Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-22T19:11:51.691Z Has data issue: false hasContentIssue false

Wet heat as a mechanism for dormancy release and germination of seeds with physical dormancy

Published online by Cambridge University Press:  20 January 2017

Lloyd Flack
Affiliation:
CSIRO Entomology, Indooroopilly, Brisbane, Queensland 4068, Australia

Abstract

Mexican palo-verde is a serious woody weed in tropical parts of the world. Like many such leguminous species, it has relatively large seeds with hard-seeded (physical) dormancy. It therefore has the potential for long-lived seed banks that are difficult to manage. The physiology of hard-seeded dormancy is still relatively poorly understood but has important implications for weed management. We propose that wet heat is a potentially important dormancy release mechanism for summer rainfall tropical regions. We described the relationships between wet heat and dormancy release (in water; three seed sources) and germination (near saturation; single seed source) by testing seeds at constant temperatures between 10 and 60 C. The logistic transformation of the temperature–dormancy relationship was best described by a quadratic equation below a threshold of ∼ 33.6 C and a linear equation above that threshold. The relationship was the same for all seed sources other than a phase shift of up to 6.6 C, which is likely to be of biological significance. Germination occurred between 15 and 40 C and was limited by cold stress at ≤ 20 C and heat stress > 35 C. The sensitivity of dormancy to naturally encountered temperature ranges suggests that wet heat is an important dormancy release mechanism and one that can be exploited when developing management strategies for invasive populations.

Type
Weed Biology and Ecology
Copyright
Copyright © Weed Science Society of America 

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.)

