Carbon Reduction and Photosystem II Deficiency in Leaves of C4 Plants

1974 ◽  
Vol 1 (1) ◽  
pp. 41 ◽  
Author(s):  
CB Osmond
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Bundle Sheath ◽  
Hill Reaction ◽  
Carbon Reduction ◽  
Chase Period ◽  
Bundle Sheath Cells ◽  
The Hill ◽  
Reducing Potential ◽  
Sheath Cells

The Hill reaction and photosystem I activity of chloroplasts isolated from mesophyll and bundle sheath cells of Atviplex spongiosa and Sorghum bicolov was measured using narrow-band, high-intensity illumination of 646, 712, and 730 nm. The photosystem I reactions (methylviologen Mehler reaction and diphenylcarbazone reduction) were equally active in 646 and 712 nm light, whereas Hill activity was reduced by 70% in 712 nm light relative to 646 nm. Intact leaves were illuminated with 646 nm light and exposed to a pulse of 14CO2. The pulse was followed by a chase in 646,712, or 730 nm light or in darkness. In A. spongiosa leaves the movement of carbon from C4 acids to carbohydrates during the chase period only occurred to a significant extent in 646 nm light. In S. bicolor leaves, 712 nm light was almost as effective as 646 nm light in inducing the movement of carbon from C4 acids to carbohydrate. Evidently in this species carbon reduction is not entirely dependent on concurrent photosystem I + II activity for the provision of reducing potential. The data are discussed in relation to the deficiency of photosystem II activity in bundle sheath cells of S. bicolor.

Comparison of photosynthetic carbon reduction (Kranz) cells having different ontogenetic origins in the C4 NADP – malic enzyme grass Arundinella hirta

1990 ◽  
Vol 68 (6) ◽  
pp. 1222-1232 ◽  
Author(s):  
Nancy G. Dengler ◽  
Ronald E. Dengler ◽  
Douglas J. Grenville
Keyword(s):  
Cell Walls ◽  
Vascular Tissue ◽  
Cell Types ◽  
Bundle Sheath ◽  
Carbon Reduction ◽  
Bundle Sheath Cells ◽  
Photosynthetic Carbon ◽  
Arundinella Hirta ◽  
Photosynthetic Carbon Reduction ◽  
Sheath Cells

The C4 grass Arundinella hirta is characterized by unusual leaf blade anatomy: photosynthetic carbon reduction takes place both within the chlorenchymatous bundle sheath cells of the longitudinal veins and within longitudinal strands of "distinctive cells" that form part of the leaf mesophyll and are often completely isolated from vascular tissue. Although they are equivalent physiologically, these two cell types have different ontogenetic origins: bundle sheath cells are delimited from procambium early in leaf development, whereas distinctive cells differentiate from ground meristem at a later developmental stage. Although the two cell types share numerous cytological features (large chloroplasts with reduced grana, thick cell walls with a suberin lamella), we also found significant differences in cell lengths, length to width ratios, cell cross-sectional areas, organelle numbers per cell cross section, phenol content of the cell walls, and numbers of pit fields in the longitudinal cell walls. The size and shape of bundle sheath cells are likely a direct consequence of procambial origin. The thicker walls of bundle sheath cells (in major veins) and their greater lignification may reflect the inductive effect of cell differentiation in the proximity of sclerenchyma and vascular tissues. Differences between major and minor vein bundle sheath cells may reflect differences in the timing of initiation of procambial strands. Our analysis of cell wall characteristics has also shown the presence of numerous primary pit fields in the transverse walls between adjacent distinctive cells in a file; plasmodesmata in these pit fields form a pathway for longitudinal symplastic transport not previously known to exist.

On a new inhibitor of photosynthetic electron-transport in isolated chloroplasts

1970 ◽  
Vol 25 (10) ◽  
pp. 1157-1159 ◽  
Author(s):  
A. Trebst ◽  
E. Harth ◽  
W. Draber
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Photosynthetic Electron Transport ◽  
Hill Reaction ◽  
High Concentration ◽  
Ferricyanide Reduction ◽  
The Hill ◽  
Photosystem I And Ii ◽  
Isolated Chloroplasts

A halogenated benzoquinone has been found to inhibit the photosynthetic electron transport system in isolated chloroplasts. 2·10-6ᴍ of dibromo-thymoquinone inhibit the Hill- reaction with NADP, methylviologen or anthraquinone to 100%, but do not effect the photoreduction of NADP at the expense of an artificial electron donor. The Hill - reaction with ferricyanide is inhibited even at the high concentration of 2·10-5ᴍ of dibromo-thymoquinone to only 60%. The remaining reduction in the presence of the inhibitor reflects the rate of ferricyanide reduction by photosystem II. It is concluded that the inhibition of electron transport by the quinone occurs between photosystem I and II and close to or at the functional site of plastoquinone.

