scholarly journals Efectividad de algunos tratamientos pre-germinativos para ocho especies leñosas de la Mixteca Alta oaxaqueña con características relevantes para la restauración

2017 ◽  
pp. 9
Author(s):  
Gilberto Martínez-Pérez ◽  
Alma Orozco-Segovia ◽  
Carlos Martorell
Keyword(s):  
Seed Coat ◽  
Native Species ◽  
Immature Embryo ◽  
New Method ◽  
Dodonaea Viscosa ◽  
Physical Dormancy ◽  
Mixteca Alta ◽  
Physiological Dormancy ◽  
Wearing Off ◽  
Do So

When restoring highly degraded areas such as the Mixteca Alta (Oaxaca State, Mexico), it is important to use native species that promote natural succession. To do so, we need to know whether their seeds have dormancy and how to break it. We compared different pre-germination treatments of eight species relevant for restoration. The results were analyzed with a new method that solves some of the statistical problems that arise when examining these experiments. In Acacia schaffneri, Ipomoea murucoides, Mimosa aculeaticarpa and Dodonaea viscosa wearing off the seed coat by means of abrasion or heating promotes rapid germination, proving the presence of physical dormancy. Despite belonging to families that show physiological dormancy only, the seeds of Arctostaphylos pungens and Juniperus flaccida germinate after immersion in acid. This procedure may have weakened the seed coat, allowing the immature embryo to break it. We found weak physiological dormancy in Quercus deserticola, and no apparent dormancy in Quercus castanea.

Physical dormancy in seeds of Dodonaea viscosa (Sapindales, Sapindaceae) from Hawaii

2004 ◽  
Vol 14 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Jerry M. Baskin ◽  
Barbara H. Davis ◽  
Carol C. Baskin ◽  
Sean M. Gleason ◽  
Susan Cordell
Keyword(s):  
Seed Coat ◽  
White Light ◽  
Red Light ◽  
Dodonaea Viscosa ◽  
Physical Dormancy ◽  
Critical Moisture Content ◽  
Temperature Regimes ◽  
Wide Range ◽  
Critical Moisture ◽  
Impermeable Seed Coat

Dormancy in seeds ofDodonaea viscosais due to a water-impermeable seed coat (physical dormancy, PY). Thus, mechanically scarified seeds imbibed water (c.95% increase in mass) and germinated to high percentages over a wide range of temperature regimes in both white light and darkness, whereas non-scarified seeds did not take up water. Dry heat at 80–160°C and dipping in boiling water for 1–60 s also broke dormancy in a high percentage of the seeds, and continuous far-red light was not inhibitory to germination. However, dry storage in the laboratory for >1 year did not overcome dormancy. Seeds made water-permeable by boiling imbibed water, and thus germinated, at a much slower rate than those made water-permeable by mechanical scarification. We suggest that boiling opened the ‘water gap’ in the seed coat (not yet described inSapindaceaebut present in other taxa with PY) and that water entered the seed only through this small opening, thereby accounting for the slow rate of imbibition and subsequent germination. Physical dormancy has now been shown to occur in seeds of this polymorphic, worldwide species from Australia, Brazil, Hawaii, Mexico and New Zealand. The low level of dormancy reported for seed lots ofD. viscosain China, India and Pakistan is probably due to collection of seeds before they dried to the critical moisture content for development of water-impermeability of the seed coat. Germination of non-dormant seeds over a wide range of temperatures and in white light, far-red (leaf-canopy shade) light and darkness are part of the germination strategy ofD. viscosaand of other taxa whose seeds have PY at maturity.

Mechanisms of seed dormancy in an annual population of Zostera marina (eelgrass) from The Netherlands

1991 ◽  
Vol 69 (9) ◽  
pp. 1972-1976 ◽  
Author(s):  
Paul Garth Harrison
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Zostera Marina ◽  
Early Winter ◽  
Physical Dormancy ◽  
Physiological Dormancy ◽  
Annual Population ◽  
Effects Of Temperature ◽  
Viable Seeds

Mechanisms of dormancy of seeds from an annual population of the seagrass Zostera marina L. (eelgrass) in the SW Netherlands were investigated in the laboratory. Both physiological dormancy (a requirement for reduced salinity for germination) and physical dormancy (imposed by the seed coat) existed in recently shed seeds. Physiological seed dormancy was partly released in the seed bank by early winter, but physical dormancy lasted longer. By March seeds germinated quickly in the dark in full-strength seawater without artificial weakening of the seed coat. Viable seeds were released with coats that ranged from green (easily ruptured by the embryo) to brown (not easily ruptured); this variation may account for the occasional seedlings that appear during winter. No significant effects of temperature or light on germination were detected. A reexamination of the literature suggests that the observed variation in timing of germination in eelgrass populations may be a result of hitherto overlooked aspects of dormancy. Key words: eelgrass, seagrass, seed coat, seed dormancy, seed germination, Zostera marina.

