Variation in seed dormancy in Echinochloa and the development of a standard protocol for germination testing. II: Breaking dormancy in seeds unresponsive to light or dark conditions alone by using heat and ethanol pretreatment

2012 ◽  
Vol 40 (3) ◽  
pp. 299-308
Author(s):  
D.A. Kovach ◽  
M.P. Widrlechner ◽  
D.M. Brenner
Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 319
Author(s):  
Yuhan Tang ◽  
Keliang Zhang ◽  
Yin Zhang ◽  
Jun Tao

Sorbus alnifolia (Siebold & Zucc.) K.Koch (Rosaceae) is an economically important tree in the temperate forests of Eastern China. In recent decades, ever-increasing use and modification of forestlands have resulted in major degeneration of the natural habitat of S. alnifolia. Moreover, S. alnifolia seeds germinate in a complicated way, leading to a high cost of propagation. The current study aimed to determine the requirements for breaking seed dormancy and for germination as well as to characterize the type of seed dormancy present in this species. Moreover, the roles of temperature, cold/warm stratification, and gibberellic acid (GA3) in breaking dormancy were tested combined with a study of the soil seed bank. The results showed that intact seeds of S. alnifolia were dormant, requiring 150 days of cold stratification to achieve the maximum germination percentage at 5/15 °C. Exposure of the seeds to ranges of temperatures at 15/25 °C and 20/30 °C resulted in secondary dormancy. Scarifying seed coat and partial removal of the cotyledon promoted germination. Compared with long-term cold stratification, one month of warm stratification plus cold stratification was superior in breaking dormancy. Application of GA3 did not break the dormancy during two months of incubation. Seeds of S. alnifolia formed a transient seed bank. The viability of freshly matured S. alnifolia seeds was 87.65% ± 11.67%, but this declined to 38.25% after 6-months of storage at room temperature. Seeds of S. alnifolia have a deep physiological dormancy; cold stratification will be useful in propagating this species. The long chilling requirements of S. alnifolia seeds would avoid seedling death in winter.


2018 ◽  
Vol 40 (3) ◽  
pp. 237-245
Author(s):  
Breno Marques da Silva e Silva ◽  
Camila de Oliveira e Silva ◽  
Fabiola Vitti Môro ◽  
Roberval Daiton Vieira

Abstract: Ormosia paraensis Ducke has ornamental seeds widely used in the manufacture of bio-jewels and wood used in the furniture industry. For seedling production, the information on its seed physiology is scarce. Thus, the aim of this study was to assess methods for breaking dormancy and relate them to integument structure and water uptake by O. paraensis seeds. Seed dormancy-breaking was performed by mechanical scarification and soaking in sulfuric acid for 0, 15, 30, 60, 120, and 240 minutes. Dormancy‐broken seeds were compared with intact seeds. Seed integument is formed by a cuticle (hydrophobic substances), epidermis (macroesclereids of the palisade layer,), hypodermis (osteosclereids), and parenchyma cells. Intact seeds did not absorb water after 72 hours of soaking. The highest percentages and rates of seed germination were observed in treatments with mechanical scarification and soaking in sulfuric acid for 60 or 120 minutes. Seed soaking in sulfuric acid (H2SO4 p.a. 98.08%) for 60 or 120 minutes or mechanical scarification are adequate to overcome physical dormancy associated with O. paraensis seed integument impermeability to water or gases.


Weed Science ◽  
2017 ◽  
Vol 65 (2) ◽  
pp. 256-265
Author(s):  
Scott N. White ◽  
Linshan Zhang ◽  
Kris Pruski

