Increase of ascorbic acid content and nutritional quality in spinach leaves during physiological acclimation to low temperature.
The effect of acclimation to 10 degrees C on the leaf content of ascorbic and oxalic acids, was investigated in spinach (Spinacia oleracea L.). At 10 degrees C the content of ascorbic acid in leaves increased and after 7 days it was about 41% higher than in plants remaining under a 25 degrees C/20 degrees C day/night temperature regime. In contrast, the content of oxalate, remained unchanged. Transfer to 10 degrees C increased the ascorbic but not the oxalic acid content of the leaf intercellular washing fluid (IWF). Oxalate oxidase (OXO EC 1.2.3.4) activity was not detected in extracts of leaf blades. Therefore, oxalic acid degradation via OXO was not involved in the control of its content. Our results show that low temperature acclimation increases nutritional quality of spinach leaves via a physiological rise of ascorbic acid that does not feed-forward on the content of oxalic acid.
Istituto di Biologia Agroambientale e Forestale, Consiglio Nazionale delle Ricerche, Viale Marconi 2, 05010 Porano (TR), Italy. simona.proietti@ibaf.cnr.it
Simona
S
Proietti
Stefano
S
Moscatello
Franco
F
Famiani
Alberto
A
Battistelli
D000064:Acclimatization / Q000502:physiology*; D001205:Ascorbic Acid / Q000378:metabolism*; D003080:Cold Temperature; D045604:Extracellular Fluid / Q000378:metabolism; D009753:Nutritive Value; D019815:Oxalic Acid / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D018724:Spinacia oleracea / Q000378:metabolism* / Q000502:physiology
D019815:Oxalic Acid; D010088:Oxidoreductases; C020598:oxalate oxidase; D001205:Ascorbic Acid