidoux 2, Wesley R. Autio 3, nd Ctherine C. Neto 2 Cn. J. Plnt Sci. Downloded from www.nrcreserchpress.com y 148.251.232.83 on 05/12/18 1 University of Msschusetts Amherst, Crnerry Experiment Sttion, 1 Stte Bog Rd., P.O. Box 569, E. Wrehm, MA 02538, USA (e-mil: justinev@umext.umss.edu); 2 Deprtment of Chemistry nd Biochemistry, University of Msschusetts Drtmouth, 285 Old Westport Rd., N. Drtmouth, MA 02747, USA; nd 3 Deprtment of Plnt, Soil, & Insect Sciences, University of Msschusetts Amherst, Amherst, MA 01003. Received 24 Novemer 2004, ccepted 22 Ferury 2005. Vnden Heuvel, J. E., Roidoux, J. L., Autio, W. R. nd Neto, C. C. 2005. Timing of prtil defolition ffects crohydrte concentrtion of vegettive tissues nd concentrtion of phenolics in erries of potted De Chunc (Vitis sp.) grpevines. Cn. J. Plnt Sci. 85: 703 708. Prtil defolition of grpevines often increses fruit phenolic content; however, improved light interception y fruit nd possile improved photosynthetic efficiency of leves re confounding fctors. In this study, potted De Chunc grpevines were prtilly defolited t three phenologicl stges, ut cluster light environment ws unffected. Prtil defolition t erry set significntly reduced glucose nd fructose concentrtions in the lef/shoot tissue, nd lso reduced totl flvonols nd totl phenolics in the fruit. Vines prtilly defolited pre-hrvest hd incresed sucrose concentrtion in the leves nd roots, incresed glucose in the roots, nd produced fruit with improved totl nthocynins compred to the control. Key words: Grpevines (French hyrid), crohydrtes, phenolics Vnden Heuvel, J. E., Roidoux, J. L., Autio, W. R. et Neto, C. C. 2005. Le moment de l défolition prtielle modifie l concentrtion d hydrtes de crone dns les tissus végéttifs et l concentrtion de phénols dns les fruits de l vigne (Vitis sp.) De Chunc cultivée en pot. Cn. J. Plnt Sci. 85: 703 708. L défolition prtielle des ceps de vigne ccroît souvent l teneur en phénols dns le fruit, mis une meilleure interception de l lumière pr les ies et éventuellement une photosynthèse plus efficce sont des vriles confusionnelles. Les uteurs ont enlevé une prtie des feuilles de ceps de vigne De Chunc cultivés en pot à trois stdes phénologiques, sns modifier l éclirge des grppes. L défolition prtielle à l nouison réduit significtivement l concentrtion de glucose et de fructose dns les pousses et les feuilles et diminue celle de flvonols et de phénols dns les fruits. Comprtivement ux témoins, les ceps prtiellement défeuillés vnt l récolte présentent une plus forte concentrtion de sucrose dns les feuilles et les rcines, plus de glucose dns les rcines et plus d nthocynine dns les fruits. Little informtion is ville concerning whole-plnt processes involved in the development of phenolics in grpe erries. Anthocynin content is ffected y environmentl conditions such s wter supply nd light (Hunter et l. 1991; Price et l. 1995), nd reserch hs een conducted on the internl control of ccumultion of nthocynins nd phenolics. Skins of grpes grown in full sunlight ccumulte greter totl concentrtions of phenolics thn those grown under shde conditions (Price et l. 1995). It is generlly hypothesized tht this results from improved photosynthetic efficiency nd crohydrte prtitioning, lthough to our knowledge, this hypothesis hs never een tested. We hypothesize tht cron production nd prtitioning of the vine cn ffect formtion of phenolic compounds in grpe erries due to vrying levels of cron vilility for shunting into secondry metolite pthwys. In order to work towrds testing this hypothesis, the ojective of this study ws to determine the effect of prtil defolition (without ffecting cluster light environment) t three phenologicl Mots clés: Vigne (hyride frnçis), hydrtes de crone, phénols 703 stges on non-structurl crohydrte concentrtions in vegettive tissues of the vine, nd on development of totl nthocynins, flvonols, nd phenolics in De Chunc erries. One hundred nd fifty dormnt 2-yr-old De Chunc grpevines (own rooted) were plnted using Pro-Mix (Premier Horticulture Inc., Qukertown, PA) into 12-L pots on 2003 Apr. 17, nd were plced in glsshouse under mient temperture nd light conditions in E. Wrehm, MA. Vines were mintined with two shoots, nd further shoot extension ws prevented y pinching when plnts ttined 12 leves. Shoots were cluster-thinned t loom to one (sl) cluster per shoot. All developing xillry shoots were removed to reduce within-plnt shding. Vines were wtered s needed nd fertilized on n pproximtely iweekly sis with 20N-8.6P-16.4K t 2 g L 1. Eighty vines were selected for the experiment sed on uniformity of cluster development. The experiment ws Arevitions: TNSC, totl non-structurl crohydrte
Cn. J. Plnt Sci. Downloded from www.nrcreserchpress.com y 148.251.232.83 on 05/12/18 704 CANADIAN JOURNAL OF PLANT SCIENCE designed s rndomized complete lock with four replictions, with four vine su-smples per repliction for ech defolition tretment. There were eight control vines per repliction in order to llow for control vines to e destructively hrvested following ech lef removl tretment, resulting in 20 vines per rep (eight control, four of ech defolition tretment). Defolition tretments removed pproximtely 50% of lef re (Tle 1). Four tretments were pplied to the vines: control (no defolition), defolition t erry set, defolition t verison, nd defolition 7 d pre-hrvest. The four sl leves were mintined on ech shoot, with susequent leves t nodes 5, 6, 8, 9, 11, nd 12 removed. Lef removl dtes were 2003 July 02 (erry set), Aug. 18 (verison), nd Sep. 15 (pre-hrvest). Due to removl of leves eginning t node 5, ech cluster hd full-sized lef immeditely ove it (on the sme side of the shoot). As vines were smll, shoots were verticlly stked, pots well spced on the greenhouse enches, nd the four sl leves remined on the shoots in ll tretments, lef defolition did not pper to ffect cluster light environment. Photosyntheticlly ctive rdition mesured t the top of the cluster supported this ssumption (verge of pproximtely 300 µmol m 2 s 1 following defolition t erry set); however, these dt were not collected in replicted fshion, nd photosyntheticlly ctive rdition interception ws vrile etween clusters. Fruit ws hrvested on 2003 Sept. 23. Potted vines were used for this experiment s they show very similr responses to defolition tretments compred to mture field-grown vines (Cndolfi- Vsconcelos nd Kolet 1991). Seven dys following ech lef removl, two of the four defolited vines, nd two of the remining control vines in ech replicte were destructively hrvested for crohydrte nlysis, eginning t 0900 EST. The destructive hrvest ws completed y 1030 EST. Vine orgns were sorted into leves/shoots, roots, nd trunks. Following shoot removl from the trunk, the top 5 cm of the trunk ws cut off, nd divided into smller pieces to fcilitte grinding. Only the top 5 cm of the trunk ws used in order to reduce cutting time nd hence respirtory losses of crohydrtes. All orgns were dried for minimum of 5 d t 80 C, nd ground to 40 mesh using Wiley mill (Fisher Scientific, Pittsurgh, PA). Concentrtion of strch, sucrose, fructose, nd glucose in leves/shoot, trunks, nd roots ws determined with HPLC using modified method sed on Hgidimitriou nd Roper (1994), except tht smple clen up involved