title: Chlorophyll fluorescence induction, chlorophyll content, and chromaticity characteristics of leaves as indicators of photosynthetic apparatus senescence in arboreous plants.
abstract: Parameters of chlorophyll fluorescence induction (CFI) are widely used for assessment of the physiological state of higher plant leaves in biochemical, physiological, and ecological studies and in agricultural applications. In this work we have analyzed data on variability of some CFI parameters - ΦPSII(max) = Fv/Fm (relative value of variable fluorescence), qNPQ (non-photochemical quenching coefficient), RFd ("vitality index") - in autumnal leaves of ten arboreous plant species of the temperate climatic zone. The correlation between the chlorophyll content in the leaves and fluorescence parameters characterizing photosynthetic activity is shown for two representative species, the small-leaved linden Tilia cordata and the rowan tree Sorbus aucuparia. During the period of mass yellowing of the leaves, the ΦPSII(max) value can be used as an adequate characteristic of their photochemical activity, while in summer the qNPQ or RFd values are more informative. We have established a correlation between the ΦPSII(max) value, which characterizes the maximal photochemical activity of the photosystem II, and "chromaticity coordinates" of a leaf characterizing its color features. The chromaticity coordinates determined from the optical reflection spectra of the leaves serve as a quantitative measure of their hues, and this creates certain prerequisites for a visual expert assessment of the physiological state of the leaves.
authors.affiliation: Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119992, Russia. fxb@genebee.msu.su.
authors.forename: V V
authors.initials: VV
authors.lastname: Ptushenko
authors.forename: O S
authors.initials: OS
authors.lastname: Ptushenko
authors.forename: A N
authors.initials: AN
authors.lastname: Tikhonov
mesh_terms: D002734:Chlorophyll / Q000737:chemistry*; D005470:Fluorometry; D007700:Kinetics; D019660:Malvaceae / Q000737:chemistry* / Q000378:metabolism; D055668:Photochemical Processes; D010788:Photosynthesis / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D012621:Seasons; D031994:Sorbus / Q000737:chemistry* / Q000378:metabolism
chemical_list: D045332:Photosystem II Protein Complex; D002734:Chlorophyll