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

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.

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Dormancy breakage in Cercis chinensis seeds

Canadian Journal of Plant Science ◽

10.1139/cjps-2019-0229 ◽

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.

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Promoting Germination in Ornamental Palm Seeds through Dormancy Alleviation

HortTechnology ◽

10.21273/hortsci.19.4.682 ◽

2009 ◽

Vol 19 (4) ◽

pp. 682-685 ◽

Cited By ~ 5

Author(s):

Hector E. Pérez

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Commercial Production ◽

Physical Dormancy ◽

Physiological Dormancy ◽

Morphological Dormancy

Delayed and inconsistent seed germination often hampers commercial production of palms (Arecaceae). Such sporadic germination is commonly due to seed dormancy. Mature, freshly shed seeds of palms typically display a combination of underdeveloped embryos (morphological dormancy) and the inability of developing embryos to rupture covering structures (physiological dormancy). Fruit and seedcoats are capable of imbibing water. Therefore, dormancy due to water-impermeable fruit or seedcoats (physical dormancy) does not occur. Removal of embryo covering structures, such as the pericarp and operculum, followed by incubation under moist, warm (25–35 °C) conditions promotes rapid and complete germination. Complete burial in soil promotes germination of seeds in intact fruit of loulu palm (Pritchardia remota).

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Practical Methods for Breaking Seed Dormancy in a Wild Ornamental Tulip Species Tulipa thianschanica Regel

Agronomy ◽

10.3390/agronomy10111765 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1765

Author(s):

Wei Zhang ◽

Lian-Wei Qu ◽

Jun Zhao ◽

Li Xue ◽

Han-Ping Dai ◽

...

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Combined Treatment ◽

Individual Treatment ◽

Cold Stratification ◽

Slight Effect ◽

Sowing Depth ◽

Physiological Dormancy ◽

Commercial Breeding ◽

Breaking Seed Dormancy

The innate physiological dormancy of Tulipa thianschanica seeds ensures its survival and regeneration in the natural environment. However, the low percentage of germination restricts the establishment of its population and commercial breeding. To develop effective ways to break dormancy and improve germination, some important factors of seed germination of T. thianschanica were tested, including temperature, gibberellin (GA3) and/or kinetin (KT), cold stratification and sowing depth. The percentage of germination was as high as 80.7% at a constant temperature of 4 °C, followed by 55.6% at a fluctuating temperature of 4/16 °C, and almost no seeds germinated at 16 °C, 20 °C and 16/20 °C. Treatment with exogenous GA3 significantly improved the germination of seeds, but KT had a slight effect on the germination of T. thianschanica seeds. The combined treatment of GA3 and KT was more effective at enhancing seed germination than any individual treatment, and the optimal hormone concentration for the germination of T. thianschanica seeds was 100 mg/L GA3 + 10 mg/L KT. In addition, it took at least 20 days of cold stratification to break the seed dormancy of T. thianschanica. The emergence of T. thianschanica seedlings was the highest with 82.4% at a sowing depth of 1.5 cm, and it decreased significantly at a depth of >3.0 cm. This study provides information on methods to break dormancy and promote the germination of T. thianschanica seeds.

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

International Journal of Biology ◽

10.5539/ijb.v8n2p77 ◽

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

The seed dormancy of Senna obtusifolia was investigated through various methods, namely pretreatments in concentrated sulfuric acid, 2% potassium nitrate (KNO3), 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 S. obtusifiolia (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 H2SO4 will soften the seed coat and permit germination. Seed dormancy in S. obtusifolia 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 S. obtusifolia 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.

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Non-Deep Physiological Dormancy in Seed and Germination Requirements of Lysimachia coreana Nakai

Horticulturae ◽

10.3390/horticulturae7110490 ◽

2021 ◽

Vol 7 (11) ◽

pp. 490

Author(s):

Saeng Geul Baek ◽

Jin Hyun Im ◽

Myeong Ja Kwak ◽

Cho Hee Park ◽

Mi Hyun Lee ◽

...

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Germination Rate ◽

Seed Viability ◽

Cold Stratification ◽

Dormancy Breaking ◽

Viability Test ◽

Physiological Dormancy ◽

Different Temperatures ◽

Germination Requirements

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.

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

Australian Journal of Crop Science ◽

10.21475/ajcs.20.14.05.p2262 ◽

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.

