German-Brazilian Workshop on Neotropical Ecosystems – Achievements and Prospects of Cooperative Research
Hamburg, September 3-8, 2000
Posters, Session 2: Biotic and Abiotic Interactions in Soil and Sediment
Mineral Exchange and Uptake in Bactris gasipaes Roots under Nutrient Solution Conditions
Emmerich, S.1,2, Kuhn, A. J.2,3, Lösch, R.1, Schröder, W. H.3 and Lieberei, R.2
1
Department of Geobotany, Heinrich-Heine-University Düsseldorf,
2
Institute of Applied Botany, University Hamburg,
3
Institute of Biological Information Processing, Research Centre Jülich
Abstract
The palm Bactris gasipaes is an important food source for
people in tropical South America and Central America. The
plant seems to adapt well even in degraded areas. In this
study, we investigated the uptake of potassium, calcium and
magnesium and the exchange of these minerals between
Bactris roots and a nutrient solution. The nutrient solution
was labelled with stable isotope tracers: 41K, 25Mg and 44Ca.
During the 48 hours of the experiment solution samples
were taken at different times. The samples were analysed by
ICP-OES and by laser-microprobe-mass-analyser. The
Bactris plants showed a distinct active net uptake of K in
spite of a great efflux of K from roots into the solution. The
results indicate different exchange mechanisms for monovalent K- and divalent Mg- and Ca-cations.
Fig. 2: 4-year old Bactris, pruned plants for palm heart production.
Bactris is probably the most suitable species for cultivation
and production of palm hearts (up to 3 t per hectare and
year) (MORAES 1994) (Fig. 2).
The Bactris root system typically develops into a compact
"carpet" with a thickness of several cm. The root layer is
located in the upper few cm of the mineral soil and at the
soil surface (Figs. 3 - 4) (EMMERICH 1997). The enormous
root layer may contribute to a successful nutrient uptake
under poor soil conditions.
In this study, we investigated the mineral uptake and the
exchange of minerals between roots and a nutrient solution.
Keywords
Ion uptake, Ion exchange, Potassium, Calcium, Magnesium,
Bactris, Root, Stable isotope
1
Introduction
The palm Bactris gasipaes is native to the Amazon region.
It is now cultivated throughout tropical South America and
Central America (FAO FORESTRY PAPER 1986). Bactris
produces high yields of fruits (Fig. 1), which are a rich
source of starch (up to 3.8 t per hectare and year in the
fruits), protein and oil (SMITH et al. 1992). Furthermore
Fig. 3: Bactris root layer.
Fig. 1: 4-year old Bactris with fruits.
Emmerich, S., Kuhn, A. J., Lösch; R., Schröder, W. H., Lieberei, R.:
Mineral Exchange and Uptake in Bactris gasipaes Roots under Nutrient Solution Conditions
863
German-Brazilian Workshop on Neotropical Ecosystems – Achievements and Prospects of Cooperative Research
Hamburg, September 3-8, 2000
Posters, Session 2: Biotic and Abiotic Interactions in Soil and Sediment
Fig. 4: Soil-core with Bactris roots mainly located in the upper
4 cm of the mineral soil.
2
Methods
Roots of seven intact young Bactris plants were exposed to
a nutrient solution for 48 hours. The conditions of the
experiment have been chosen according to the climate and
soil solution conditions of the agroforestry plantation near
Manaus / Brazil - solution pH 4.6, solution temperature
26 °C, 12 hour diurnal light rhythm, nutrient concentrations
similar to the soil solution (Fig. 5). The nutrient solution
41
25
contained stable isotope tracers: K - 36 µmol/l, Mg –
26 µmol/l and 44Ca - 70 µmol/l. During the 48 hours of the
experiment solution samples have been taken at different
times. The samples have been analysed by ICP-OES and by
laser-microprobe-mass-analyser (LAMMA). The LAMMA
is a laser light microscope with a high energy pulsed laser
fitted to a time-of-flight mass spectrometer. The instrument
is described in detail elsewhere (HILLENKAMP et al. 1975).
Isotope ratios of the labelled solution samples were determined by LAMMA (Fig. 6). Using this method it was possible to analyse not only the uptake of the cations but also
the exchange of the cations between the plants and the labelled nutrient solution (KUHN et al. 2000).
Fig. 6: a) LAMMA spectrum with natural isotope composition. b) LAMMA spectrum with different isotope ratios
after labelling with 25Mg, 41K, and 44Ca.
a.m.u.= atomic mass unit
V = detector voltage
3
Results and discussion
3.1
Uptake of cations
Five of seven Bactris plants examined showed a distinct
uptake of K (Fig. 7). Plants No. 3 and 7 showed a net release
of K into the nutrient solution. The K uptake was in close
linear correlation with the time (Fig. 9). The net uptake rate
of K amounted 2.2 µg per g root dry weight and hour (Fig.
8). The K uptake was 14-fold higher, than an exclusive
uptake with the transpiration stream would have caused.
Thus, K was actively transported across root membranes.
Fig. 5: The experimental conditions.
Emmerich, S., Kuhn, A. J., Lösch; R., Schröder, W. H., Lieberei, R.:
Mineral Exchange and Uptake in Bactris gasipaes Roots under Nutrient Solution Conditions
864
German-Brazilian Workshop on Neotropical Ecosystems – Achievements and Prospects of Cooperative Research
Hamburg, September 3-8, 2000
Posters, Session 2: Biotic and Abiotic Interactions in Soil and Sediment
Fig. 7: K release (-) and uptake (+) into the single plants.
