Book of Abstracts - Geyseco

FESPB 2010 - XVII Congress of the Federation of European Societies of Plant Biology
the function of Si in mitigation of toxic effects of Cd in widely
used crop – maize. Seedlings of Zea mays L. cv. Jozefina were
cultivated in hydroponics in Hoagland solution in standard control
conditions and in excess of Cd, Si and both Cd+Si. Various
treatments have been compared: control (C), Cd (5μM
Cd(NO 3
).4 H 2
O), Si (5 mM Si in the form of sodium silicate
solution) and Cd+Si. Cadmium caused decrease of growth parameters
(root length, root and shoot fresh and dry weight, leaf
area). Extensibility of root cell walls was decreased by Cd, this
was significantly alleviated when Si was added to Cd treatment.
When Cd+Si was applied, the content of Cd was higher both in
the below-and above-ground plant parts when compared with the
control. This corresponded with the changes in apoplastic barrier
development – endodermal suberin lamellae formed more distant
from the root apex when Si was applied together with Cd. Activity
of four antioxidative enzymes and non-enzymatic antioxidant
ascorbate, as well as content of chlorophyll and carotenoids in
the first two fully developed leaves were also significantly influenced
by Si when compared with non-Si treated plants. We
suppose that beneficial role of Si in mitigation of Cd toxicity is
based on “in planta mechanism” and Si is probably actively involved
in several metabolic pathways running in plants.
P01-046: ENHANCED SALT STRESS TOLERANCE OF
CYANOBACTERIUM SYNECHOCYSTIS EXPRES-
SING PLANT AND MICROBIAL MEMBRANE PYRO-
PHOSPHATASES
Serrano, A* - Drake, R. - Perez C.
IBVF, CSIC-Univ. de Sevilla
*Corresponding author, e-mail: aurelio@ibvf.csic.es
Cyanobacteria are unique prokaryotes performing oxygenic photosynthesis,
and possessing plasma- and thylakoid membranes.
However, in contrast to other major groups of photosynthetic
prokaryotes they lack of proton-translocating pyrophosphatases
(H-PPases), the simplest primary proton pumps known to date.
Genes encoding H-PPases of the embriophyte Arabidopsis thaliana
(AVP1 isoform), the euglenozoan protist Trypanosoma
cruzi and the green non-sulfur photobacterium Chloroflexus
aurantiacus have been functionally expressed in the freshwater
(moderately salt tolerant) cyanobacterium Synechocystis
PCC6803. In contrast to control cells, the transformed clones exhibited
high levels of membrane-bound PPase activity and the
70 kDa H-PPase subunit was immunodetected in both thylakoid
and plasma membranes. Noteworthy, the transformed PCC6803
clones show enhanced tolerance to severe salt stress, being able
to growth in the presence of 1.0-1.5, M NaCl, which are lethal
conditions for control cells. The comparatively higher PSII activity
measured in the transformed clones indicates a better preserved
photosynthetic apparatus. These results strongly suggest that
pyrophosphate (PPi) can be used as alternative energy source by
the transformed clones, and are in agreement with our proposal
of PPi and H-PPases being involved in a PPi-based sustainable
bioenergetics that should be an adaptative advantage under environmental
conditions that severely constrain the cellular energy
status. Supported by grant BFU2007-61887/BMC (MICINN,
Spain) and PAIDI group BIO-261 (Junta de Andalucía)
P01-047: EFFECT OF AQUAPORIN EXPRESSION ON
LOW ROOT TEMPERATURE RESPONSES IN ARABI-
DOPSIS
Zwiazek, J.* - Lee, S-H. - Chung, G-C. - Oh, M-N - Hong, S-W. -
Kang, H.
University of Alberta
*Corresponding author, e-mail: jzwiazek@ualberta.ca
Effects of low root temperature were studied in the wild-type
and transgenic Arabidopsis that constitutively overexpress
PIP1;4, PIP2;5 aquaporins (AQPs) and in double knockout
(PIP1;1×PIP2;6, PIP1;2×PIP2;6, TIP3;1×TIP3;2) lines. Plants
were grown in solution culture in a growth room at 25oC with
their roots exposed to temperatures ranging from 5ºC to 25ºC.
