Circular spectropolarimetric sensing of higher plant and algal chloroplast structural variations

TL;DR

This study uses circular spectropolarimetry to analyze structural variations in chloroplasts across different photosynthetic organisms, revealing significant diversity and potential for life detection.

Contribution

It provides new measurements of circular polarizance in various algae and plants, uncovering greater molecular organization variability than previously known.

Findings

Large variations in circular spectropolarimetric signals among species

Discovery of spectral features not previously reported

Signal strength varies by three orders of magnitude

Abstract

Photosynthetic eukaryotes show a remarkable variability in photosynthesis, including large differences in light harvesting proteins and pigment composition. In vivo circular spectropolarimetry enables us to probe the molecular architecture of photosynthesis in a non-invasive and non-destructive way and, as such, can offer a wealth of physiological and structural information. In the present study we have measured the circular polarizance of several multicellular green, red and brown algae and higher plants, which show large variations in circular spectropolarimetric signals with differences in both spectral shape and magnitude. Many of the algae display spectral characteristics not previously reported, indicating a larger variation in molecular organization than previously assumed. As the strengths of these signals vary by three orders of magnitude, these results also have important implications in terms of detectability for the use of circular polarization as a signature of life.