pssing filtrte through conditioned C18 Sep-Pk crtridge (Wters Corp., Milford, MA). Crohydrtes were quntified using Breeze system fitted with refrctive index detector (40 ± 1 C) nd Shodex Sc1011 column (Wters Corp.). The moile phse ws 80 o C wter. Using this method, recovery of soritol (internl stndrd) verged pproximtely 95%. Crohydrtes were expressed s concentrtion (mg 100 1 mg), nd on content per orgn sis (concentrtion totl orgn dry weight). Must composition nlysis ws determined within 48 h of hrvest fter storing rndom smple of 30 erries t 3 C. Berries were wrmed to room temperture, crushed, strined, nd the must ws then nlyzed for solule solids, Tle 1. The effect of defoliting tretments on lef re per vine (n = 8) Timing of defolition Tretment Lef re per vine (m 2 ) Berry set Control 0.218 Defolited 0.119 Verison Control 0.273 Defolited 0.140 Pre-hrvest Control 0.264 Defolited 0.139 ph, nd titrtle cidity. Percent solule solids ws determined using portle refrctometer (Fisher Scientific). Must ph ws then mesured using n Accumet temperturecompensted ph meter (Fisher Scientific). Titrtle cidity ws determined ccording to Amerine nd Ough (1988). Totl phenolic, nthocynin, nd flvonol content ws quntified nd expressed s function of the whole erry rther thn only the erry skin. Although recently pulished works hve quntified phenolic content of the skin lone, mny of these ppers hve not ccounted for the confounding fctor of erry size. As whole erries re used in the production of wine, phenolic content of the pressed juice is function of the skin surfce-to-erry volume rtio. The use of whole erries for nlysis is common in other fruits nd other compositionl components of grpe erries. Smples for nlysis of totl phenolics, flvonols, nd nthocynins were prepred from ll remining erries on the clusters following the removl of 30 erries for must nlysis (with fruit from su-smple vines comined). For totl phenolics, rndom smple of pproximtely ⅓ of the remining fruit ws lyophilized, nd then nlyzed in triplicte ccording to Vinson (2002). Smples were prepred for determintion of totl nthocynins nd flvonols y dividing the remining fruit into triplicte replictions. Smples were prepred nd quntified using modifiction of Lees nd Frncis (1971). All dt were sujected to nlysis of vrince with the Mixed Procedure of the SAS softwre (SAS Institute, Cry, NC). If the interction ws significnt, then the sums of squres of the min effect of primry interest nd the interction sums of squres were pooled nd reprtitioned s the sums of squres of the min effect of primry interest within ech level of the other min effect involved in the interction. This procedure ws performed with the SLICE option of the LSMEANS sttement in PROC MIXED. Seprtion of timing mens ws performed with Tukey s HSD (P = 0.05). Person correltion coefficients were determined for the reltionships etween crohydrtes nd phenolics. Prtil defolition of potted De Chunc grpevines generlly ffected oth solule crohydrte concentrtion of vegettive tissues, nd solule crohydrte content per orgn (Tle 2). Trunk crohydrte concentrtion ws not ffected y defolition (dt not shown). Totl non-structurl crohydrte (TNSC) concentrtions in the trunk rnged from 1.7 to 3.8 mg 100 mg 1 t erry set, from 3.8 to 5.4 mg 100 mg 1 t verison, nd from 4.7 to 6.5 mg 100 mg 1 t pre-hrvest. Prtil defolition of vines t erry set decresed glucose concentrtion in the lef/shoot tissue y 30%, fructose concentrtion in the lef/shoot tissue y 20%, fructose concentrtion in the roots y 62%, strch content in the lef/shoot tissue y
