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 Seed anatomy and water uptake and their relation to seed dormancy of Ormosia paraensis Ducke

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
Keyword(s):  
Sulfuric Acid ◽  
Seed Dormancy ◽  
Water Uptake ◽  
Furniture Industry ◽  
Palisade Layer ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Seed Physiology ◽  
Breaking Dormancy ◽  
Hydrophobic Substances

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.

scholarly journals Overcoming seed dormancy and rooting in air-layering polyembryonic seedlings of sapucaia (Lecythis pisonis Cambess.)

2020 ◽  
pp. 816-821
Author(s):  
Caroline Palacio de Araujo ◽  
Rodrigo Sobreira Alexandre ◽  
Thuanny Lins Monteiro Rosa ◽  
Edilson Romais Schmildt ◽  
José Carlos Lopes ◽  
...  
Keyword(s):  
Seed Dormancy ◽  
Seed Coat ◽  
Block Design ◽  
Adjacent Region ◽  
Physical Dormancy ◽  
Functional Elements ◽  
Lateral Region ◽  
Design Environments ◽  
Randomized Complete Block Design ◽  
Edible Seeds

Lecythis pisonis produces edible seeds rich in nutritional and functional elements such as selenium and are a great alternative to Brazilian nuts. The seeds have low germination, which may be related to physical dormancy imposed by tegument, meaning that polyembryonic seedlings can be a strategy to increase final stand. The objective of this work was to study methods to overcome seed dormancy and auxin induction in polyembryonic seedlings of pisonis. The experiment to break dormancy consisted of seven treatments: T1: intact seeds; T2: seeds scarified on hilum’s opposite side; T3: seeds scarified hilum’s adjacent region; T4: seeds scarified in lateral region; T5: seeds scarified in both opposite and adjacent region to the hilum; T6: T2 + immersion in water at 40 °C/20 minutes; T7: T2 + immersion in water at 60 °C/5 minutes. The experiment to induce rooting was arranged in a 2 x 6 factorial randomized complete block design (environments: A. greenhouse and B. greenhouse covered with black polyolefin (80% shading) x concentrations of indole-3-butyric acid (IBA): 0; 1000; 2000; 3000; 4000 and 5000 mg L-1), with four replicates of eight polyembryonic seedlings. Seed coat scarification in hilum’s adjacent (T3) and lateral regions (T4) was the most efficient methods for breaking physical dormancy. IBA at 5000 mg L-1 promoted the greatest rhizogenesis of L. pisonis layers.

Physical dormancy in Senna multijuga (Fabaceae: Caesalpinioideae) seeds: the role of seed structures in water uptake

2014 ◽  
Vol 24 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Ailton G. Rodrigues-Junior ◽  
José M.R. Faria ◽  
Tatiana A.A. Vaz ◽  
Adriana T. Nakamura ◽  
Anderson C. José
Keyword(s):  
Water Uptake ◽  
Seed Coat ◽  
Parenchyma Cell ◽  
Hot Water ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Short Term Exposure ◽  
Hilar Region ◽  
Senna Multijuga

AbstractStructural studies in seeds with physical dormancy (PY) are important to better understand its causes and release when subjected to treatments for dormancy breaking. The aims of this study were to (1) characterize the PY break; (2) examine the role of different seed structures in water uptake; and (3) identify the water gap in Senna multijuga seeds. Imbibition patterns of dormant and non-dormant (subjected to dormancy breaking treatments) seeds and the morphological changes during dormancy breaking and germination were evaluated. To identify the water gap, the micropyle and lens were blocked separately, and the water absorption by seed parts was determined. Structural characteristics of the seed coat were also examined. Immersion in water at 80°C was efficient in breaking seed dormancy and imbibition occurred first at the hilar region, through the lens. Water was not absorbed through the micropyle or the extra-hilar region. S. multijuga seeds have a testa with a linearly aligned micropyle, hilum and lens. The seed coat consisted of a cuticle, macrosclereids, one (hilar region) or two (extra-hilar region) layer(s) of osteosclereids and parenchyma cell layers. The lens has typical parenchyma cells underneath it and two fragile regions comprised of shorter macrosclereids. Heat treatment stimulated the lens region, resulting in the opening of fragile regions at the lens, allowing water to enter the seeds. It is concluded that short-term exposure to a hot water treatment is sufficient for the formation of a water gap in S. multijuga seeds, and only the lens acts in the imbibition process.

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.

scholarly journals The genetics and physiology of seed dormancy, a crucial trait in common bean domestication

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ali Soltani ◽  
Katelynn A. Walter ◽  
Andrew T. Wiersma ◽  
James P. Santiago ◽  
Michelle Quiqley ◽  
...  
Keyword(s):  
Common Bean ◽  
Candidate Genes ◽  
Seed Dormancy ◽  
Water Uptake ◽  
Seed Coat ◽  
Physiological Mechanism ◽  
Causative Mutation ◽  
Integrative Approach ◽  
Functional Allele ◽  
Pectin Acetylesterase

