Dormancy-breaking and germination requirements for seeds of Acacia papyrocarpa, Acacia oswaldii and Senna artemisioides ssp.×coriacea, three Australian arid-zone Fabaceae species

2014 ◽  
Vol 62 (7) ◽  
pp. 546 ◽  
Author(s):  
Leanne M. Pound ◽  
Phillip J. Ainsley ◽  
José M. Facelli
Keyword(s):  
Arid Zone ◽  
South Australia ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Dry Heat ◽  
Seed Mortality ◽  
Wet Heat ◽  
Pre Treatment ◽  
Unpredictable Environment ◽  
Germination Requirements

Physical dormancy is common in seeds of arid-land legumes. Improved understanding of germination requirements of hard-seeded species will further our understanding of arid lands and aid restoration projects. We studied the germination responses of Acacia papyrocarpa (Benth.), A. oswaldii (F.Muell) and Senna artemisioides (Gaudich. ex DC.) Randell ssp. × coriacea (Benth.) Randell from a chenopod shrubland in South Australia. Imbibition testing indicated that all three species had physical dormancy, but the proportion of dormant seeds was lower in A. oswaldii. This corresponded to a thinner testa in this species. Mechanisms tested to scarify seeds included mechanical scarification and different durations of wet or dry heat. Mechanically scarified seeds germinated readily, reaching maximum numbers in 10–15 days, independently of incubation temperatures, with the exception of S. artemisioides seeds, which germinated at a slower rate in cooler temperatures. Overall, wet heat was more effective than dry heat to alleviate physical dormancy, whereas dry heat in some cases resulted in seed mortality. On the basis of these results, it is recommended that seeds of A. papyrocarpa and S. artemisoides be pretreated with wet heat in future restoration programs. No pre-treatment is required for dormancy loss in A. oswaldii seeds. The different responses of seeds of these species suggest that their populations have varying strategies for persistence in this unpredictable environment.

Overcoming physical seed dormancy in priority native species for use in arid-zone restoration programs

2016 ◽  
Vol 64 (5) ◽  
pp. 401 ◽  
Author(s):  
Todd E. Erickson ◽  
David J. Merritt ◽  
Shane R. Turner
Keyword(s):  
Native Species ◽  
Arid Zone ◽  
Relative Effectiveness ◽  
Heat Treatments ◽  
Treatment Temperature ◽  
Physical Dormancy ◽  
Dry Heat ◽  
Wet Heat ◽  
Seed Handling ◽  
Species Specific

The relative effectiveness of wet- and dry-heat treatments on alleviating physical dormancy (PY) of seeds of seven species of Fabaceae and five species of Malvaceae was determined to optimise seed handling procedures for ecological restoration. Seeds of all species were treated at different temperatures (40−100°C) for various durations (2 and 5 min of wet heat, and 5, 10 and 30 min of dry heat). Prior to treatment, seeds of all species exhibited low germination (0–38%). As hypothesised, there was variation among species with respect to the efficacy of the heat treatments. In general, wet-heat treatments at temperatures >70°C for 2 or 5 min were effective in breaking PY for all Fabaceae species, and two Malvaceae species, with resultant germination typically >75%. For dry-heat treatments, higher temperatures and longer durations were required to achieve similar germination results. In the three Malvaceae species that were least responsive to heat (Abutilon otocarpum, Hibiscus haynaldii and Sida echinocarpa), there was a trade-off between treatment temperature and duration; lower temperatures (<70°C) failed to alleviate PY, whereas higher temperatures either rendered seeds permeable but not germinable (70−90°C), or resulted in seeds losing viability (e.g. 100°C). Therefore, combinational dormancy (PY + physiological dormancy) appears to be present in a proportion of the seeds of these Malvaceae species (i.e. those that imbibed and remained viable, but did not germinate). Scanning electron imagery established that the majority of wet-heat treatments resulted in the rupture of the water gap in the seed testa of all species. The results clearly demonstrate that optimal heat treatments for the alleviation of PY are species-specific. Restoration practitioners handling seeds of diverse species should be mindful of treating seeds at the lowest effective temperature (70−90°C) to avoid injury through inadvertent exposure to temperatures that are higher and longer than necessary to break dormancy.