Fig. 11: Mean net release of Mg per hour.
Fig. 8: Mean net uptake of K per hour.
Fig. 12: Ca release and uptake into the single plants.
Fig. 9: Linear regression of K uptake.
Fig. 13: Mean net release of Ca per hour.
Fig. 10: Mg release and uptake into the single plants.
Fig. 14: Label in % of total element content in the nutrient
solutions at different times of plant No. 6 as an example (2 min-48 h,
0 min=100% label). The decline of the curves reflects the release
of unlabelled K (Ca, Mg) from the plant into the solution.
Emmerich, S., Kuhn, A. J., Lösch; R., Schröder, W. H., Lieberei, R.:
Mineral Exchange and Uptake in Bactris gasipaes Roots under Nutrient Solution Conditions
865
German-Brazilian Workshop on Neotropical Ecosystems – Achievements and Prospects of Cooperative Research
Hamburg, September 3-8, 2000
Posters, Session 2: Biotic and Abiotic Interactions in Soil and Sediment
After one hour the Mg- and Ca-isotope ratio were nearly
constant. In contrast the labelled 41K decreased down to
about 5% of total K-content in the solution. This indicates
different exchange mechanisms for monovalent K- and
divalent Mg- and Ca-cations. The comparison of the
element exchange at the end of the experiment shows a high
variability between the 7 plants (Fig. 15). The absolute ion
fluxes can be calculated from these data.
Fig. 15: Remaining label in % of total element content in the nutrient solutions at the end of the experiment.
4
EMMERICH, S 1997: Distribution of roots of tropical useful plants in an
agroforestry system four years after installation. in: Annual Report 1997,
SHIFT-Project ENV 23/2, BMBF No. 0339457B, Institute of Applied
Botany, University of Hamburg and Empresa Brasileira de Pesquisa
Agropecuária- Amazônia Ocidental (EMBRAPA), 32-36
FAO FORESTRY PAPER 44/3 1986: Food and fruit-bearing forest
species, 3: Examples from Latin America., Food and Agriculture
Organisation of the United Nations, Rome, 45-48
HILLENKAMP, F., UNSÖLD, E., KAUFMANN, R., NITSCHE, R. 1975: A high
sensitivity laser microprobe mass analyser. Appl Phys, 8, 341-348
KUHN, A.J., SCHRÖDER, W.H., BAUCH, J., 2000: The kinetics of calcium
and magnesium entry into mycorrhizal spruce roots. Planta, 210,
488-496
MORAES, V.H. DE F., MÜLLER, C.H., SOUZA, A.G.C. DE, ANTONIO, I.C.,
1994: Native Fruit Species of Economic Potential from the Brazilian
Amazon, Angew. Bot. 68, 47-52
SMITH, N.J.H., WILLIAMS, J.T., PLUCKNETT, D.L., TALBOT, J.P., 1992:
Tropical Forests and their Crops. Cornell University Press. Ithaca
London, 303-310
Obviously the uptake of the divalent cations Mg and Ca
followed different kinetics (Figs. 10-13). The Bactris plants
needed about 48 hours to adapt to the solution conditions.
Under the given experimental conditions an efflux of these
cations was measured.
3.2
References
Exchange of cations
The net uptake or net release of elements is the difference
between the influx into roots and the efflux from roots into
a solution. Labelling of a nutrient solution with stable isotope tracers allows to study these element exchange
processes in detail. The exchange kinetics (Fig. 14, plant 6)
show a rapid element exchange during the first hour. For
example, after one hour about 52% of the K content in the
solution originated from the offered 41K-label and the remaining 48% from the plant. A fast element exchange between
the solution and the apoplasm of the roots is supposed.
Acknowledgement
The research project was carried out under the auspices of the agreement
on scientific-technological cooperation signed by the goverments of
Germany and Brazil. The German partner was sponsored by the Federal
Ministry of Education and Research (BMBF – project no. 01LT 0009). The
Brazilian Partner was sponsored by the Council for Scientific and
Technological Development (CNPq project no. 23/2).
The authors are grateful to MS. H. LIPPERT (Central Department of
Analytical Chemistry / Research Centre Jülich) for the ICP-OES
measurements.
Emmerich, S., Kuhn, A. J., Lösch; R., Schröder, W. H., Lieberei, R.:
Mineral Exchange and Uptake in Bactris gasipaes Roots under Nutrient Solution Conditions
866
Reinhard Lieberei 1, Helmut K. Bianchi 2, Vera Boehm 1, Christoph Reisdorff 1
Editors
1
Universität Hamburg, Institut für Angewandte Botanik, Ohnhorststr. 18, 22609 Hamburg, Germany
2
GKSS-Forschungszentrum Geesthacht GmbH, Max-Planck-Straße 1, 21502 Geesthacht Germany
Layout
Helmut K. Bianchi, GKSS, Karsten Bittner, Documedia, Geesthacht, Germany
Printing
GKSS-Forschungszentrum Geesthacht GmbH, Geesthacht, Germany
ISBN 3-00-010691-X
Lieberei, R., Bianchi, H-K., Boehm, V., Reisdorff, C., (eds.) 2002:
Neotropical Ecosystems, Proceedings of the German-Brazilian Workshop,
Hamburg 2000. GKSS-Geesthacht .
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