Glyoxylate cycle in germination of Pinus laricio seeds: effects of phenolic compounds extracted from different forest soils

Low molecular weight phenolic compounds, identified in two different soils with vegetative cover, Fagus sylvatica L. and Pinus laricio Poiret, spp. calabrica, were tested at different concentrations on seed of Pinus laricio. We determined the activity of catalase, responsible for degradation of fatty acid to provide substrates for gluconeogenesis and malate synthase, phosphoenolpyruvate carboxykinase and isocitrate lyase, enzymes of the glyoxylic pathway. The data obtained show that all the phenolic compounds bioassayed affected seed germination inhibiting catalase and glyoxylic enzymes. The results show that the inhibition of Pinus laricio seed germination by phenolic compounds is clearly linked to low utilisation of storage lipids with a consequent deficit in glucose, the main respiratory substrate.