In apple production, the incidence of hailstorms during the growing season is high in some regions. The damage to leaves caused by hail decreases photosynthesis, causes damage to the fruit during the growing season (Tartachnyk and Blanke, 2002), and is an infection entry point for diseases such as fireblight. To protect the assimilation area and ensure high fruit quality, apple trees are increasingly grown under hail nets. The nets used for protection against hail represent an additional investment (Stampar et al., 2002).
Several different types of nets are used to protect fruit crops against hail. In European fruit orchards, most of the hail nets used are black, some white, and since 2007 colored (red and green) (Blanke, 2007) hail nets have also become available. However, on a sunny summer day, light intensities under the hail nets are lower compared with the outside control (Solomakhin and Blanke, 2008). Black hail nets greatly reduce incident solar light, and they may have a negative impact on fruit development and on the final color of fruit (Guerrero et al., 2002; Stampar et al., 2002). Fruit grown under these hail nets suffers from lower fruit quality, i.e., less (red) coloration, less firm fruit flesh, less sugar, and therefore less taste (Funke and Blanke, 2005). White and colored hail nets reduced light less than black hail nets and the black hail nets decreased fruit coloration in the poorly colored apple cultivar Pinova more than white and colored (Blanke, 2007).
Reflective white woven cloth placed in the grass alleys between the tree rows under the hail net can overcome these shortcomings (Funke and Blanke, 2005). Relative to the grassed control, two tested reflective cloths increased the percentage of Class I fruit with greater than 25% coloration by 12% (from 82% to 94%) without hail nets and by 23% (from 69% to 89%) under hail nets (Solomakhin and Blanke, 2007). Reflective foil appears to be a method for increasing red skin coloration in ‘Gala’ apples (Layne et al., 2002). Glenn and Puterka (2007) reported that the use of reflective, aluminized plastic film increased fruit red color and that the use of reflective, particle films increased average fruit weight. These mulches reflect solar radiation into the tree canopy and may increase canopy absorption of photosynthetic photon flux by up to 40% (Green et al., 1995). This additional light is useful for both photosynthesis and anthocyanin pigment production (Jakopic et al., 2007; Layne et al., 2002). Although the red color of apple fruit is determined by the concentration of anthocyanin in the fruit peel, it is also affected by concentrations of other pigments like flavonoids, chlorophyll, and carotenoids (Lancaster, 1992). A variety of red colors are produced by cyanidin glycosides copigmented with flavonols and other compounds (Lancaster, 1992).
Apple fruit is known to be rich in flavonoid compounds such as anthocyanins, dihydrochalcones, quarcetin 3-glycosides, catechin, and epicatechin and its polymers, which are mainly located in the skin (Awad et al., 2001; Lata et al., 2009). Polyphenols are a major antioxidant in apples. Antioxidants scavenge and neutralize free radicals, which in turn play a role in the onset of cardiovascular disease and cancer (Biedrzycka and Amarowicz, 2008). The main anthocyanin pigment is cyanidin 3-galactoside, which can scavenge superoxide radicals in an in vitro system (Yamasaki et al., 1996).
One factor among those that may affect the concentration of phenolic components in apples is light exposure (Awad et al., 2000). Flavonoid and chlorogenic acid contents in fruit vary greatly among cultivars, orchards, positions within the tree, and even within individual fruit (Awad et al., 2000).
Jakopic et al. (2007) demonstrated that light use of ‘Fuji’ apple trees grown under hail nets could be improved using reflective groundcover, resulting in better fruit coloration. The objective of the present work was to evaluate the effect of netting and reflective foil on the contents of individual phenolics compounds. We measured changes in the concentrations of four cyanidin glycosides, seven quercetin glycosides and aglycone quercetin as well as catechin, epicatechin, and chlorogenic acid as a result of the lighting changes created by hail nets and reflective foil.
