Presentation on theme: "Forest tree seed research Independent Isolated from seed research more widely & Timber Industry/Forest Environment focused Research Organisations specialising."— Presentation transcript:
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 cm Woody seed coat 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 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
Negative logarithmic relation between seed longevity and moisture content Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
RECALCITRANT Acer pseudoplatanus 1. Hong, T.D. and Ellis, R.H., 1990. New Phytologist, 116, 589- 596.
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.
Coffea arabica Ellis, R.H., Hong, T.D. and Roberts, E.H. 1990. Journal of Experimental Botany, 41, 1167-1174.
Oil palm (Elaeis guineensis) Ellis, R.H., Hong, T.D., Roberts, E.H. and Soetisna, U. 1991. Seed Science Research, 1, 99-104.
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
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)
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
Species with recalcitrant seeds Darwin Initiative for the Survival of Species
Picea sitchensis Jones, S.K., Gosling, P.G., and Ellis, R.H. 1998. Seed Sci Res. 8: 113-122. Effect of duration of storage at 3 0 C on viability () and ability to germinate at 10 0 C 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 0 C after moist pre-treatment at a constant temperature of 20 0 C in two separate experiments (, ). Solid line shows a multiplicative model for changes in ability to germinate with period of moist pre-treatment at 20 0 C 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.
DEVELOPMENT OF DESICCATION TOLERANCE IN ORTHODOX SEEDS Acer platanoides 1. Hong, T.D. and Ellis, R.H. 1992. Seed Science Research, 2, 169-172.
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.
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.
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.
OnionSugar beet Barley Wheat Lower-moisture-content limit for crops Ellis, R.H., Hong, T.D. and Roberts, E.H. 1989. Annals of Botany, 63, 601-611.
Lower-moisture-content limit in two tree species Pedro Leon-Lobos, Ph.D. Thesis, The University of Reading, 2001
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.
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