Effect of some flavonoids and phenolic acids on seed germination and rooting

Abstract

Effects of isovitexin (isolated from leaves of Rhynchosia minima), leucocyanidin, gallic acid, and protocatechuic acid on seed germination and subsequent seedling growth of a crucifer Brassica campestris, and two legumes Lens esculenta and R. minima, as well as effects of isovitexin on rooting of onion bulbs are described. Neither of the flavonoids affected seed germination in any of the three systems studied. However, both the flavonoids promoted seedling growth in B. campestris and L. esculenta; the promotion of root growth was more marked. At 10⁻⁵ and 10⁻⁷M, isovitexin also promoted rooting of onion bulbs. In the range of 2.27 × 10⁻⁴M to 3.28 × 10⁻³M, leucocyanidin promoted growth of both root and shoot in L. esculenta, whereas in the range 3.28 × 10⁻³M to l.64 × lO⁻³M it suppressed seedling growth. In contrast to the flavonoids, the two phenolic acids tested inhibited seed germination at 10⁻³M, and at lower concentrations they suppressed seedling growth. The promotive effects of the flavonoids isovitexin and leucocyanidin, especially on root growth, hold promise for the use of such naturally occurring plant substances in studies on the physiology of plant growth and development.