ISSN:
1432-2048
Keywords:
Chilling
;
Chlorophyll fluorescence
;
Lycopersicon (chilling)
;
Photoinhibition
;
Photosynthate partitioning
;
Photosynthesis (chilling effects)
;
Ribulose-1,5-bisphosphate carboxylase/oxygenase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract 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° C for two weeks under low illumination during the daily light period (60–100 μmol 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° 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° 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00196247
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