HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplementary Data Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Muhaidat, R. Articles by Dengler, N. G. Search for Related Content PubMed Articles by Muhaidat, R. Articles by Dengler, N. G. Agricola Articles by Muhaidat, R. Articles by Dengler, N. G.

Diversity of Kranz anatomy and biochemistry in C₄ eudicots¹

Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 1A1, Canada; Department of Biological Sciences, Yarmouk University, Irbid, Hashemite Kingdom of Jordan

ABSTRACT

C₄ photosynthesis and Kranz anatomy occur in 16 eudicot families, a striking example of convergent evolution. Biochemical subtyping for 13 previously undiagnosed C₄ eudicot species indicated that 10 were NADP-malic enzyme (ME) and three were NAD-ME. A total of 33 C₄ species, encompassing four Kranz anatomical types (atriplicoid, kochioid, salsoloid, and suaedioid), and 21 closely related C₃ species were included in a quantitative anatomical study in which we found that, unlike similar studies in grasses and sedges, anatomical type had no predictive value for the biochemical subtype. In a multivariate canonical discriminant analysis, C₄ species were distinguished from C₃ species by the mesophyll to bundle sheath ratio and exposure of the bundle sheath surface to intercellular space. Discrimination between NADP-ME and NAD-ME was not significant, although in a Mantel test grouping by biochemical subtype was significant, while grouping by family was not. This comprehensive survey of C₄ anatomy and biochemistry unequivocally demonstrated that atriplicoid anatomy and NADP-ME biochemistry predominate in many evolutionary lineages. In addition to a main decarboxylating enzyme, high activity of a second decarboxylating enzyme was often observed. Notably, PEP-carboxykinase activity was significant in a number of species, demonstrating that this enzyme could also serve as a secondary pathway for C₄ metabolism in eudicots.

Key Words: C₄ photosynthesis • Kranz anatomy • mesophyll to bundle sheath ratio • NAD-malic enzyme • NADP-malic enzyme • PEP-carboxykinase enzyme • vein density

This article has been cited by other articles:

				H. Akhani, M. Ghasemkhani, S. D. X. Chuong, and G. E. Edwards Occurrence and forms of Kranz anatomy in photosynthetic organs and characterization of NAD-ME subtype C4 photosynthesis in Blepharis ciliaris (L.) B. L. Burtt (Acanthaceae) J. Exp. Bot., May 1, 2008; 59(7): 1755 - 1765. [Abstract] [Full Text] [PDF]

				L. J. Guralnick, A. Cline, M. Smith, and R. F. Sage Evolutionary physiology: the extent of C4 and CAM photosynthesis in the genera Anacampseros and Grahamia of the Portulacaceae J. Exp. Bot., May 1, 2008; 59(7): 1735 - 1742. [Abstract] [Full Text] [PDF]

				R. F. Sage, T. L. Sage, R. W. Pearcy, and T. Borsch The taxonomic distribution of C4 photosynthesis in Amaranthaceae sensu stricto Am. J. Botany, December 1, 2007; 94(12): 1992 - 2003. [Abstract] [Full Text] [PDF]

				A. D. McKown and N. G. Dengler Key innovations in the evolution of Kranz anatomy and C4 vein pattern in Flaveria (Asteraceae) Am. J. Botany, March 1, 2007; 94(3): 382 - 399. [Abstract] [Full Text] [PDF]