The QB site was changed reflected by the fluorescence transient and Vt curve, which was the key factor leading to inhibition of electron transporting to QB from QA resulting in the decline of primary photochemistry.

• 另外通过瞬时荧光曲线和Vt曲线可知衰老叶片中PSII反应中心QB位点发生了变化，并且我们认为该位点的变化导致了QA到QB的电子传递受到抑制（受体端抑制），并最终引起PSII原初光化学反应的降低。