Longevity of seeds in a glacier foreland of the Central Alps - a burial experiment Erich...
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Longevity of seeds in a glacier foreland of the Central Alps - a burial experiment Erich Schwienbacher & Brigitta Erschbamer Institute of Botany University of Innsbruck Contact: [email protected] 15th annual meeting of the Section Plant Population Biologie of the Society for Ecology, May 2002
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Transcript of Longevity of seeds in a glacier foreland of the Central Alps - a burial experiment Erich...
Longevity of seeds in a glacier foreland of the Central Alps
- a burial experiment
Erich Schwienbacher & Brigitta Erschbamer Institute of Botany
University of Innsbruck Contact: [email protected]: [email protected]
15th annual meeting of the Section Plant Population Biologie of the Society for Ecology, May 200215th annual meeting of the Section Plant Population Biologie of the Society for Ecology, May 2002
Introduction
Seed germination:
important life history trait
Seed banks:
important sources for the regeneration
Lack of knowledge about longevity of alpine seeds
Introduction
• Controversial opinions about the glacier foreland
burial experiment
• persistence of seeds is dependent on size
(1) small seeds long-lived
(2) big seeds short-lived
Hypotheses
• but independently of the size
(3) hard-coated seeds long-lived
ROTMOOSFERNERTyrol, Austria
burial site
2300 - 2400 m a.s.l. 46°49‘N 11°02‘E
glacier foreland
0 100 200 300 400
weight per 100 seeds [mg]
Saxifraga aizoidesSaxifraga oppositifolia
Linaria alpinaAchillea moschata
Artemisia genipiTrifolium pallescens
Oxyria digynaGeum reptans
Anthyllis alpestris
Species used for the experiment
Types of seeds
1 mm
• small
Saxifraga aizoides5 mm
• big
Anthyllis alpestris
1 mm
Trifolium pallescens
• hard-coated
Design of experiment
1-year
2-year
5-year
• 4 groups• 9 species • 100 seeds• 5 replicates
fresh
fiel
d e
xper
imen
t
Protocol of the burial experiment and the germination test
stratification (+ 4°C)
growth chamber: germination test - 10 daysgermination rate‚scarified seeds‘
scarification of hard-coated seeds
germination rate‚growth chamber‘growth chamber: germination test - 100 days
fresh seeds
field experiment
1-year burial
Protocol of the burial experiment and the germination test
fresh seeds
growth chamber: germination test - 10 days
scarification of hard-coated seeds
germination rate‚scarified seeds‘
germination rate‚growth chamber‘
growth chamber: germination test - 100 days
stratification (+ 4°C)
stratification +germination in the field
germination rate‚field‘
Protocol of the burial experiment and the germination test
field experiment
1-year burialfresh seeds
growth chamber: germination test - 10 days
scarification of hard-coated seeds
germination rate‚scarified seeds‘
germination rate‚growth chamber‘
growth chamber: germination test - 100 days
stratification + germination in the field
stratification (+ 4°C)
germination rate‚field‘
2-year burial 5-year burial
Results
• fresh seeds
0
25
50
75
100
0 25 50 75 100
time [days]
germ
inatio
n r
ate
[%
]
Saxifraga aizoides
Artemisia genipi
Oxyria digyna
Anthyllis alpestris
Results
• fresh seeds:
• 1-year burial:
but: increasing germination rates
with increasing seed weight
high germination rates
(42.7 % ± 34.7)
mostly low germination rates
(10.6 % ± 13.8)
Results
-2.5 -2.0 -1.5 -1.0 -0.5
-0.4
0.4
1.2
2.0
log seed weight
log
no
. o
f se
edli
ng
s
R²=0.82
Regression: seed weight/number of seedlings
• 1-year burial
Results
• fresh seeds • 1-year burial
hard-coated seeds:
germination rate [%]
0
25
50
75
no scarification scarification
germination rate [%]
0
25
50
75
no scarification scarification
Linaria alpina, Trifolium pallescens, Anthyllis alpestris
Conclusions
(1) hard-coated seeds
(2) big seeds
(3) small seeds
loose their viability during the first winter ?
secondary dormancy takes place ?or
potential to form persistent seed banks
germinate after the first year in the field
Future
• For how long do seeds persist in the glacier foreland?
• 2-year burial
• 5-year burial
Acknowledgements
• Jürg Stöcklin
• Colleagues of the Univ. Innsbruck
• Austrian Academy of Science
Thank you for your attention!
Contact: [email protected]: [email protected]