Differential accumulation of plastid transcripts encoding photosystem II components in the mesophyll and bundle-sheath cells of monocotyledonous NADP-malic enzyme-type C4 plants

Planta ◽  
1991 ◽  
Vol 184 (3) ◽  
Author(s):  
Peter Westhoff ◽  
Karin Offermann-Steinhard ◽  
Michael H�fer ◽  
Kenneth Eskins ◽  
Angela Oswald ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Malic Enzyme ◽  
Bundle Sheath ◽  
C4 Plants ◽  
Bundle Sheath Cells ◽  
Sheath Cells

Effect of an Antiserum to a Thylakoid Membrane Polypeptide on the Primary Photoreaction of Photosystem II

1976 ◽  
Vol 31 (9-10) ◽  
pp. 594-600 ◽  
Author(s):  
Georg H. Schmid ◽  
Gernot Renger ◽  
Michael Gläser ◽  
Friederike Koenig ◽  
Alfons Radunz ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Electron Flow ◽  
Primary Electron ◽  
Hill Reaction ◽  
Ps Ii ◽  
Absorption Change ◽  
Oxygen Evolving ◽  
The Hill

Abstract As was described previously, an antiserum to polypeptide 11000 inhibited photosynthetic elec­tron transport on the oxygen evolving side of photosystem II. The effect of the antiserum on chloro­plasts from two tobacco mutants also clearly showed that the inhibition site is on the photosystem II-side of the electron transport chain. One of the two tobacco mutants lades the oxygen evolving capacity but exhibits some electron transport with tetramethyl benzidine, an artificial donor to PS II. In this mutant electron transport was barely inhibited. The effect of the antiserum on the primary photoevents showed that the initial amplitude of the absorption change of chlorophyll an at 690 nm and that of the primary electron acceptor X320 at 334 nm both diminished in the presence of the antiserum. Both signals were restored upon addition of diphenylcarbazide another artificial donor to photosystem II. Comparison of the degree of inhibition on the amplitudes of the fast and slow components of the 690 nm absorption change with the manometrically measured inhibition of electron transport shows that besides a full inactivation of a part of the reaction centers of photosystem II another part apparently mediates a fast cyclic electron flow around photosystem II as reported by Renger and Wolff earlier for tris-treated chloroplasts. Moreover, the antiserum affects the low temperature fluorescence in a way which is opposite to Murata’s effect of the Mg2+ -ion induced inhibition of energy spill-over from photosystem II to photosystem I. The antiserum under the condition in which the Hill reaction is inhibited lowered the 686 nm emission and enhanced the 732 nm emission which indicates an enhanced energy spill-over to photosystem I.

The effect of alpha terthienyl on photosynthesis

1982 ◽  
Vol 60 (12) ◽  
pp. 2565-2569 ◽  
Author(s):  
John Sinclair ◽  
Thor Arnason
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Electron Acceptor ◽  
Hill Reaction ◽  
Spinach Chloroplasts ◽  
Near Ultraviolet ◽  
A Site ◽  
The Hill ◽  
Clark Electrode

Alpha terthienyl (α-T), an allelopathic polyacetylene derivative occurring in the Asteraceae, was examined for its photosensitizing effect on respiration in Chlorella and photosynthesis in Chlorella and isolated spinach chloroplasts. In experiments with the Clark electrode, O2 evolution in saturating light with Chlorella was much more sensitive to α-T plus near ultraviolet (UV) treatments than respiration. O2 transients at the onset of illumination as measured with the modulated O2 polarograph were also inhibited by α-T plus near UV. The Hill reaction in uncoupled spinach chloroplasts using ferricyanide as electron acceptor is sensitive to photosensitization with α-T, but electron transport through photosystem I operating on its own showed no decrease in activity. The results are interpreted as an indication of a site of inhibition near photosystem II and possibly in CO2 fixation as well.

Sign in / Sign up

Export Citation Format

Share Document