Skip to main content Accessibility help
×
×
Home

Vapour is the principal source of water imbibed by seeds in unsaturated soils

  • Stewart Wuest (a1)

Abstract

The assumption that seeds imbibe most of the water required for germination as liquid through seed-to-soil contact has been a dominant theme in germination research and seeding technology. Under most conditions, seeds are also exposed to water vapour during imbibition, but the relative contributions of liquid and vapour are difficult to assess. In water uptake models that include vapour, procedures used to estimate potential vapour imbibition have underappreciated the effect of distance on diffusion rate. At the same time, the amount of seed-to-soil contact and the liquid bridge from soil water to the seed tend to be greatly overestimated, considering the soil water contents often found in the field. Most researchers have recorded an approximately equal time to germination at soil water contents ranging from field capacity to nearly permanent wilting point, and little response to bulk density, soil type or seed–soil contact. While hydraulic conductivity decreases by several orders of magnitude as soil water content, bulk density and seed-contact decrease, relative humidity remains near 100%. There are several experiments demonstrating timely germination in water vapour alone. The combined evidence contradicts the assumption that seed–soil contact is important for imbibition of water by seeds. Water vapour should be considered the primary source of water for seeds in unsaturated soils.

Copyright

Corresponding author

*Correspondence: Fax: 541-278-4372 Email: Stewart.Wuest@oregonstate.edu

References

Hide All
Blackshaw, R.E. (1991) Soil temperature and moisture effects on downy brome vs. winter canola, wheat, and rye emergence. Crop Science 31, 10341040.
Bouaziz, A. and Bruckler, L. (1989) Modeling of wheat imbibition and germination as influenced by soil physical properties. Soil Science Society of America Journal 53, 219227.
Bruckler, L. (1983) Rôle des propriétés physiques du lit de semences sur l'imbibition et la germination. I. Elaboration d'un modèle du système ‘terre-graine’. Agronomie (Paris) 3, 213222.
Choudhary, M.A. and Baker, C.J. (1982) Effects of drill coulter design and soil moisture status on emergence of wheat seedlings. Soil and Tillage Research 2, 131142.
Collins, G., Stibbe, E. and Kroesbergen, B. (1984) Influence of soil moisture stress and soil bulk density on the imbibition of corn seeds in a sandy soil. Soil and Tillage Research 4, 361370.
Collis-George, N. and Hector, J.B. (1966) Germination of seeds as influenced by matric potential and by area of contact between seed and soil water. Australian Journal of Soil Research 4, 145164.
Collis-George, N. and Melville, M.D. (1975) Water absorption by swelling seeds. I. Constant surface boundary condition. Australian Journal of Soil Research 13, 141158.
Collis-George, N. and Melville, M.D. (1978) Water absorption by swelling seeds. II. Surface condensation boundary condition. Australian Journal of Soil Research 16, 291310.
de Jong, R. and Best, K.F. (1979) The effect of soil water potential, temperature and seeding depth on seedling emergence of wheat. Canadian Journal of Soil Science 59, 259264.
Denny, M.W. (1993) Air and water: The biology and physics of life's media. Princeton, New Jersey, Princeton University Press.
Etherington, J.R. and Evans, C.E. (1986) Technique for ecological studies of seed germination in relation to soil water potential. Plant and Soil 95, 285288.
Hadas, A. and Russo, D. (1974) Water uptake by seeds as affected by water stress, capillary conductivity, and seed–soil water contact. I. Experimental study. Agronomy Journal 66, 643647.
Hanks, R.J. (1965) Estimating infiltration from soil moisture properties. Journal of Soil and Water Conservation 20, 4951.
Harper, J.L. and Benton, R.A. (1966) The behaviour of seeds in soil. II. The germination of seeds on the surface of a water supplying substrate. Journal of Ecology 54, 151166.
Lafond, G.P. and Fowler, B.D. (1989) Soil temperature and water content, seeding depth, and simulated rainfall effects on winter wheat emergence. Agronomy Journal 81, 609614.
Lindstrom, M.J., Papendick, R.I. and Koehler, F.E. (1976) A model to predict winter wheat emergence as affected by soil temperature, water potential and depth of planting. Agronomy Journal 68, 137141.
Livingston, N.J. and de Jong, E. (1990) Matric and osmotic potential effects on seedling emergence at different temperatures. Agronomy Journal 82, 995998.
Martin, D.L. and Thrailkill, D.J. (1993) Moisture and humidity requirements for germination of surface seeded corn. Applied Engineering in Agriculture 9, 4348.
Owen, P.C. (1952) The relation of germination of wheat to water potential. Journal of Experimental Botany 3, 188203.
PAMI (2000) Does soil packing matter? Research Update No. 749. Humbolt, Saskatchewan, Canada, Prairie Agricultural Machinery Institute, Web sitehttp://www.pami.ca/pdfs/reports_reasearch_updates/749_does_soil_packing_matter.pdf (accessed 22 November 2006).
Papendick, R.I. and Campbell, G.S. (1981) Theory and measurement of water potential in soil, organic materials, plants, seeds, and microorganisms. pp. 122 in Parr, J.F.; Gardner, W.R.; Elliot, L.F. (Eds) Water potential relations in soil microbiology. Madison, Wisconsin, Soil Science Society of America.
Pawloski, M.C. and Shaykewich, C.F. (1972) Germination of wheat as affected by soil water stress. Canadian Journal of Plant Science 52, 619623.
Rogers, R.B. and Dubetz, S. (1980) Effect of soil–seed contact on seed imbibition. Canadian Agricultural Engineering 22, 8992.
Schneider, A. and Renault, P. (1997) Effects of coating on seed imbibition: II. Effect of coating rates. Crop Science 37, 18501857.
Studdert, G.A., Wilhelm, W.W. and Power, J.F. (1994) Imbibition response of winter wheat to water-filled pore space. Agronomy Journal 86, 9951000.
Wuest, S.B. (2002) Water transport from soil to seed: The role of vapor transport. Soil Science Society of America Journal 66, 17601763.
Wuest, S.B., Albrecht, S.L. and Skirvin, K.W. (1999) Vapor transport vs. seed–soil contact in wheat germination. Agronomy Journal 91, 783787.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Seed Science Research
  • ISSN: 0960-2585
  • EISSN: 1475-2735
  • URL: /core/journals/seed-science-research
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed