Distribution and metabolism of polyacetylenes in safflower

Safflower seedlings, tissues and subcellular fractions were used to investigate the distribution and biosynthesis of polyacetylenes. The polyacetylenes rapidly increased during germination, but were not detected in mature seeds. The polyacetylenes in the seedlings accumulated mainly in cotyledons rather than in hypocotyls and roots. Polyacetylenic hydrocarbons were distributed in the microsomes obtained from leaves and roots of the mature plants, while polyacetylenic epoxide was found in chloroplasts. A 1000 X g pellet from the immature seeds showed the highest activity for the incorporation of labeled acetate into the hydrocarbons. The epoxide was synthesized by chloroplasts from the cotyledons. These results, together with the data of polyacetylene distribution and tissue culture, suggest that chloropoasts may be essential for the formation and metabolism of the epoxide.