Bundle sheath cells of small veins in maize leaves are the location of uptake from the xylem
2001
Keunecke, M. | Lindner, B. | Seydel, Uwe | Schulz, A. | Hansen, U.P.
Rb(+) as a tracer for K(+) was used to test the hypothesis that uptake of K(+) from xylem vessels of small veins into the symplast of maize leaves occurs at the xylem/bundle sheath cell interface. 22.5 min after immersing cut leaves into 20 mM RbCl + 1 mM KCl, Rb(+) appeared in the cells of the leaves. Sections of these leaves were freeze-dried. In cryo-thin sections (5 micrometer), 85Rb(+) and 41K(+) content was determined by laser microprobe mass analysis with a large resolution of about 1 micrometer. Determining the ratio of 85Rb(+) to 41K(+) in the cell walls and cytosols of bundle sheath cells, mesophyll cells, and in the cells between the xylem elements resulted in the following picture: In small veins, Rb(+) entered the symplast directly at the xylem/bundle sheath cell interface.
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