Dormancy breakage in Cercis chinensis seeds

2020 ◽  
Vol 100 (6) ◽  
pp. 666-673
Author(s):  
Yunpeng Gao ◽  
Mingwei Zhu ◽  
Qiuyue Ma ◽  
Shuxian Li
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Germination Percentage ◽  
Physical Dormancy ◽  
Optimal Method ◽  
Hard Seed ◽  
Positive Effects ◽  
Physiological Dormancy ◽  
Hard Seed Coat

The seeds of Cercis chinensis Bunge are important for reproduction and propagation, but strong dormancy controls their germination. To elucidate the causes of seed dormancy in C. chinensis, we investigated the permeability of the hard seed coat and the contribution of the endosperm to physical dormancy, and we examined the effect of extracts from the seed coat and endosperm. In addition, the effectiveness of scarification methods to break seed dormancy was compared. Cercis chinensis seeds exhibited physical and physiological dormancy. The hard seed coat played an important role in limiting water uptake, and the endosperm acted as a physical barrier that restricted embryo development in imbibed seeds. Germination percentage of Chinese cabbage [Brassica rapa subsp. chinensis (L.) Hanelt] seeds was reduced from 98% (control) to 28.3% and 56.7% with a seed-coat extract and an endosperm extract, respectively. This demonstrated that both the seed coat and endosperm contained endogenous inhibitors, but the seed-coat extract resulted in stronger inhibition. Mechanical scarification, thermal scarification, and chemical scarification had positive effects on C. chinensis seed germination. Soaking non-scarified seeds in gibberellic acid (GA3) solution did not promote germination; however, treatment with exogenous GA3 following scarification significantly improved germination. The optimal method for promoting C. chinensis seed germination was soaking scarified seeds in 500 mg·L−1 GA3 for 24 h followed by cold stratification at 5 °C for 2 mo.

scholarly journals Effect of the seed coat on dormancy and germination in Stylosanthes humilis H. B. K. Seeds

2017 ◽  
Vol 39 (2) ◽  
pp. 114-122 ◽  
Author(s):  
Izabel de Souza Chaves ◽  
Nilo Cesar Queiroga Silva ◽  
Dimas Mendes Ribeiro
Keyword(s):  
Seed Coat ◽  
Room Temperature ◽  
Low Ph ◽  
Physical Dormancy ◽  
Hard Seed ◽  
Stylosanthes Humilis ◽  
Physiological Dormancy ◽  
Radicle Protrusion ◽  
Townsville Stylo ◽  
Hard Seed Coat

Abstract: Seed of Townsville stylo (Stylosanthes humilis H.B.K.) is known to exhibit a hard seed coat and when freshly harvested also show a physiological dormancy, however, the nature of the co-actions between seed coat and embryo growth that determine dormancy is poorly understood. In this study, physical dormancy of Townsville stylo seeds was not reduced during natural ageing at room temperature, in contrast to the physiological dormancy, which is gradually overcome during after-ripening. Furthermore, the permeability of seed coat was affected by scarification treatments as well as by low-pH solutions. Together, these data indicate that physical dormancy overcome of seed is prerequisite for radicle protrusion and physiological dormancy of Townsville stylo seeds contribute to its timing.

Physical dormancy in seeds of Dodonaea viscosa (Sapindaceae) from India

2005 ◽  
Vol 15 (1) ◽  
pp. 59-61 ◽  
Author(s):  
S.S. Phartyal ◽  
J.M. Baskin ◽  
C.C. Baskin ◽  
R.C. Thapliyal
Keyword(s):  
Seed Dormancy ◽  
Seed Coat ◽  
Geographical Range ◽  
Western India ◽  
Dodonaea Viscosa ◽  
Physical Dormancy ◽  
Impermeable Seed Coat ◽  
North Western

In contrast to reports in the literature that seeds of Dodonaea viscosa from China and Pakistan are non-dormant, or nearly so, we found that a high percentage of seeds of this species collected in north-western India have a water-impermeable seed coat at maturity, i.e. physical dormancy. Thus, seeds that were mechanically scarified and boiled (to open a ‘water gap’ in the seed coat) germinated to much higher percentages (84% and 77%, respectively) than did those that were non-scarified (24%). Our results agree with studies of seed dormancy in this species in various other parts of its large geographical range.

scholarly journals Effect of seed coat rupture on the germination of Mimosa flocculosa Burkart (Leguminosae) seeds

