Progeny from the crosses of two transgenic potato lines csr2-1 and csr4-8, containing two different
antisense constructs, csr2 and csr4 had been previously characterized to exhibit altered tuber
production. Histochemical staining and microscopic examinations of the tubers were made to
investigate cellular phenotype in the tubers. We observed ectopic proliferation of xylem, which is most
pronounced in the csr2 tubers. Light microscopy of csr2 tubers revealed that the proliferation of xylem
was associated with lignification of their cell walls. This paper provides evidence of cellular phenotype
as a consequence of the presence of the antisense construct