Differential Protein Composition and Gene Expression in Leaf Mesophyll Cells and Bundle Sheath Cells of the C4 Plant Digitaria sanguinalis (L.) Scop.

The intercellular and intracellular distributions of nitrate assimilating enzymes were studied. Nitrate reductase was found to be localized on the chloroplast envelope membranes. The chloroplastic NADPH – glutamate dehydrogenase was concentrated in the mesophyll cells. The extrachloroplastic NADH – glutamate dehydrogenase was localized in the bundle sheath cells. Glutamate synthesized in the mesophyll chloroplasts was interpreted to be utilized exclusively in the synthesis of aspartate, while in the bundle sheath cells it was thought to be consumed in other cellular metabolic processes. Based on the results, a scheme is proposed to account for the nitrate metabolism in the leaves of Eleusine coracana Gaertn. in relation to its aspartate-type C-4 pathway of photosynthesis.

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Phenolic Deposits and Kranz Syndrome in Leaf Tissues of Spotted (Euphorbia maculata) and Prostrate (Euphorbia supina) Spurge

Weed Science ◽

10.1017/s0043174500068685 ◽

1983 ◽

Vol 31 (1) ◽

pp. 131-136 ◽

Cited By ~ 2

Author(s):

C. Dennis Elmore ◽

Rex N. Paul

Keyword(s):

Electron Microscopy ◽

Phenolic Compounds ◽

Light And Electron Microscopy ◽

Bundle Sheath ◽

Fixation Technique ◽

Mesophyll Cells ◽

Kranz Anatomy ◽

Bundle Sheath Cells ◽

Leaf Tissues ◽

Sheath Cells

Spotted spurge (Euphorbia maculataL.) and prostrate spurge (E. supinaRaf.), both in subgenusChamesyce,were examined by light and electron microscopy using a caffeine - fixation technique to sequester the phenolic pools intercellularly. Both species have typical dicotyledon-type Kranz anatomy. Sequestered phenolic pools were located in vacuoles in epidermal and mesophyll cells. Only in spotted spurge, however, were additional phenolic pools formed in bundle - sheath cells. This study was undertaken because allelopathy has been demonstrated in prostrate spurge and because phenolic compounds have been implicated in allelopathy. These results would indicate that spotted spurge should also be allelopathic.

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Photosynthesis in Gomphrena celosioides and Its Classification Amongst C4-pathway Plants

Functional Plant Biology ◽

10.1071/pp9760863 ◽

1976 ◽

Vol 3 (6) ◽

pp. 863 ◽

Cited By ~ 5

Author(s):

E Repo ◽

MD Hatch

Keyword(s):

Malate Dehydrogenase ◽

Malic Enzyme ◽

Bundle Sheath ◽

Mesophyll Cells ◽

C4 Species ◽

Bundle Sheath Cells ◽

Major Route ◽

Gomphrena Celosioides ◽

A Minor ◽

Sheath Cells

Monocotyledonous C4 species classified as NADP-ME-type transfer malate from mesophyll to bundle sheath cells where this acid is decarboxylated via NADP malic enzyme (EC 1.1.1.40) to yield pyruvate and CO2. The dicotyledon G. celosioides is most appropriately classified in thls group on the basis of high leaf activities of NADP malic enzyme and NADP malate dehydrogenase (EC 1.1.1.82). However, this species contains high aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) activities and centripetally located bundle sheath chloroplasts, features more typical of other groups of C4 species that cycle aspartate and alanine between mesophyll and bundle sheath cells. During the present study, we found that these aminotransferases and NADP malate dehydrogenase were predominantly located in mesophyll cells, that malate was the major C4 acid labelled when leaves were exposed to 14CO2, and that label was initially lost most rapidly from the C-4 of malate during a chase in 12CO2. These results are consistent with the major route of photosynthetic metabolism being the same as that operative in other NADP-ME-type species, although this may be supplemented by a minor route utilizing aspartate. In contrast to monocotyledonous NADP-ME-type C4 species, isolated bundle sheath cells from G. celosioides were capable of rapid photoreduction of NADP as judged by products formed during assimilation of 14CO2 and their capacity for light-dependent oxygen evolution. This was related to a relatively high frequency of single unstacked granum in the chloroplasts of these cells.

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Light-Induced Ascorbate-Dependent Electron Transport and Membrane Energization in Chloroplasts of Bundle Sheath Cells of the C4 Plant Maize

Archives of Biochemistry and Biophysics ◽

10.1006/abbi.2000.2156 ◽

2001 ◽

Vol 385 (1) ◽

pp. 145-153 ◽

Cited By ~ 17

Author(s):

Boris N. Ivanov ◽

Colette A. Sacksteder ◽

David M. Kramer ◽

Gerald E. Edwards

Keyword(s):

Electron Transport ◽

Bundle Sheath ◽

C4 Plant ◽

Bundle Sheath Cells ◽

Membrane Energization ◽

Sheath Cells

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Arabidopsis leaf hydraulic conductance is regulated by xylem-sap pH, controlled, in turn, by a P-type H+-ATPase of vascular bundle sheath cells

10.1101/234286 ◽

2017 ◽

Cited By ~ 1

Author(s):

Yael Grunwald ◽

Noa Wigoda ◽

Nir Sade ◽

Adi Yaaran ◽

Tanmayee Torne ◽

...

Keyword(s):

Proton Pump ◽

Vascular Bundle ◽

Xylem Sap ◽

Hydraulic Conductance ◽

Bundle Sheath ◽

List Type ◽

Mesophyll Cells ◽

Leaf Hydraulic Conductance ◽

Bundle Sheath Cells ◽

Sheath Cells

AbstractThe leaf vascular bundle sheath cells (BSCs) that tightly envelop the leaf veins, are a selective and dynamic barrier to xylem-sap water and solutes radially entering the mesophyll cells. Under normal conditions, xylem-sap pH of <6 is presumably important for driving and regulating the transmembranal solute transport. Having discovered recently a differentially high expression of a BSCs proton pump, AHA2, we now test the hypothesis that it regulates this pH and leaf radial water fluxes.We monitored the xylem-sap pH in the veins of detached leaves of WT Arabidopsis, AHA mutants, and aha2 mutants complemented with AHA2 gene solely in BSCs. We tested an AHA inhibitor and stimulator, and different pH buffers. We monitored their impact on the xylem-sap pH and the whole leaf hydraulic conductance (Kleaf), and the effect of pH on the water osmotic permeability (Pf) of isolated BSCs protoplasts.Our results demonstrated that AHA2 is necessary for xylem-sap acidification, and in turn, for elevating Kleaf. Conversely, knocking out AHA2 alkalinized the xylem-sap. Also, elevating xylem sap pH to 7.5 reduced Kleaf and elevating external pH to 7.5 decreased the BSCs Pf.All these demonstrate a causative link between AHA2 activity in BSCs and leaf radial water conductance.One-sentence summaryBundle-sheath cells can control the leaf hydraulic conductance by proton-pump-regulated xylem sap pH

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