The relationship between chlorophyll content and photosynthetic performance in leaf segments during senescence.

Relationships between the quantum yield for electron transport further than QA (ETo/ABS) (A), WK (B), net O2 evolution rate (C), maximum quantum yield of PSII (Fv/Fm = TRo/ABS) (D), efficiency of electron move beyond QA (ETo/TRo) (E),absorption flux per cross section of leaf (ABS/CSo) (F), density of QAreducing PSII reaction centers(RC/CSo) (G), maximum PSI redox activity (ΔI/Io) (H) and leaf chlorophyll content in leaf segments treated with 0.7 mmol L−1 ethephon or water. “•” and “○” represent the stay-green inbred line of maize Q319 and the quick-leaf-senescence inbred lines of maize HZ4, respectively. The initial values of all the parameters in leaf segments before treatment were taken as 1, whereas those after treatment were taken as the proportion of the initial values. (Each datum is the average of 6 independent measurements.).