| Abstract
| - It has previously been shown that cotyledonary pricks induced modifications of ion levels (H+ and K+) in hypocotyl cells of Bidens pilosa. These modifications differed according to the light quality: H + levels increased and K+ levels decreased in white light (WL), whereas H+ levels decreased and K+ levels increased in blue light (BL). In this study, in order to determine the mechanism responsible for these ionic modifications, plasma membrane vesicles have been isolated and characterized from hypocotyl cells. The effects of light quality and cotyledonary pricks on plasma-lemma ATPase activity (EC 3.6.1.3) were studied. Cotyledonary pricks induced, in WL, rapid (5 min) and transient (restoration in 60 min) inhibition of plasmalemma ATPase activity. Conversely, in BL, a rapid and transient stimulation was observed. These results suggest that, in Bidens pilosa, plasmalemma ATPase is involved in 'short-term' ionic level modifications induced by traumatisms.
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