Figure 1.

Effects of exogenously supplied synthetic NAEs (0.1 mm) on alkalinization of the tobacco cell culture medium induced by xylanase (1 μg mL⁻¹). The specific NAE molecular species tested were: NAE 12:0 (A); NAE 14:0 (B); NAE 16:0 (C); NAE 18:0 (D); NAE 18:1 (E); and NAE 20:4 (F). NAEs were added to cultures as described in “Materials and Methods.” Cells in log phase (3–4 d after subculture) were treated with or without xylanase and incubated with or without NAE with continuous gentle stirring. The change in pH of the culture medium was recorded every 2 min for 40 min. Controls and experimental treatments were carried out on the same population of cells. Results presented are representative; similar trends were observed in experiments repeated three to six times. A, ▪, xylanase; ▴, xylanase plus NAE12:0; ▾, NAE12:0; ●, control. B, ▪, xylanase; ▴, xylanase plus NAE14:0; ▾, NAE14:0; ●, control. C, ▪, xylanase; ▾, xylanase plus NAE16:0; ▴, NAE16:0; ●, control. D, ▪, xylanase; ▾, xylanase plus NAE18:0; ●, control; ▴, NAE18:0. E, ▪, xylanase; ▴, xylanase plus NAE18:1; ▾, NAE18:1; ●, control. F, ▪, xylanase; ▴, xylanase plus NAE20:4; ●, control; ▾, NAE20:4.