Sequential Loss of Photosynthetic Functions during Leaf Desiccation as Monitored by Chlorophyll Fluorescence Transient

概要

論文の詳細を見る
The effect of reduction in leaf water content on the complete chlorophyll α fluorescence transient of Dolichos leaf was monitored using a kinetic fluorescence monitor. Specific and sequential alterations in the profile of the fluorescence transient was observed as leaf water content was progressively decreased. Of all the characteristic, the PS_1M_1S_2M_2T (cf. Govindjee and Papageorgiou 1971) points of the fluorescence induction curve, the M_2 peak which is linked to CO_2 fixation potential of leaf, was extremely sensitive to desiccation. The extent of PS_1 phase of the transient diminished almost proportionally to leaf water content until the water content approached about 30%. The effect of strong additional illumination administered during the fluorescence transient suggests that the quenching of fluorescence due to desiccation is mostly linked to the redox-level of Q_A; the stable electron acceptor of photosytem II, and not to the changes in ΔpH formation or 'state changes'. Rewatering of desiccated leaves restored the fluorescence transient except in case of severe desiccation. The monitoring of fluorescence transient thus offers a diagnostic tool to assess the nature and the level of impairments due to loss in leaf water content.
日本植物生理学会の論文