What determines the complex kinetics of stomatal conductance under blueless PAR in Festuca arundinacea? Subsequent effects on leaf transpiration

Light quality and, in particular, its content of blue light is involved in plant functioning and morphogenesis. Blue light variation frequently occurs within a stand as shaded zones are characterized by a simultaneous decrease of PAR and blue light levels which both affect plant functioning, for example, gas exchange. However, little is known about the effects of low blue light itself on gas exchange. The aims of the present study were (i) to characterize stomatal behaviour in Festuca arundinacea leaves through leaf gas exchange measurements in response to a sudden reduction in blue light, and (ii) to test the putative role of Ci on blue light gas exchange responses. An infrared gas analyser (IRGA) was used with light transmission filters to study stomatal conductance (gs), transpiration (Tr), assimilation (A), and intercellular concentration of CO2 (Ci) responses to blueless PAR (1.80 μmol m−2 s−1). The results were compared with those obtained under a neutral filter supplying a similar photosynthetic efficiency to the blueless PAR filter. It was shown that the reduction of blue light triggered a drastic and instantaneous decrease of gs by 43.2% and of Tr by 40.0%, but a gradual stomatal reopening began 20 min after the start of the low blue light treatment, thus leading to new steady-states. This new stomatal equilibrium was supposed to be related to Ci. The results were confirmed in more developed plants although they exhibited delayed and less marked responses. It is concluded that stomatal responses to blue light could play a key role in photomorphogenetic mechanisms through their effect on transpiration

Analyse du rendement de la conversion de l'énergie solaire par un couvert végétal

166 ref. Annexe 26 p. *INRA Bioclimatologie Centre Versailles-Grignon Diffusion du document : INRA Bioclimatologie Centre Versailles-Grignon Diplôme : Dr. d'Universit

Comparaison de modèles de transferts radiatifs pour simuler la distribution du rayonnement actif sur la morphogenèse ( MAR ) au sein d'un peuplement végétal à une échelle locale

CLERMONT FD-BCIU Sci.et Tech. (630142101) / SudocSudocFranceF

Characterization of photomorphogenetic responses of forage plants

International audienc

Empreintes genetiques chez les plantes : utilisation de sondes oligonucleotidiques a motifs simples repetes

Diplôme : D

Application aux couverts végétaux des lois de rayonnement en milieu diffusant. I - Etablissement des lois et vérifications expérimentales

National audienc

Assessment of morphogenetically active radiation within plant canopies from light tranfer modelling

International audienc