Seed yield and components of alkaloid of meadow saffron (Colchicum autumnale) in natural grassland and under cultivation

Abstract

Alkaloids extracted from meadow saffron seeds are used in numerous medicines. To test the influence of cultivation and climatic conditions on the production and the quality of meadow saffron seeds, we studied seed alkaloid yield on a natural site (grassland) and in a cultivated crop over several years. Seeds contained in capsules harvested before their dehiscence were dried and ground. The alkaloids of the extracts (colchicoside, demethylcolchicine and colchicine) were analyzed by high-pressure liquid chromatography. Seed alkaloid content was not influenced by year, inter-plant competition, or number of capsules per plant. Seed dry matter yield per plant, however, practically tripled in the cultivated crop due to an increase in the number of capsules per plant compared to the grassland. In the cultivated crop, 47% of fruiting plants produced two new plants (corms) every year. Four years after planting, this vegetative multiplication resulted in intraspecific competition, inducing a decline in seed yield per plant linked to a decrease in the weight of seeds per capsule. We were able to show that cultivated production of meadow saffron greatly increased dry matter and alkaloid yield per plant and per hectare, but that it could lead to the need to thin after several years. Key words: meadow saffron, alkaloids, colchicine, cultivation