Book with abstracts from the COST Action 0905 meeting in ... - UMB

IV. SIMULTANEOUS BIOFORTIFICATION OF Zn AND Fe IN
Triticum aestivum L. – KINETICS OF PHOTOCHEMICAL
REACTIONS IN ISOLATED THYLAKOIDS FRACTIONS ALONG
THE LIFE CYCLE
Fernando Cebola Lidon 1 , José Cochicho Ramalho 2 ,Paula Scotti-Campos 3 , Isabel P. Pais 3 ,
António Eduardo Leitão 2 , Ana Sofia Almeida 3 , Benvindo Maçãs 3 , José Prates Coutinho 3 ,
Maria Manuela Abreu da Silva 4 , Maria Paula Duarte 1 , Ana Luísa Fernando 1 , Ana Isabel
Ribeiro 2 , Luís Filipe Goulão 2 , Fernanda Simões 3 , Ana Rita Costa 3 , José Matos 3 , Fernando
Henrique Reboredo 1
1 DCTB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da
Torre, 2829-516 Caparica, Portugal.
2 Centro de Ecofisiologia, Bioquímica e Biotecnologia Vegetal, Instituto de Investigação
Científica Tropical, Quinta do Marquês, 2784-505 Oeiras, Portugal.
3 Instituto Nacional de Recursos Biológicos, Estrada de Gil Vaz, Apartado 6, 7350-591
Elvas / Estrada do Paço do Lumiar, 22 Ed. 5, 1649-038 Lisboa/ URGEMP, Quinta do
Marquês, 2784-505, Oeiras, Portugal.
4 ESE Almeida Garrett, Grupo Universidade Lusófona, COFAC, Palácio de Santa Helena,
Largo do Sequeira nº 7, Lisboa, Portugal.
Keywords: Photochemical reactions, Photosynthetic electron transporters, Triticum
biofortification
Certified seeds of Triticum aestivum L. cv Nabão (0Ts) were grown in walk-in growth
chamber (EHHF10000, Aralab, Portugal), under environmental controlled conditions (80%
RH; 24/20ºC day/night temperatures; PPFD of ca 700 µmol m -2 s -1 , 12 h photoperiod), in
pots irrigated with a standard solution (1Ts), during 1 month following germination.
Thereafter, until the end of the reproductive phase, half of the pots kept the same irrigation
solution (1Ts), but the others were submitted to a five fold concentration of all nutrients
(1T5s). The seeds 1T5s were grown again under the initial standard solution of nutrients
(2Ts) and to 5 times higher concentration of all the nutrients (2T5s). It was found that,
relatively to 0Ts, in the seeds of 2Ts and 2T5s, Zn concentration increased about 9.92 and
8.87 fold, whereas Fe augmented 3.91 and 4.95 times, respectively. In order to evaluate the
yield of quanta conversion implicating ATP and reducing equivalents synthesis, the
accumulation of Chl and carotenoids, as well as the Hill and Mehler reactions (H 2 O-MV,
H 2 O-DCPIP, DPC-DCPIP, DCPIPH 2 -MV) and photosynthetic electron carriers (Cyt f, b 563 ,
b 559LP , b 559HP and plastocyanin) were determined 52, 74 and 94 days following
germination. Trends of Chl and carotenoids content were 2T5s>2Ts>1Ts in the 52 nd day,
but in the other periods the higher values were detected in the 74 th day. The functioning of
PSII-OEC, PSI and PSI+PSII in most of the experimental periods showed higher rates in
2Ts. The contents of all the electron transport carriers kept its proportionality relatively to
Chl accumulation. In this context, specific targets in the thylakoid machinery, prompting
negative impacts or downregulation processes are presented and discussed.