Simultaneous measurement of stomatal conductance, non-photochemical quenching, and photochemical yield of photosystem II in intact leaves by thermal and chlorophyll fluorescence imaging.
A new imaging system capable of simultaneously measuring stomatal conductance and fluorescence parameters, non-photochemical quenching (NPQ) and photochemical yield of photosystem II (Phi(PSII)), in intact leaves under aerobic conditions by both thermal imaging and chlorophyll fluorescence imaging was developed. Changes in distributions of stomatal conductance and fluorescence parameters across Phaseolus vulgaris L. leaves induced by abscisic acid treatment were analyzed. A decrease in stomatal conductance expanded in all directions from the treatment site, then mainly spread along the lateral vein toward the leaf edge, depending on the ABA concentration gradient and the transpiration stream. The relationships between stomatal conductance and fluorescence parameters depended on the actinic light intensity, i.e. NPQ was greater and Phi(PSII) was lower at high light intensity. The fluorescence parameters did not change, regardless of stomatal closure levels at a photosynthetically active photon flux (PPF) of 270 micro mol m(-2) s(-1); however, they drastically changed at PPF values of 350 and 700 micro mol m(-2) s(-1), when the total stomatal conductance decreased to less than 80 and 200 mmol m(-2) s(-1), respectively. This study has, for the first time, quantitatively analyzed relationships between spatiotemporal variations in stomatal conductance and fluorescence parameters in intact leaves under aerobic conditions.
Omasa
Kenji
K
Department of Biological and Environmental Engineering, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-8675 Japan. aomasa@mail.ecc.u-tokyo.ac.jp
Takayama
Kotaro
K
D000040:Abscisic Acid / Q000494:pharmacology; D000332:Aerobiosis; D000465:Algorithms; D002734:Chlorophyll / Q000378:metabolism* / Q000528:radiation effects; D005453:Fluorescence; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008027:Light; D027805:Phaseolus / Q000502:physiology / Q000528:radiation effects; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D019441:Plant Epidermis / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D018526:Plant Transpiration / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D013696:Temperature; D014867:Water / Q000502:physiology
D045322:Photosynthetic Reaction Center Complex Proteins; D010937:Plant Growth Regulators; D014867:Water; D002734:Chlorophyll; D000040:Abscisic Acid