Oxygen deficiency affects carbohydrate reserves in overwintering forage crops.
Anaerobic conditions developing under an ice cover affect winter survival and spring regrowth of economically important perennial crops. The objective was to compare, during a prolonged period of low (<2%) O2 at low temperature, the concentration of carbohydrates of four plant species contrasting in their resistance to oxygen deficiency. Four perennial forage species, lucerne (Medicago sativa L.), red clover (Trifolium pratense L.), timothy (Phleum pratense L.), and cocksfoot (Dactylis glomerata L.) were subjected to a progressively developing oxygen deficiency stress by enclosing potted plants in gas-tight bags in late autumn for overwintering in an unheated greenhouse. Timothy was previously reported to be more resistant to oxygen deficiency than the three other species. Non-structural carbohydrates increased and remained at a higher concentration in timothy than in the other three species under low O2 concentration. Concentrations of sucrose, fructose, glucose, and fructans increased in response to oxygen deficiency in timothy, whereas the concentration of soluble sugars decreased under the same conditions in lucerne, red clover, and cocksfoot. The gene expression of glyceraldehyde-3-phosphate dehydrogenase increased in response to low oxygen concentration in oxygen deficiency-sensitive lucerne while it remained unchanged in the oxygen deficiency-resistant timothy. It is concluded that timothy maintains higher carbohydrate reserves under oxygen deficiency, a specific feature that could favour its winter survival and spring regrowth.
Bertrand
Annick
A
Soils and Crops Research and Development Centre, Agriculture and Agri-Food Canada, 2560 Hochelaga Blvd., Sainte-Foy, Québec, Canada G1V 2J3. bertranda@agr.gc.ca
Castonguay
Yves
Y
Nadeau
Paul
P
Laberge
Serge
S
Michaud
Real
R
Bélanger
Gilles
G
Rochette
Philippe
P
D050260:Carbohydrate Metabolism; D003080:Cold Temperature; D031745:Dactylis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D024602:Glyceraldehyde-3-Phosphate Dehydrogenase (NADP+)(Phosphorylating) / Q000235:genetics / Q000378:metabolism; D019684:Magnoliopsida / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D000455:Medicago sativa / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology*; D031784:Phleum / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012621:Seasons; D029921:Trifolium / Q000187:drug effects / Q000235:genetics / Q000502:physiology
D024602:Glyceraldehyde-3-Phosphate Dehydrogenase (NADP+)(Phosphorylating); D010100:Oxygen