American burnweed is an increasingly common annual weed in wild blueberry fields in Atlantic Canada and Maine. Knowledge of seed dormancy characteristics and potential for this species to form persistent seedbanks in wild blueberry soils, however, is lacking. A series of experiments were therefore conducted to investigate potential mechanisms regulating American burnweed seed dormancy in wild blueberry fields. Seeds were dormant at maturity and did not germinate in dark or light under warm conditions. Cold moist stratification (CMS) at 4 C for 90 d followed by exposure to warm conditions (22/15 C day/night) and light caused >90% germination, and germination was generally maximized following 80 d CMS. Exogenous potassium nitrate applied as a 5% solution did not stimulate germination, but nearly all seeds (>95%) germinated following treatment with 200, 400, 600, or 800 ppm (w/v) gibberellic acid (GA3) solution. Physical removal of the seed coat or seed exposure to short durations of dry heat did not increase germination. Seed exposure to 1 s of direct flame increased germination, but germination was low relative to germination following CMS and treatment with GA3. Based on these results, we conclude that American burnweed seeds in wild blueberry fields exhibit non–deep physiological dormancy that is most readily broken by CMS and light or seed treatment with GA3. Seeds will likely be exposed to favorable conditions for breaking dormancy (cold temperatures and light) in wild blueberry fields due to lack of tillage and seed burial, indicating high potential for this weed species to proliferate in wild blueberry fields if not properly managed.


2015 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
S. MUNAWAR ◽  
M. NAEEM ◽  
H.H. ALI ◽  
M. JAMIL ◽  
M. IQBAL ◽  
...  

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.


1994 ◽  
Vol 74 (1) ◽  
pp. 19-24 ◽  
Author(s):  
J. Q. Hou ◽  
G. M. Simpson

Effects of immersing dry seeds in KOH and NaOH solutions on seed dormancy and water uptake were studied in three dormant lines of wild oat (Avena fatua L.). KOH was more effective than NaOH in breaking dormancy. Maximum dormancy-breaking effect of 5.3 N KOH could be achieved with a 10- or 15-min treatment. Increase in treatment time did not necessarily increase germination; rather, it caused damage to the seeds. For 10-min treatment, 5.3 and 7.6 N KOH solutions were more effective than 3 and 9.8 N. Genetic lines responded differently to the KOH treatment. Initial rate and amount of water uptake by KOH-treated seed were significantly higher than by the untreated. It is believed that breaking dormancy by the alkaline treatment is related to removing the barrier to water uptake formed by the seed coat. Key words: Alkalis, Avena fatua, dormancy, seed coat, seedling growth


1998 ◽  
Vol 8 (4) ◽  
pp. 501-512 ◽  
Author(s):  
Jerry M. Baskin ◽  
Xiaoying Nan ◽  
Carol C. Baskin

AbstractSeed dormancy and germination ofSenna marilandicaandS. obtusifoliawere compared in greenhouse and laboratory studies. About 90% of theS. obtusifoliaseeds were green and had hard seed coat dormancy, whereas the other 10% were brown and nondormant. Seed-colour morphs did not occur inS. marilandica, and nearly 100% of the seeds had hard seed coat dormancy. Seeds ofS. obtusifoliawere significantly heavier than those ofS. marilandica. Mechanical scarification was very effective in overcoming dormancy in seeds of both species. However, concentrated sulfuric acid, absolute ethanol and boiling water were less effective in breaking dormancy in seeds ofS. marilandicathan in those ofS. obtusifolia. Further, incubating seeds at 30/15 to 40/25°C and dry-heat treatments at 80–100°C were ineffective in breaking dormancy inS. marilandica, but significantly increased germination percentages inS. obtusifolia. In neither species were simulated daily/seasonal temperature shifts effective in breaking dormancy. Scarified seeds of both species germinated over a wide range of temperatures in both light and darkness. Under near-natural temperature conditions, seeds ofS. marilandicagerminated in spring only, whereas those ofS. obtusifoliaemerged in late spring and throughout summer. Both species can form a long-lived seed bank. Dormancy break by high field temperatures in seeds ofS. obtusifoliaallows this species to germinate throughout the warm growing season and thus contributes to its success as a weed in arable crops.


