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.