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