BARBAGALLO, Maria Gabriella

Downey, MO

SCAFIDI, Pietro

Archivio istituzionale della ricerca - Università di Palermo

INFLUENCE OF LIGHT EXCLUSION ON ANTHOCYANIN COMPOSITION IN ‘CABERNET SAUVIGNON’1   Pietro SCAFIDI1, Maria Gabriella BARBAGALLO1, Mark O. DOWNEY2 1 University of Palermo – Dipartimento di Colture Arboree – Viale delle Scienze 11 - 90128 Palermo, I. E-mail: p.scafidi@unipa.it  2 Department of Primary Industries Victoria, PO Box 905, Mildura, Vic. 3502, AUS.  Key words: artificial bunch shading, anthocyanin composition and accumulation.  1. INTRODUCTION In previous studies, the effect of bunch shading has been investigated by using of opaque polypropylene boxes (Downey et al., 2004; 2007) from fruit set to harvest. These boxes did not significantly alter berry development or ripening. Artificially shaded bunches had similar levels of total anthocyanins and tannins in the skins compared to sun-exposed fruit, although the composition of both anthocyanins and tannins were changed (Downey et al., 2004). In this study, differently from previous studies, the influence of artificial shading by applying of boxes over three different developmental stages was evaluated in ‘Cabernet sauvignon’.  2. MATERIALS AND METHODS  2.1. Field experiments The study was carried out in a E-W orientated ‘Cabernet sauvignon’ vineyard, located in Mildura, Australia (34°25’ 28.70” S/ 142° 17’ 02.02” E), trained to a two-wire vertical trellis. The boxes, designed by Downey et al. (2004) maintain airflow, exclude light and minimise changes in temperature and humidity, were made from a polypropylene sheet (0.6 mm), and were white outside and black inside. The dimensions were 0,25x0,20x010 m. Boxes were applied to bunches over three different developmental stages: 1) from fruit-set to harvest (BFSH); 2) from fruit-set to veraison (BFSV): 3) from veraison of exposed bunches to harvest (BVH). Each trial was randomly replicated three times on three adjacent rows. All vines were defoliated in the bunch zone after fruit set to nullify the shading by leaves and boxed treatments were compared to the exposed fruit. 2.1.1 Berry sampling and analysis Five bunches were sampled from each field replicate. Berries were removed and 30 berries were randomly sampled and weighed. For each 30-berry sample, the flesh was separated from the skins and then was crushed, centrifuged and juice total soluble solids (°Brix) measured using a refractometer. Each 30-berry sample represented one field replicate. The skin weight of each sub-samples was recorded and then, skins were ground to a fine powder in liquid nitrogen, and their total anthocyanin concentration and anthocyanin                                                1 QUAD. VITIC. ENOL. UNIV. TORINO, 31, 2009-2010 pattern of accumulation were determined by HPLC (Downey et al., 2007; Downey, Rochfort, 2008).  3. RESULTS AND DISCUSSION The berries boxed at fruit-set had delayed growth and ripening. When exposed bunches were fully coloured (14 January), boxed clusters had only 20 % of berries coloured. On February 4, the percentage of coloured berries in the boxed clusters (BFSH: 93 % BVH: 91 %) was still significantly lower than that of exposed berries. Berries, boxed until veraison (14 January) and exposed after this phenological stage, stopped their growth, while at harvest no difference in berry weight was found between the other treatments (tab. 1). It is uncertain what the mechanism for this sunlight shock would be.  Tab. 1 -  Berry weight (g) during ripening. Values represent mean ± SE (n=3).  Treatment 16/12 14/01 04/02 25/02 Exposed 0.450.03 0.720.02 1.040.07 1.04 0.01 BFSH 0.380.02 0.530.02 0.820.02 1.03 0.02 BFSV 0.380.02 0.530.02 0.890.03 0.860.08 BVH 0.450.03 0.720.02 0.99 0.05 1.120.03  At harvest similar values were found in total soluble solids concentration among treatments, except for the grapes shaded from veraison to harvest (BVH) ( 2). Sugar accumulation is independent from bunch shading, being due to photosynthetic activity of leaves, as previously reported by Haselgrove et al. (2000) and Downey et al. (2004).  Tab. 2 - Total soluble solids (°Brix) during ripening. Values represent mean ± SE (n=3). Treatment 14/01 04/02 25/02 Exposed 12.300.93 18.100.21 22.950.18 BFSH 9.670.47 16.530.50 23.030.24 BFSV 9.670.47 18.330.37 23.630.19 BVH 12.300.93 16.600.40 21.300.35  Bunch shading delayed anthocyanin accumulation, as already found by Dokoozlian and Kliewer (1996), Barbagallo et al. (2007), Chorti et al. (2010). Light was crucial for anthocyanin synthesis from veraison, but not before this stage (tab. 3).   Tab. 3 - Total skin anthocyanins (mg g-1 of skin)during ripening. Values represent mean ± SE (n=3).  