The purpose of this experiment was to determine if beta carotene prevents the development of crown gall disease (cancer) in sunflower plants. The experiment was performed by inoculating three groups of sunflower plants with Agrobactrium tumefacians, a plant pathogen. Group A was germinated and watered with a high dose solution of beta carotene (100 mg/750 mL of water). Group B was germinated in and watered with low dose beta carotene (50 mg/750 mL water). Group C was germinated in and watered with tap water. Group D (control) was germinated in and watered with tap water and was not infected with Agrobacterium tumefacians.
The four groups of sunflower plants were exposed to room temperature and ten hours of fluorescent light per day. Plants in groups A,B, and C were inoculated with Agrobacterium tumefacians at the internode when the plant reached a height of 18cm. The height of each sunflower plant and circumference of tumors were recorded weekly.
After completing the experiment it was found that 29% of the plants in group A and B did not develop tumors. In group C, 100% of the plants developed tumors. No plants developed tumors in group D. At eight weeks post-germination the plants in group B were the tallest (42.6cm). The tumor circumference was smaller in all three groups, 2.9cm in group A, 2.9 in group B, and 3.0 in group C. This experiment suggests that both high and low dose beta carotene solutions reduce the percentage of plants that develop cancer.