VANDEN HEUVEL ET AL. PARTIAL DEFOLIATION EFFECTS ON GRAPEVINES 705 Tle 2.The effect of prtil defolition (~50%) t erry set, verison, nd 7-d pre-hrvest on sucrose, glucose, fructose, strch, nd totl non-structurl crohydrte concentrtion (TNSC) in leves nd roots of potted De Chunc grpevines (n = 8) Lef/shoot Root Timing Content per orgn Content per orgn of defolition Tretment Conc. (mg 100 mg 1 ) z (mg orgn 1 ) y Conc. (mg 100 mg 1 ) (mg orgn 1 ) Sucrose Berry set Control 0.00 0.00 0.18 11.00 Defolited 0.00 0.00 0.11 8.19 P vlue 1.0000 1.0000 0.3838 0.3502 Cn. J. Plnt Sci. Downloded from www.nrcreserchpress.com y 148.251.232.83 on 05/12/18 Verison Control 0.00 0.00 0.16 25.33 Defolited 0.00 0.00 0.02 2.31 P vlue 0.9999 1.0000 0.0080 0.0031 Pre-hrvest Control 0.00 0.00 0.00 0.00 Defolited 0.23 84.8 0.30 66.43 P vlue <0.0001 <0.0001 <0.0001 <0.0001 Glucose Berry set Control 0.70 109.23 0.25 15.97 Defolited 0.49 54.17 0.15 10.01 P vlue 0.0094 0.0570 0.1058 0.2700 Verison Control 0.75 254.28 0.35 52.69 Defolited 0.22 56.49 0.05 4.62 P vlue <0.0001 <0.0001 <0.0001 <0.0001 Pre-hrvest Control 0.98 404.63 0.00 0.00 Defolited 1.01 354.91 0.24 52.05 P vlue 0.8926 0.7567 <0.0001 <0.0001 Fructose Berry set Control 1.56 250.11 0.53 33.96 Defolited 1.24 133.04 0.25 17.50 P vlue 0.0026 0.0135 0.0025 0.1663 Verison Control 0.91 303.37 0.41 61.97 Defolited 0.56 136.05 0.30 24.29 P vlue 0.0013 0.0002 0.0013 <0.0001 Pre-hrvest Control 1.16 481.56 0.30 60.09 Defolited 1.14 398.2 0.37 77.27 P vlue 0.6697 0.4937 0.5124 0.5151 Strch Berry set Control 0.59 96.36 3.63 248.92 Defolited 0.25 27.08 2.55 196.78 P vlue 0.1696 0.0006 0.5228 0.2246 Verison Control 1.70 601.89 9.71 1492.52 Defolited 1.70 482.94 9.92 1366.92 P vlue 0.9673 0.1315 0.6115 0.6911 Pre-hrvest Control 2.85 1244.01 11.77 2829.55 Defolited 2.75 960.22 9.80 2301.38 P vlue 0.6795 0.7756 0.0632 0.7858 TNSC Berry set Control 2.85 455.70 4.56 309.85 Defolited 2.01 214.29 3.08 232.10 P vlue 0.0206 0.0067 0.3289 0.1619 Verison Control 3.38 1157.07 10.6 1632.51 Defolited 2.44 675.48 10.3 1398.13 P vlue 0.0231 0.0035 0.2328 0.4910 Pre-hrvest Control 5.00 2130.20 12.07 2889.64 Defolited 5.01 1789.15 10.67 2497.12 P vlue 0.7562 0.7899 0.1809 0.9879 z Clculted on dry weight sis. y Clculted s concentrtion orgn dry weight.
Cn. J. Plnt Sci. Downloded from www.nrcreserchpress.com y 148.251.232.83 on 05/12/18 706 CANADIAN JOURNAL OF PLANT SCIENCE 72%, with n overll decrese in TNSC in the leves/shoots of 29%. These decreses in crohydrte concentrtions indicte tht the vine ws le to prtilly, ut not fully, compenste for the loss of lef re. At verison, prtil defolition decresed sucrose concentrtion of the roots y 85%, glucose concentrtion of the leves/shoots y 71%, glucose concentrtion of the roots y 86%, fructose concentrtion in the leves/shoots y 39%, fructose concentrtion in the roots y 27%, nd TNSC concentrtion in the leves/shoots y 34%. Prtil defolition of vines pre-hrvest incresed sucrose in the leves/shoots nd roots y 0.23 nd 0.30 mg 100 mg 1, respectively (Tle 2), nd glucose in the root tissue y 0.24 mg 100 mg 1. Strch concentrtion, prticulrly in the roots, ws decresed y defolition pre-hrvest (significnt t P 0.10 ut not P 0.05) (Tle 2), suggesting tht some of the incresed concentrtion of solule sugrs my hve come from strch rekdown. Net cron ssimiltion my hve een sink-limited prior to defolition (Cndolfi-Vsconcelos nd Kolet 1990), or improved light interception y upper leves on the prtilly defolited shoots my hve resulted in incresed net cron ssimiltion. The hypothesis of control vines eing sink-limited throughout this study is supported y previous work on the photosynthetic cpcity nd crohydrte concentrtion of leves of