Abenavoli M R, Cacco G, Sorgonà A, Marabottini R, Paolacci A R, Ciaffi M, Badiani M
Dipartimento di Biotecnologie per il Monitoraggio Agro-Alimentare ed Ambientale (BIOMAA), Facoltà di Agraria, Università Mediterranea di Reggio Calabria, Loc. Feo di Vito, I-89124 Reggio Calabria, RC, Italy.
J Chem Ecol. 2006 Feb;32(2):489-506. doi: 10.1007/s10886-005-9011-x. Epub 2006 Apr 6.
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 microM: , 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 O(2) 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 chaperones involved in secretory pathways. Insufficient and/or late seed rehydration caused by coumarin could have delayed membrane stabilization or decreased respiratory O(2) consumption, both of which are conducive to an overproduction of reactive O(2) species. Being unbalanced by an adequate upsurge of antioxidant defense systems, the resulting oxidative stress might have ultimately interfered with the germination program.
研究了暴露于化感物质香豆素（2H-色烯-2-酮）的硬粒小麦（Triticum turgidum ssp. durum Desf.）种子中导致萌发受阻的事件链。对被认为对种子成功萌发至关重要的生理和生化方面进行了测定。在浓度高于200微摩尔时，香豆素以浓度依赖的方式抑制种子萌发。抑制作用在种子吸胀早期（阶段I）就已出现，迅速且不可逆。在阶段I期间，香豆素抑制水分吸收、电解质保留能力和氧气消耗。随后，香豆素延迟了过氧化物酶的重新激活，增强了超氧化物歧化酶的活性，降低了用于代谢恢复的特定标记酶的活性，并抑制了参与分泌途径的分子伴侣的转录。香豆素导致的种子复水不足和/或延迟可能会延迟膜稳定或降低呼吸氧气消耗，这两者都有利于活性氧的过量产生。由于抗氧化防御系统没有足够的增强来平衡，由此产生的氧化应激最终可能干扰了萌发程序。
