Effects of MG132, epoxomicin, and E-64 on P. wilsonii pollen tube growth. A, Effects of MG132 on pollen tube growth. CK, 10, 20, 40, and 80 μm represent pollen grains/tubes treated with 0, 10, 20, 40, or 80 μm MG132, respectively. B, Effects of epoxomicin on pollen tube growth. CK, 1, 2, and 4 μm represent pollen grains/tubes treated with 0, 1, 2, or 4 μm epoxomicin, respectively. C, Effects of E-64 on pollen tube growth. CK, 40 and 80 μm represent pollen grains/tubes treated with 0, 40, or 80 μm E-64, respectively. All data represent means ± sd of three independent experiments.