AOBPreview originally published online on January 19, 2006
Annals of Botany 2006 97(3):429-441; doi:10.1093/aob/mcj046
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Effects of Cultivar, Fruit Number and Reflected Photosynthetically Active Radiation on Fragaria x ananassa Productivity and Fruit Ellagic Acid and Ascorbic Acid Concentrations
1 East Malling Research, New Road, East Malling, Kent ME19 6BJ, UK and 2 Department of Biological Sciences, Lancaster University, Lancaster LA1 4YQ, UK
* For correspondence. E-mail chris.atkinson{at}emr.ac.uk
Received: 22 August 2005 Returned for revision: 3 October 2005 Accepted: 16 November 2005 Published electronically: 19 January 2006
Background and Aims A number of strawberry varieties were surveyed for their total ellagic acid concentration, and attempts were made to determine if ellagic acid and ascorbic acid concentrations of two strawberry cultivars could be increased by polythene reflective mulches.
Methods After adjusting crop yields and cultivation using polythene mulches with two different PAR reflective capacities, field- and polytunnel-grown strawberries were analysed for ellagic acid and ascorbic acid concentrations by HPLC. Comparative measurements of yield and fruit quality were determined along with plant developmental changes.
Key Results Ellagic acid concentration varied widely with strawberry cultivar (60341 µg g1 frozen weight), as did the ratio of conjugated ellagic acid : free ellagic acid. Also, there was significant year-to-year variation in total ellagic acid concentration with some cultivars. Mulches with different reflective capacities impacted on strawberry production; highly reflective mulches significantly increased growth and yield, the latter due to increases in fruit size and number.
Conclusions Highly reflective mulches significantly increased total concentrations of ellagic acid and ascorbic acid relative to control in fruit of different cultivars. The potential of agronomic practices to enhance the concentration and amounts of these important dietary bioactive compounds is discussed.
Key words: Ellagic acid, ellagitannins, ascorbic acid, Fragaria, PAR, everbearers, June bearers, light reflectance, reflective mulch, strawberries, vitamin C