2021 Volume 24 Issue 3-4 Pages 63-65
Rumex acetosa is a dioecious plant which has sex chromosomes of XX in females (2n=14=12A+XX) and XY1Y2 in males (2n=15=12A+XY1Y2). While most plants of this species are diploid, roughly 1% of wild R. acetosa distributed in Japan are triploid with 2n=21=18A+XXX or 2n=22=18A+XXY1Y2. Tetraploid plants with 2n=28=24A+XXXX or 2n=29=24A+XXXY1Y2 and hyperdiploid plants exist in the natural population. A diploid R. acetosa lacking one autosomal chromosome (hypodiploid plant) was also reported by Kuroki and Kurita (1975).
Recently, the author identified a diploid plant missing the Y2 chromosome (2n=14=12A+XY1) in a roadside grassland. This plant bloomed male flowers, and its progeny after crossing with a normal female plant had a chromosome complement of 2n=14=12A+XX, suggesting that pollen grains with a chromosome set of 6A+X can fertilize, whereas those with a 6A+Y1 chromosome set do not mature until fertilization or are incapable of fertilizing.
