PLANT PHYSIOLOGY , Vol 110, Issue 3 997-1005, Copyright © 1996 by American Society of Plant Biologists
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WHOLE PLANT, ENVIRONMENTAL, AND STRESS PHYSIOLOGY |
Cool-Temperature-Induced Chlorosis in Rice Plants (I. Relationship between the Induction and a Disturbance of Etioplast Development)
R. Yoshida, A. Kanno, T. Sato and T. Kameya
Institute of Genetic Ecology, Tohoku University, Aoba-ku, Sendai 980-77, Japan
We have established an experimental system for mimicking the phenomenon of
cool-temperature-induced chlorosis (CTIC) in rice plants (Oryza sativa L.).
Rice seedlings were initially grown in darkness under cool-temperature
conditions and then exposed to light and warm conditions to follow the
expression of CTIC. Induction of CTIC in the sensitive cultivar (cv
Surjamukhi) was bimodally dependent on the temperatures experienced during
the initial growth in darkness. CTIC was maximally induced between 15 and
17[deg]C. A positive correlation was demonstrated between induction of CTIC
and the growth activity of shoots during growth in darkness.
Electrophoretic and immunoblot analysis revealed that accumulation of
NADPH-protochlorophyllide oxidoreductase in plastids was also bimodally
dependent on the temperatures during the growth in darkness with minimum
accumulation between 15 and 17[deg]C, suggesting that the reduction of
NADPH-protochlorophyllide oxidoreductase accumulation in plastids might be
closely linked to a disturbance in transformations of plastids to
etioplasts during the dark growth under the critical temperatures and
thereby to the CTIC phenomenon. This was corroborated by electron
microscopic observations. These results suggest that growth is one of the
determining factors for the expression of CTIC phenotype in rice under cool
temperature.