Transmitting energy spectra of 500keV—1MeV He+ ions penetrating 50—90μm thick seed coat of maize, fruit peel of grape and of tomato are measured. The results indicate that these thick biological targets, as seen by penetrating ions, are inhomogencous and there are open“channel like” paths along which the incident ions can transmit the targets easily. While most of the incident ions are stopped in the targets, some of the transmitting ions only lose a small fraction of their initial incident energy. The transmitting energy spectra show a pure electronic stopping feature. Transmission electron microscopic taken from these samples with thickness of 30μm indicate that 150keV electron beam can penetrate the thick samples to give very good images with clear contrast. The electronic structures of β-1,4-glucosan molecular chains, which is deemed as the important constituent of the cell walls of seed coats and peels of fruits, are calcuated to show the possible channeling directions existing in biological samples.