Fig. 2

Seed germination and plant growth of Vinca rosea raised in soils treated with different crude oil levels of 0% (control), 1%, 3%, 5%, and 7%. A Seed germination percentage, B plant height, C Vinca rosea growth after a 5-month growth period, D number of branches per individual, and E root/shoot ratio. Different letters indicate significant differences among different soil treatments at p ≤ 0.05. Values are expressed as mean ± SE (n= 5). The dashed line in 1D is the linear regression of root/shoot ratio against the percentage of crude oil treatment