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Cold acclimation and freezing tolerance. A complex interaction of light and temperature

Author:
Gary, G.R., Chauvin, L.P., Sarhan, F., Huner, N.P.A.
Source:
Plant physiology 1997 v.114 no.2 pp. 467-474
ISSN:
0032-0889
Subject:
messenger RNA, dose response, redox reactions, net assimilation rate, light intensity, acclimation, Secale cereale, gene expression, transcription (genetics), frost resistance, photosynthesis, genes, temperature, plant morphology, chloroplasts
Abstract:
By comparing growth under five different temperature and irradiance regimes (20 degrees C and 800, 250, and 50 micromoles m-2 s-1 and 5 degrees C and 250 and 50 micromoles m-2 s-1), we have examined the effects of light, temperature, and the relative reduction state of photosystem II on plant morphology, freezing tolerance (lethal temperature at which freezing injury occurs [LT50]), transcript levels of Lhcb and two cold-stimulated genes (Wcs19 and Wcs120), and photosynthetic adjustment in winter rye (Secale cereale L. cv Musketeer). We show, for the first time to our knowledge, that in addition to adjustments in photosynthetic capacity, nonphotochemical quenching capacity and tolerance to photoinhibition, the accumulation of the cold-induced transcript Wcs19, and the compact plant morphology usually associated with cold-hardening are correlated with the relative reduction state of photosystem II rather than with growth temperature or growth irradiance per se. In contrast, the acquisition of maximal LT50, as well as Lhcb and Wcs120 mRNA accumulation, appears to be dependent on both growth temperature and growth irradiance but in an independent, additive manner. The results are discussed with respect to the possible role of the modulation of chloroplastic redox poise in photosynthetic acclimation to cold-hardening temperatures and the attainment of maximal LT50.
Agid:
664905