Following Spatial Distribution of Photosynthetic Pigments Across the Development of a Leaf using Hyperspectral Fluorescence Microscopy

Abstract

Leaves on plants undergo a transition from a sink (a net carbon importer) to a source (a net carbon exporter) during their development. This conversion from sink to a photosynthetic source marks a fundamental transition in the physiology of the leaf, profoundly altering the carbohydrate metabolism and acting as one of the major determinants of plant performance. Hence a considerable amount of study is underway to understand its biochemical and structural characteristics. In plants, the process by which undifferentiated plastids differentiate into mature functional chloroplasts begins in the shoot apical meristem (SAM) and young leaf primordia (sink tissue), and continues along leaf development. In this work, we follow the spatial distribution of these plastids and their abundance of photosynthetic pigments in a gradient from sink to source by imaging laser induced fluorescence using a home-built laser scanning hyperspectral microscope. The line-scanning hyperspectral microscope combines fast scanning with optical sectioning to record 4-D datasets with spatial (x, y, z) and spectral (λ) information. We will present three dimensional observations of photosynthetic pigment carrying plastids in C4 plants during the different phases of leaf cell development.