Wet-season Dormancy Release in Seed Banks of a Tropical Leguminous Shrub is Determined by Wet Heat

Klinken, Rieks D. van; Flack, Lloyd K.; Pettit, William J

doi:10.1093/aob/mcl171

Cited by 34 publications

(40 citation statements)

References 27 publications

(33 reference statements)

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“…Williams et al (2003) reported that fire-related factors released seed dormancy in six annual native legumes species but not in two perennial species in northeastern Australia. More recently, Van-Klinken (2005) and Van-Klinken et al (2006) identified wet heat as a mechanism for physical dormancy release in a tropical legume shrub Parkinsonia aculeata. However, for most species with physical dormancy, previous research (Baskin and Baskin 1998;Loi et al 1999;Mennan 2003) has largely been limited to describing the initial level of physical dormancy, subsequent release of seed dormancy, and effect of artificial procedures such as acid scarification and boiling water, rather than examining mechanisms that are likely to occur naturally.…”

Section: Introductionmentioning

confidence: 99%

Different requirements for physical dormancy release in two populations of Sophora alopecuroides relation to burial depth

Wang

2009

Ecological Research

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Most species of Fabaceae produce seeds with physical dormancy which was broken by some environmental factors in the field, yet for the mechanism of physical dormancy release in the natural condition is still poorly understood. In present study, seeds of Sophora alopecuroides from two populations were placed on the soil surface or buried at depths of 2 and 7 cm in the field and were exhumed at time intervals to assess the changes of dormancy. Also, microenvironments were simulated in the laboratory to determine the possible components (temperature, temperature fluctuation, and moisture) involved in physical dormancy release. The laboratory work indicated that wet heat is an important dormancy release mechanism for both populations; and dry heat for one of them, but showed no effects on the other one. Consistent with that, burial experiment showed seeds of two populations had two contrasting-dormancy release patterns in the field. Most seeds of the dry heat sensitive population released dormancy but the other one remained dormant when seeds placed on the soil surface for 11 months (where seeds were exposed to dry heat but not wet heat). The difference of physical dormancy release pattern response to burial depth and simulated condition may attribute to seed coat color and hilum thickness which showed significantly different between two populations. This conclusion may improve understanding of physical dormancy release mechanism among populations and have a practical use for grassland management and weed control.

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Section: Introductionmentioning

confidence: 99%

Different requirements for physical dormancy release in two populations of Sophora alopecuroides relation to burial depth

Wang

2009

Ecological Research

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“…Variation in temperature and substrate moisture content among different burial periods and depths are considered key factors that influence PY-breaking in natural conditions (Norman et al 2002; Van Klinken et al 2006, 2008; Hu et al 2009). However, substrate moisture does not seem to play an important role in modulating PY- break of E. songoricum seeds under natural conditions.…”

Section: Discussionmentioning

confidence: 99%

“…As burial depth increases, the rate of PY release may decrease (Taylor and Ewing 1988; Van Klinken and Flack 2005; Van Klinken et al 2006), increase (Hu et al 2009) or increase and then decrease (Loi et al 1999; Zeng et al 2005). Burial depth is closely related to soil temperature and moisture.…”

Section: Introductionmentioning

confidence: 99%

Seed dormancy-breaking in a cold desert shrub in relation to sand temperature and moisture

et al. 2017

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Eremosparton songoricum (Litv.) Vass. (Fabaceae, Papilionoideae) is a perennial semi-shrub, inhabiting the cold desert. Freshly matured seeds of E. songoricum have physical dormancy (PY). In this study, we determined whether seeds of E. songoricum exhibit seasonal periodicity of seed germination and the relationship between seed dormancy break and soil temperature and moisture. To our knowledge this is the first study to document seasonal periodicity in seed germination in a cold desert species with PY and to identify the mechanism (at the whole-seed level) of its occurrence.

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“…Available evidence suggests species differences in dormancy-release mechanisms. As already described, P. aculeata has a quadratic response to wet heat but is not sensitive to fluctuating temperatures per se (van Klinken and Flack, 2005;van Klinken et al, 2006). In contrast, the available evidence suggests that M. pigra seeds are only sensitive to fluctuating temperatures in moist conditions, with little temperature effect on dormancy release when tested at constant temperatures (Dillon and Forcella, 1985;Lonsdale et al, 1988;Lonsdale, 1993).…”

Section: Introductionmentioning

confidence: 97%

“…Dormancy release of seeds of one wetland species, Parkinsonia aculeata L., showed a quadratic response to wet heat, with the proportion released increasing strongly above a temperature threshold (van Klinken and Flack, 2005). Dormancy release was thereby minimized when seeds are under dense ground or canopy cover (where competition will be highest), under water (where seeds will rot or seedlings will drown), deeply buried or on the soil surface; and maximized when there is little competition and when temperature and moisture are not limiting (van Klinken et al, 2006(van Klinken et al, , 2008.…”

Section: Introductionmentioning

confidence: 99%

Habitat-specific seed dormancy-release mechanisms in four legume species

Klinken

Goulier

2013

Seed Sci. Res.

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Physical seed dormancy is a common attribute among plants, and a wide range of dormancy-release mechanisms have been described, but their ecological significance is rarely tested through comparative study. This study tests whether dormancy-release responses to wet heat in four legume species with physical dormancy are correlated with habitat: two wetland species (Mimosa pigra and Parkinsonia aculeata, both dispersed primarily by water) and two terrestrial species (Acacia nilotica and Prosopis pallida, both dispersed primarily through vertebrate herbivores). Dormancy release was compared at three moisture levels (80% relative humidity, saturated and submerged) at constant (20 -458C) and diurnally fluctuating (20/408C) temperatures for 14 d. Seed viability was tested by germinating at 258C. The functional relationship between temperature and dormancy release after 14 d differed between species: submerged seeds of the two wetland species showed a quadratic response, with low rates of imbibition below 20 -258C and complete imbibition at around 408C; P. pallida seeds showed a linear positive relationship, whereas there was no temperature response for A. nilotica seeds below 458C. Surprisingly, dormancy release after 14 d was relatively insensitive to moisture levels, although rate of dormancy release was generally slower under drier conditions. Dormancy release was not influenced by fluctuating temperatures. Seed viability was largely unaffected by temperature or moisture regime, although it did differ with species and was lower for non-dormant seeds. Our results suggest that a functional dormancy-release response to wet heat provides important fitness benefits for wetland species, but not for species dispersed through vertebrate herbivores, for which it may be maladaptive.

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Wet-season Dormancy Release in Seed Banks of a Tropical Leguminous Shrub is Determined by Wet Heat

Abstract: These results demonstrate that wet heat is the principal dormancy release mechanism for P. aculeata when conditions are hot and wet. They also highlight the potential importance of microclimate in driving the population dynamics of such species.

Cited by 34 publications

References 27 publications

Different requirements for physical dormancy release in two populations of Sophora alopecuroides relation to burial depth

Different requirements for physical dormancy release in two populations of Sophora alopecuroides relation to burial depth

Seed dormancy-breaking in a cold desert shrub in relation to sand temperature and moisture

Habitat-specific seed dormancy-release mechanisms in four legume species

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