greenhouse-grown Chrdonny vines with nd without fruit (Chumont et l. 1994). Time of prtil defolition significntly ffected production of flvonols, nthocynins, nd totl phenolics y the grpe erries (Fig. 1). Vines defolited t erry set produced fruit 14% lower in phenolics nd 24% lower in flvonols compred with the control. Flvonol ccumultion my strt s erly s loom time (Keller nd Hrzdin 1998). Anthocynin production hs lso een demonstrted to e ffected y light interception of the cluster t this erly stge of erry growth (Dokoozlin nd Kliewer 1996). Totl flvonols nd phenolics were not ffected y prtil defolition t verison or pre-hrvest. The fruit re reported to e very powerful sink during ripening (Cndolfi- Vsconcelos et l. 1994); however, if cron ws re-routed due to defolition t verison in this experiment, it did not result in incresed production of phenolics or flvonols. Dokoozlin nd Kliewer (1996) lso reported tht light environment of the cluster t verison did not hve lrge effect on nthocynin development. Totl nthocynin concentrtion in the erries ws unffected y defolition t either erry set or verison, ut ws incresed y pproximtely 39% when defolition ws pplied 7 d pre-hrvest (Fig. 1B). Hunter et l. (1991) noted n increse of pproximtely 10% in nthocynin concentrtion when prtil defolition of Cernet Suvignon ws pplied t verison compred with the control, nd n increse of pproximtely 30% compred with vines defolited t erry set, lthough those results my e ttriuted to improved light interception y clusters. The results presented here cnnot e ttriuted to improved light interception y the clusters, s these vines were smll, well spced (minimum of 0.5 m etween vines) on the greenhouse ench, shoots were verticlly stked, nd ech cluster hd full lef immeditely ove it. Totl flvonols (mg/g frwt.) Totl nthocynins (mg/g frwt.) Totl phenolics (mg GAE/g frwt.) 0.25 0.20 0.15 0.10 0.05 0.00 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 2.5 2.0 1.5 1.0 0.5 0.0 Con Bset Ver Hr Time of Defolition Hunter et l. (1991) suggested tht the higher pigment ccumultion of vines sujected to defolition t verison my hve resulted from incresed vilility of precursors derived from higher photosynthetic ctivity of leves. Dt presented here support tht hypothesis, s prtil defolition Fig 1. The effect of prtil defolition of potted De Chunc grpevines on (A) totl flvonol concentrtion, (B) totl nthocynin concentrtion, nd (C) totl phenolic concentrtion of erries. Concentrtions re expressed in mg g 1 fresh weight. Arevitions for timing of prtil defolition: Con = control (not defolited); Bset = defolited t erry set, Ver = defolited t verison, Hr = defolited pre-hrvest. Men seprtion mong timings y Tukeys HSD (P = 0.05). P vlues from the ANOVA were < 0.0001 for totl flvonols, < 0.0001 for totl nthocynins, nd < 0.0001 for totl phenolics. A C B
VANDEN HEUVEL ET AL. PARTIAL DEFOLIATION EFFECTS ON GRAPEVINES 707 Cn. J. Plnt Sci. Downloded from www.nrcreserchpress.com y 148.251.232.83 on 05/12/18 pre-hrvest incresed concentrtions of sucrose in the leves nd roots, nd glucose in the roots (Tle 2). The stress of reduced lef re on the vines likely resulted in either incresed net cron ssimiltion of remining leves, nd/or incresed rekdown of strch into solule crohydrtes, possily resulting in incresed cron vilility for formtion of nthocynins. Reduced phenolics content mesured t hrvest in the vines defolited erlier in the seson my e due to delyed mturtion (Bureu et l. 2000). However, the lck of long growing seson in mny coolclimte growing res my result in fruit from vines with reduced crohydrte vilility for phenolic production eing hrvested