References

Literature Cited

Alvarez Rangel, R. A. 1984a. Caracterizacion de los mecanismos de control de la latencia y germinacion de las semillas de Parkinsonia aculeata L. I. Respuestas de las semillas a los tratamientos para romper la latencia y sus implicaciones ecologicas. Rev. Fac. Agron. (Maracay, Unversidad Central de Venezuela) 8:530.Google Scholar
Alvarez Rangel, R. A. 1984b. Caracterizacion de los mecanismos de control de la latencia y germinacion de las semillas de Parkinsonia aculeata L. II. Respuestas de las semillas a algunos factores ambientales y sus implicaciones ecologicas. Rev. Fac. Agron. (Maracay, Unversidad Central de Venezuela) 8:3145.Google Scholar
Auld, T. D. and O'Connell, M. A. 1991. Predicting patterns of post-fire germination in eastern Australian Fabaceae. Aust. J. Ecol 16:5370.Google Scholar
Baskin, C. C. 2003. Breaking physical dormancy in seeds—focussing on the lens. New Phytol 158:227238.Google Scholar
Baskin, C. C. and Baskin, J. M. 1998. Seeds: Ecology, Biogeography and Evolution of Dormancy and Germination. New York: Academic Press, 700: p.Google Scholar
Baskin, C. C., Baskin, J. M., and Li, X. 2000. Taxonomy, anatomy and evolution of physical dormancy in seeds. Plant Species Biol 15:139152.CrossRefGoogle Scholar
Baskin, J. M. and Baskin, C. C. 1984. Environmental conditions required for germination of prickly acacia (Sida spinosa). Weed Sci 32:786–91.CrossRefGoogle Scholar
Baskin, J. M. and Baskin, C. C. 2004. A classification system for seed dormancy. Seed Sci. Res 14:116.CrossRefGoogle Scholar
Benech-Arnold, R. L., Sanchez, R. A., Focella, F., Kruk, B. C., and Ghersa, C. M. 2000. Environmental control of dormancy in weed seed banks in soil. Fields Crop Res 67:105122.Google Scholar
Boesewinkel, F. D. and Bouman, F. 1995. The seed: structure and function. Pages 124 in Kigel, J. and Galili, G. eds. Seed Development and Germination. New York: Marcel Dekker Inc.Google Scholar
Bradford, K. J. 1995. Water relations in seed germination. Pages 351396 in Kigel, J. and Galili, G. eds. Seed Development and Germination. New York: Marcel Dekker Inc.Google Scholar
de Villalobos, A. E. and Pelaez, D. V. 2001. Influences of temperature and water stress on germination and establishment of Prosopis caldenia . Burk. J. Arid Environ 49:321328.Google Scholar
Egley, G. H. 1989. Water-impermeable seed coverings as barriers to germination. Pages 207223 in Taylorson, R. B. ed. Recent Advances in the Development and Germination of Seeds. New York: Plenum Press.Google Scholar
Everitt, J. H. 1983. Seed germination characteristics of two woody legumes (retama and twisted acacia) from south Texas. J. Range Manage 36:411414.CrossRefGoogle Scholar
Flanagan, G. J., van Rangelrooy, D. S., and Kerin, S. 1996. Integrated management of Parkinsonia aculeata on the Roper Rive, Northern Territory, Australia. Pages 441443 in Moran, V. C. and Hoffmann, J. H. eds. Proceedings of the IX International Symposium on Biological Control of Weeds. Cape Town: University of Cape Town.Google Scholar
Foley, M. E. 2001. Seed dormancy: an update on terminology, physiological genetics, and quantitative trait loci regulating germinability. Weed Sci 49:305317.Google Scholar
Hastie, T. J. and Tibshirani, R. J. 1990. Generalized Additive Models. London: Chapman and Hall.Google Scholar
Hughes, C. E. and Styles, B. T. 1984. Exploration and seed collection of multiple-purpose dry zone trees in central America. Int. Tree Crops J 3:131.CrossRefGoogle Scholar
Khurana, E. and Singh, J. S. 2001. Ecology of tree seed and seedlings: implications for tropical forest conservation and restoration. Curr. Sci 80:748757.Google Scholar
Kigel, J. 1995. Seed germination in arid and semiarid regions. Pages 645699 in Kigel, J. and Galili, G. eds. Seed Development and Germination. New York: Marcel Dekker Inc.Google Scholar
Larsen, A. L. 1971. Two-Way Thermo-Gradient Plate for Seed Germination Research: Construction Plans and Procedures. Washington, DC: U.S. Department of Agriculture Research Services Bulletin 18.Google Scholar
Lehman, E. L. 1975. Nonparametric Statistical Methods Based on Ranks. San: Francisco: Holden-Day.Google Scholar
Martin, J. N. 1945. Germination studies of sweet clover seed. Iowa State College Journal of Science 19:289300.Google Scholar
McCullagh, P. and Nelder, J. A. 1989. Generalized Linear Models. 2nd ed. London: Chapman and Hall.CrossRefGoogle Scholar
McDonald, C. K. 2000a. Germination response to temperature in tropical and subtropical pasture legumes. 1. Constant temperature. Aust. J. Exp. Agric 42:407419.CrossRefGoogle Scholar
McDonald, C. K. 2000b. Germination response to temperature in tropical and subtropical pasture legumes. 1. Alternating temperatures. Aust. J. Exp. Agric 42:421429.Google Scholar
McKeon, G. M. and Nott, J. J. 1982. The effect of temperature on the field softening of hard seed of Stylonanthes humilis and S. hamata in a dry monsoonal climate. Aust. J. Exp. Agric 33:7585.CrossRefGoogle Scholar
Mohnot, K. and Chatterji, U. N. 1965. Chemico-physiological studies on the imbibition and germination of seeds of Parkinsonia aculeata Linn. Oesterr. Bot. Z 112:576585.Google Scholar
Morrison, D. A., McClay, K., Porter, C., and Rish, S. 1998. The role of the lens in controlling heat-induced breakdown of testa-imposed dormancy in native Australian legumes. Ann. Bot 82:3540.CrossRefGoogle Scholar
Murdoch, A. J. and Ellis, R. H. 1992. Longevity, viability and dormancy. Pages 193229 in Fenner, M. ed. The Ecology of Regeneration in Plant Communities. Wallingford, UK: CAB International.Google Scholar
Norman, H. C., Cocks, P. S., and Galwey, N. W. 2002. Hardseedness in annual clovers: variation between populations from wet and dry environments. Aust. J. Agric. Res 53:821829.CrossRefGoogle Scholar
Probert, R. J. 1992. The role of temperature in germination ecophysiology. Pages 285326 in Fenner, M. ed. The Ecology of Regeneration in Plant Communities. Wallingford, UK: CAB International.Google Scholar
Rice, K. J. 1987. Evidence for the retention of genetic variation in erodium seed dormancy by variable rainfall. Oecologia 72:589596.Google Scholar
Roberts, E. H. and Ellis, R. H. 1981. Water and seed survival. Ann. Bot 63:3952.Google Scholar
Taylor, G. B. 1981. Effect of constant temperature treatments followed by fluctuating temperatures on the softening of hard seeds of Trifolium subterraneium L. Aust. J. Plant Physiol 8:547558.Google Scholar
Teketay, D. 1996. Germination ecology of twelve indigenous and eight exotic multipurpose leguminous species from Ethiopia. For. Ecol. Manage 80:209223.Google Scholar
Thorpe, J. R. and Lynch, R. 2000. The Determination of Weeds of National Significance. Launceston, Australia: National Weeds Strategy Executive Committee.Google Scholar
van Assche, J. A., Debucquoy, K. L. A., and Rommens, W. A. F. 2003. Seasonal cycles in the germination capacity of buried seeds of some Leguminosae (Fabaceae). New Phytol 158:315323.Google Scholar
van Klinken, R. D. 2005. Total annual seed loss on a perennial legume through predation by insects: the importance of within-season seed and seed-feeder dynamics. Aust. Ecol 20(4):414425.Google Scholar