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Seed mass variation potentially masks a single critical water content in recalcitrant seeds

Published online by Cambridge University Press:  22 February 2007

Matthew I. Daws ,
Christiane S. Gaméné ,
Sheila M. Glidewell  and
Hugh W. Pritchard
Matthew I. Daws*
Affiliation:
Seed Conservation Department, Royal Botanic Gardens Kew, Wakehurst Place, Ardingly, West Sussex, RH17 6TN, UK
Christiane S. Gaméné
Affiliation:
Centre National de Semences Forestières, Ouagadougou 01, 01 BP 2682, Burkina Faso
Sheila M. Glidewell
Affiliation:
Scottish Crop Research Institute, Invergowrie, Dundee, DD2 5DA, UK
Hugh W. Pritchard
Affiliation:
Seed Conservation Department, Royal Botanic Gardens Kew, Wakehurst Place, Ardingly, West Sussex, RH17 6TN, UK
*
*Correspondence Fax: +44 (0) 1444 894110, Email: [email protected]
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Abstract

For recalcitrant seeds, mortality curves of germination versus water content typically imply a wide range of desiccation sensitivities within a seed population. However, seed to seed differences in water content, during desiccation, may confound our interpretation of these mortality plots. Here, we illustrate this problem for two batches of Vitellaria paradoxa (Sapotaceae) seeds collected in 1996 and 2002. Whole seeds were desiccated to various target water contents (TWCs) using silica gel. During desiccation, smaller seeds in the population dried most rapidly. Consequently, there was a significant linear relationship between whole-seed water content and seed mass during the drying process. In addition, following desiccation to low TWCs, only the largest seeds in the population retained viability. Taken together, this suggests that the larger seeds survived, not as a consequence of great relative desiccation tolerance, but as a result of taking longer to desiccate. Subsequently, the critical water content (CWC) for viability loss was calculated, based on the assumptions that in the seed population whole-seed water content during desiccation was normally distributed and the smallest, and hence driest, seeds were killed first. Using this approach, the driest seeds in the population that were killed, at each TWC, were always below a single CWC (c. 20% and 26% in 1996 and 2002, respectively). In subsequent experiments the effect of seed size variation on the response to desiccation was confirmed by conducting desiccation screens on seeds sorted into two discrete size classes, i.e. the seed-lot heterogeneity in mass was reduced. Using this approach, the mortality curves had a steeper slope. Furthermore, data for 24 tropical tree species from the Database of Tropical Tree Seed Research (DABATTS) revealed that seed lots with less variability in mass had steeper mortality curves. Thus, taken together, the data suggest that, at least for whole seeds, the wide range of desiccation sensitivities typically inferred is an artefact of seed to seed variation in mass, and hence water contents, during drying.

Keywords

critical water contentdesiccationseed massVitellaria paradoxa
Type
Research Article
Information
Seed Science Research , Volume 14 , Issue 2 , May 2004 , pp. 185 - 195
Copyright
Copyright © Cambridge University Press 2004