prior to pek mturity. Anthocynin ccumultion in erry skins is ffected y vrious fctors (light, ethephon, nd sucrose ppliction) differently thn totl phenolics ccumultion (Rouelkis- Angelkis nd Kliewer 1986), suggesting tht those two pools of compounds re independently regulted in grpe erry skins. There is no reson, however, to elieve tht the regultory mechnisms involved re limited only to the erry environment, s dt presented here demonstrte tht prtil defolition ffects production of nthocynins differently thn totl phenolics. Cndolfi-Vsconcelos et l. (1994) showed tht greter retrnsloction rte of cron to fruit occurred with defolition during the ripening period. In our experiment, only nthocynin concentrtion ws incresed when defolition ws pplied prior to hrvest (Fig. 1). The concentrtion of solule solids in the erries t hrvest ws ffected y timing of defolition (P = 0.004). Prtil defolition t erry set nd t verison reduced totl solule solid concentrtion to 15.2 nd 16.2 Brix, respectively, while prtil defolition pre-hrvest did not significntly ffect totl solule solids (19.0 Brix) compred with the control (18.3 Brix). Titrtle cidity ws incresed to 3.0 g L 1 in vines sujected to prtil defolition t erry set compred to the control (2.6 g L 1 ) (P = 0.012), while vines defolited lter in the seson were unffected. ph of the must ws unffected y timing of defolition (P = 0.470), nd verged 3.2 in ll tretments. No cler reltionship existed etween totl solule solids nd phenolic concentrtion. Totl nthocynins were most positively correlted with lef TNSC (r = 0.7366; P 0.0027), ut were lso positively correlted with trunk TNSC (r = 0.6448; P 0.0128) nd root TNSC (r = 0.5731; P 0.0321). The highest correltion etween totl nthocynins nd crohydrte ws with lef strch (r = 0.8139; P 0.0004). Correltions etween totl nthocynins nd lef sucrose nd glucose concentrtions were lso positive nd significnt; however, there ws no reltionship etween totl nthocynin production nd fructose concentrtion in the leves. Totl flvonols were significntly correlted with lef TNSC (r = 0.5304; P 0.0045), trunk TNSC (r = 0.6043; P 0.0132), nd root TNSC (r = 0.6320; P 0.0086), nd gin the most significnt correltions were with strch, prticulrly in the roots (r = 0.6258; P 0.0095). Totl flvonols were not significntly correlted with solule crohydrte concentrtions in the leves, trunk, or roots. These positive correltions indicte tht fctors tht ffect production nd lloction of nonstructurl crohydrtes (such s improved photosynthesis) my lso ffect production of totl nthocynins nd flvonols. Totl phenolics were not significntly correlted with ny of the crohydrtes in the leves, roots, or trunk, indicting tht not ll phenolic compounds my e ffected y plnt cron vilility t these phenologicl stges. Dt presented here support the suggestions of previous workers (Hunter et l. 1991; Price et l. 1995; Bureu et l. 2000) tht incresed production of phenolic compounds is linked to cron production nd prtitioning. This positive reltionship ws most pprent when prtil defolition ws pplied to the vines t erry set. At this time, concentrtions of glucose nd fructose in the lef/shoot tissue were significntly reduced. These vines produced fruit t hrvest tht hd lower totl flvonols nd lower totl phenolics. Dokoozlin nd Kliewer (1996) demonstrted tht, lthough pigments do not ccumulte during stges I nd II of erry growth, exposure to light during these periods is necessry for mximum pigment production during stge III; crohydrtes my lso e required during these erly periods of erry growth for mximum phenolic production. Vines prtilly defolited pre-hrvest produced fruit with