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Kranz Anatomy and the C4 Pathway

  1. James O Berry,
  2. Minesh Patel

Published Online: 15 DEC 2008

DOI: 10.1002/9780470015902.a0001295.pub2

eLS

eLS

How to Cite

Berry, J. O. and Patel, M. 2008. Kranz Anatomy and the C4 Pathway. eLS. .

Author Information

  1. State University of New York, Buffalo, NY, USA

Publication History

  1. Published Online: 15 DEC 2008

Abstract

C4 photosynthesis incorporates novel leaf anatomy, metabolic specializations and modified gene expression. Plants that utilize this pathway typically possess a distinctive Kranz (or wreath) leaf anatomy, consisting of two photosynthetic cell types. These are the bundle sheath (bs) cells, which surround the vascular centres, and the mesophyll (mp) cells, which surround the bs cells. This structural framework allows for the compartmentalization and functional separation of two sets of carboxylation and decarboxylation reactions. Within C4 leaves, selective expression of bs and mp cell-specific genes leads to the selective accumulation of key photosynthetic enzymes which catalyse the different sets of cell-type-specific reactions, thereby enabling these plants to assimilate atmospheric carbon dioxide with very high efficiency. For some plants, C4 photosynthesis has facilitated their adaptation to arid conditions, high temperatures and marginal environments. Understanding the basis of this pathway has applications for improvements in agricultural productivity and alternative fuel development.

Keywords:

  • C4;
  • photosynthesis;
  • bundle sheath and mesophyll cells;
  • evolution and adaptability;
  • C4 enzymes;
  • gene regulation;
  • biotechnology