Effects of temperature and plant growth regulators on anthocyanin synthesis and phenylalanine ammonia-lyase activity in chicory (Cichorium intybus L.)

Abstract

SummaryThis study addresses the effects of air temperature and plant growth regulators on anthocyanin synthesis, sugar content and phenylalanine ammonia-lyase (PAL) activity in chicory (Cichorium intybus L.). Anthocyanin in chicory was synthesised at the highest level under 15°/10°C (day/night) temperatures, followed by 20°/15°C, and 25°/20°C; while synthesis was inhibited > 90% at 30°/25°C, resulting in an almost green colour. Sugar contents paralleled anthocyanin development under the same temperatures. The plant growth regulators, abscisic acid (ABA), ethephon and uniconazole all stimulated anthocyanin synthesis, with uniconazole treatment showing the greatest effect. Gibberellic acid (GA3) inhibited anthocyanin development, while GA3 in combination with uniconazole alleviated this inhibition.PAL activity was higher at 15°/10°C or 20°/15°C (day/night) temperatures when plants were treated with ABA, ethephon or GA3, than at 25°/20°C and 30°/25°C (day/night) temperatures. These results suggest that, under lower temperatures, plant growth regulators may play an important role in anthocyanin synthesis and PAL activity in chicory.