2020 ◽  
Vol 8 (2) ◽  
pp. 391
Author(s):  
Jefi Saputra ◽  
Riska Audina Amir ◽  
Nur Mumin ◽  
Gusti Ayu Kade Sutariati

Persistence and Breaking of Local Chilli Seed Dormancy Using Seed Bio-Invigoration Techniques. This study aims to evaluate the persistence of local chilli seed dormancy while evaluating seed bio-invigoration techniques that effectively break the dormancy of local chilli. The study consisted of two series of experiments, namely: the persistence test of local chilli. seed dormancy (Series 1) was observed descriptively using a germination indicator for several weeks to reach a germination percentage ≥ 80%. Testing of seed dormancy breakage by seed bio-invigoration technique (Series 2) using a randomized complete design with 3 replications and 7 treatments namely: no treatment (A0), matriconditioning of husk charcoal powder (SAS) + Bacillus sp. CKD061 (A1), matriconditioning SAS + Pseudomonas sp. TBT214 (A2), red brick powder matriconditioning (SBM) + Bacillus sp. CKD061 (A3), matriconditioning SBM + Pseudomonas sp. TBT214 (A4), matriconditioning SAS + Bacillus sp. CKD061 + Pseudomonas sp. TBT214 (A5), and matriconditioning SBM + Bacillus sp. CKD061 + Pseudomonas sp. TBT214 (A6). The results showed that the persistence of local chilli seed dormant cultivars Konsel 1 and Konsel 2 cultivars were 6 weeks. While the dormancy break test on the Konsel 1 cultivar was 2 weeks at A1 treatment with breaking dormancy of 90.00%. While in Konsel 2 cultivar which is 4 weeks in the A6 treatment with breaking dormancy  86.67% which is significantly different from the control. This study shows that A1 treatment can break dormancy of chilli seeds in Konsel 1 cultivar and A6 treatment in Konsel 2 cultivar. 


1991 ◽  
Vol 9 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Stanley G. Kitchen ◽  
Susan E. Meyer

Abstract Propagation of the genus Penstemon for use in landscape horticulture has been handicapped by a lack of understanding of seed dormancy and a practical method for breaking dormancy for numerous species. The extent of dormancy in seeds of 27 wild populations of Penstemon representing 16 Intermountain species was investigated by subjecting seeds to stratification (moist prechilling) of 2 to 16 weeks at 2°C (36°F) and varying concentrations of gibberellic acid (GA3). Germination varied from 0 to 88% for non-treated seeds and from 13 to 100% for seeds treated with 250 ppm GA3. Collections from 10 species required 12 or more weeks of stratification for complete germination. Three species exhibited reduced germination after stratification when compared to the non-chilled control. Gibberellic acid significantly reduced the stratification requirement of seeds for the more dormant species. Concentrations of 150, 250, and 500 ppm GA3 were equally effective in breaking dormancy for most species. The considerable variability in seed dormancy suggests that the most practical solution to penstemon propagation from seed may be the selection of species and ecotypes with minimal dormancy.


2020 ◽  
Vol 48 (1) ◽  
pp. 101-116
Author(s):  
Milène N. Koutouan-Kontchoi ◽  
Shyam S. Phartyal ◽  
Sergey Rosbakh ◽  
Edouard K. Kouassi ◽  
Peter Poschlod

Information on the regeneration ecology of native woody species of the forest-savanna ecotone of West Africa is scarce, which is a major impediment to their optimal utilization in large-scale restoration programmes. The scattered information that is available for some of these species reveals that freshly matured seed are dormant. However, environmental heterogeneity among different habitats may results in inter-population seed dormancy variation. Thus, our objective was to re-examine the dormancy of 12 species from the forest-savanna ecotone that have been targeted for reforestation. Specifically, we aimed to examine the water-permeability of the seeds and explore the effectiveness of acid scarification and heat treatment to alleviate dormancy. Four species belonging to families other than Fabaceae and Malvaceae had water-permeable seeds. Two of them had nondormant (ND) seeds, and seeds of the other two species had a mixture of ND and other kinds of dormancy (possibly physiological dormancy, PD). Most species of Fabaceae and Malvaceae had water-impermeable seeds. All seeds of three species had physical dormant (PY), and some seeds of the remaining species had PY, while others were ND or had PD. Acid-scarification was effective in breaking PY and in augmenting imbibition and germination of non-PY seeds, while heat treatment was moderately effective in breaking dormancy. In general, acid scarification for 1-30 minutes and heat treatment for one hour at 55-75°C were optimal to enhance seed germination, depending on species. The present study has wide practical implications for park conservationists and restoration ecologists interested in producing bulk quantities of high-quality planting stocks of native woody species for large-scale restoration programmes.


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