Detection of starch granules in a living plant by optical second harmonic microscopy

We demonstrate a new method for detecting starch granules in a plant, based on optical second harmonic microscopy. In this method a plant is irradiated with infrared laser pulses and the image formed by scattered light at the second harmonic frequency is observed. A starch granule consists of well-ordered arrays of chiral glucose molecules and shows an intense optical second harmonic response. Thus they are selectively seen in the SH intensity image. (C) 2000 Elsevier Science B.V. All rights reserved.