Awad, M.A. & de Jager, A. 2002 Formation of flavonoids, especially anthocyanin and chlorogenic acid in ‘Jonagold’ apple skin: Influences of growth regulators and fruit maturity Sci. Hort. 93 257 266
Awad, M.A. , de Jager, A. , Dekker, M. & Jongen, W.M.F. 2001 Formation of flavonoids and chlorogenic acid in apples as affected by crop load Sci. Hort. 91 227 237
Awad, M.A. , de Jager, A. & van Westing, L.M. 2000 Flavonoid and chlorogenic acid levels in apple fruit: Characterization of variation Sci. Hort. 83 249 263
Blanke, M.M. 2007 Farbige Hagelnetze: Ihre Netzstruktur sowie Licht- und UV-Durchlässigkeit bestimmen die Ausfärbung der Apfelfrüchte Erwerbs-Obstbau 49 127 139
Escarpa, A. & Gonzalez, M.C. 1998 High-performance liquid chromatography with diode-array detection for the determination of phenolic compounds in peel and pulp from different apple varieties J. Chromatography 823 331 337
Felicetti, D.A. & Schrader, L.E. 2009 Changes in pigment concentrations associated with sunburn browning of five apple cultivars. II. Phenolics Plant. Sci. 176 84 89
Funke, K. & Blanke, M.M. 2005 Can reflective ground cover enhance fruit quality and colouration? J. Food Agr. Environ. 3 203 206
Glenn, D.M. & Puterka, G.J. 2007 The use of plastic films and sprayable reflective particle films to increase light penetration in apple canopies and improve apple color and weight HortScience 42 91 96
Green, S.R. , McNaughton, K.G. , Greer, D.H. & McLeod, D.J. 1995 Measurement of the increased PAR and net all-wave radiation absorption by an apple tree caused by applying a reflective ground covering Agr. For. Meteorol. 76 163 183
Guerrero, V.M. , Orozco, J.A. , Romo, A. , Gardea, A.A. , Molina, F.J. , Sastré, B. & Martinez, J.J. 2002 The effect of hail nets and ethephon on color development of ‘Redchief Delicious’ apple fruit in the highlands of Chihuahua, Mexico J. Am. Pomol. Soc. 56 132 135
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Guerrero, V.M. Orozco, J.A. Romo, A. Gardea, A.A. Molina, F.J. Sastré, B. Martinez, J.J. 2002 The effect of hail nets and ethephon on color development of ‘Redchief Delicious’ apple fruit in the highlands of Chihuahua, MexicoJ. Am. Pomol. Soc. 56 132 135
Jakopic, J. , Veberic, R. & Stampar, F. 2007 The effect of reflective foil and hail nets on the lighting, color and anthocyanins of ‘Fuji’ apple Sci. Hort. 115 40 46
Ju, Z. , Duan, Y. & Ju, Z. 1999 Effects of covering the orchard floor with reflecting films on pigment accumulation and fruit coloration in ‘Fuji’ apples Sci. Hort. 82 47 56
Lata, B. , Trampczynska, A. & Paczesna, J. 2009 Cultivar variation in apple peel and whole fruit phenolic composition Sci. Hort. 121 176 181
Layne, D.R. , Jiang, Z. & Rushing, J.W. 2002 The influence of reflective film and ReTain on red skin coloration and maturity of ‘Gala’ apples HortTechnology 12 640 645
Marks, S.C. , Mullen, W. & Crozier, A. 2007 Flavonoid and chlorogenic acid profiles of English cider apples J. Sci. Food Agr. 87 719 728
Reay, P.F. & Lancaster, J.E. 2001 Accumulation of anthocyanins and quercetin glycosides in ‘Gala’ and ‘Royal Gala’ apple fruit skin with UV-B-visible irradiation: Modifying effects of fruit maturity, fruit side, and temperature Sci. Hort. 90 57 68
Singleton, V.L. & Rossi J.A. Jr 1965 Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents Amer. J. Enol. Viticult. 16 144 158
Solomakhin, A. & Blanke, M.M. 2008 Coloured hailnets alter light transmission, spectra and phytochrome, as well as vegetative growth, leaf chlorophyll and photosynthesis and reduce flower induction of apple Plant Growth Regulat. 56 211 218
Solomakhin, A.A. & Blanke, M.M. 2007 Overcoming adverse effects of hailnets on fruit quality and microclimate in an apple orchard J. Sci. Food Agr. 87 2625 2637
Stampar, F. , Veberic, R. , Zadravec, P. , Hudina, M. , Usenik, V. , Solar, A. & Osterc, G. 2002 Yield and fruit quality of apples cv. ‘Jonagold’ under hail protection nets Gartenbauwissenschaft 67 205 210
Tartachnyk, I. & Blanke, M.M. 2002 Effect of mechanically-simulated hail on photosynthesis, dark respiration and transpiration of apple leaves Environ. Exp. Bot. 48 169 175
Veberic, R. , Zadravec, P. & Stampar, F. 2007 Fruit quality of ‘Fuji’ apple (Malus domestica Borkh.) strains J. Sci. Food Agr. 87 593 599
Yamasaki, H. , Uefuji, H. & Sakihama, Y. 1996 Bleaching of the red anthocyanin induced by superoxide radical Arch. Biochem. Biophys. 332 183 186