Temperate and Tropical Tree Seed Physiology and the

Report
Forest tree seed research
Research Organisations specialising in above tend to be …
•Independent
•Isolated
from seed research more widely
&
•Timber Industry/Forest Environment focused
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)
Woody seed coat
1 cm
Massive in relation to embryo
Germination requires 3 years
95% of seeds of Ficus carica in this lot from Brazil were
without an embryo
60% seeds of Ficus lundellii from this lot from
Mexico were empty
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!
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)
Acer platanoides
5.00
4.00
3.00
2.00
80
Longevity (s, d)
Germination (%)
100
60
40
20
0.50
0.25
0.10
0.05
a
b
0.02
0
0
1.00
5
10
15
20
25
30
7
8
9 10
12 14 16 18 20
Moisture content (%, w.b.)
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 52°C (Dickie, J.B., May, B., Morris,
S.V.A., Titley, S.E. 1991. Seed Science Research 1: 149-162).
N
o
t
h
o
f
a
g
u
s
o
b
l
i
q
u
a
1
0
0
8
0
6
0
4
0
Normal germination (%)
2
0
1
3
.
8
%
1
2
.
6
%
1
0
.
2
%
7
.
3
%
5
%
2
.
9
%
0
1
0
0
8
0
6
0
4
0
2
0
0
1
0
0
8
0
6
0
4
0
2
0
0
01
8
03
6
05
4
07
2
00 1
8
03
6
05
4
07
2
0
S
t
o
r
a
g
e
p
e
r
i
o
d
s
(
d
a
y
s
)
o
0
C
o
1
0
C
o
2
0
C
Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
Negative logarithmic relation between seed
longevity and moisture content
N. alpina lot 1
1000
N. alpina lot 2
N. obliqua
Seed longevity (s.d; days)
100
10
1
1000
2N. glauca
3 4 5 6 8 10
15
2N. leonii
3 4 5 6 8 10
15
N. dombeyi
2
15
2
15
2
100
10
1
3 4 5 6 8 10
3 4 5 6 8 10
Seed moisture content (%, wb)
3 4 5 6 8 10
15
RECALCITRANT
Acer pseudoplatanus
Germination (%)
100
80
60
40
20
0
0
10
20
30
40
50
Moisture content (%, w.b.)
1.
Hong, T.D. and Ellis, R.H., 1990. New Phytologist, 116, 589-
60
Desiccation sensitivity
100
Castanea sativa
Quercus ilex
Quercus cerris
Germination (%)
80
60
40
20
0
10
15
20
25
30
35
40
45
Moisture content (% wb)
Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
50
55
60
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 10°C 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.
Coffea arabica
100
60
40
20
7.9% mc
10.5% mc
0
100
5.6% mc
15oC
0oC
-20oC
80
10.0% mc
cv. K7
Germination (%)
cv. N39
80
5.7% mc
7.9% mc
60
40
20
0
0
6
12 0
6
12 0
6
12
Storage duration (m)
Ellis, R.H., Hong, T.D. and Roberts, E.H. 1990. Journal of Experimental Botany, 41, 1167-1174.
Oil palm (Elaeis guineensis)
11.8%
100
6.5%
3.9%
Viability (%)
80
60
40
15oC
0oC
-20oC
20
0
0
6
12
0
6
12
0
6
12
Storage period (months)
Ellis, R.H., Hong, T.D., Roberts, E.H. and Soetisna, U. 1991. Seed Science Research, 1, 99-104.
Royal palm (Oreodoxa regia)
100
13.6% mc
10.4% mc
Germination (%)
80
60
40
20
20oC
0oC
-20oC
0
0
3
6 0
3
6
Storage period (months)
Ellis, R.H., Hong, T.D., Roberts, E.H. and Soetisna, U. 1991. Seed Science Research, 1, 99-104.
Fagus sylvatica
(a)
Temperate tree
species with
intermediate seed
storage behaviour
León-Lobos, P. and Ellis, R.H. 2002
Seed Sci. Res. 12: 31-37.
(b)
(a) observed viability after 730 days of
hermetic storage
(b) estimated viability after 730 days from
a model fitted to observations
throughout the 730-day storage period
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
Species with orthodox seeds
Diospyros mollis
Cananga odorata
Dracontomelon duperreanum
100
80
60
40
20
0
Germination (%)
100
Acacia auriculiformis
80
80
60
60
40
40
20
20
0
0
100
Afzelia xylocarpa
100
Sindora siamensis
0
Cassia splendida
10
20
30
40
50
Lagerstroemia speciosa
Chukrasia tabularis
80
60
40
20
0
0
10
20
30
40
50 0
10
20
30
40
50 0
Moisture content (%. w.b.)
