scholarly journals Fluorescence and Delayed Light Emission from Mesophyll and Bundle Sheath Cells in Leaves of Normal and Salt-Treated Panicum miliaceum

1989 ◽  
Vol 89 (1) ◽  
pp. 211-219 ◽  
Author(s):  
Quanning Li ◽  
Eugene A. Nothnagel
Keyword(s):  
Light Emission ◽  
Bundle Sheath ◽  
Panicum Miliaceum ◽  
Delayed Light Emission ◽  
Bundle Sheath Cells ◽  
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.

Effects of External Mg2+ and Ph on the Photosynthetic Activities and Stromal pH of Intact Chloroplasts Isolated From C4 Plants

1989 ◽  
Vol 16 (5) ◽  
pp. 379
Author(s):  
S Boag ◽  
A Agostino ◽  
RT Furbank ◽  
MD Hatch
Keyword(s):  
Bundle Sheath ◽  
O2 Evolution ◽  
Ionophore A23187 ◽  
Panicum Miliaceum ◽  
Bundle Sheath Cells ◽  
Photosynthetic O2 Evolution ◽  
Photosynthetic Activities ◽  
Isolated Chloroplasts ◽  
External Ph ◽  
Sheath Cells

Exogenous Mg2+ inhibited PGA- and OAA-dependent photosynthetic O2 evolution by isolated mesophyll chloroplasts from Zea mays and also HCO3--dependent O2 evolution by chloroplasts from Panicum miliaceum bundle sheath cells. Inhibition of 50-75% was observed with 3-5 mM Mg2+; this varied to some extent with pH but was not reversed by K+ . Inhibition of HCO3-- and PGA-dependent O2 evolution by the divalent cation ionophore A23187 was reversed by adding Mg2+ . Notably, HCO3-- dependent O2 evolution by isolated bundle sheath cells from P. miliaceum was not inhibited by [Mg2+] up to 20 mM. Addition of Mg2+ in the light decreased the stromal pH of mesophyll chloroplasts by less than 0.2 units but reduced apparent stromal volume by as much as 25%. At least for bundle sheath chloroplasts, stromal pH varied with external pH over the range from 7 to 8 but remained about 0.3 units higher throughout this range. Oxygen evolution by isolated mesophyll chloroplasts, and bundle sheath cells and chloroplasts, was relatively insensitive to external pH in the range from 7 to 8. The results are considered in terms of likely mechanisms for the effects of exogenous Mg2+ and pH on photosynthesis by isolated chloroplasts and the physiological significance of Mg2+ effects.

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.

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