The hallmark of apoptosis

in suspension cultures of Taxus spp. cells induced by fungal extractive or by abiotic means

was studied by total DNA agarose gel electrophoresis and in situ end-labeling. The cleavage of nuclear DNA (nDNA) into oligonucleosomal fragments(DNA laddering) was a characteristic of apoptosis

which involved cell shrinkage

condensation of cytoplasm and tracheary elements differentiation. Terminal deoxynucleotidy transferase-mediated dUTP nick end in situ labeling (TUNEL) assay of Taxus spp. cells showed that fungal extractive or abiotic elicltors (Ce4+

Taxol

H2O2) induced TUNEL positive. Also

the increase of the apoptotic cell ratio was accompanied by the increase of secondary metabolites (especially Taxol). These results suggest that apoptosis may have some coincidence with biosynthesis of Taxol. The implication of apoptosis for the production of secondary metabolites in plant cell cultures is discussed.