This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Lapointe, L. Articles by Ottander, C. Search for Related Content PubMed PubMed Citation Articles by Lapointe, L. Articles by Ottander, C. Agricola Articles by Lapointe, L. Articles by Ottander, C.

Environmental and Stress Physiology

Resistance to Low Temperature Photoinhibition Is Not Associated with Isolated Thylakoid Membranes of Winter Rye ¹

Department of Plant Sciences, University of Western Ontario, London, Canada N6A 5B7, Centre de Recherche en Photophysique, University du Québec à Trois Rivières, Québec, G9A 5H7, Department of Plant Physiology, University of Umeå, S-901 87 Umeå, Sweden

In vivo measurements of chlorophyll a fluorescence indicate that cold-hardened winter rye (Secale cereale L. cv Musketeer) develops a resistance to low temperature-induced photoinhibition compared with nonhardened rye. After 7.2 hours at 5°C and 1550 micromoles per square meter per second, the ratio of variable fluorescence/maximum fluorescence was depressed by only 23% in cold-hardened rye compared with 46% in nonhardened rye. We have tested the hypothesis that the principal site of this resistance to photoinhibition resides at the level of rye thylakoid membranes. Thylakoids were isolated from cold-hardened and nonhardened rye and exposed to high irradiance (1000-2600 micromoles per square meter per second) at either 5 or 20°C. The photoinhibitory response measured by room temperature fluorescence induction, photosystem II electron transport, photoacoustic spectroscopy, or [¹⁴C]atrazine binding indicates that the differential resistance to low temperature-induced photoinhibition in vivo is not observed in isolated thylakoids. Similar results were obtained whether isolated rye thylakoids were photoinhibited or thylakoids were isolated from rye leaves preexposed to a photoinhibitory treatment. Thus, we conclude that increased resistance to low temperature-induced photoinhibition is not a property of thylakoid membranes but is associated with a higher level of cellular organization.

¹ This research was supported by Natural Sciences and Engineering Research Council of Canada (NSERCC) operating grants to N.P.A.H. and R.C. L.L. gratefully acknowledges the support of an NSERCC postgraduate scholarship.