INVESTIGADORES
FLEXER Victoria
congresos y reuniones científicas
Título:
REAL TIME PHOTOSYNTHETIC MEASUREMENTS IN A LIVING PLANT
Autor/es:
VICTORIA FLEXER; MANO, N.
Lugar:
Sinaia
Reunión:
Conferencia; Journées d?Electrochemie 2009; 2009
Institución organizadora:
Groupe Électrochimie de la Société Chimique de France
Resumen:
Photosynthesis is one of the most important chemical reactions in nature. Plant metabolism alternates production and consumption of glucose and oxygen and this is mainly regulated by daylight. Most commercially available devices for measuring photosynthesis are based on CO2 consumption. In the work presented here we measured glucose and O2 production/consumption. We prepared all integrated redox enzyme biosensors to measure in real time the photosynthesis evolution and the plant respiration by following the glucose and O2 concentration increase or decrease during continuous illumination/darkness cycles. The enabling chemical components of the biosensors are electrocatalyic?wired? enzyme films comprising immobilized redox enzymes and redox hydrogels ?wiring? the enzymes reaction centers to electrodes. Phase separation of the enzyme and the hydrogel-forming cross-linked redox polymer is avoided by forming electrostatic adducts of the enzymes, which are polyanions, and their ?wires?, which are polycations. The glucose sensor film comprises polymer I (PVP-[Os(N,N?-dialkylated -2,2?-bis-imidazole)3]2+/+3 redox ) and glucose oxidase (GOx) from Aspergillus niger [1]; while the cathode electrocatalyst consists of bilirubin oxidase (BOD) from Trachyderma tsunodae and the copolymer of polyacrylamide and poly (N-vinylimidazole) complexed with [Os (4,4?-dichloro-2,2?-bipyridine)2Cl]+/2+ II  [2]. The electrodes were implanted in a plant and the glucose and oxygen generation or consumption were measured by chronoamperometry by poising the potential positive with respect to the GOx wire potential or negative with respect to the BOD wire potential. The experimental measurements were carried out on the whole leaf, i.e. no pretreatment or experimental preparation was performed on the plant other than implanting the three electrodes in it. Quantitative and reproducible cycles of current increases or decreases were measured upon illumination/darkness cycles.