Cytogenetics of tropical bulbous ornamentals III. Mitotic mosaicism in 3x Crinum augustum

Abstract

Triploid Crinum augustum contains two types of complements (2 n = 33, 32 + Te) in the meristems of primary and secondary roots, together with a small amount of aneusomaty. This condition is maintained by efficient vegetative reproduction. The normal complement (2 n = 33) contains 11 triplets. The 32 + Te complement tallies with the former except that one of the small submedian chromosomes of the XIth triplet is replaced by a telocentric which more or less tallies in size with the short arm of the missing chromosome. The telocentric probably arose through misdivision early in ontogeny in which the complete centromere was in the smaller arm. The longer acentric arm, lost in a few subsequent cell generations, is not expected to exercise any deleterious effect because of the polyploid nature of the taxon. Only cells containing the full complement of 33 chromosomes are selected in the male germ line.