Annual dormancy cycles in buried seeds of shrub species: germination ecology ofSideritis serrata(Labiatae)

Plant Biology ◽  
2015 ◽  
Vol 17 (4) ◽  
pp. 798-807 ◽  
Author(s):  
M. A. Copete ◽  
J. M. Herranz ◽  
P. Ferrandis ◽  
E. Copete
Plant Biology ◽  
2017 ◽  
Vol 19 (5) ◽  
pp. 818-823 ◽  
Author(s):  
T. G. S. Oliveira ◽  
I. P. Diamantino ◽  
Q. S. Garcia

2019 ◽  
Vol 29 (3) ◽  
pp. 179-183 ◽  
Author(s):  
Túlio G. S. Oliveira ◽  
Queila S. Garcia

AbstractGermination ecology was investigated in a natural population of Xyris longiscapa, a perennial herbaceous species endemic to the Brazilian campo rupestre. Seeds were collected over four consecutive years (2014 to 2017) to evaluate germination responses to a range of temperatures (from 15 to 30°C). The light requirement was evaluated in seeds collected in 2014. Seeds collected in 2014 were also buried in soil in the natural habitat of the species to evaluate changes in germinability at different temperatures over the time. Seeds showed an absolute light requirement for germination. Seed germination was affected by temperature, collection year and the interaction between these two factors. Seeds collected in 2014 showed a narrower temperature range for germination (15–20°C), compared with the seeds collected in 2015, 2016 and 2017 that germinated in a temperature range of 15–25°C. Buried seeds remained viable in soil for at least 14 months and exhibited seasonal dormancy cycling. Secondary dormancy was induced during the rainy season and alleviated during the dry season, following a conditional dormancy/dormancy cycle. The degree of primary dormancy appeared to be influenced by the environmental conditions experienced by seeds during maturation. Primary dormancy (when present), seed persistence in soil and seasonal dormancy cycles are strategies of X. longiscapa to enhance regeneration success in the harsh environment of the Brazilian campo rupestre.


1994 ◽  
Vol 72 (6) ◽  
pp. 779-782 ◽  
Author(s):  
Carol C. Baskin ◽  
Jerry M. Baskin

Buried seeds of Oenothera biennis, which have the potential to form long-lived seed banks, were investigated to determine whether or not they (i) undergo seasonal changes in their dormancy states and (ii) require light for germination. Seeds were buried in soil and exposed to natural seasonal temperature changes. Samples of seeds were exhumed at monthly intervals for 31 months and tested for germination in light and darkness at 12-h daily thermoperiods of 15:6, 20:10, 25:15, 30:15, and 35:20 °C. At maturity in autumn, seeds germinated to 84–95% in light at 30:15 and 35:20 °C, but to 0–69% at other test conditions. By late winter, seeds germinated to 95–100% at the five thermoperiods in light and in darkness. In summer and autumn, germination in light decreased at 15:6 °C, and in darkness it dropped to 0% at 15:6 °C and decreased at 20:10, 25:15, 30:15, and 35:20 °C. Following the second winter of burial, seeds germinated to near 100% at all thermoperiods in light and darkness. Thus, seeds exhibited an annual nondormancy – conditional dormancy cycle, being nondormant from midwinter to late spring and conditionally dormant in summer and autumn. Oenothera biennis is 1 of 10 species whose seeds live for 39–40 years or longer in soil and also have an annual conditional dormancy – nondormancy cycle. Seeds of six of these species, including O. biennis, can germinate in darkness in spring or summer at simulated habitat temperatures. Therefore, a light requirement for germination is not necessarily a prerequisite for long-term survival of buried seeds, and something other than darkness prevents germination of seeds of some species buried in soil. Key words: seed banks, buried seeds, germination, dormancy cycles, light requirement, Oenothera.


1996 ◽  
Vol 74 (12) ◽  
pp. 2002-2005 ◽  
Author(s):  
Carol C. Baskin ◽  
Jerry M. Baskin

At maturity in September, about half the seeds (achenes) of Erechtites hieracifolia (Asteraceae) collected in Kentucky were dormant (did not germinate at any test condition), whereas the others were conditionally dormant (germinated only at a narrow range of test conditions). Seeds sown on top of soil in an unheated greenhouse in September failed to germinate in autumn because temperatures were below those required for germination; however, they germinated at comparable temperatures the following spring. Seeds buried in soil in September 1987 and exposed to natural seasonal temperature changes were nondormant (germinated over full range of test conditions) by April 1988, but they entered conditional dormancy by October 1988. Each October through 1995, exhumed seeds exhibited conditional dormancy. Since 89% of the seeds were viable after 8 years of burial, it appears that although seeds of this species are wind dispersed, they also have the potential to form a long-lived seed bank. Thus, soil disturbance at any time from May to September could result in establishment of plants from seeds in the seed bank. Keywords: seed dormancy, Asteraceae, dormancy cycles, buried seeds, light.


Wetlands ◽  
1996 ◽  
Vol 16 (1) ◽  
pp. 84-88 ◽  
Author(s):  
Carol C. Baskin ◽  
Edward W. Chester ◽  
Jerry M. Baskin
Keyword(s):  

Weed Science ◽  
1985 ◽  
Vol 33 (3) ◽  
pp. 340-343 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin

Seed dormancy does not play a role in the germination ecology of curly dock (Rumex crispusL. ♯ RUMCR). This study confirms reports that freshly matured seeds are nondormant, and it shows that buried seeds exposed to natural seasonal temperature changes remain nondormant. From October 1981 through June 1983, seeds exhumed at monthly intervals germinated 80 to 100% at all thermo-periods. These results do not support suggestions that seeds of curly dock buried in soil enter dormancy. However, the results do explain why seeds of this species in the Beal and Duvel buried-seed experiments germinated when exhumed at various times during the growing season.


2020 ◽  
Vol 52 (6) ◽  
Author(s):  
Muhammad Mansoor Javaid ◽  
Zaigham Abbas ◽  
Hasnain Waheed ◽  
Athar Mahmood ◽  
Tasawer Abbas ◽  
...  

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