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References

Berjak, P., Pammenter, N.W. and Vertucci, C.W. (1992) Homoio-hydrous (recalcitrant) seeds: developmental status, desiccation sensitivity and the state of water in axes of Landolphia kirkii Dyer. Planta 186, 249–261.CrossRefGoogle ScholarPubMed
Berjak, P., Vertucci, C.W. and Pammenter, N.W. (1993) Effects of developmental status and dehydration rate on characteristics of water and desiccation-sensitivity in recalcitrant seeds of Camellia sinensis. Seed Science Research 3, 155–166.Google Scholar
Bonner, F.T. (1996) Responses to drying of recalcitrant seeds of Quercus nigra L. Annals of Botany 78, 181–187.Google Scholar
Crawley, M.J. (1993) GLIM for ecologists. Oxford, Blackwell Scientific Publications.Google Scholar
Danthu, P., Gueye, A., Boye, A., Bauwens, D. and Sarr, A. (2000) Seed storage behaviour of four Sahelian and Sudanian tree species (Boscia senegalensis, Butyrospermum parkii, Cordyla pinnata and Saba senegalensis). Seed Science Research 10, 183–187.Google Scholar
Daws, M.I., Lydall, E., Chmielarz, P., Leprince, O., Matthews, S., Thanos, C.A. and Pritchard, H.W. (2004) Developmental heat sum influences phenotypic plasticity of recalcitrant seed traits in Aesculus hippocastanum L. across Europe. New Phytologist 162, 157–166.Google Scholar
Dickie, J.B., May, K., Morris, S.V.A. and Titley, S.E. (1991) The effects of desiccation on seed survival in Acer platanoides L. and Acer pseudoplatanus L. Seed Science Research 1, 149–162.Google Scholar
Dussert, S., Chabrillange, N., Engelmann, F. and Hamon, S. (1999) Quantitative estimation of seed desiccation sensitivity using a quantal response model: application to nine species of the genus Coffea L. Seed Science Research 9, 135–144.CrossRefGoogle Scholar
Farrant, J.M. and Walters, C. (1998) Ultrastructural and biophysical changes in developing embryos of Aesculus hippocastanum in relation to the acquisition of tolerance to drying. Physiologia Plantarum 104, 513–524.Google Scholar
Farrant, J.M., Berjak, P. and Pammenter, N.W. (1985) The effect of drying rate on viability retention of recalcitrant propagules of Avicennia marina. South African Journal of Botany 51, 432–438.Google Scholar
Finch-Savage, W.E. (1992) Embryo water status and survival in the recalcitrant species Quercus robur L.: evidence for a critical moisture content. Journal of Experimental Botany 43, 663–669.Google Scholar
Hong, T.D. and Ellis, R.H. (1990) A comparison of maturation drying, germination, and desiccation tolerance between developing seeds of Acer pseudoplatanus L. and Acer platanoides L. New Phytologist 116, 589–596.Google Scholar
Hong, T.D. and Ellis, R.H. (1996) A protocol to determine seed storage behaviour. IPGRI, Technical Bulletin No. 1. Rome, International Plant Genetic Resources Institute.Google Scholar
International Seed Testing Association (ISTA). (1999) International rules for seed testing. Seed Science and Technology 27, Supplement.Google Scholar
Kermode, A.R. and Finch-Savage, W.E. (2002) Desiccation sensitivity in orthodox and recalcitrant seeds in relation to development. pp. 149–184 in Black, M. and Pritchard, H.W.Desiccation and survival in plants: Drying without dying. Wallingford, CABI Publishing.Google Scholar
Liang, Y.H. and Sun, W.Q. (2000) Desiccation tolerance of recalcitrant Theobroma cacao embryonic axes: the optimal drying rate and its physiological basis. Journal of Experimental Botany 51, 1911–1919.Google Scholar
Liang, Y.H. and Sun, W.D.Q. (2002) Rate of dehydration and cumulative desiccation stress interacted to modulate desiccation tolerance of recalcitrant cocoa and Ginkgo embryonic tissues. Plant Physiology 128, 1323–1331.Google Scholar
Normah, M.N., Ramiya, S.D. and Gintangga, M. (1997) Desiccation sensitivity of recalcitrant seeds – A study on tropical fruit species. Seed Science Research 7, 179–183.Google Scholar
