Physiological Studies on Pea Tendrils. IV. Flavonoids and Contact Coiling.

Pea tendrils contain high concentrations of flavonoids, mainly quercetin-triglucosyl-p-coumarate (QGC). QGC is most abundant near the highly responsive apex of the tendril, and least abundant at the base. After mechanical stimulation, and during coiling of the tendril, the QGC titer drops to about 30% of its original value. The kinetics of flavonoid disappearance are significantly correlated with the kinetics of coiling.Aqueous extracts of unstimulated pea tendrils or 10 mum QGC inhibit contact coiling of excised tendrils. Extracts of coiled tendrils do not. The evidence indicates a possible regulatory role for flavonoids in contact coiling.