scholarly journals A comparison based on delayed light emission and fluorescence induction of intact chloroplasts isolated from mesophyll protoplasts and bundle-sheath cells of maize

1979 ◽  
Vol 180 (1) ◽  
pp. 253-256 ◽  
Author(s):  
R P Gregory ◽  
M Droppa ◽  
G Horváth ◽  
E H Evans
Keyword(s):  
Zea Mays ◽  
Light Emission ◽  
Fluorescence Induction ◽  
Bundle Sheath ◽  
Mesophyll Protoplasts ◽  
Delayed Light Emission ◽  
Low Intensity ◽  
Bundle Sheath Cells ◽  
Intact Chloroplasts ◽  
Dimethyl Urea

Chloroplasts or cells from maize (Zea mays) bundle sheath show a very low intensity of delayed light emission compared with mesophyll protoplasts or chloroplasts. The bundle-sheath chloroplasts retain only the fast (less than 1 ms) component of the emission. They also fail to show fluorescence induction in contrast to the mesophyll, which behaved normally. The mesophyll material could be made to resemble the bundle-sheath chloroplasts in respect of both phenomena by adding to it 1-(3′,4′-dichlorophenyl)-3,3-dimethyl-urea and hydroxylamine, together. It is concluded that Photosystem II, that gives rise to both effects, is not active in the bundle sheath but may be present in an inhibited form.

Functional characteristics of intact chloroplasts isolated from mesophyll protoplasts and bundle sheath cells of maize

Planta ◽  
1978 ◽  
Vol 141 (3) ◽  
pp. 239-244 ◽  
Author(s):  
G. Horv�th ◽  
M. Droppa ◽  
L. A. Must�rdy ◽  
�. Faludi-D�niel
Keyword(s):  
Bundle Sheath ◽  
Functional Characteristics ◽  
Mesophyll Protoplasts ◽  
Bundle Sheath Cells ◽  
Intact Chloroplasts ◽  
Sheath Cells

scholarly journals Excellent wavelength-dependence of laser-induced delayed light-emission from mesophyll and bundle-sheath cells of maize

1982 ◽  
Vol 206 (2) ◽  
pp. 415-418 ◽  
Author(s):  
D A Ross ◽  
S W McCauley ◽  
R H Ruby
Keyword(s):  
Methyl Viologen ◽  
Light Emission ◽  
Wavelength Dependence ◽  
Bundle Sheath ◽  
Excitation Wavelength ◽  
Mesophyll Cells ◽  
Delayed Light Emission ◽  
Tunable Dye Laser ◽  
Bundle Sheath Cells ◽  
Sheath Cells

Mesophyll and bundle-sheath cells from maize (Zea mays) were examined for delayed light-emission. An enzymic procedure was used to isolate the mesophyll and bundle-sheath cells. A tunable dye laser was used at 695-720 nm to excite delayed light-emission. The mesophyll cells show a typical Photosystem-II dependence on excitation wavelength for delayed light-emission, and this emission was eliminated by hydroxylamine and 3-(3,4-dichlorophenyl)-1,1-dimethylurea. The bundle-sheath cells show no delayed light-emission with these excitation wavelengths. Photosystem-I emission was not observed from either cell type, there being no effect of Methyl Viologen on the observed signals.

The photosynthetic carbon metabolism of Zea mays and Gomphrena globosa: the location of the CO2 fixation and the carboxyl transfer reactions

1970 ◽  
Vol 48 (4) ◽  
pp. 777-786 ◽  
Author(s):  
J. A. Berry ◽  
W. J. S. Downton ◽  
E. B. Tregunna
Keyword(s):  
Zea Mays ◽  
Bundle Sheath ◽  
Oxidative Decarboxylation ◽  
Gomphrena Globosa ◽  
Phosphorylated Compounds ◽  
Bundle Sheath Cells ◽  
Phosphoglyceric Acid ◽  
Photosynthetic Carbon Metabolism ◽  
Gradient Separation ◽  
Density Gradient Separation

Zea mays and Gomphrena globosa form labeled aspartate and malate (C4-acids) via β-carboxylation of P-enolpyruvate during photosynthesis. Studies of the redistribution of 14C in pulse- and chase-type feedings of 14CO2 indicate that most labeled phosphorylated compounds are formed from the C4-acids. A mechanism involving CO2 as a transitory intermediate is advanced to explain the carboxyl transfer from the C4-acids to 3-phosphoglyceric acid (3-PGA). In this model, CO2 is generated through the oxidative decarboxylation of malic acid by "malic" enzyme, and is refixed by RuDP carboxylase to form 3-PGA. The pattern of labeling of photosynthetic products, the extractable enzyme activities, and the gas exchange properties of these plants appear to be consistent with this proposed sequence of reactions. The location of 14C-labeled compounds was determined by radioautography, and by nonaqueous density gradient separation. Differential grinding was used to study the location of some photosynthetic enzymes. These indicate that CO2 fixation by β-carboxylation occurs in the leaf mesophyll. The carboxyl transfer and the reactions leading to the photosynthesis of starch appear to be confined predominantly to the bundle sheath cells. Rapid transport of C4-acids from the site of CO2 fixation in the mesophyll to the bundle sheath may occur by plasmodesmata.

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