Temperate and Tropical Tree Seed Physiology and the Economy of Nature

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Forest tree seed research
Research Organisations specialising in above tend
to be

• Independent
• Isolated
• from seed research more widely
• Timber Industry/Forest Environment focused

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DIFFICULTIES WITH TREE SEED RESEARCH

• Poor viability
• Considerable dormancy
• Full germination can take a long time
• Non-homogeneous seed lots
• Limited seed supply
• Variable supply (Inter-Annual Variation)

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Woody seed coat Massive in relation to
embryo Germination requires 3 years
1 cm
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95 of seeds of Ficus carica in this lot from
Brazil were without an embryo
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60 seeds of Ficus lundellii from this lot from
Mexico were empty
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SEED STORAGE SURVIVAL

• Three distinct categories of seed storage
  behaviour
• Orthodox
• Intermediate
• Recalcitrant
• Economy of Nature and the Search for Patterns
• If all 250,000 spp of flowering plants were
  unique in terms of post-collection physiology
  then agriculture, horticulture and forestry would
  probably never have developed!

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ORTHODOX

• Not just desiccation tolerance to very low
  moisture contents, but .
• Longevity increases in a predictable way with
  reduction in seed storage temperature and/or
  moisture content
• (Roberts, E.H. 1973, Seed Sci. Tech. 1, 499-514)

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Acer platanoides
a. Relation between seed moisture content (,
w.b.) and viability of Acer platanoides
harvested at maturity (31 Oct. 1991) (Hong, T.D.
and Ellis, R.H. 1992. Seed Science Research, 2,
169-172.) b. Negative logarithmic relation
between moisture content (, w.b) and longevity
(?, d) in hermetic storage of Acer platanoides
seeds at 52C (Dickie, J.B., May, B., Morris,
S.V.A., Titley, S.E. 1991. Seed Science Research
1 149-162).
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Pedro Leon-Lobos, Ph.D. Thesis, The University of
Reading, 2001
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Negative logarithmic relation between seed
longevity and moisture content
Pedro Leon-Lobos, Ph.D. Thesis, The University of
Reading, 2001
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RECALCITRANT
Acer pseudoplatanus
1.  Hong, T.D. and Ellis, R.H., 1990. New
Phytologist, 116, 589-596.
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Desiccation sensitivity
Pedro Leon-Lobos, Ph.D. Thesis, The University of
Reading, 2001
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INTERMEDIATE SEED STORAGE BEHAVIOUR
Seed storage longevity benefits to a considerable
extent from desiccation and/or reduction in
temperature, but longevity is decreased by
further reduction in temperature below about 10C
and/or by further reduction in moisture content
below apparent optimum values in equilibrium with
about 40-50 relative humidity. Ellis, R.H.,
Hong, T.D. and Roberts, E.H. 1990. Journal of
Experimental Botany, 41, 1167-1174.
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Coffea arabica
Ellis, R.H., Hong, T.D. and Roberts, E.H. 1990.
Journal of Experimental Botany, 41, 1167-1174.
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Oil palm (Elaeis guineensis)
Ellis, R.H., Hong, T.D., Roberts, E.H. and
Soetisna, U. 1991. Seed Science Research, 1,
99-104.
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Royal palm (Oreodoxa regia)
Ellis, R.H., Hong, T.D., Roberts, E.H. and
Soetisna, U. 1991. Seed Science Research, 1,
99-104.
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Fagus sylvaticaTemperate tree species with
intermediate seed storage behaviour
(a)
León-Lobos, P. and Ellis, R.H. 2002 Seed Sci.
Res. 12 31-37.  
(b)

• observed viability after 730 days of hermetic
  storage
• estimated viability after 730 days from a model
  fitted to observations throughout the 730-day
  storage period

