Structural features of NAD-malic enzyme type C4
Eleocharis: An additional report of C4 acid decarboxylation types of the cyperaceae |
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Authors: | Osamu Ueno Muneaki Samejima |
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Institution: | (1) Department of Applied Physiology, National Institute of Agrobiological Resources, 305 Tsukuba Science City, Ibaraki, Japan |
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Abstract: | The genusEleocharis, a blade-less sedge group, has been very recently recorded to include NAD-malic enzyme type C4 species. The ultrastructural features of culms of two C4 representatives in the genus were examined in relation to the C4 acid decarboxylation type. They possessed non-chlorophyllous mestome sheath cells between mesophyll cells and Kranz cells,
and were confirmed biochemically to be NAD-malic enzyme type. The oval or lenticular chloroplasts with well-developed grana
are scattered in the Kranz cells with abundant large mitochondria, and do not show such centripetal position as is known in
the “classical NAD-malic enzyme type”. The suberized lamellae occur in the mestome sheath cells internally surrounding the
Kranz sheath and may contribute to maintaining high CO2 concentration in the Kranz cells. These new structural features of the NAD-malic enzyme type found inEleocharis are added to the structural and functional relationships of the C4 types in the Cyperaceae reported previously |
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Keywords: | C4 plants Cyperaceae Eleocharis Kranz cells NAD-malic enzyme type Suberized lamella |
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