Acclimation of Arabidopsis leaves developing at low temperatures. Increasing cytoplasmic volume accompanies increased activities of enzymes in the Calvin cycle and in the sucrose-biosynthesis pathway.
Photosynthetic and metabolic acclimation to low growth temperatures were studied in Arabidopsis (Heynh.). Plants were grown at 23 degrees C and then shifted to 5 degrees C. We compared the leaves shifted to 5 degrees C for 10 d and the new leaves developed at 5 degrees C with the control leaves on plants that had been left at 23 degrees C. Leaf development at 5 degrees C resulted in the recovery of photosynthesis to rates comparable with those achieved by control leaves at 23 degrees C. There was a shift in the partitioning of carbon from starch and toward sucrose (Suc) in leaves that developed at 5 degrees C. The recovery of photosynthetic capacity and the redirection of carbon to Suc in these leaves were associated with coordinated increases in the activity of several Calvin-cycle enzymes, even larger increases in the activity of key enzymes for Suc biosynthesis, and an increase in the phosphate available for metabolism. Development of leaves at 5 degrees C also led to an increase in cytoplasmic volume and a decrease in vacuolar volume, which may provide an important mechanism for increasing the enzymes and metabolites in cold-acclimated leaves. Understanding the mechanisms underlying such structural changes during leaf development in the cold could result in novel approaches to increasing plant yield.
Strand
A
A
Department of Plant Physiology, University of Umeå, S-901 87 Umeå, Sweden.
Hurry
V
V
Henkes
S
S
Huner
N
N
Gustafsson
P
P
Gardeström
P
P
Stitt
M
M
D000064:Acclimatization; D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D002451:Cell Compartmentation; D003081:Cold Climate; D003593:Cytoplasm / Q000648:ultrastructure; D008854:Microscopy, Electron; D010710:Phosphates / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D013213:Starch / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014617:Vacuoles / Q000648:ultrastructure
D010710:Phosphates; D013395:Sucrose; D013213:Starch