Figure 2.

Morphology of L. formosanum pollen tubes (A) and pseudocolor ratio images of intracellular Ca²⁺ distribution in L. formosanum pollen tubes (C) exposed to 10 units mL⁻¹ orange peel PME. B, Morphology of N. tabacum pollen tubes exposed to 30 units mL⁻¹. Numbers represent minutes after addition of PME to the growth medium. The [Ca²⁺]_i gradient shown extends from 1 to 3 μm at the apex of the growing tube to basal values of around 0.15 μm within 20 μm from the apex. Scale bar = 10 μm.