Location of Gold Particles and Puncture of Tobacco Leaf Epidermis by Particle Bombardment

Abstract

Scanning electron microscopy (SEM) is used to observe surface structures. The electron beam generally scans the cell surface at an acceleration voltage of 10–15 kV. We observed buried gold particles in cells at an acceleration voltage of 30 kV. In this paper, dim, opaque particles were observed on a leaf surface that was bombarded with gold particles using a particle gun. These gold particles were buried in epidermal cells and the outline of the particle was not clear compared to adhered particles on the leaf surface. A 1-µm hole (0.785 µm² in area) made by a 1-µm gold particle was observed around the buried particle. We measured the areas of holes made by the passage of gold particles at 1 min (n=61), 2 min (n=56), 5 min (n=110), and 10 min (n=61) after bombardment using images obtained using a scanning electron microscope and ImageJ software. The size of the holes became smaller over time and was very small 10 min after bombardment. From these results, we reveal that the holes formed by gold particle bombardment are repaired after about 10 min.