Abstract Background Physical seed dormancy is an important trait in legume domestication. Although seed dormancy is beneficial in wild ecosystems, it is generally considered to be an undesirable trait in crops due to reduction in yield and / or quality. The physiological mechanism and underlying genetic factor(s) of seed dormancy is largely unknown in several legume species. Here we employed an integrative approach to understand the mechanisms controlling physical seed dormancy in common bean (Phaseolus vulgaris L.). Results Using an innovative CT scan imaging system, we were able to track water movements inside the seed coat. We found that water uptake initiates from the bean seed lens. Using a scanning electron microscopy (SEM) we further identified several micro-cracks on the lens surface of non-dormant bean genotypes. Bulked segregant analysis (BSA) was conducted on a bi-parental RIL (recombinant inbred line) population, segregating for seed dormancy. This analysis revealed that the seed water uptake is associated with a single major QTL on Pv03. The QTL region was fine-mapped to a 118 Kb interval possessing 11 genes. Coding sequence analysis of candidate genes revealed a 5-bp insertion in an ortholog of pectin acetylesterase 8 that causes a frame shift, loss-of-function mutation in non-dormant genotype. Gene expression analysis of the candidate genes in the seed coat of contrasting genotypes indicated 21-fold lower expression of pectin acetylesterase 8 in non-dormant genotype. An analysis of mutational polymorphism was conducted among wild and domesticated beans. Although all the wild beans possessed the functional allele of pectin acetylesterase 8, the majority (77%) of domesticated beans had the non-functional allele suggesting that this variant was under strong selection pressure through domestication. Conclusions In this study, we identified the physiological mechanism of physical seed dormancy and have identified a candidate allele causing variation in this trait. Our findings suggest that a 5-bp insertion in an ortholog of pectin acetylesterase 8 is likely a major causative mutation underlying the loss of seed dormancy during domestication. Although the results of current study provide strong evidences for the role of pectin acetylesterase 8 in seed dormancy, further confirmations seem necessary by employing transgenic approaches.

Effects of immersing dry seeds in alkaline solutions on seed dormancy and water uptake in wild oat (Avena fatua)

1994 ◽  
Vol 74 (1) ◽  
pp. 19-24 ◽  
Author(s):  
J. Q. Hou ◽  
G. M. Simpson
Keyword(s):  
Seed Dormancy ◽  
Water Uptake ◽  
Seed Coat ◽  
Treatment Time ◽  
Alkaline Treatment ◽  
Avena Fatua ◽  
Alkaline Solutions ◽  
Wild Oat ◽  
Dormancy Breaking ◽  
Breaking Dormancy

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

scholarly journals Physiological, physical, and morpho-anatomical changes in Libidibia ferrea ((Mart. ex Tul.) L.P. Queiroz) seeds after overcoming dormancy

2015 ◽  
Vol 37 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Antônio César Batista Matos ◽  
Glauciana da Mata Ataíde ◽  
Eduardo Euclydes de Lima e Borges
Keyword(s):  
Sulfuric Acid ◽  
Seed Coat ◽  
Germination Percentage ◽  
Seedling Production ◽  
Forest Species ◽  
Physical Dormancy ◽  
Anatomical Changes ◽  
Time Of Application ◽  
Before And After ◽  
Triphasic Pattern

Seed dormancy is a phenomenon that affects the distribution of plant species in time. However, it may slow germination and consequently hinder seedling production in nurseries. Many seeds of forest species of the Fabaceae family, such as Libidibia ferrea (Brazilian ironwood), have physical dormancy caused by impermeability of the seed coat to water. Therefore, the aim of this study was to evaluate the physiological, physical, and morpho-anatomical characteristics of L. ferrea seeds before and after application of different treatments for overcoming dormancy. We evaluated the imbibition curves, germination percentage, germination speed index (GSI), the force required to puncture the micropylar region, and morpho-anatomical changes through images obtained from a scanning electron microscope (SEM) before and after application of treatments for overcoming dormancy. L. ferrea seeds immersed in sulfuric acid show a triphasic pattern of imbibition. The required force to puncture the micropylar region of L. ferrea seeds is less for both the treatment with boiling water and for treatments with sulfuric acid. In addition, the required force to puncture the micropylar region decreases during imbibition of the seeds after application of sulfuric acid. The time of application of sulfuric acid influences the thickness of the material removed from the macrosclereid layer of the seed coat.

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 Pretreatments on Seed Germination of Prunus mahaleb L.

2012 ◽  
Vol 40 (2) ◽  
pp. 183 ◽  
Author(s):  
Elias PIPINIS ◽  
Elias MILIOS ◽  
Olga MAVROKORDOPOULOU ◽  
Christina GKANATSIOU ◽  
Maria ASLANIDOU ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Seed Germination ◽  
Gibberellic Acid ◽  
Seed Dormancy ◽  
Mechanical Resistance ◽  
Cold Stratification ◽  
Long Period ◽  
Prunus Mahaleb ◽  
Sexual Propagation ◽  
Improve Seed Germination

Sexual propagation of Prunus mahaleb is difficult due to seed dormancy. To overcome dormancy and maximize germination, various pretreatments have been applied, including stratification (warm and cold), gibberellic acid (GA3), sulfuric acid scarification (AS), and endocarp removal. The results show that warm stratification (WS) prior to cold stratification (CS) does not improve seed germination and a long period of WS (3 months) is disastrous for germination. CS alone (up to 4 months) has been found to hasten and increase seed germination. Pretreatment of the seeds with exogenous GA3, during the CS period, has been observed to result in significantly higher seed germination. AS of seeds for 45 minutes prior to GA3 (1000 ppm for 24 hours) plus CS (up to 1 month) pretreatment has been considered to reduce the mechanical resistance of endocarp and improve germination. However, extended time of AS (180 minutes) prior to GA3 plus CS pretreatment has been found to harm the seeds. The removal of endocarp has been noted to significantly improve germination. Seeds without endocarp, which were pretreated with GA3 (1000 or 2000 ppm for 24 hours) and then cold stratified for 1 month, have been noted to exhibit the highest germination percentages.

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.

Sign in / Sign up

Export Citation Format

Share Document