Overcoming physiological dormancy in Prostanthera eurybioides (Lamiaceae), a nationally endangered Australian shrub species

2008 ◽  
Vol 56 (3) ◽  
pp. 214 ◽  
Author(s):  
P. J. Ainsley ◽  
M. K. Jones ◽  
T. E. Erickson
Keyword(s):  
South Australia ◽  
Physical Dormancy ◽  
Shrub Species ◽  
Dry Heat ◽  
Pulse Heat ◽  
Germination Process ◽  
Physiological Dormancy ◽  
Continuous Application ◽  
Persistent Calyx

Prostanthera eurybioides (Lamiaceae) is an endangered shrub endemic to South Australia. Fruits consist of four mericarps enclosed by a persistent calyx, with each seed characterised by the presence of what we are defining as a mericarp plug. Research focussed on understanding the role of the mericarp plug in the germination process, determining seed dormancy classification and germination cues. Treatments tested included combinations of pulse dry heat (60–120°C) for up to 60 min, continuous application of gibberellic acid (100 mg L–1), smoked water (10% (v/v)) and excision of the mericarp plug. Seed imbibition experiments dispelled the presence of physical dormancy. The mericarp plug was found to be acting as a mechanical barrier preventing germination. Pulse dry heat (80°C) significantly improved germination, as did removal of the mericarp plug. Smoked water inhibited germination. Based on germination response, seeds have been classified as having non-deep physiological dormancy, with maximum germination (86%) observed following a pulse heat treatment (80°C, 10 min) and removal of the mericarp plug. Natural mechanisms for overcoming dormancy are proposed.

Temperature and dormancy-breaking treatments: germination of endemic and geographically restricted herbaceous perennials

2006 ◽  
Vol 54 (4) ◽  
pp. 349 ◽  
Author(s):  
Anne Cochrane ◽  
Robin Probert
Keyword(s):  
Surgical Treatment ◽  
Surgical Excision ◽  
Potassium Nitrate ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Herbaceous Perennials ◽  
Treatment Conditions ◽  
Effects Of Temperature ◽  
Pre Treatment ◽  
Mean Time

This paper describes the effects of temperature and simple or multiple dormancy-breaking treatments (potassium nitrate, surgical treatment, gibberellic acid (GA3), after-ripening at 45°C and nitrogen dioxide gas) on germination of five endemic and geographically restricted herbaceous perennials (Apium prostratum Vent. subsp. phillipii Keighery ms, Goodenia stenophylla F.Muell., Marianthus granulatus (Turcz.) Benth, Myriocephalus suffruticosus Benth. and Velleia foliosa (Benth.) K.Krause) from the species-rich south-west of Western Australia. Except for seeds of A. prostratum that were non-dormant, seeds were partially dormant or fully dormant when incubated without pre-treatment at three temperatures (15, 20 and 25/10°C). Low germination (≤52%) was detected in M. granulatus under the best identified conditions, and seeds of G. stenophylla showed little to no response to any germination cue. In M. granulatus, M. suffruticosus and V. foliosa combinations of treatments were found that led to enhanced germination and in the case of V. foliosa, germination was not significantly different from a tetrazolium test of viability when seeds were surgically treated and then incubated with KNO3. Although none of the species studied exhibited physical dormancy, surgical excision of the seed coat in the vicinity of the embryo featured in the most successful combination of treatments in every case. Whilst seeds of M. granulatus responded positively to surgical treatment, after-ripening of seeds at 45°C for 2, 4 or 6 weeks did not increase either speed or final germination compared with other treatments. The mean time to germinate (MTG) ranged from 12.6 days (A. prostratum ssp. phillipii) to 46.5 days (G. stenophylla) under the best treatment conditions for each species.

scholarly journals SEED DORMANCY BREAKING TREATMENTS FORAFRICAN PURSLANE (Zaleya pentandra)

2015 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
S. MUNAWAR ◽  
M. NAEEM ◽  
H.H. ALI ◽  
M. JAMIL ◽  
M. IQBAL ◽  
...  
Keyword(s):  
Seed Dormancy ◽  
Arid Zone ◽  
Hot Water ◽  
Plant Management ◽  
Dormancy Breaking ◽  
Invasive Weed ◽  
Hard Seed ◽  
Dry Heat ◽  
Breaking Dormancy ◽  
Seed Scarification