Hoehnea ◽  
2020 ◽  
Vol 47 ◽  
Author(s):  
Maiara Iadwizak Ribeiro ◽  
Guilherme Almeida Garcia Rodrigues ◽  
Gabriele Larissa Mathias ◽  
Shirley Martins Silva ◽  
Jaqueline Malagutti Corsato ◽  
...  
Keyword(s):  
Seed Coat ◽  
Native Species ◽  
Large Scale ◽  
Germination Percentage ◽  
Distilled Water ◽  
Seedling Production ◽  
Physical Dormancy ◽  
Anatomical Analysis ◽  
Heated Water ◽  
Mean Germination Time

ABSTRACT Mimosa flocculosa Burkart is a native species used for the recovery of degraded areas. Large scale seedling production in nurseries is hindered due to seed physical dormancy. This study evaluated the germination and seed coat anatomy of M. flocculosa seeds subjected to dormancy overcome treatments. Seeds of M. flocculosa were subjected to: control with distilled water, heated water at 50, 80 and 100 °C, and H2SO4 for 1, 3 and 5 minutes. Germination tests were conducted with four replicates of 25 seeds in an entirely casualized delineation, analyzing germination percentage, mean germination time and germination speed index. Moreover, anatomical analysis of the seed coat was conducted. The treatments with heated water at 80 ºC, and sulfuric acid for 3 and 5 minutes promoted benefic anatomical alterations in the seed integument, reflecting in higher and faster in germination rates. Heated water at 80 ºC is recommended because of its efficiency and safety.

Mechanical scarification technique breaks seed coat-mediated dormancy in wild oat (Avena fatua)

2021 ◽  
pp. 1-25
Author(s):  
Roberto Lujan Rocha ◽  
Yaseen Khalil ◽  
Aniruddha Maity ◽  
Hugh J. Beckie ◽  
Michael B. Ashworth
Keyword(s):  
Growth Rate ◽  
Seed Coat ◽  
Research Effort ◽  
Economic Losses ◽  
Wild Oat ◽  
Weed Species ◽  
Physical Dormancy ◽  
No Donor ◽  
Seedling Growth Rate ◽  
Oat Seeds

Abstract Wild oat is a herbicide resistance-prone global weed species that causes significant economic losses in dryland and horticultural agriculture. As a result, there has been a significant research effort in controlling this species. A major impediment to this research is the seed coat-mediated dormancy of wild oat, requiring a labor-intensive incision or puncturing of the seed coat to initiate seed germination. This study defines the most efficient settings of a mechanical thresher to overcome wild oat seed dormancy and then validates these settings using multiple populations collected from the Western Australian grain belt. We also compare the effects of rapid mechanical scarification and known germination stimulus tactics such as scarification with sulfuric acid (H2SO4), partial endosperm removal, sandpaper scarification of the seed coat, and immersion in sodium nitroprusside (NO donor SNP) solution on wild oat seedling growth rate. Threshing treatment of 1,500 rpm for 5 s provides equivalent germination compared with manually puncturing individual wild oat seeds, with no difference in seedling relative growth rate. The mechanical scarification of seeds using the thresher resulted in greater germination (66%) than H2SO4 scarification (0%), partial endosperm removal (10%), sandpaper seed coat scarification (25%), and exposure to NO donor SNP (34%). This study demonstrates that the physical dormancy of wild oat can be rapidly overcome using a commercially available mechanical thresher.

scholarly journals Effects of Different Pretreatments and Seed Coat on Dormancy and Germination of Seeds of Senna obtusifolia (L.) H.S. Irwin & Barneby (Fabaceae)

2016 ◽  
Vol 8 (2) ◽  
pp. 77
Author(s):  
Stephen I. Mensah ◽  
Chimezie Ekeke
Keyword(s):  
Sulfuric Acid ◽  
Seed Dormancy ◽  
Water Uptake ◽  
Seed Coat ◽  
Critical Factor ◽  
Potassium Nitrate ◽  
Ex Situ ◽  
Mechanical Resistance ◽  
Physical Dormancy ◽  
Senna Obtusifolia

