Figure 2. Monoterpene-induced physiological changes in tomato.

(A) Development of necrosis in leaves of 45-days old tomato plants and 15-days old tomato seedlings-treated with monoterpene volatiles geraniol, geranyl acetate, citral and β-citronellol. Photographs were taken at 48 and 72 hr after volatile treatments to tomato seedlings and plants, respectively. Trypan blue staining of the leaves, taken from 48 hr monoterpene volatile-treated plants, was carried out to determine the extent of cell death. (B) The electrolyte leakage rate from the leaves was measured at 12 hr after treatment of tomato plants with monoterpene volatiles. Data are mean ± SEM (n = 3).