Germination and Seedling Growth of 48 Plant Species as Affected by a Leachate from Seeds of Coronilla Varia L.

The study found that while the germination of seeds from 48 plant species was not inhibited by leachate from viable crownvetch seeds, the leachate significantly affected seedling growth. Freeze-dried crownvetch leachate at dilutions up to 1:2,000 caused severe shortening of shoots and roots, almost eliminated root hair growth, and resulted in necrotic and thickened root tips. Some species' roots exhibited negative geotropism. Even at a dilution of 1:10,000, some seedlings were adversely affected. The osmotic pressure of the leachate was too low to explain these effects, suggesting that the phytotoxicity was due to low molecular weight phenols and polyphenols. Crownvetch leachate was more phytotoxic than leachates from sweetclover and aged red clover seeds.