The tips of cotyledon-stage seedlings of three crape myrtle cultivars (‘‘Zi Wei’’, ‘‘Hong Wei’’ and ‘‘Yin
Wei’’) were treated with colchicine. Various concentrations of colchicine and different treatment
durations were tested. Seedlings of ‘‘Zi Wei’’ treated with 0.5% colchicine for 72 h and seedlings of ‘‘Yin
Wei’’ treated with colchicine (0.2% for 96 h, 0.5% for 48 h and 0.8% for 72 h) demonstrated high rates of
mutation; ‘‘Hong Wei’’ showed a slightly lower rate. The highest rate of morphological variation was
54.17% and this was achieved when tips were treated with 0.5% colchicine for 72 h. Putative tetraploid
plants were identified with morphological and cytological variations, such as larger and thicker leaves,
darker green coloration, larger stomata, lower density of stomata across the lower leaf epidermis and
increased numbers of chloroplasts per stomata guard cell. Flow cytometric analysis demonstrated that
the nuclear DNA content of 15 of these putative tetraploids (of which 7 were ‘‘Zi Wei’’, 5 were ‘‘Yin Wei’’,
and 3 were ‘‘Hong Wei’’) was indeed doubled relative to that of control diploid plants. The chromosome
number of the tetraploid plants was 2n = 4x = 96, while that of the control diploid plants was
2n = 2x = 48. Ornamental characteristics were also enhanced in the tetraploid plants, with increased
diameter of the individual flowers and greater basal length of the petals and claws. Pollen diameter and
the size of capsules and seeds were also significantly greater than those of diploid plants
The tips of cotyledon-stage seedlings of three crape myrtle cultivars (‘‘Zi Wei’’, ‘‘Hong Wei’’ and ‘‘Yin
Wei’’) were treated with colchicine. Various concentrations of colchicine and different treatment
durations were tested. Seedlings of ‘‘Zi Wei’’ treated with 0.5% colchicine for 72 h and seedlings of ‘‘Yin
Wei’’ treated with colchicine (0.2% for 96 h, 0.5% for 48 h and 0.8% for 72 h) demonstrated high rates of
mutation; ‘‘Hong Wei’’ showed a slightly lower rate. The highest rate of morphological variation was
54.17% and this was achieved when tips were treated with 0.5% colchicine for 72 h. Putative tetraploid
plants were identified with morphological and cytological variations, such as larger and thicker leaves,
darker green coloration, larger stomata, lower density of stomata across the lower leaf epidermis and
increased numbers of chloroplasts per stomata guard cell. Flow cytometric analysis demonstrated that
the nuclear DNA content of 15 of these putative tetraploids (of which 7 were ‘‘Zi Wei’’, 5 were ‘‘Yin Wei’’,
and 3 were ‘‘Hong Wei’’) was indeed doubled relative to that of control diploid plants. The chromosome
number of the tetraploid plants was 2n = 4x = 96, while that of the control diploid plants was
2n = 2x = 48. Ornamental characteristics were also enhanced in the tetraploid plants, with increased
diameter of the individual flowers and greater basal length of the petals and claws. Pollen diameter and
the size of capsules and seeds were also significantly greater than those of diploid plants
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