Certain biominerals in leaves function as light scatterers

Assaf Gal, Vlad Brumfeld, Steve Weiner, Lia Addadi, Dan Oron

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

Cystoliths are amorphous calcium carbonate bodies that form in the leaves of some plant families. Cystoliths are regularly distributed in the epidermis and protrude into the photosynthetic tissue, the mesophyll. The photosynthetic pigments generate a steep light gradient in the leaf. Under most illumination regimes the outer mesophyll is light saturated, thus the photosynthetic apparatus is kinetically unable to use the excess light for photochemistry. Here we use micro-scale modulated fluorometry to demonstrate that light scattered by the cystoliths is distributed from the photosynthetically inefficient upper tissue to the efficient, but light deprived, lower tissue. The results prove that the presence of light scatterers reduces the steep light gradient, thus enabling the leaf to use the incoming light flux more efficiently. MicroCT and electron microscopy confirm that the spatial distribution of the minerals is compatible with their optical function. During the study we encountered large calcium oxalate druses in the same anatomical location as the cystoliths. These druses proved to have similar light scattering functions as the cystoliths. This study shows that certain minerals in the leaves of different plants distribute the light flux more evenly inside the leaf. Leaf minerals function as internal light scatterers inside leaves. They transfer light from the saturated upper tissue into the light deprived lower tissue. This eases the steep light gradient inside the leaf and improves photosynthetic efficiency on the tissue scale.

Original languageEnglish
Pages (from-to)OP77-OP83
JournalAdvanced Materials
Volume24
Issue number10
DOIs
Publication statusPublished - Mar 8 2012

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Keywords

  • biomineralization
  • calcium oxalate
  • cystolith
  • leaf optics
  • photosynthetic efficiency

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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