The great diversity in kinds of seed dormancy: a revision of the Nikolaeva–Baskin classification system for primary seed dormancy

2021 ◽  
pp. 1-29
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seed Dormancy ◽  
Seed Coat ◽  
Classification System ◽  
Primary Dormancy ◽  
Morphophysiological Dormancy ◽  
Physiological Dormancy ◽  
Whole Seed ◽  
Dust Seeds ◽  
Impermeable Seed Coat ◽  
Morphological Dormancy

Abstract This review provides a revised and expanded word-formula system of whole-seed primary dormancy classification that integrates the scheme of Nikolaeva with that of Baskin and Baskin. Notable changes include the following. (1) The number of named tiers (layers) in the classification hierarchy is increased from three to seven. (2) Formulae are provided for the known kinds of dormancy. (3) Seven subclasses of class morphological dormancy are designated: ‘dust seeds’ of mycoheterotrophs, holoparasites and autotrophs; diaspores of palms; and seeds with cryptogeal germination are new to the system. (4) Level non-deep physiological dormancy (PD) has been divided into two sublevels, each containing three types, and Type 6 is new to the system. (5) Subclass epicotyl PD with two levels, each with three types, has been added to class PD. (6) Level deep (regular) PD is divided into two types. (7) The simple and complex levels of class morphophysiological dormancy (MPD) have been expanded to 12 subclasses, 24 levels and 16 types. (8) Level non-deep simple epicotyl MPD with four types is added to the system. (9) Level deep simple regular epicotyl MPD is divided into four types. (10) Level deep simple double MPD is divided into two types. (11) Seeds with a water-impermeable seed coat in which the embryo-haustorium grows after germination (Canna) has been added to the class combinational dormancy. The hierarchical division of primary seed dormancy into many distinct categories highlights its great diversity and complexity at the whole-seed level, which can be expressed most accurately by dormancy formulae.

A revision of Martin's seed classification system, with particular reference to his dwarf-seed type

2007 ◽  
Vol 17 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Carol C. Baskin ◽  
Jerry M. Baskin
Keyword(s):  
Seed Size ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Classification System ◽  
The State ◽  
Phylogenetic Position ◽  
Embryo Morphology ◽  
Seed Type ◽  
Morphophysiological Dormancy ◽  
Endosperm Texture

AbstractMartin's (1946) seed classification system has 10 types based on embryo and endosperm characteristics and two additional types based on seed size: dwarf (0.3–2.0 mm) and micro ( ≤ 0.2 mm). He listed 17 families and 12 genera (in five other families) as having dwarf seeds. Our recent discovery of morphophysiological dormancy in dwarf seeds of several taxa ofCampanulaceaeand one ofGentianaceaeprompted an evaluation of dwarf seeds. Martin's paper contains 37 families with one to several small (0.3–2.0 mm) seeded species that he did not list as being dwarf. Comparison of Martin's dwarf families and the 37 small-seeded non-dwarf families revealed no consistent differences between the two groups in endosperm texture, seed-coat anatomy, embryo morphology, class of seed dormancy or phylogenetic position. Also, Martin's dwarf seeds include a variety of embryo morphologies. Consequently, we have revised Martin's key to seed types. The dwarf category has been removed and the micro category replaced by ‘undifferentiated’ to reflect the state of the embryo in fresh seeds. Further, the key now includes linear fully developed, linear underdeveloped, spatulate fully developed and spatulate underdeveloped seed types, which Martin illustrated but did not include in his key. In the revised key, all seeds are distinguished on the basis of embryo and endosperm characteristics.

Underdeveloped embryos in dwarf seeds and implications for assignment to dormancy class

2005 ◽  
Vol 15 (4) ◽  
pp. 357-360 ◽  
Author(s):  
Carol C. Baskin ◽  
Jerry M. Baskin
Keyword(s):  
Seed Dormancy ◽  
Evolutionary Relationship ◽  
The Other ◽  
Length Ratio ◽  
Morphophysiological Dormancy ◽  
Physiological Dormancy ◽  
Radicle Emergence ◽  
Relationship Of ◽  
Embryo Length ◽  
Morphological Dormancy

Studies were conducted to determine if small embryos (i.e. low embryo length:seed length ratio) in mature dwarf seeds (0.2–2 mm) are underdeveloped. In this case, they would grow (inside the seed) prior to germination, and seeds would have morphological or morphophysiological dormancy. Prior to radicle emergence, embryo length in seeds of Drosera anglica (Droseraceae), Campanula americana, Lobelia appendiculata, L. spicata (Campanulaceae) and Sabatia angularis (Gentianaceae) increased 0, 103, 182, 83 and 57%, respectively. Since embryo growth did not occur in seeds of D. anglica prior to germination, embryos, although small, are fully developed; seeds have only physiological dormancy. The underdeveloped embryo in seeds of C. americana has little or no physiological dormancy; thus, seeds have morphological dormancy. On the other hand, underdeveloped embryos in seeds of L. appendiculata, L. spicata and S. angularis are physiologically dormant, and seeds have morphophysiological dormancy. Therefore, since small embryos in dwarf seeds may or may not be underdeveloped, assignment of seeds to a dormancy class requires that studies be done to determine if embryos grow inside the seed before germination can occur. Such information is important in understanding the evolutionary relationship of the different kinds of seed dormancy.

