Does Bienertia cycloptera with the single-cell system of C4 photosynthesis exhibit

AKHANI, HOSSEIN; LARA, MARÍA VALERIA; GHASEMKHANI, MARYAM; ZIEGLER, HUBER; EDWARDS, GERALD E.

PHOTOSYNTHESIS RESEARCH

SPRINGER

Año: 2009 vol. 99 p. 23 - 36

0166-8595

Family Chenopodiaceae is an intriguing lineage,having the largest number of C4 species among dicots,including a number of anatomical variants of Kranz anatomyand three single-cell C4 functioning species. In someprevious studies, during the culture of Bienertia cyclopteraBunge ex Boiss., carbon isotope values (d13C values) ofleaves deviated from C4 to C3-C4 intermediate type,raising questions as to its mode of photosynthesis duringgrowth in natural environments. This species usually cooccurswith several Kranz type C4 annuals. The developmentof B. cycloptera morphologically and d13C valuesderived from plant samples (cotyledons, leaves, bracts,shoots) were analyzed over a complete growing season in asalt flat in north central Iran, along with eight Kranz typeC4 species and one C3 species. For a number of species,plants were greenhouse-grown from seeds collected fromthe site, in order to examine leaf anatomy and C4 biochemicalsubtype. Among the nine C4 species, thecotyledons of B. cycloptera, and of the Suaeda spp. havethe same respective forms of C4 anatomy occurring inleaves, while cotyledons of members of tribe Caroxyloneaelack Kranz anatomy, which is reflected in the d13C valuesfound in plants grown in the natural habitat. The nine C4species had average seasonal d13C values of -13.9% (witha range between species from -11.3 to -15.9%). Themeasurements of d13C values over a complete growingseason show that B. cycloptera performs C4 photosynthesisduring its life cycle in nature, similar to Kranz type species,with a seasonal average d13C value of -15.2%.