The event chain leading to germination blockage in durum wheat (Triticum turgidum ssp. durum Desf.) seeds exposed to the allelochemical coumarin (2H-chromen-2-one) was studied. The physiological and biochemical aspects thought to be critical for a successful seed germination were measured. At concentrations above 200 2M, coumarin inhibited seed germination in a concentration-dependent manner. Inhibition occurred early during seed imbibition (phase I), was rapid, and irreversible. During phase I, coumarin inhibited water uptake, electrolyte retention capacity, and O2 consumption. Later on, coumarin delayed the reactivation of peroxidases, enhanced the activity of superoxide dismutase, decreased the activities of selected marker enzymes for metabolic resumption, and repressed the transcription of molecular chaperons involved in secretory pathways. Insufficient and/or late seed rehydration caused by coumarin could have delayed membrane stabilization or decreased respiratory O2 consumption, both of which are conducive to an overproduction of reactive O2 species. Being unbalanced by an adequate upsurge of antioxidant defense systems, the resulting oxidative stress might have ultimately interfered with the germination program.
|Titolo:||The inhibitory effects of coumarin on seed germination in Triticum durum Desf. cv. Simeto|
|Data di pubblicazione:||2006|
|Appare nelle tipologie:||1.1 Articolo in rivista|