Darwin Initiative for the Survival of Species
10
20
30
40
50
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)
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)
Species with intermediate seeds
100
Carissa carandas
Anisoptera cochinchinensis
Averrhoa carambola
Citrofortunella microcarpa
Hydnocarpus anthelmintica
Aphanamixis polystachya
80
Germination (%)
60
40
20
0
100
Citrus grandis
Mimusops elengi
80
60
40
20
0
0
10
20
30
40
50 0
10
20
30
40
50 0
10
20
30
Moisture content (%, w.b.)
Darwin Initiative for the Survival of Species
40
50 0
10
20
30
40
50
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)
Species with recalcitrant seeds
Melanorrhea laccifera
100
Dipterocarpus chartaceus
Melanorrhea usitata
80
60
40
20
0
Hopea odorata
Germination (%)
100
Machilus odoratissimus
Beitchmiedia roxburghii
80
60
40
20
0
100
Caryota mitix
Syzygium cinereum
Dimocarpus sp.
80
60
40
20
0
0
10
20
30
40
50 0
10
20
30
40
50 0
10
Moisture content (%, w.b.)
Darwin Initiative for the Survival of Species
20
30
40
50
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)
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 subsamples 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.
Picea sitchensis
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.
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.
DEVELOPMENT OF DESICCATION
TOLERANCE IN ORTHODOX SEEDS
Germination (%)
100
80
60
Acer platanoides
40
3 Sept. 1991
24 Sept. 1991
31 Oct. 1991
20
0
0
1.
10 20 30 40 50 60
Moisture content (%, w.b.)
Hong, T.D. and Ellis, R.H. 1992. Seed Science Research, 2, 169-172.
70
Survival curves of kapok (sumauma, Ceiba pentandra [L.]
Gaertn.) harvested at different dates
100
Germination (%)
80
Hermetic
storage at
40°C with 15.0
(0.2)% mc
60
40
5 Nov. 1996
18 Nov. 1996
29 Nov. 1996
9 Dec. 1996
19 Dec. 1996
20
0
0
20
40
60
80
100
120
Storage period (d)
Lima, M. de J.V.Jr., Ellis, R.H. and Ferraz, I.D.K. 2000. Seed Sci. & Tech., 28, 739-751.
EFFECT OF DRYING RATE ON DESICCATION
TOLERANCE OF IMMATURE SEEDS
Germination (%)
100
80
Acer platanoides
Harvested at mass maturity, about
40 d before natural shedding
60
dry rapidly
dry slowly for 24 d to 40.9% mc
dry slowly for 32 d to 29.9%mc
dry slowly for 39 d to 15.1% mc
dry slowly for 50 d to 5.6% mc
seeds stored moist for 21 d
Fruits stored moist for 21 d
40
20
0
10
20
30
40
Moisture content (%)
50
Hong, T.D. and Ellis, R.H. 1992. Seed Science Research, 2, 169-172.
60
Effect of post-harvest treatments on survival of
immature seeds of Cedrela odorata
Hermetic storage at 40oC with 15% mc
100
Viability (%)
80
60
40
Dried after harvest
Polythene bag, 10 d
20
Polythene bag, 20d
Open, 10 d
Open, 20 d
0
0
3
6
9
12
Storage period (d)
Lima, M.de J.V. Jr., Ellis, R.H., Hong, T.D. and Ferraz, I.D.K. 1998. Seed Sci. & Tech. 26, 813-821.
Lower-moisture-content limit for crops
Ellis, R.H., Hong, T.D. and Roberts, E.H. 1989. Annals of Botany, 63, 601-611.
Onion
Barley
Sugar beet
Wheat
Lower-moisture-content limit in two tree species
Seed longevity (s.d., days)
10.00
1.00
0.10
Nothofagus alpina
Nothofagus obliqua
0.01
1
2
3
4 5 6 7 8 1012 16
Moisture content (%, w.b)
Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
Lower-moisture-content limit for fungal spores
Metarhizium anisopliae
Longevity (s.d., days)
100.0
10.0
1.0
0.1
2
3 4 5
7
10
15 20
30 40
Moisture content (%, w.b.)
Hong, T.D., Jenkins, N.E., Ellis, R.H. and Moore, D. 1998. Annals of Botany, 81, 625-630.
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.
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

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