Forest tree seed research Independent Isolated from seed research more widely & Timber...
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Transcript of Forest tree seed research Independent Isolated from seed research more widely & Timber...
Forest tree seed research
•Independent
•Isolated
from seed research more widely
&
•Timber Industry/Forest Environment focused
Research Organisations specialising in above tend to be …
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)
1 cmWoody seed coatMassive in relation to embryoGermination 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)
a
Moisture content (%, w.b.)
0 5 10 15 20 25 30
Ger
min
atio
n (%
)
0
20
40
60
80
100
b
7 8 9 10 12 14 16 18 20
Long
evity
(s,
d)
0.02
0.05
0.10
0.25
0.50
1.00
2.003.004.005.00
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 52°C (Dickie, J.B., May, B., Morris, S.V.A., Titley, S.E. 1991. Seed Science Research 1: 149-162).
Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
2 3 4 5 6 8 10 15
See
d lo
ngev
ity (
s.d;
day
s)
1
10
100
1000
2 3 4 5 6 8 10 15
2 3 4 5 6 8 10 15
Seed moisture content (%, wb)
2 3 4 5 6 8 10 15
1
10
100
1000
2 3 4 5 6 8 10 15
N. alpina lot 1 N. alpina lot 2 N. obliqua
N. leoniiN. glauca N. dombeyi
Negative logarithmic relation between seed longevity and moisture content
Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
RECALCITRANT
Moisture content (%, w.b.)
0 10 20 30 40 50 60
Ge
rmin
atio
n (
%)
0
20
40
60
80
100
Acer pseudoplatanus
1. Hong, T.D. and Ellis, R.H., 1990. New Phytologist, 116, 589-
596.
Moisture content (% wb)
10 15 20 25 30 35 40 45 50 55 60
Ger
min
atio
n (%
)
0
20
40
60
80
100Castanea sativa
Quercus ilex
Quercus cerris
Desiccation sensitivity
Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
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.
10.5% mc
Ge
rmin
atio
n (
%)
0
20
40
60
80
100
15oC
0oC
-20oC
7.9% mc 5.6% mc
10.0% mc
Storage duration (m)0 6 12
0
20
40
60
80
100
7.9% mc
0 6 12
5.7% mc
0 6 12
cv.
N3
9c
v. K
7
Coffea arabica
Ellis, R.H., Hong, T.D. and Roberts, E.H. 1990. Journal of Experimental Botany, 41, 1167-1174.
11.8%
Storage period (months)
0 6 12
Via
bilit
y (%
)
0
20
40
60
80
100
15oC 0oC-20oC
6.5%
0 6 12
3.9%
0 6 12
Oil palm (Elaeis guineensis)
Ellis, R.H., Hong, T.D., Roberts, E.H. and Soetisna, U. 1991. Seed Science Research, 1, 99-104.
Storage period (months)
0 3 6
Ge
rmin
atio
n (%
)
0
20
40
60
80
100
0 3 6
20oC 0oC
-20oC
10.4% mc 13.6% mc
Royal palm (Oreodoxa regia)
Ellis, R.H., Hong, T.D., Roberts, E.H. and Soetisna, U. 1991. Seed Science Research, 1, 99-104.
Fagus sylvatica
Temperate tree species with
intermediate seed storage behaviour León-Lobos, P. and Ellis, R.H. 2002 Seed Sci. Res. 12: 31-37.
(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
(a)
(b)
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
Dracontomelon duperreanum
Ge
rmin
atio
n (
%)
0
20
40
60
80
100 Cananga odorata Diospyros mollis
Afzelia xylocarpa
0 10 20 30 40 50
0
20
40
60
80
100
Chukrasia tabularis
Moisture content (%. w.b.)0 10 20 30 40 50
Acacia auriculiformis
0
20
40
60
80
100
Sindora siamensis
0 10 20 30 40 50
0
20
40
60
80
100
Cassia splendida
Lagerstroemia speciosa
0 10 20 30 40 50
Species with orthodox seeds
Darwin Initiative for the Survival of Species
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)
Species with orthodox seeds
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)
Carissa carandas
0
20
40
60
80
100 Anisoptera cochinchinensis Hydnocarpus anthelmintica Aphanamixis polystachya
Averrhoa carambola
Moisture content (%, w.b.)