<p class="1Body">The seed dormancy of <em>Senna obtusifolia</em> was investigated through various methods, namely pretreatments in concentrated sulfuric acid, 2% potassium nitrate (KNO<sub>3</sub>), 99% ethanol, 99% methanol, and in hydrogen perioxide; examination of the seed coverings; and the determination of water uptake by the seeds in order to ascertain the most effective technique for breaking dormancy and also determine the dormancy type. The results showed that sulfuric acid treatment recorded the highest germination (100%); followed by 2% hydrogen peroxide treatment (24%) in 15minutes immersion. The methanol and ethanol pretreatments gave 18.33% and 16.5% germinations respectively. Pretreatment in 2% potassium nitrate gave the lowest germination (8.50%), while the intact seeds of <em>S. obtusifiolia</em> (control) gave 0% germination. The anatomy of the seed coat indicated the presence of hard, thickened and specialized cells of cuticle, macrosclereids, osteoscereids, and disintegrated parenchyma layers. The water uptake of intact seeds was low (13.5%) after 24 hr imbibitions. These findings revealed that the seed coat acts as barrier to germination by preventing water absorption, possibly gaseous diffusion in and out of the seed and conferring mechanical resistance to the protrusion of embryo. Pretreatments, such as immersion in H<sub>2</sub>SO<sub>4 </sub>will soften the seed coat and permit germination. Seed dormancy in <em>S. obtusifolia </em>can be considered of physical nature and classified as physical dormancy. The results obtained in this study may serve as useful information in the production and improvement of <em>S. obtusifolia </em>seedlings, as knowledge on seed dormancy and germination is a critical factor and requirements to the understanding of the propagation of this plant either in situ or ex-situ, in view of the economic potentials/attributes of this species.</p>

scholarly journals Morphological aspects of fruits, seeds, seedlings and in vivo and in vitro germination of species of the genus Cleome

2014 ◽  
Vol 36 (3) ◽  
pp. 326-335 ◽  
Author(s):  
Tatiana Carvalho de Castro ◽  
Claudia Simões-Gurgel ◽  
Ivan Gonçalves Ribeiro ◽  
Marsen Garcia Pinto Coelho ◽  
Norma Albarello
Keyword(s):  
Urban Areas ◽  
Native Species ◽  
Human Impacts ◽  
In Vitro Germination ◽  
Morphological Aspects ◽  
Physiological Dormancy ◽  
Cleome Spinosa ◽  
The Tropics

The genus Cleome is widely distributed in drier areas of the tropics and subtropics. Cleome dendroides and C. rosea are Brazilian native species that occur mainly in Atlantic Forest and sandy coastal plains, respectively ecosystems negatively affected by human impacts. Cleome spinosa is frequently found in urban areas. Many Cleome species have been used in traditional medicine, as C. spinosa. In the present work, was investigated C. dendroides, C. rosea and C. spinosa germinative behavior under in vivo conditions, as well as was established suitable conditions to in vitro germination and seedling development. The in vivo germination was performed evaluating the influence of temperature, substrate and light. It was observed that only C. spinosa seeds presents physiological dormancy, which was overcome by using alternate temperatures. The substrate influenced significantly the germination of C. rosea and the seeds of C. dendroides showed the highest germination percentages in the different conditions evaluated. The post-seminal development stages under in vivo and in vitro conditions were defined. It was observed that the development was faster under in vitro than in vivo conditions. An effective methodology for in vitro germination, enabling the providing of material to experiment on plant tissue culture was established to C. dendroides and C. spinosa.

Seed development in Malva parviflora: onset of germinability, dormancy and desiccation tolerance

2007 ◽  
Vol 47 (6) ◽  
pp. 683 ◽  
Author(s):  
Pippa J. Michael ◽  
Kathryn J. Steadman ◽  
Julie A. Plummer
Keyword(s):  
Moisture Content ◽  
Seed Development ◽  
Desiccation Tolerance ◽  
Dry Weight ◽  
Physical Dormancy ◽  
Seed Moisture Content ◽  
Physiological Maturity ◽  
Seed Moisture ◽  
Physiological Dormancy ◽  
Malva Parviflora

Seed development was examined in Malva parviflora. The first flower opened 51 days after germination; flowers were tagged on the day that they opened and monitored for 33 days. Seeds were collected at 12 stages during this period and used to determine moisture content, germination of fresh seeds and desiccation tolerance (seeds dried to 10% moisture content followed by germination testing). Seed moisture content decreased as seeds developed, whereas fresh (max. 296 mg) and dry weight (max. 212 mg) increased to peak at 12–15 and ~21 days after flowering (DAF), respectively. Therefore, physiological maturity occurred at 21 DAF, when seed moisture content was 16–21%. Seeds were capable of germinating early in development, reaching a maximum of 63% at 9 DAF, but germination declined as development continued, presumably due to the imposition of physiological dormancy. Physical dormancy developed at or after physiological maturity, once seed moisture content declined below 20%. Seeds were able to tolerate desiccation from 18 DAF; desiccation hastened development of physical dormancy and improved germination. These results provide important information regarding M. parviflora seed development, which will ultimately improve weed control techniques aimed at preventing seed set and further additions to the seed bank.

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