Recovery of Digital Information Stored in Living Plant Leaf Photosynthetic Apparatus as Fluorescence Signals

Abstract

A CCD (charge-coupled device)-equipped, imaging spectroscopic instrument is discussed that can be reversible and rapidly reconfigured to image photosynthetic fluorescence, allowing two-dimensional spatial estimates of fluorescence quantum yield ( Y′). Y′ images of leaf areas with immediately functional photosynthetic apparatus appear smooth and uniform and are much less affected by variations in chlorophyll content and light path through the leaf. However, areas of the leaf where the photosynthetic apparatus has different light history, pathology, or other damage generate different Y′ value images. This characteristic allowed storage and recovery of images from leaves. Extending this finding, we prepared binary data coding for the value of π to 99 decimal places (100 digits), on living leaves. The images containing the binary codes for these digits can be “read” by eye, because the human brain interprets visual data with great skill. However, it was necessary to enhance the images to facilitate instrument “reading”. A program was developed to enhance the images and “read” the data images with no errors. The photosynthetic mechanism involved (nonphotochemical quenching), the role of leaf age and germplasm variation, and the potential applications of this finding in terms of bioelectronics are discussed.