ABSTRACT Understanding the mechanisms involved in releasing seed dormancy is crucial for effective plant management and renewal of species in the arid zone. Zaleya pentandra is an emerging invasive weed of the arid areas of Pakistan. We investigated the effects of different dormancy breaking treatments on the germination of Z. pentandra seeds. Seeds were treated with hot water (by placing them in boiling water for 5, 15, 30, 60, 90, 120, and 150 min), dry heat (by placing them in a preheated oven at 70 oC for 1, 2, and 4 hours; at 70 oC for 1, 2, 3, and 4 days, and at 200 oC for 5, 10, 15, 30, and 45 min) and stratification (by placing them at 2-5 ºC in a refrigerator for 5, 10, 30, and 60 min; for 3, 6, and 12 hours, and for 1, 2, 4, 8, 15, and 30 days). Seeds also were soaked in thiourea ([(NH2)2CS] (0, 2,500, 5,000, 7,500, and 10,000 mg L-1 for 24 h at 30 oC) and in KNO3 (0, 10,000, 20,000, 30,000, 40,000, 50,000, and 60,000 mg L-1 for 24 h at 30 oC). Additionally, seeds were scarified with HCl (for 3, 6, 9, 12, 15, 18, and 21 h), HNO3 (for 3, 6, 9, 12, 15, 18, and 21 h), and H2SO4 (for 20, 40, 60, 80, 100, and 120 min at 30 oC) and also mechanically scarified with sandpaper. Zaleya pentandra seeds showed typical signs of hard seed coat dormancy. Mechanical scarification and acid treatments promoted seed germination to a varying degree. Seed scarification with HNO3 for 12 to 18 h as well as with HCl for 12 h and 15 h was efficient in breaking dormancy of Z. pentandra seeds, providing germination up to 92.5%. Seed scarification with H2SO4 from 20 to 120 min showed little effect, whereas hot water, dry heat, stratification and various concentrations of thiourea and KNO3 were ineffective in breaking Z. pentandra seed dormancy.

Germination behaviour of forbs native to the southwestern United States following exposure to short-term seed bank conditions (−20°C)

2020 ◽  
Vol 30 (2) ◽  
pp. 81-91
Author(s):  
Alexandra E. Seglias ◽  
Jessamine Finch ◽  
Andrea T. Kramer
Keyword(s):  
United States ◽  
Seed Bank ◽  
Storage Temperature ◽  
Seed Banks ◽  
Ex Situ ◽  
Southwestern United States ◽  
Dormancy Breaking ◽  
Short Term ◽  
Physical Dormancy ◽  
Germination Requirements

AbstractSeeds are increasingly being stored in seed banks for ex situ conservation, food security, and restoration reserves. Although it is hypothesized that seeds of many species can survive the dry, freezer conditions (−20°C) of seed banks for many years, shelf life is unknown for many species. In particular, changes to dormancy and germination requirements following freezer storage have not yet been studied extensively. To improve our understanding of how seed dormancy and germination respond to seed banking conditions, we evaluated seed of six restoration-priority species in the southwestern United States, which is a region of increasing restoration need. Germination tendencies of seeds that were and were not exposed to a −20°C treatment for 4–6 months were evaluated under 22 cold-moist stratification and incubation treatments to broadly assess changes to dormancy and germination requirements and speed. Direct or indirect (via interactions with stratification and/or incubation treatments) differences in dormancy breaking and germination were observed in seeds for four of the six species studied. Specifically, storage temperature accounted for differences in the final germination proportion, germination during stratification, and/or rate of germination in five of the six species. Notably, seeds of the one species that exhibit a combination of physiological and physical dormancy showed significant differences in all germination measures. However, while significant differences were found between seeds exposed to short-term seed bank storage and those that were not, these differences were small and may not be biologically meaningful, indicating that seed banking these species should not change how they are used for restoration or reintroduction purposes.

Are wildfires an adapted ecological cue breaking physical dormancy in the Mediterranean basin?

2015 ◽  
Vol 25 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Ganesh K. Jaganathan
Keyword(s):  
Mediterranean Ecosystems ◽  
Seasonal Temperature ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Anatomical Structures ◽  
Temperature Changes ◽  
Seed Mortality ◽  
Fire Environment ◽  
Impermeable Seed Coat

AbstractMany studies have claimed that fire acts as the chief ecological factor cueing dormancy break in seeds with a water-impermeable seed coat, i.e. physical dormancy (PY), in Mediterranean ecosystems. However, a proposal is made that seasonal temperature changes must be viewed as more meaningful dormancy-breaking cues because: (1) fire is erratic and may break PY in seasons during which seedlings cannot complete their life cycle; (2) fire may not occur for long periods, thereby only providing an opportunity for dormancy break and germination once in every several years; and (3) if fire opens the specialized anatomical structures called ‘water gaps’, in seconds, their evolutionary role of detecting environmental conditions becomes irrational. Although fire breaks dormancy in a proportion of seeds, given the risk of seed mortality and the post-fire environment providing cues for dormancy break, it is suggested that fire might possibly be an exaptation.

