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

III. SIMULTANEOUS BIOFORTIFICATION OF Zn AND Fe IN
Triticum aestivum L. – IMPLICATIONS ON THE PHOTOSYNTHETIC
MACHINERY DURING THE LIFE CYCLE
José Cochicho Ramalho 1 , Ana Isabel Ribeiro 1 , Luís Filipe Goulão 1 , Paula Scotti-Campos 2 ,
Isabel P. Pais 2 , Benvindo Maçãs 2 , José Prates Coutinho 2 , Ana Sofia Almeida 2 , Ana Luísa
Fernando 3 , Maria Paula Duarte 3 , Maria Manuela Abreu da Silva 4 , António Eduardo
Leitão 1 , Fernanda Simões 2 , Ana Rita Costa 2 , José Matos 2 , 3 Fernando Henrique Reboredo,
3 Fernando Cebola Lidon 3
1 Centro de Ecofisiologia, Bioquímica e Biotecnologia Vegetal, Instituto de Investigação
Científica Tropical, Quinta do Marquês, 2784-505 Oeiras, Portugal.
2 Instituto Nacional de Recursos Biológicos, Estrada de Gil Vaz, Apartado 6, 7350-
591Elvas / Estrada do Paço do Lumiar, 22 Ed. 5, 1649-038 Lisboa/ URGEMP, Quinta do
Marquês, 2784-505, Oeiras, Portugal.
3 DCTB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da
Torre, 2829-516 Caparica, Portugal.
4 ESE Almeida Garrett, Grupo Universidade Lusófona, COFAC, Palácio de Santa Helena,
Largo do Sequeiro nº 7, Lisboa, Portugal
Keywords: Fluorescence, Photosynthesis, Scanning electron microscopy, 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. To understand the
mechanisms of photoassimilates mobilization to the seeds in these treatments, Chl a
fluorescence parameters (F o , F m , F v /F m , ETR, Φ e , q P , q N , NPQ and F v´/F m´) where
monitored 55, 73 and 91 days following germination. A progressive increase from 1Ts to
2Ts and between 2Ts and 2T5s was observed in most parameters. In these experimental
time periods the trend displayed by stomatal conductance (g s ) was 1Ts>2Ts>2T5s, but no
structural changes of stomata were found, as evaluated by SEM. Moreover, the rate of
photosynthesis (P n ) and the leaf internal CO 2 concentration (C i ) showed maximum values
in 2Ts and 1Ts, respectively. The transpiration rate (Tr) displayed higher values only in
2Ts, 55 and 73 days after germination. Considering these in vivo determinations, specific
targets prompting negative impacts or downregulation processes in the photosynthetic
machinery are presented and discussed.