Báo cáo khoa học: Compared sensitivity of seedlings from 3 woody species (Quercus robur L, Quercus rubra L and Fagus silvatica L) to water-logging and associated root hypoxia: effects on water relations and photosynthesis

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Báo cáo khoa học: "Compared sensitivity of seedlings from 3 woody species (Quercus robur L, Quercus rubra L and Fagus silvatica L) to water-logging and associated root hypoxia: effects on water relations and photosynthesis" article Original Compared sensitivity of seedlings from 3 woody species (Quercus robur L, Quercus rubra L and Fagus silvatica L) to water-logging and associated root hypoxia: effects on water relations and photosynthesis E Dreyer Écophysiologie, Unité d’Écophysiologie Forestière, INRA-Nancy, Bioclimatologie et F 54280 France Champenoux, 1993; accepted 25 October 1993) 7 June (ReceivedSummary - Seedlings of Quercus robur, Q rubra and Fagus silvatica were submitted to a period ofpartial (water table at 6 cm below ground) or total water-logging for 4 weeks. Important disorderswere induced by the latter treatment in growth (root decay, partial leaf wilting), water relations(decreased predawn water potential) and photosynthesis (stomatal closure, reduced netassimilation rates, lowered O evolution under saturating CO and irradiance, and limited 2 2photochemical efficiency of PS II). It has been concluded that the observed stomatal closure wasaccompanied by strong disorders at chloroplast level, which happened without visible water-logging-induced deficiencies in mineral nutrient supply. Reactions to partial water-logging weremuch more limited. F silvatica displayed the strongest disorders in response to both treatments, Qrobur showed only slight stress effects in response to partial water-logging and Q rubra hadintermediate behaviour. These observations are in agreement with the reported differences in to water-logging of adult trees in the stand. The precise chain of events leading to thesesensitivitydisorders in the shoots of water-logged seedlings remains to be elucidated.stomatal conductance / conductance / mineral nutrition / / hydraulic photochemistryphotosystem IIAbbreviations. ψ and ψ midday and predawn leaf water potential (MPa); PFD: photon flux density (μmol : wα wm-2 -1m s A: net CO assimilation rate (μmol m s g leaf conductance to water vapour (mmol m s c -2 -1 w -2 -1 i );: 2 ); ); :intercellular concentration of CO (μmol mol Δw: leaf to air difference in vapour mole fraction; g specific 2 ); -1 : Lhydraulic conductance from soil to leaves (mmol m s MPa Fo, Fm and Fo’, Fm’: basal and maximal -2 -1 -1);fluorescence after dark adaptation and 10 min at 220 μmol s respectively; Fv/Fm: photochemical efficiency of -2 -1 ,PS II in dark-adapted leaves: ΔF/Fm’ and Fv’/Fm’: photochemical efficiency of PS II and of open PS II centresafter 10 min at a given irradiance (220 or 800 μmol m s qp: photochemical quenching of fluorescence; A -2 -1 ); : maxmaximal rate of photosynthetic O evolution under 5% CO and 800 μmol mol irradiance (μmol O m s C: -1 2 -2 -1), 2 2control treatment; PF: partially water-logged treatment; F: completely water-logged treatment.Résumé - Sensibilité de jeunes ...