Pachytene chromosome morphology with reference to sex instability in Ricinus communis L.

Summary The morphology of the pachytene chromosomes of Ricinus communis L. (2n=20), the castor plant, was examined and compared, using light microscopy, in two sex forms, one having an apical distribution of pistillate flowers (wild type), the other having a uniform distribution of pistillate flowers (mutant). Nonreverted mutants resulting from sex instability of the wild type did not display microscopically discernable alterations in chromosome morphology.