Chlorophylls, carotenoids and anthocyanin concentrations in the skin of ‘Gala’ apples during maturation and the influence of foliar applications of nitrogen and magnesium

Abstract

GalaÏ apple fruit were sampled over two growing seasons, to determine the e †ects of maturation, and of foliar applications of nitrogen and magnesium on pigment concentrations and colour development in maturing fruit. Treatments of urea and/or magnesium sulphate sprays were applied to the trees in a commercial orchard. The chlorophyll, carotenoid and anthocyanin concentrations in the fruit skin were determined for both the blush and back sides over 15 harvests in 1991È1992. In 1990È1991, the skin chlorophyll concentrations were determined only for the back side of the fruit. The fruit nitrogen, magnesium and sulphur concentrations were determined near maturity. The concentrations of chlorophyll and carotenoids in apple skin decreased from the Ðrst harvest in 1991È1992 as the fresh weight increased from 12 g, 40 days from Ñowering to 140 g, 138 days from Ñowering. Chlorophyll continued to decrease whereas carotenoid concentrations increased after 138 days and until at least 153 days. The average skin chlorophyll and carotenoid concentrations were higher on the blush side of the fruit than on the back. The total chlorophyll per fruit increased from the Ðrst harvest to a peak about 70 days after Ñowering in 1990È1991 and then decreased over the remainder of the period studied. The time of this peak was about 40 days later in the 1991È1992 season compared with the 1990È1991 season. The total carotenoid increased up to about 50 days after Ñowering in 1991È1992, Ñuctuated and then decreased up to 138 days when the amount increased again. The ratio of carotenoids to chlorophylls was highest for the Ðrst three harvests, Ñuctuated somewhat up to c 138 days after Ñowering after which the ratio increased rapidly. The anthocyanin concentrations were low and Ñuctuated up to 130 days from Ñowering and then increased markedly only on the blush side at 130 days, about 14 days before the carotenoids started to increase. The treatment of the tree canopy with urea increased the chlorophyll and carotenoid concentrations in the fruit skin, 14È20 days after the Ðrst application until after maturity, more so on the blush side than on the back side. These increased concentrations were maintained up to the harvest after which carotenoid concentrations increased. The urea treatment lessened the increase of anthocyanin concentrations in the blush side skin of the fruit, at maturity. At maturity, the nitrogen concentration of fruit from urea treated trees was higher than those from untreated trees. The magnesium sulphate treatment of the canopy increased the chlorophyll and carotenoid concentration on the back of the fruit within 20È30 days from commencing spraying. The "ground colourÏ scores for the back sides of the fruit (used for fruit picking and grading) were greener for the urea treated fruit and reached an acceptable score about two weeks later than the untreated fruit.

Minimal nitrogen and water use in horticulture: Effects on quality and content of selected nutrients

“…Limited N could also result in higher phenylalanine availability for flavonoid synthesis, as the decline in protein synthesis resulting from a decrease in cell growth and metabolism (Sato, Nakayama, & Shigeta, 1996) would free up amino acid availability. In addition, N-stressed plants have lower chlorophyll levels and starch accumulation in photosynthetic membranes, leading to greater sensitivity to light, which could be compensated for by higher flavonol production in photosynthetic tissues (Guidi et al, 1998;Reay et al, 1998).…”

“…Leaching of N and phosphorous (P) due to excessive applications in agriculture are widely considered the main cause of eutrophication in fresh and salt water supplies throughout the world (Burt et al, 2009b;Erhart, Feichtinger, & Hart, 2007). Several practices have recently been implemented to try to reduce ground water pollution by N, such as split applications (Drake, Raese, & Smith, 2002), target timing (Tagliavini & Marangoni, 2002;Wade, Holzapfel, Degaris, Williams, & Keller, 2004), integrated production (Ganeshamurthy et al, 2004;Peck et al, 2006), fertigation (Neilsen, Neilsen, & Herbert, 2009;Raina, Thakur, Shashi, & Spehia, 2005), best management practices (Alva, Paramasivam, Fares, Obreza, & Schumann, 2006;, foliar applications (Dong, Neilsen, Neilsen, & Fuchigami, 2005;Reay, Fletcher, & Thomas 1998), and varying the type of N sources (El-Boray, Mostafa, Iraqi, & Mohamed, 2006;Erhart et al, 2007;Racskó et al, 2008;Rosen & Allan, 2007). While not all of the above mentioned practices reduced the total amount of N applied; all were effective in limiting pollution by increasing plant N use efficiency.…”

“…Furthermore, high N availability also affected wine quality by reducing total phenolic, anthocyanin and flavonol contents (Table 1) (Keller & Hrazdina, 1998). Significant N stress (zero application), or N applications that significantly depressed yield resulted in the highest content of phenolic compounds in Chinese cabbage (Zhu, Lin, Jin, Zhang, & Fang, 2009), broccoli heads (Jones, Imsic, Franz, & Tomkins, 2007), apple (Reay et al, 1998), basil (Nguyen & Niemeyer, 2008), pak choi (Zhao, Carey, Young, Wang, & Iwamoto, 2007), lettuce (Coria-Cayupan, Sanchez de Pinto, & Nazareno, 2009), tomato (Be'nard et al, 2009)., olives (Fernandez-Escobar et al, 2006), and strawberries (Anttonen, Hoppula, Nestby, Verheul, & Karjalainen, 2006) (Table 1). Polyphenol concentration declined as N availability increased in olives, diminishing the resulting oil quality (Table 1) (Fernandez-Escobar et al, 2006;Morales-Sillero et al, 2008).…”

“…Applied N at the highest rate generally resulted in higher carotenoids in apples (Reay et al, 1998), carrot (Hochmuth, Brecht, & Bassett, 1999), kale (Kopsell, Kopsell, & Curran-Celentaro, 2007), while mid-range applications were most effective in tomatoes (Dorais, 2007;Simonne, Fuzere, Simonne, Hochmuth, & Marshall, 2007), lettuce (CoriaCayupan et al, 2009) and watercress (Kopsell, Barickman, Sams, & McElroy, 2007) (Table 1). A decrease in NO À 3 from 12 to 4 mM/plant resulted in a slight reduction in tomato yield (7.5%), and an increase in fruit eating quality as determined by lower fruit acidity and higher soluble sugars (Be'nard et al, 2009) Bryant et al, 1983).…”

Interactive effects of salicylic acid and silicon on oxidative damage and antioxidant activity in spinach (Spinacia oleracea L. cv. Matador) grown under boron toxicity and salinity

“…The extracts were filtered and centrifuged at 2,500g. The absorbance of the supernatants was measured at 530 and 657 nm, and anthocyanin concentrations were calculated using the (A = A 530 -1/3A 657 ) equation (Reay et al 1998). …”