Pigment chemistry and colour of Pelargonium flowers

• Published in: Phytochemistry (Oxford) 1998-02, Vol.47 (3), p.355-361
• Main Authors: Mitchell, Kevin A., Markham, Kenneth R., Boase, Murray R.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Metabolism; Nitrogen metabolism and other ones (excepting carbon metabolism); Nutrition. Photosynthesis. Respiration. Metabolism; Plant physiology and development; Storage and secretion, pigments, phytochrome
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/S0031-9422(97)00595-5

The major factors responsible for colour variation in a range of Pelargonium species and cultivars were shown to be the types and relative levels of pigments present. Variations in pH and copigment levels were not found to contribute significantly. Flowers with colours ranging from cream and pink through to deep purple, including salmon, orange and red, were studied. While either flavonols or carotenoids were responsible for cream/yellow colouration, all other colours resulted from anthocyanin mixes. The pigments were isolated, quantified and identified by combinations of column and HPL chromatography, absorption spectroscopy and NMR. The major anthocyanins were identified as the 3,5-diglucosides and 3-glucoside-5-(6-acetyl)glucosides of pelargonidin, cyanidin, peonidin, delphinidin, petunidin and malvidin. The acetates, four of which have not been reported previously, were found predominantly in the regal Pelargonium cultivars. Key factors in Pelargonium flower colour are the types and levels of pigments present. Four new acylated anthocyanins were characterised where R 1 = OH, R 2 = H; R 1 = OH; R 2 = OH; R 1 = OCH 3, R 2 = H; R 1 = OCH 3, R 2 = OH.