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Seed Germination of selected Taxa from Kachchh Desert, India

Notulae Scientia Biologicae ◽

10.15835/nsb223692 ◽

2010 ◽

Vol 2 (2) ◽

pp. 41-45 ◽

Cited By ~ 1

Author(s):

Vinay Madhukar RAOLE ◽

Aruna Girish JOSHI ◽

Sandhya Kiran GARGE ◽

Rinku Jitendrakumar DESAI

Keyword(s):

Seed Germination ◽

Growth Regulators ◽

Seed Coat ◽

Native Species ◽

Arid Regions ◽

Conservation Status ◽

Storage Period ◽

The Other ◽

Viable Seeds ◽

Semi Arid

The district of Kachchh contains many culturally important plants. However, their conservation status is little known due to direct and indirect human activities. This study was undertaken with the aim of contributing to the conservation of the native species of these semi-arid regions through germination trials under laboratory conditions. Mature fruits of ten selected species were collected randomly from the known habitats to obtain viable seeds. These seeds were pre-treated with growth regulators singly or in combination after acid scarification or without scarification. Seeds were found to be dormant due to presence of thick seed coat or due to low level of endogenous hormonal level. Most of these seeds required different storage period to mature. Only seeds of Capparis cartilaginea germinated without treatment while the other species required treatments. Addition of growth regulators has enhanced seed germination in few taxa singly and in some plant cases in combination.

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Seed germination of coastal monsoon vine forest species in the Northern Territory, Australia, and contrasts with evergreen rainforest

Australian Journal of Botany ◽

10.1071/bt17243 ◽

2018 ◽

Vol 66 (3) ◽

pp. 218 ◽

Cited By ~ 1

Author(s):

Vidushi Thusithana ◽

Sean M. Bellairs ◽

Christine S. Bach

Keyword(s):

Seed Germination ◽

Seed Storage ◽

Pioneer Species ◽

Physical Dormancy ◽

Climax Species ◽

Seed Biology ◽

Light Requirements ◽

Physiological Dormancy ◽

Germination Traits ◽

Prevalent Form

Seed germination traits of seasonal rainforest species differ from permanently moist evergreen rainforest species due to the prolonged seasonal drought. We investigated whether seed germination traits used to categorise evergreen rainforest species into pioneer and climax guilds were applicable to seasonal rainforest species. Seed dormancy, light requirements for germination and seed storage types of five climax and thirteen pioneer species of a coastal vine thicket were studied. Results were compared with published studies of evergreen rainforest species. Evergreen rainforest pioneer species are typically dormant, require light to germinate and tolerate desiccation, whereas climax species are typically non-dormant, tolerate shade during germination and are sensitive to desiccation. In seasonal rainforest we found that a high proportion of pioneer species had seeds that were non-dormant (62%), and a high proportion of pioneer species germinated equally well in light and dark conditions. In seasonal rainforest, we found that the majority of climax species had desiccation tolerant seeds, whereas in evergreen rainforest the proportion of climax species producing desiccation sensitive seeds is equal to or greater than the proportion of species with desiccation tolerant seeds. In seasonal rainforest species physical, physiological and epicotyl dormancy types were found. Generally, for seasonal rainforest species, the prevalent form of dormancy in pioneer species was physical dormancy whereas physiological dormancy was most common in evergreen rainforest pioneer species with dormancy. Our results suggest that the contrasting seed biology traits that typically apply to pioneer and climax species of evergreen rainforest species don’t typically apply to seasonal rainforest species.

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Effects of Chemical Treatments on Seed Germination of Zoysia (Zoysia japonica Steud.)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.850-851.1295 ◽

2013 ◽

Vol 850-851 ◽

pp. 1295-1302

Author(s):

Li Li Qian ◽

Shan Wang ◽

Kai Ye ◽

Cheng Fang

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Seed Coat ◽

Treatment Time ◽

Warm Season ◽

Dormancy Breaking ◽

Zoysia Japonica ◽

Chemical Treatments ◽

Chemical Agents ◽

The Right

Zoysia (Zoysia japonica Steud.) is a warm-season turf grass, which possess seed coat-imposed dormancy that hampers germination. The objective of the present study was to determine the most effective methods in breaking the seed dormancy of zoysia. This experiment was used to find the right concentration and treatment time. KOH, NaOH, C3H6O, and H2SO4solutions are the four kinds of chemical agents used which were evaluated and sixty four treatments were conducted. The results indicated that all chemical agents investigated can successfully remove glumes and promote seed germination of zoysia under certain concentrations and treatment times. The best method for seed dormancy breaking in zoysia was 20% KOH solution for 30 min.

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

Botanical Sciences ◽

10.17129/botsci.1729 ◽

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.

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