Full text: Mesures physiques et signatures en télédétection

50 
WAVELENGTH (nm) 
Fig. 8 Chlorophyll fluorescence spectra of a rice wild- 
type plant (Norin 8 ) leaf and chlorina mutant plant 
(CMV-15 and MGS- 88 ) leaves. Chlorophyll content 
and chlorophyll a/b ratio of the wild-type plant (a) 
were 45.0 nmol cm -2 and 2.9, the CMV-15 (b) 26.9 
nmol cm ' 2 and 8.5, and the MGS -88 (c) 22.9 nmol cm -2 
and more than 40.0. Fluorescences were induced by the 
At laser light (477 & 488 nm). 
and that by both antennas of photosystem I and II at 
60°C based on resolution of the spectra into the emitter 
component peaks (Figs. 1 & 2). High temperature is 
reported to induce dissociation of light-harvesting 
peripheral antenna from photosystem II (Goltsev et al., 
1987; Schreiber & Armond, 1978) which is caused by 
increased fluidity of thylakoid membrane lipids and 
thermal dénaturation of the membrane protein 
components (Berry & Bjorkman, 1980; Goltsev et al., 
1987), and to block activity of photosystem II (Berry & 
Björkman, 1980; Schreiber & Armond, 1978; Terzaghi 
et al., 1989). These facts are considered to induce the 
decrease of emissions from peripheral antennas of 
photosystem II, F680 and F685, and the increase of 
emissions from core antennas, F695 and F725. Further 
Fig. 9 Changes of proportions of the emitters in 
chlorophyll fluorescence with chlorophyll a/b ratio. 
Leaves of rice wild-type plants (Nipponbare and Norin 
8 ) and chlorina mutant plants (CMV-15, CMV-16, 
CMV-17, CMV-44 and MGS- 88 ) were used. The data 
used were the same as Fig. 8 . Symbols indicate • F680, 
O F685, □ F695, OF725 and A F745. 
LU 
GC 
WAVELENGTH (nm) 
Fig. 18 Chlorophyll fluorescence spectra of rice wild- 
type (Norin 8 ) and chlorina mutant (MGS- 88 ) plant 
leaves induced by 693 nm (diode-laser) light. 
Chlorophyll content of the wild-type plant(a) was 632 
nmol cm ' 2 and the chlorina mutant plant (b) 22.9 
nmol cm' 2 . 
perturbations on thylakoid membrane lipids and protein 
components above 50°C may induce dissociation of 
peripheral antenna of photosystem I (Fig. 2). 
Similar changes to that observed at 45°C were 
observed for leaves fumigated with exhaust gases of 
automobiles containing sulphur oxides and nitrogen 
oxides (Fig. 3). Sulphur oxides contained in the exhaust 
gases are reported to block the reaction center of 
photosystem II (Shimazaki & Sugahara, 1979), 
accounting for the increase of emissions from core 
antennas, F695 and F725. However, the chemicals seem 
to dissociate peripheral antenna of photosystem II based 
on the results of Fig. 3. The action of O 3 was different 
from that of the exhaust gases; mild fumigation of 0 ] 
decreased emission from peripheral antenna of 
photosystem I (Fig. 4b). The O 3 incorporated into cells
	        
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