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 differentsoils with vegetative cover, Fagus sylvatica L. andPinus laricio Poiret, spp. calabrica, were tested atdifferent concentrations on seed of Pinus laricio. Wedetermined the activity of catalase, responsible for degradation of fatty acidto provide substrates for gluconeogenesis and malate synthase,phosphoenolpyruvate carboxykinase and isocitrate lyase, enzymes of theglyoxylicpathway. The data obtained show that all the phenolic compounds bioassayedaffected seed germination inhibiting catalase and glyoxylic enzymes. Theresultsshow that the inhibition of Pinus laricio seed germinationby phenolic compounds is clearly linked to low utilisation of storage lipidswith a consequent deficit in glucose, the main respiratory substrate.