2644 - CSUN ScholarWorks - California State University, Northridge

Journal of Student Research Abstracts · 41
A. tumefaciens should be pricked into the plants using a sterile needle. The galls were cut off the sunflower
stem with a sterilized scalpel and forceps. The gall was then divided into two sections, the inner (1-2 mm) and
outer (2-4 mm). The internal tissue of each divided section was removed by scraping the tissue with a scalpel.
The scrapings were aseptically placed in a sterile petri dish with a drop of sterilized water and set out
overnight. The water, with the diffused bacteria, was collected, spread over nutrient agar, and incubated. Dishes
containing the outer scrapings contained about 1600 small colonies of A. tumefaciens. Dishes containing inner
scrapings contained about 50 large colonies. It can be concluded that there was more Agrobacterium tumefaciens
on the outer scrapings not due to chance but due to the location of the bacterium (p