Pammenter, N.W. and Berjak, P. (1999) A review of recalcitrant seed physiology in relation to desiccation-tolerance mechanisms. Seed Science Research 9, 13–37.Google Scholar
Pammenter, N.W., Vertucci, C.W. and Berjak, P. (1991) Homeohydrous (recalcitrant) seeds: dehydration, the state of water and viability characteristics in Landolphia kirkii. Plant Physiology 96, 1093–1098.CrossRefGoogle ScholarPubMed
Pammenter, N.W., Greggains, V., Kioko, J.I., Wesley-Smith, J., Berjak, P., Finch-Savage, W.E. (1998) Effects of differential drying rates on viability retention of recalcitrant seeds of Ekebergia capensis. Seed Science Research 8, 463–471.Google Scholar
Pritchard, H.W. (1991) Water potential and embryonic axis viability in recalcitrant seeds of Quercus rubra. Annals of Botany 67, 43–49.Google Scholar
Pritchard, H.W. (2004) Classification of seed storage ‘types’ for ex situ conservation in relation to temperature and moisture content. pp. 139–161in Guerrant, E., Havens, K. and Maunder, M. (Eds) plant conservation: supporting species survival in the wild. Washington, DC, USA Island Press.Google Scholar
Pritchard, H.W. and Manger, K.R. (1998) A calorimetric perspective on desiccation stress during preservation procedures with recalcitrant seeds of Quercus robur L. Cryo-Letters 19, (suppl. 1), 23–30.Google Scholar
Pritchard, H.W., Haye, A.J., Wright, W.J. and Steadman, K.J. (1995a) A comparative study of seed viability in Inga species – desiccation tolerance in relation to the physical characteristics and chemical composition of the embryo. Seed Science and Technology 23, 85–100.Google Scholar
Pritchard, H.W., Tompsett, P.B., Manger, K. and Smidt, W.J. (1995b) The effect of moisture content on the low temperature responses of Araucaria hunsteinii seeds and embryos. Annals of Botany 76, 79–88.Google Scholar
Pritchard, H.W., Gaméné, C. and Daws, M.I. (1997) Vitellaria paradoxa. Annual Report 1996 p. 51. Rome, International Plant Genetic Resources Institute.Google Scholar
Pritchard, H.W., Wood, C.B., Hodges, S. and Vautier, H.J. (2004) 100-seed test for desiccation tolerance and germination: a case study on 8 tropical palm species. Seed Science and Technology (n press).Google Scholar
Probert, R.J. and Longley, P.L. (1989) Recalcitrant seed storage physiology in three aquatic grasses (Zizania palustris, Spartina angelica, and Porteresia coarctata). Annals of Botany 63, 53–63.Google Scholar
Sokal, R.R. and Rohlf, F.J. (1995) Biometry (3rd edition). New York, W.H. Freeman and Company.Google Scholar
Sun, W.Q. and Liang, Y. (2001) Discrete levels of desiccation sensitivity in various seeds as determined by the equilibrium dehydration method. Seed Science Research 11, 317–323.Google Scholar
Tabachnick, B.G. and Fidell, L.S. (2001) Using multivariate statistics (4th edition). Boston, Allyn and Bacon.Google Scholar
Tompsett, P.B. (1982) The effect of desiccation on the longevity of seeds of Araucaria hunsteinii and Araucaria cunninghamii. Annals of Botany 50, 693–704.Google Scholar
Tompsett, P.B. (1984) Desiccation studies in relation to the storage of Araucaria seed. Annals of Applied Biology 105, 581–586.Google Scholar
Tompsett, P.B. (1987) Desiccation and storage studies on Dipterocarpus seeds. Annals of Applied Biology 110, 371–379.Google Scholar
Tompsett, P.B. and Kemp, R. (1996) Database of tropical tree seed research. Richmond, Royal Botanic Gardens.Google Scholar
Tompsett, P.B. and Pritchard, H.W. (1993) Water status changes during development in relation to the germination and desiccation tolerance of Aesculus hippocastanum L. seeds. Annals of Botany 71, 107–116.Google Scholar
Walters, C. (1998) Levels of recalcitrance in seeds. pp. 1–13in Marzalina, M., Khoo, K.C., Jayanthi, N., Tsan, F.Y. and Krishnapillay, B. (Eds) Recalcitrant seed. Kuala Lumpur, Malaysia, Forest Research InstituteGoogle Scholar