Chl a fluorescence transients normalized between Fo to F_J in detached leaf segments during senescence.

<p>Chl a fluorescence transients in leaf segments from the two inbred lines of maize (Q319 and HZ4) before treatment (A), and after 3 days of treatment with 0.7 mmol L⁻¹ ethephon or water (B). Chl a fluorescence transients were normalized between Fo to F_J (Wt = (Ft–Fo)/(F_J–Fo)) (A, B). ΔWt (C) was obtained by subtracting the kinetics of the leaf segments before treatment from the kinetics of leaf segments 3 days after treatment. O indicates the O step at about 20 µs; K indicates the K step at about 300 µs; J indicates the J step at about 2 ms. (Each datum is the average of 6 independent measurements.).