Treatment 16/12 14/01 04/02 25/02 Exposed 0.080.01 0.800.21 2.470.26 3.480.13 BFSH 0.070.01 0.180.02 0.840.05 2.110.17 BFSV 0.070.01 0.180.02 3.040.73 4.570.52 BVH 0.080.01 0.800.21 1.080.19 1.600.22  However, berries shaded from fruit set to harvest also produced anthocyanins, so light was not the unique factor affecting anthocyanin biosynthesis, consistent with the observations of Downey et al. (2004). At harvest (25 February), concentration (mg g-1 of skin) of non-acylated anthocyanins was higher in the skin of berries exposed after veraison (Exposed, BFSV). In these treatments, malvidin-3-glucoside was lower, while delphinidin-3-glucoside and petunidin-3-glucoside were higher, indicating a decrease of the methylating process. The higher content of acylated anthocyanins in boxed berries was due to a higher level of acetyl-glucoside anthocyanins (tab. 4). The shift in hydroxylation pattern with shading reported by Downey et al. (2004) was not observed in ‘Cabernet sauvignon’  (tab. 4).  Tab. 4 - Anthocyanin composition at harvest (25/02/2008) expressed as %  Values represent mean ± SE (n=3)  Treatment Non-acylated Glucoside 3’-hydroxylated 3’,5’-hydroxylated Acylated  glucoside Acetyl glucoside Exposed 56.60.33 8.50.16 91.50.16 43.40.55 31.70.37 BFSH 47.70.33 5.60.19 94.40.19 52.30.37 41.00.11 BFSV 58.10.26 9.50.25 90.50.25 41.90.39 32.10.23 BVH 45.31.47 6.60.35 93.40.35 54.71.52 38.90.76  4. CONCLUSION Bunch shading delayed ripening and reduced anthocyanin concentration (Dokoozlian, Kliewer, 1996). Light was decisive from veraison for anthocyanin accumulation. In other plant species, eg. apple and petunia, where light is essential for anthocyanin accumulation; tissues grown in the dark do not accumulate anthocyanins (Dong et al., 1998, Katz, Weiss, 1999). In our trial in the absence of light, there was an accumulation of anthocyanins.We concluded that light was not the only determining factor for anthocyanin accumulation in ‘Cabernet sauvignon’.  Bunch shading after veraison (BVH) reduced anthocyanins synthesis (Barbagallo et al., 2007; Chorti et al., 2010). As found by Takeda et al. (1988), after anthocyanin synthesis began, light was important for holding maximum activity of enzymes involved in the production of these compounds. The light conditions after veraison changed anthocyanin pattern. The light exclusion in the last stage of ripening caused esterification processes that led to the production of the acetate form, as reported by Ristic et al. (2007) in ‘Shiraz’.  Abstract The aim of this study was to determine how artificial shading influenced berry development and anthocyanin accumulation in ‘Cabernet sauvignon’. Opaque polypropylene boxes were applied to grape bunches over three different developmental stages. The vines were defoliated in the bunch zone to nullify the shading by leaves. Bunch shading before veraison delayed growth and ripening. Light exposure after veraison influenced anthocyanin components and pattern.   Literature cited Barbagallo M.G., Grippi O., Scafidi P., Lino T. - 2007 - Effetti delle modifiche artificiali del microclima sulla qualità dell’uva della cv Pinot Nero. Quad. Vitic. Enol. Univ. Torino, 29, 125-140. Chorti E., Guidoni S., Ferrandino A., Novello V. – 2010- Effect of different cluster sunlight exposure levels on ripening and anthocyanin accumulation in Nebbiolo grapes. Am. J. Enol. Vitic., 61,  23-30. Dokoozlian N.K., Kliewer. W.M. – 1996 – Influence of light on grape berry growth and composition varies during fruit development. Amer. J. Soc. Hort. Sci. 121, 869-874. Dong Y.H., Beuning L., Davies K., Mitra D., Morris B. and Kootstra A. - 1998 – Expression of pigmentation genes and photo-regulation of anthocyanin biosynthesis in developing Royal Gala apple flowers. Aust J. Plant Phys, 25, 245-252. Downey M.O., Harvey J.S., Simon S.P. – 2004 - The effect of bunch shading on berry development and flavonoid accumulation in Shiraz grape. Australian J. of Grape and Wine Research, 10, 55-73. Downey M.O., Mazza M., Kristic M.P. – 2007 – Development of a stable extract for anthocyanins and flavonols from grape skin. Am. J. Enol. Vitic., 58, , 358 – 364. Downey M.O., Rochfort S. – 2008 – Simultaneous separation by reversed-phase high-performance liquid chromatography and mass spectral identification of anthocyanins and flavonols in Shiraz grape skin. J. Chromatog. A., 1201, 43-47.   Haselgrove L., Botting D., Van Heeswijck R., HǾj P.B., Dry P.R., Ford C., Iland P.G. – 2000 – Canopy microclimate and berry composition: the effect of bunch exposure on the phenolic composition of Vitis Vinifera L. cv Shiraz grape berries. Aust J. of  Grape and Wine Research., 6, 141 –149. Katz A., Weiss D. – 1999 – Light regulation of anthocyanin accumulation and chalcone synthase gene expression in petunia flowers. Israel J. Plant Sci., 47, 225-229. Ristic R., Downey M.O., Iland P.G., Bindon K., Francis I.L, Herderich M., Robinson S.P. - 2007 – Exclusion of sunlight from Shiraz grapes alters wine colour, tannin and sensory properties. Australian  J. of  Grape and Wine Reserch, 13, 53-65. Takeda K., Fisher D., Griesebach H. – 1988 – Anthocyanin composition of Sinapis alba, light induction of enzymes and biosynthesis. Phytochem., 27, 1351-1353.  

Influence of light exclusion on anthocyanin composition in "Cabernet Sauvignon"

https://iris.unipa.it/retrieve/handle/10447/62104/40320/INFLUENCE%20OF%20LIGHT%20EXCLUSION%20ON%20ANTHOCYANIN%20COMPOSITION%20IN%20CABERNET%20SAUVIGNON.pdf

Influence of light exclusion on anthocyanin composition in "Cabernet Sauvignon"

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