incresed nthocynins, nd hd incresed sucrose in the leves nd roots, nd incresed glucose in the roots. Further experimenttion is required in order to elucidte the reltionship etween whole-vine cron vilility nd development of secondry metolites in erries. Understnding the role of cron vilility in development of phenolic compounds will llow for future reserch into trgeted production prctices to increse their concentrtion in grpes nd grpe products, which will e helpful to growers in regions with shorter growing sesons. We thnk Amer Teixeir for her technicl ssistnce, nd Jon Dvenport for her review of this rticle. Amerine, M. A. nd Ough, C. S. 1988. Methods for nlysis of musts nd wines. Wiley & Sons, Toronto, ON. Bureu, S. M., Bumes, R. L. nd Rzungles, A. J. 2000. Effects of vine or unch shding on the glycosylted flvor precursors in grpes of Vitis vinifer L. Cv. Syrh. J. Agric. Food Chem. 48: 1290 1297. Cndolfi-Vsconcelos, M. C. nd Kolet, W. 1990. Yield, fruit qulity, ud fertility nd strch reserves on the wood s function of lef removl in Vitis vinifer Evidence of compenstion nd stress recovering. Vitis 29: 199 221. Cndolfi-Vsconcelos, M. C. nd Kolet, W. 1991. Influence of prtil defolition on gs exchnge prmeters nd chlorophyll content of field-grown grpevines. Mechnisms nd limittions of the compenstion cpcity. Vitis 30: 129 141. Cndolfi-Vsconcelos, M. C., Cndolfi, M. P. nd Kolet, W. 1994. Retrnsloction of cron reserves from the woody storge tissues into the fruit s response to defolition stress during the ripening period in Vitis vinifer L. Plnt 192: 567 573. Chumont, M., Morot-Gudry, J. F. nd Foyer, C. H. 1994. Sesonl nd diurnl chnges in photosynthesis nd cron prtitioning in Vitis vinifer leves in vines with nd without fruit. J. Exp. Bot. 45: 1235 1243. Dokoozlin, N. K. nd Kliewer, W. M. 1996. Influence of light on grpe erry growth nd composition vries during fruit development. J. Am. Soc. Hortic. Sci. 121: 869 874.
Cn. J. Plnt Sci. Downloded from www.nrcreserchpress.com y 148.251.232.83 on 05/12/18 708 CANADIAN JOURNAL OF PLANT SCIENCE Hgidimitriou, M. nd Roper, T. R. 1994. Sesonl chnges in nonstructurl crohydrtes in crnerry. J. Am. Soc. Hortic. Sci. 119: 1029 1033. Hunter, J. J., De Villiers, O. T. nd Wtts, J. E. 1991. The effect of prtil defolition on qulity chrcteristics of Vitis vinifer L. cv. Cernet Suvignon grpes. II. Skin color, skin sugr, nd wine qulity. Am. J. Enol. Vitic. 42: 13 18. Keller, M. nd Hrzdin, G. 1998. Interction of nitrogen vilility during loom nd light intensity during verison. II. Effects on nthocynin nd phenolics development during grpe ripening. Am. J. Enol. Vitic. 49: 341 349. Lees, D. H. nd Frncis, F. J. 1971. Quntittive methods for nthocynins, 6. Flvonols nd nthocynins in crnerries. J. Food Sci. 36: 1056 1060. Price, S. F., Breen, P. J., Vlldo, M. nd Wtson, B. T. 1995. Cluster sun exposure nd quercetin in Pinot noir grpes nd wine. Am. J. Enol. Vitic. 46: 187 194. Rouelkis-Angelkis, K. A. nd Kliewer, W. M. 1986. Effects of exogenous fctors on phenyllnine mmoni-lyse ctivity nd ccumultion of nthocynins nd totl phenolics in grpe erries. Am. J. Enol. Vitic. 37: 275 280. Vinson, J. 2002. Mesuring quntity of polyphenols in foods nd everges. Methods in Enzymology 335: 103 114.
Cn. J. Plnt Sci. Downloded from www.nrcreserchpress.com y 148.251.232.83 on 05/12/18 This rticle hs een cited y: 1. Ntli Boeic, Stefno Poni, Ghisline Hilert, Christel Renud, Eric Gomà s, Serge Delrot, Zhnwu Di. 2015. Differentil responses of sugr, orgnic cids nd nthocynins to source-sink modultion in Cernet Suvignon nd Sngiovese grpevines. Frontiers in Plnt Science 06.. [Crossref]