Abstract
We have established polyploid series of four strains of Arabidopsis thaliana (Columbia, Landsberg erecta, Wassilewskija, and C24), and with these, quantitatively analyzed the ploidy effects on primary root growth by the kinematic method. In all strains, there were increases in cell size and cell volume growth rate of tetraploid plants compared to diploids, while no significant differences were found in the rate and location of cell proliferation.
We additionally analyzed the root growth of the hexaploid and octoploid of Columbia strain. The cell size and cell volume growth rate of hexaploid were larger than those of tetraploid, and thus the ploidy changes from tetraploid to hexaploid and from diploid to tetraploid had a similar effect on root growth. The root growth of octoploid, however, decreased compared to that of hexaploid and two groups were recognized in octoploid plants; one group showed a slightly lower volume growth rate than hexaploid and the other showed a much lower growth rate. The ploidy level was reduced to tetraploid in the next generation of the latter group, suggesting that some chromosomal disorder may affect the volume growth rate in octoploid.