An evaluation of methods for breaking seed dormancy in kudzu (Pueraria lobata)

2001 ◽  
Vol 79 (2) ◽  
pp. 197-203 ◽  
Author(s):  
David J Susko ◽  
J Paul Mueller ◽  
Janet F Spears
Keyword(s):  
Weather Conditions ◽  
Cold Stratification ◽  
Pueraria Lobata ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Invasive Weed ◽  
Dry Heat ◽  
Breaking Dormancy ◽  
Influence Of Temperature On ◽  
Percent Germination

We evaluated several methods for breaking dormancy in seeds of the invasive weed Pueraria lobata (Willd.) Ohwi (kudzu). Seedlings from untreated seeds emerged from late March to early October 1999 in trays placed outdoors under natural weather conditions; mean cumulative percentage emergence was low (11%). In growth chamber experiments, germination percentages of untreated seeds ranged from 6 to 17%. All hand-scarified seeds germinated, whereas only 6% of intact seeds germinated. Other dormancy-breaking methods that produced higher germination percentages included exposure to ethyl alcohol for 6-12 h (24-86%), exposure to concentrated sulfuric acid for 1-2 h (65-81%), and exposure to moist heat for 5-300 s (30-80%). The influence of temperature on germination percentages of seeds following dry heat treatments depended on the duration of exposure. At 60 and 80°C, germination percentages increased with longer exposures to dry heat and were greatest after 720 min (27 and 60%, respectively). At 100°C, percent germination was greatest when seeds were exposed to dry heat for only 10 min (93%). Cold stratification at 5°C for 0-6 weeks did not increase seed germination percentages after exposure to a range of alternating thermoperiods. Similarly, dry storage at room temperature for 0, 200, or 400 days did not affect germination percentages in light or dark treatments.Key words: Pueraria lobata, physical dormancy, germination, phenology, acid scarification, warm stratification, cold stratification.

Comparison of pre-treatments for inducing germination in highly dormant wheat genotypes

2003 ◽  
Vol 83 (4) ◽  
pp. 729-735 ◽  
Author(s):  
M. A. Matus-Cádiz ◽  
P. Hucl
Keyword(s):  
Seedling Growth ◽  
Biomass Yield ◽  
Triticum Aestivum L ◽  
Potassium Nitrate ◽  
Dormancy Breaking ◽  
Yield Data ◽  
Breeding Populations ◽  
Breaking Dormancy ◽  
Seedling Length ◽  
Pre Treatment

An effective dormancy-breaking method may be of interest to wheat (Triticum aestivum L.) breeders selecting for increased seed dormancy prior to advancing their populations in greenhouse grow-outs. The objective of this study was to identify an effective pre-treatment for breaking dormancy in wheat that did not result in seedling etiolation. In 2000, eight dormant (W98616, line 211, EMDR-4, EMDR-9, EMDR-14, RL4137, Columbus, and AC Domain) and one nondormant line (Roblin) were grown at two locations in Saskatchewan. Seeds were: (i) stored for zero to 21 wks at 24°C before incubating at 20°C for 7 d; (ii) incubated at 5, 10, 15, 20, and 25°C for 14 d; and (iii) treated with gibberellic acid (GA3) (0.0006 and 0.0014 M), potassium nitrate (KNO3) (0.01 and 0.02 M), chilling, heating, chilling with 0.01 M KNO3, and heating with 0.01 M KNO3 before incubating at 10°C for 14 d. Seedling growth was observed in a duplicated growth chamber experiment. Seedling length, first inter-node length, and biomass yield data were collected from plants grown from seeds treated with four effective pretreatments. Data were subjected to an ANOVA. Six to 18 weeks of storage at 24°C were required to break the dormancy (≥ 95% germination) in dormant genotypes. Incubation at 10°C was the most effective temperature for promoting germination in dormant seeds after 10d of testing. Four pre-treatments including 0.0006 M GA3, 0.0014 M GA3, chilling with 0.01 M KNO3, and heating with 0.01 M KNO3 led to ≥ 95% germination within 10 d of testing. Only GA3 treatments were associated with etiolated seedling growth. Heating with 0.01 M KNO3 or chilling with 0.01 M KNO3, applied before incubating at 10°C in darkness, may be of interest to breeders selecting for increased dormancy before advancing breeding populations in greenhouse grow-outs. Key words: Triticum, dormancy, nitrate, chilling, heating, etiolated seedling

scholarly journals Effect of dry heat treatment along with some dormancy breaking chemicals on oil palm seed germination

2017 ◽  
Vol 112 ◽  
pp. 489-493
Author(s):  
K.M. Tabi ◽  
G.F. Ngando Ebongue ◽  
G.N. Ntsomboh ◽  
E. Youmbi
Keyword(s):  
Heat Treatment ◽  
Seed Germination ◽  
Oil Palm ◽  
Dormancy Breaking ◽  
Dry Heat ◽  
Dry Heat Treatment
Sign in / Sign up

Export Citation Format

Share Document