Les flavonoides des tiges principales de Periploca graeca cultive en conditions uniformes

The level of flavonoids does not change significantly when the main stem of plants cultivated in a controlled environment change from the short upright type to the twining type, but the quantity of cafeic acids derivatives is greater. The flavonoid content changes with temperature and light, with no correlation between the variation in elongation rate and stem type. Nevertheless, stems maintained in the short upright stage at a temperature of 15° are richer in derivatives of esculetin, ferulic acid and p-coumaric acid. The flavonoid content of these short upright main stems resemble that of short upright lateral stems grown under natural conditions. In the controlled environment, the axillary buds of the main stem give rise to short upright lateral stems and twining lateral stems which possess the same flavonoids as lateral stems under natural conditions. There is no evidence of any relationship between the stem type and the flavonol content and this group of compounds are not responsible for circumnutation in Periploca graeca.