Tetraploid plants were successfully obtained through the use of
colchicine in all three of the crapemyrtle cultivars tested. This study
also indicated that measuring stomata size and density as an early
stage preliminary screen, and assessing fruit size or seed size in the
later reproductive phase, provided a relatively simple and reliable
method for the identification of tetraploid plants of crape myrtle.
These initial screens were subsequently combined with flow
cytometric analysis to ensure the accuracy of ploidy identification.
Key morphological variations observed in the tetraploid plants
included larger and thicker leaves, darker green coloration, larger
stomata, lower stomata density across the lower leaf epidermis,
increased numbers of chloroplasts in the stomata guard cells and
increased pollen diameter. Flowcytometric analysis confirmed that
the nuclear DNA content of the tetraploid plants was doubled
compared with that of the control plants. The ornamental value of
the single flowers of the tetraploid plants also appeared to be
improved, with increases in flower diameter, petal length and claw
basal length. The size of the capsules and seeds of the tetraploid
plants were also significantly greater than those of diploid plants.