The Influence of Polyacetylenes on the Susceptibility of Carrots to Storage Diseases

The amounts of the polyacetylenes falcarindiol (heptadeca-], 9(Z)-dien-4,6-diyn- 3,8-diol) and falcarino! (heptadeca-i ,9{Z)-dien-4.6-diyn-3-ol) were determined in the roots of a number of commercial carrot cultivars in order to study their influence on resistance to storage rots caused by three different fungi. The content of the diol was much higher in periderm/pericyclic parenchyma than in phloem parenchyma and the outer tissues were less susceptible lo Mxcocentrospora acerina than the inner tissues. A strong and significant negative relationship was found between falcarindiol contents in the periderm/ pericyclic parenchyma and susceptibility to Mycocenlrospora acerina for 14 of the 16 cultivars lested. The relationship was less nolicable for Sclerotinia sclerotiorum and not significant for Rhizoctonia carotae.