No differences in growth were observed in the wild-type, overexpressing
PIPs and double knockout lines at higher root temperatures.
However, plants overexpressing PIP2;5 had higher growth
rates under the low root temperature (10ºC). When measured at
20 and 25ºC, hydraulic conductivity of root cortical cells (Lp)
was similar in the wild-type plants and plants overexpressing
PIPs. However, in the double knockout plants, Lp was lower
compared with the wild-type plants. Descending temperatures
series (from 25 to 10ºC in 5ºC steps) caused a strong reduction
of L p
in the wild-type, double knockout PIP and TIP plants, but
not in the plants overexpressing PIP2;5 and PIP1;4. Whenthe
temperature was increased from 10 to 25ºC, irreversible changes
of half-times of water exchange (T 1/2
) were obtained in the
wild-type, double knockout PIP and TIP plants suggesting longer-term
conformation changes of AQPs. Application of HgCl2
(AQP blocker) reversibly inhibited L p
by about 3-4-fold in the
wild-type and double knockout PIP plants, and caused smaller
reductions of L p
in plants overexpressing PIPs and double TIP
knockout plants. The results suggest that increased abundance
of PIPs was helpful in maintaining water uptake under low root
temperature and that the overexpression of AQPs may be a useful
trait in plants growing in cold soils.
P01-048: ARE THERE CULTIVAR DIFFERENCES
ALONG EARLY RICE DEVELOPMENT THAT REFLECT
THE FURTHER EFFECT OF SALINITY ON PRODUCTI-
VITY?
Wankhade, S. - Cornejo, M.J. - Mateu, I. - Sanz, A.*
Universitat de València
*Corresponding author, e-mail:amparo.Sanz@uv.es
The traditional rice cultivar Bomba is highly appreciated due to
the grain organoleptic properties. Its productivity, however, is
affected not only by high plant size but also by salt sensitivity.
We compared the effects of saline stress on development and leaf
anatomical features of this cultivar with other japonica cultivars
less affected by salinity (Taipei 309, Bahia). Our results show
that salt sensitivity is mainly associated with the ionic component
of salinity. Thus, the inhibition of growth in cv Bomba seedlings
was stronger under saline than under osmotic stress and some
anatomical features, particularly those related to the conducting
tissue (i.e. size of xylem vessels) were altered to a higher extent
by NaCl than by sorbitol. Along the vegetative growth stage the
pattern of anatomical variations caused by salinity in leaves persisted.
Concomitantly, there was a stronger reduction in chlorophyll
content and in maximum potential efficiency of PSII (Fv/
Fm), together with a decrease of net CO 2
assimilation rate (P N
).
Since transpiration rates (E) were scarcely affected, it results in
lowered water use efficiency (WUE) values. Only plants subjected
to low NaCl concentrations (10 and 20 mM) reached the
reproductive stage. The anatomical variations observed at this
stage showed that even 20 mM NaCl appeared to be an excessive
dosage for this cv, which reduced four-fold the number of panicles
formed in comparison to cv Bahia. Thus, differences in sensitivity
to osmotic and saline stress between developing seedlings
of these cultivars reflect further differences in salt sensitivity during
flowering. The genetic relations among these cultivars has
been studied by SSR markers and will also be presented.
P01-049: CELL LINES WITH DIFFERENT LEVELS OF
STRESS TOLERANCE ASA MODEL SYSTEM TO STUDY
RESPONSES TO DEHYDRATION STRESSES IN RICE.
Sanz, A. - Pons, R. - Cornejo, M.J.*
Universitat de València
*Corresponding author, e-mail: Maria.J.Cornejo@uv.es
As compared to plants, cell lines are a relatively homogeneous
and simplified experimental system which avoids tissue speci-