Search for an endotherm in chloroplast lamellar membranes associated with chilling-inhibition of photosynthesis

P. S. Low, D. R. Ort, W. A. Cramer, J. Whitmarsh, B. Martin

Research output: Contribution to journalArticle

Abstract

The phase transition of chloroplast lamellar membrane lipids has been proposed to be the underlying cause of chilling-induced inhibition of photosynthesis in sensitive plants. Differential scanning calorimetry has been used to search for any endotherms arising from lipid state changes in chloroplast lamellar membranes of the chilling-sensitive plants cantaloupe, kidney bean, domestic tomato, and soybean. For comparison, calorimetric scans of chloroplast lamellar membranes from the chilling-insensitive plants spinach, pea, and wild tomato were made. A large reversible endotherm, extending from below 10 ° to nearly 40 °C, was observed in chloroplast membranes from tomatoes of both chilling-sensitive (Lycopersicon esculentum Mill. cv. Floramerica) and chillinginsensitive (L. hirsutum LA 1361) species. A much smaller endotherm, approximately 5 to 10% of the area of that seen in the two tomato species, and extending over a similar temperature range, was detected in chloroplasts from chilling-insensitive spinach and peas, and also was generally observed in chloroplasts from chilling-sensitive cantaloupe, kidney bean, and soybean. The enthalpy of these smaller endotherms indicates that, if the endotherm arose entirely from a lipid transition, then it corresponded to the melting of less than about 10% of the total membrane polar lipid. On the basis of these data it is concluded that there is no correlation between chilling sensitivity of photosynthesis and the presence or absence of a phase transition of bulk membrane lipids of the chloroplast lamellar membrane at temperatures above 5 °C.

Original languageEnglish (US)
Pages (from-to)336-344
Number of pages9
JournalArchives of Biochemistry and Biophysics
Volume231
Issue number2
DOIs
StatePublished - Jun 1984

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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