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