doubling rhe chromosomes of rose seedlings
"The technique used to double the chromosome number of C. japonica was applied to the three species mentioned to determine if it would be effective for inducing polyploidy and, if so, optimal duration of treatment. Seedlings were treated at the cotyledon stage for 0 (control), 10, 20, or 30 days with an aqueous solution containing 150 ÃÂ¼M oryzalin + 0.1% TweenÃÂ® 20 using a standard household spray bottle that created a fine mist."
See the "Abstract for research paper" link below.
If you are going to spray, I suggest a long sleeve shirt, long pants, face mask and double gloves (rubber and plastic). When I did this type of experiment, instead of spraying; I painted the solution on the buds (but I used the more dangerous DMSO instead of the safer Tween).
Here is a link that might be useful: Abstract for research paper