0 10 20 30 40 50
Ger
min
atio
n (%
)
0
20
40
60
80
100 Citrofortunella microcarpa
0 10 20 30 40 50
Citrus grandis
0 10 20 30 40 50
Mimusops elengi
0 10 20 30 40 50
Species with intermediate seeds
Darwin Initiative for the Survival of Species
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 intermediate seeds
Caryota mitix
0 10 20 30 40 50
Dimocarpus sp.
0 10 20 30 40 50
Melanorrhea laccifera
0
20
40
60
80
100 Dipterocarpus chartaceus
Hopea odorata
Ge
rmin
atio
n (
%)
0
20
40
60
80
100 Beitchmiedia roxburghii Machilus odoratissimus
Syzygium cinereum
Moisture content (%, w.b.)
0 10 20 30 40 50
0
20
40
60
80
100
Melanorrhea usitata
Species with recalcitrant seeds
Darwin Initiative for the Survival of Species
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)
Picea sitchensisJones, S.K., Gosling, P.G., and Ellis, R.H. 1998. Seed Sci Res. 8: 113-122.
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
Picea sitchensis
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.
From: Jones, S.K., Ellis, R.H., and Gosling, P.G. 1997.
Seed Sci. Res. 7: 351-358.
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.
Moisture content (%, w.b.)0 10 20 30 40 50 60 70
Ger
min
atio
n (%
)
0
20
40
60
80
100
3 Sept. 199124 Sept. 199131 Oct. 1991
DEVELOPMENT OF DESICCATION TOLERANCE IN ORTHODOX SEEDS
Acer platanoides
1. Hong, T.D. and Ellis, R.H. 1992. Seed Science Research, 2, 169-172.
Storage period (d)
0 20 40 60 80 100 120
Ger
min
atio
n (%
)
0
20
40
60
80
100
5 Nov. 199618 Nov. 199629 Nov. 19969 Dec. 199619 Dec. 1996
Survival curves of kapok (sumauma, Ceiba pentandra [L.]
Gaertn.) harvested at different dates
Hermetic storage at 40°C 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.
Moisture content (%)
0 10 20 30 40 50 60
Ger
min
atio
n (%
)
20
40
60
80
100
dry rapidlydry slowly for 24 d to 40.9% mcdry slowly for 32 d to 29.9%mcdry slowly for 39 d to 15.1% mcdry slowly for 50 d to 5.6% mcseeds stored moist for 21 dFruits stored moist for 21 d
Acer platanoides
Harvested at mass maturity, about 40 d before natural shedding
EFFECT OF DRYING RATE ON DESICCATION TOLERANCE OF IMMATURE SEEDS
Hong, T.D. and Ellis, R.H. 1992. Seed Science Research, 2, 169-172.
Hermetic storage at 40oC with 15% mc
Storage period (d)
0 3 6 9 12
Via
bilit
y (%
)
0
20
40
60
80
100
Dried after harvest
Polythene bag, 10 d
Polythene bag, 20dOpen, 10 d
Open, 20 d
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.
Onion Sugar beet
Barley Wheat
Lower-moisture-content limit for cropsEllis, R.H., Hong, T.D. and Roberts, E.H. 1989. Annals of Botany, 63, 601-611.
Moisture content (%, w.b)
1 2 3 4 5 6 7 8 1012 16
Se
ed
lon
ge
vity
(s.
d.,
da
ys)
0.01
0.10
1.00
10.00
Nothofagus alpinaNothofagus obliqua
Lower-moisture-content limit in two tree species
Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
Metarhizium anisopliae
Moisture content (%, w.b.)
2 3 4 5 7 10 15 20 30 40
Lo
ng
evi
ty (
s.d
., d
ays
)
0.1
1.0
10.0
100.0
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.
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.
ACKNOWLEDGEMENTSIUFRO 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