| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4566596 | Scientia Horticulturae | 2014 | 8 Pages |
•Tetraploids of Hebe were induced in vitro with colchicine and oryzalin.•Oryzalin was more efficient than colchicine and both chemicals produced mixoploids.•Stomatal density was lower and stomatal length was higher in tetraploids.•Tetraploids had thicker stems, were shorter and had fewer nodes than diploids.
Nodal segments of Hebe Comm. ex Juss. ‘Oratia Beauty’ were treated in vitro with colchicine (500 and 1000 μM) and oryzalin (11.5, 58 and 289 μM) to induce polyploid plants. Survival rates from treatments were greater than 73%. All explants were rooted, acclimatized and the morphological traits of plants with different ploidy levels were compared. Flow cytometry was used to confirm diploids, mixoploids and polyploids. The highest frequency of tetraploids was 45.7% using oryzalin (289 μM) and 28.6% using colchicine (1000 μM). Leaves of diploids and tetraploids were not significantly different for length and width, while some tetraploids showed altered phyllotaxis. Stomatal density was significantly lower and stomatal length was significantly higher in tetraploids when compared to diploids. Principal component analysis (PCA) revealed that stomatal traits accounted for a large proportion of variability. Tetraploids (4x) and controls (2x) were propagated vegetatively and morphology compared. Rooting percentage, number of nodes, height and stem diameter were recorded. There was no difference in the rooting percentage (100%), but tetraploids had thicker stems, were shorter and had fewer nodes than diploids.
