Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-23T10:29:57.695Z Has data issue: false hasContentIssue false
  • English
  • Français

Hard-seededness and seed bank dynamics of six pasture legumes

Published online by Cambridge University Press:  19 September 2008

L. Russi ,
P. S. Cocks  and
E. H. Roberts
L. Russi*
Affiliation:
International Center for Agricultural Research in the Dry Areas (ICARDA), PO Box 5466, Aleppo, Syria
P. S. Cocks
Affiliation:
International Center for Agricultural Research in the Dry Areas (ICARDA), PO Box 5466, Aleppo, Syria
E. H. Roberts
Affiliation:
Department of Agriculture, University of Reading, Earley Gate, PO Box 236Reading RG6 2AT, UK
*
* Present address and correspondence Istituto di Miglioramento Genetico VegetaleUniversita di Perugia, Borgo XX Giugno, 74 06100 Perugia, Italy
Get access Rights & Permissions [Opens in a new window]

Abstract

Six pasture legumes, common in Syrian grasslands, were investigated. Medicago orbicularis and M. rotata had the largest number of hard seeds, with >90% still hard 5 months after shedding; Trifolium stellatum had the least with <30% of hard seeds; T. campestre, M. rigidula and T. tomentosum were intermediate. Hard-seededness in M. orbicularis and M. rotata varied between years. Scarification of hard seeds resulted in almost complete germination in all species. Alternating temperatures (10/20°C) reduced the rate of germination of scarified T. campestre seeds, but had no effect on germination of scarified or unscarified seeds of T. stellatum. The breakdown of hard-seededness in the field in Syria did not begin until 3 months after shedding and greatly increased when seeds overwintered. Breakdown of hard-seededness was slower when seeds were buried at 5 and 10 cm than when seeds remained on the soil surface. Seedling emergence after the rains started in November was highly correlated with the number of soft seeds observed in October. Similarly, a high correlation was found between the percentage of hard seeds in October and carry-over in the seed bank. In small-seeded species (Trifolium spp.), 39% of the initial seed bank was lost in 2 years by causes other than emergence as seedlings. Such losses were only 7% in larger-seeded species (Medicago spp.). The implications of hard-seededness on the utilization and survival of legumes in grasslands are discussed.

Keywords

annual pastureshard seedsMedicagoseed bankTrifolium
Type
Research Papers
Information
Seed Science Research , Volume 2 , Issue 4 , December 1992 , pp. 231 - 241
Copyright
Copyright © Cambridge University Press 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

†

Present address Crop and Pasture Science Department, University of Western Australia, Nedlands, Perth, WA 6009, Australia

References

Abd El Moneim, A.M. and Cocks, P.S. (1986) Adaptation of Medicago rigidula to a cereal-pasture rotation in north-west Syria. Journal of Agricultural Science 107, 179–186.CrossRefGoogle Scholar
Cohen, D. (1966) Optimising reproduction in a randomly varying environment. Journal of Theoretical Biology 12, 119–129.CrossRefGoogle Scholar
Crawford, E.J., Lake, A.W.H. and Boyce, H.G. (1989) Breeding annual Medicago species for semiarid conditions in southern Australia. Advances in Agronomy 42, 399–437.CrossRefGoogle Scholar
Dennett, M.D., Rodgers, J.A. and Keatinge, J.D.H. (1983) Simulation of a rainfall record for the site of new agricultural development: an example from northern Syria. Agricultural Meteorology 29, 247–258.CrossRefGoogle Scholar
Donald, C.M. (1954) Competition among pasture plants. II. The influence of density on flowering and seed production in annual pasture plants. Australian Journal of Agricultural Research 5, 585–597.CrossRefGoogle Scholar
Major, J. and Pyott, W.T. (1966) Buried viable seeds in two California bunchgrass sites and their bearing on the definition of the flora. Vegetatio 13, 253–282.CrossRefGoogle Scholar
Morley, F.H.W. (1958) The inheritance and ecological significance of seed dormancy in subterranean clover (Trifolium subterraneum L.). Australian Journal of Biological Science 11, 261–274.CrossRefGoogle Scholar
Nahal, I. (1981) The Mediterranean climate from a biological viewpoint. pp. 63–86 in di Castri, F., Goodall, D.W. and Specht, R.L. (Eds) Mediterranean-type shrublands. Amsterdam, Elsevier Press.Google Scholar
Osman, A.E., Cocks, P.S., Russi, L. and Pagnotta, M.A. (1991) Response of Mediterranean grasslands to phosphate and stocking rate: biomass production and botanical composition. Journal of Agricultural Science 116, 37–46.CrossRefGoogle Scholar
Quinlivan, B.J. (1966) The relationship between temperature fluctuations and the softening of hard seeds of some legume species. Australian Journal of Agricultural Research 17, 625–631.CrossRefGoogle Scholar
Quinlivan, B.J. (1968) Seed coat impermeability in the common annual legume pasture species of Western Australia. Australian Journal of Experimental Agriculture and Animal Husbandry 8, 695–700.CrossRefGoogle Scholar
Quinlivan, B.J. and Nicol, H.I. (1971) Embryo dormancy in subterranean clover seeds. I. Environmental control. Australian Journal of Agricultural Research 22, 599–606.CrossRefGoogle Scholar
Roberts, E.H. (1986) Quantifying seed deterioration. pp. 101–123 in McDonald, M.B. and Nelson, C.I. (Eds) Physiology of seed deterioration 11. Madison, Crop Science Society ofAmerica.Google Scholar
Roberts, H.A. (1981) Seed banks in soils. Advances in Applied Biology 6, 1–55.Google Scholar
Russi, L. (1989) Ecological and physiological aspects of seeds of annual grasslands in a Mediterranean environment. PhD thesis, University of Reading UK.Google Scholar
Russi, L., Cocks, P.S. and Roberts, E.H. (1992a) Seed bank dynamics in a Mediterranean grassland. Journal of Applied Ecology 29, 763–771.CrossRefGoogle Scholar
Russi, L., Cocks, P.S. and Roberts, E.H. (1992b) The fate of seeds eaten by sheep from a Mediterranean grassland. Journal of Applied Ecology 29, 772–778.CrossRefGoogle Scholar
Russi, L., Cocks, P.S. and Roberts, E.H. (1992c) Coat thickness and hard-seededness in some Medicago and Trifolium species. Seed Science Research 2, 243–249.CrossRefGoogle Scholar
Taylor, G.B. (1984) Effect of burial on the softening of hard seeds of subterranean clover. Australian Journal of Agricultural Research 35, 201–210.CrossRefGoogle Scholar
Thompson, K. and Grime, J.P. (1979) Seasonal variation in the seed banks of herbaceous species in ten contrasting habitats. Journal of Ecology 67, 893–921.CrossRefGoogle Scholar
Thomson, E.F., Rihawi, S., Cocks, P.S., Osman, A.E. and Russi, L. (1990) Recovery and germination rates of seeds from Mediterranean medics and clovers offered to sheep at a single meal or continuously. Journal of Agricultural Science 114, 295–299.CrossRefGoogle Scholar