Long-term chilling of young tomato plants under low light and subsequent recovery. II. Chlorophyll fluorescence, carbon metabolism and activity of ribulose-1,5-bisphosphate carboxylase/oxygenase

• Published in: Planta Vol. 186; no. 2; pp. 179 - 187
• Main Authors: Bruggemann, W. (Heinrich-Heine-Universitat, Dusseldorf, FRG), Kooij, T.A.W. van der, Hasselt, P.R. van
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 1992; Springer
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Biological and medical sciences; CHLOROPHYLLE; Chlorophylls; CLOROFILAS; Cooling; ENFRIAMIENTO; Fluorescence; FOTOSINTESIS; Fundamental and applied biological sciences. Psychology; Leaves; LIASAS; Low temperature; LUMIERE; LUZ; LYASE; LYCOPERSICON ESCULENTUM; Metabolism; METABOLISME DES GLUCIDES; METABOLISMO DE CARBOHIDRATOS; Phosphates; PHOTOSYNTHESE; Photosynthesis; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plants; PROPIEDADES OPTICAS; PROPRIETE OPTIQUE; REFROIDISSEMENT; Starches; Sugars; Chlorophyll; Temperature; Cold; Enzyme; Fluorescence; Ribulosebisphosphate carboxylase; Vegetable crop; Enzymatic activity; Dicotyledones; Angiospermae; Lycopersicon esculentum; Photoinhibition; Spermatophyta; Carbohydrate; Solanaceae; Biological accumulation; Photosynthesis
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/BF00196247

To identify possible reasons for the persisting impairment of photosynthesis after long-term chilling, young tomato (Lycopersicon esculentum Mill.) plants were exposed to 6-10 degrees C for two weeks under low illumination during the daily light period (60-100 micromole quanta.m-2.s-1). The time courses of leaf carbohydrate contents, phosphorylated intermediates and chlorophyll-fluorescence parameters were followed. While starch formation was impaired during chilling at 6 degrees C, soluble sugar contents increased from the first day onwards and reached up to eightfold the values found in unchilled plants within two weeks. At 8 and 10 degrees C, a less drastic increase in soluble-carbohydrate contents was observed. During chilling, glucose-6-phosphate and fructose-6-phosphate accumulated up to 16 mM (assuming they are restricted to the cytoplasm). At the same time, non-photochemical quenching of chlorophyll fluorescence had increased and did not return to control values during the first week of recovery. The 3-phosphoglyceric acid/triose phosphate ratio remained nearly unaffected by the chilling treatment, indicating that the assimilatory power of the plants was still high even at the low temperatures. As a consequence of the chilling treatment, ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco) activity in the chilled leaves was irreversibly decreased. It is suggested that, in addition to a possible (orthophosphate-mediated) feedback inhibition by internal sugar accumulation, the low activity of Rubisco can play a significant role in the strong decrease of photosynthetic capacity during long-term chilling in tomato