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Tree Seed Science Research Project with Vietnam
(Darwin Initiative for the Survival of Species)
Among 33 tree species endemic to Vietnam
investigated, 16 showed orthodox seed storage
behaviour 9 showed recalcitrant seed storage
behaviour 8 showed intermediate seed storage
behaviour UAF Ms Truong Mai Hong, Mr Nguyen Duc
Xuan Chuong, Dr Le Quang Hung Forest Seed
Enterprise Ms Banh Ngoc Tam, Ms Vo Le Tam The
University of Reading Dr Tran Dang Hong,
Professor Richard Ellis
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Species with orthodox seeds
Darwin Initiative for the Survival of Species
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Species with orthodox seeds
Afzelia xylocarpa (Kurz.) Craib.
(Leguminosae) Adenanthera pavonina L.
(Leguminosae) Cassia fistula L. (Leguminosae)
Cassia javanica L. (Leguminosae) Dalbergia
bariaensis Pierre (Leguminosae) Peltophorum
pterocarpum (Leguminosae) Sindora siamensis
Teysm. Ex Miq. (Leguminosae) Lagerstroemia
speciosa (L.) Pers. (Lythraceae)
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Diospyros mollis Griff. (Ebenaceae) Melaleuca
cajuputi (Myrtaceae) Chukrasia tabularis A. Juss.
(Meliaceae) Pinus khasya Royle (Pinaceae) Pinus
massoniana Lambert (Pinaceae) Pinus merkusii
Jungh. de Vriese (Pinaceae) Dracontomelon
Duperreanum Pierre (Anacardiaceae) Sterculia
foetida L. (Sterculiaceae)
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Species with intermediate seeds
Darwin Initiative for the Survival of Species
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Species with intermediate seeds
Carissa carandas L. (Apocynaceae) Hydnocarpus
anthelmintica (Flacourtiaceae) Mimusops elengii
L. (Sapotaceae) Aphanamixis polystachya J.N.
Parker (Meliaceae) Averrhoa carambola
(Oxalydaceae) Citrofortunella microcarpa
(Rutaceae) Citrus grandis (Rutaceae) Anisoptera
cochinchinensis (Dipterocarpaceae)
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Species with recalcitrant seeds
Darwin Initiative for the Survival of Species
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Species with recalcitrant seeds
Beilschmiedia Roxburghiana Nees. (Lauraceae)
Caryota mitis Lour. (Palmae) Melanorrhoea
laccifera (Anacardiaceae) Melanorrhoea usitata
(Anacardiaceae) Dipterocarpus chartaceus
(Dipterocarpaceae) Hopea odorata
(Dipterocarpaceae) Machilus odoratissimus
(Lauraceae) Syzygium cinereum (Myrtaceae)
Dimocarpus spp. (Sapindaceae)
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Picea sitchensis
Effect of duration of storage at 3 0C on
viability (?) and ability to germinate at 10 0C
of Picea sitchensis Bong. Carr. Untreated
seeds (?) were prechilled for 14 weeks and then
tested for ability to germinate (?), redried and
samples tested for ability to germinate (?)
during subsequent air-dry storage. Results for
sub-samples prechilled for a second 14-week
period after 121 weeks of air-dry storage (?, ?)
are also shown
Jones, S.K., Gosling, P.G., and Ellis, R.H. 1998.
Seed Sci Res. 8 113-122.
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Picea sitchensis
From Jones, S.K., Ellis, R.H., and Gosling, P.G.
1997. Seed Sci. Res. 7 351-358.
Change in ability of seeds of Picea sitchensis
Bong. Carr. to germinate at 10 0C after moist
pre-treatment at a constant temperature of 20 0C
in two separate experiments (?, ). Solid line
shows a multiplicative model for changes in
ability to germinate with period of moist
pre-treatment at 20 0C comprising four submodels
loss in viability loss in conditional dormancy
re-imposition of conditional dormancy and
finally loss of this re-imposed conditional
dormancy.
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Dormancy cycling is not unique to this
species See Totterdell, S., and Roberts,
E.H. 1979. Effects of low temperatures on the
loss of innate dormancy and the development of
induced dormancy in seeds of Rumex obtusifolius
L. and Rumex crispus L. Pl. Cell Env. 2
131-137. but has not been widely
investigated.
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DEVELOPMENT OF DESICCATION TOLERANCE IN ORTHODOX
SEEDS
Acer platanoides
1.   Hong, T.D. and Ellis, R.H. 1992. Seed
Science Research, 2, 169-172.
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Survival curves of kapok (sumauma, Ceiba
pentandra L. Gaertn.) harvested at different
dates
Hermetic storage at 40C with 15.0 (?0.2) mc
Lima, M. de J.V.Jr., Ellis, R.H. and Ferraz,
I.D.K. 2000. Seed Sci. Tech., 28, 739-751.
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EFFECT OF DRYING RATE ON DESICCATION TOLERANCE OF
IMMATURE SEEDS
Hong, T.D. and Ellis, R.H. 1992. Seed Science
Research, 2, 169-172.
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Effect of post-harvest treatments on survival of
immature seeds of Cedrela odorata
Lima, M.de J.V. Jr., Ellis, R.H., Hong, T.D. and
Ferraz, I.D.K. 1998. Seed Sci. Tech. 26,
813-821.
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Lower-moisture-content limit for cropsEllis,
R.H., Hong, T.D. and Roberts, E.H. 1989. Annals
of Botany, 63, 601-611.
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Lower-moisture-content limit in two tree species
Pedro Leon-Lobos, Ph.D. Thesis, The University of
Reading, 2001
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Lower-moisture-content limit for fungal spores
Hong, T.D., Jenkins, N.E., Ellis, R.H. and Moore,
D. 1998. Annals of Botany, 81, 625-630.
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Lower-moisture-content limit for pollen
Hong, T.D., Ellis, R.H., Buitink, J., Walters,
C., Hoekstra, F.A. and Crane, J. 1999. Annals of
Botany, 83, 167-173.
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ACKNOWLEDGEMENTS

• IUFRO Symposium organisers
• Darwin Initiative for the Survival of Species
• Truong Mai Hong, Mr Nguyen Duc Xuan Chuong, Dr Le
  Quang Hung,
• Ms Banh Ngoc Tam, Ms Vo Le Tam
• Dr Pedro Leon, Dr Manuel Lima, Dr Steve Jones
• and particularly Dr Tran Dang Hong