1 September 2005 Wet heat as a mechanism for dormancy release and germination of seeds with physical dormancy
Rieks D. van Klinken, Lloyd Flack
Author Affiliations +

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.

Nomenclature: Mexican palo-verde, Parkinsonia aculeata L. PAKAC.

Rieks D. van Klinken and Lloyd Flack "Wet heat as a mechanism for dormancy release and germination of seeds with physical dormancy," Weed Science 53(5), 663-669, (1 September 2005). https://doi.org/10.1614/WS-05-008R.1
Received: 26 January 2005; Accepted: 1 May 2005; Published: 1 September 2005
seed longevity
Get copyright permission
Back to Top