Dormancy-breaking and germination requirements for seeds of Diervilla lonicera (Caprifoliaceae), a species with underdeveloped linear embryos

2000 ◽  
Vol 78 (9) ◽  
pp. 1199-1205 ◽  
Author(s):  
Siti N Hidayati ◽  
Jerry M Baskin ◽  
Carol C Baskin
Keyword(s):  
Seed Dormancy ◽  
Constant Darkness ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Morphophysiological Dormancy ◽  
Germination Phenology ◽  
Physiological Dormancy ◽  
Temperature Controlled ◽  
Germination Requirements ◽  
Morphological Dormancy

Dormancy-breaking requirements and type of dormancy were determined for seeds of Diervilla lonicera Mill. Seeds have an underdeveloped linear embryo that is about 35% of the length of the seed at maturity. Embryos (in intact seeds) grew at 25:15°C but not at 5°C. Up to 85% of the freshly matured seeds had morphological dormancy (MD), and thus, they germinated within about 30 days on a moist substrate in light at 30:15°C; a maximum of 3% of the seeds germinated in constant darkness. The other portion of fresh seeds had nondeep simple morphophysiological dormancy (MPD) and required a period of warm stratification or treatment with GA3 to break dormancy. These seeds also required light to germinate. In contrast, cold stratification induced dormancy, and dry storage for up to 1 year did not effectively break dormancy. Seeds with MD germinated to significantly higher percentages on soil than on filter paper or on sand. Seeds sown on soil in a non-temperature-controlled greenhouse in mid-November germinated mostly in late May, whereas those sown in mid-April germinated in early May. Apparently, embryos of November-sown seeds were induced into physiological dormancy during winter. Thus, seeds had MPD in spring and needed several weeks of warm temperatures for dormancy break, embryo growth, and germination. This is the first report on seed dormancy in the genus Diervilla.Key words: embryo growth, germination phenology, Diervilla lonicera, morphological seed dormancy, morphophysiological seed dormancy, underdeveloped linear embryo.

scholarly journals Techniques for breaking seed dormancy of rainforest species from genus Acronychia

2020 ◽  
Vol 48 (2) ◽  
pp. 159-165
Author(s):  
Ganesha S. Liyanage ◽  
Catherine A. Offord ◽  
Karen D. Sommerville
Keyword(s):  
Gibberellic Acid ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Similar Pattern ◽  
Dormancy Breaking ◽  
Eastern Australia ◽  
Radicle Emergence ◽  
Breaking Seed Dormancy ◽  
Impermeable Seed Coat

We tested for dormancy in three species of Acronychia (Rutaceae) occurring in the rainforest in eastern Australia, A. imperforata, A. laevis and A. oblongifolia, by incubating fresh intact seeds on 0.8% water agar for one month at 25/10°C. Four different techniques were then tested for their effect on dormancy: (i) incubation of intact seeds on agar incorporating gibberellic acid (GA3); (ii) seed coat removal (decoating); (iii) scarification near the radicle emergence point (scarification-emergence point); and (iv) scarification opposite the radicle emergence point (scarification-back). Imbibition tests were performed to determine whether dormancy was due to an impermeable seed coat. Germination differed among treatments, but all three species showed a similar pattern. Intact seeds showed < 6% germination after one month indicating the presence of dormancy. Highest germination (> 65%) was observed following scarification-emergence point treatment. Seed coat removal also resulted in increased germination (40-47%), in comparison with intact seeds, but GA3 and scarification-back treatments did not (< 12%). Though the seedcoats of all species were permeable, increased germination responses to decoating and scarification-emergence point treatments suggest scarification is required to clear the radicle emergence point. This may be a useful dormancy-breaking technique for Acronychia spp. and may be suitable for related Rutaceae species.

scholarly journals Different levels of morphophysiological seed dormancy in Ribes alpinum and R. uva-crispa (Grossulariaceae) facilitate adaptation to differentiated habitats

2020 ◽  
Vol 29 (2) ◽  
pp. e017
Author(s):  
Raquel Herranz-Ferrer ◽  
Miguel Ángel Copete-Carreño ◽  
José María Herranz-Sanz ◽  
Elena Copete-Carreño ◽  
Pablo Ferrandis-Gotor
Keyword(s):  
Seed Dormancy ◽  
Seedling Emergence ◽  
Late Summer ◽  
Late Winter ◽  
Minimal Size ◽  
Morphophysiological Dormancy ◽  
Radicle Emergence ◽  
Embryo Length ◽  
Different Levels ◽  
Morphological Dormancy

Aim of the study: To study the germination ecology of two species of the genus Ribes to reveal their levels of morphophysiological dormancy (MPD) and to facilitate the production of plants from seeds, a key tool for population reinforcement.Area of study: Experiments were carried out both outdoors and in the laboratory in Albacete (Spain) with seeds from the Meridional Iberian System mountain range.Material and methods: Seeds from one population of Ribes alpinum and from other of Ribes uva-crispa were collected during several years. Embryo length, radicle and seedling emergence, and effects on germination of stratification and GA3 were analysed to determine the level of MPD.Main results: In R. alpinum, embryo length in fresh seeds was 0.49 mm, needing to grow to 1.30 mm to germinate. Warm stratification (25/10ºC) promoted embryo length enlargement to 0.97 mm. Afterwards, seeds germinated within a wide temperature range. Embryo growth and seedling emergence occur late summer-early autumn. In R. uva-crispa, embryo length in fresh seeds was 0.52 mm, being 2.10 mm the minimal size to germinate. Embryos exposed to a moderately warm stratification (20/7ºC + 15/4ºC) followed by cold (5ºC) grew to 2.30 mm. Then, seeds germinated ≥ 80% when incubated at temperatures ≥ 15/4ºC. Embryos grew in autumn/early winter, and seedlings emerged late winter-early spring.Research highlights: These results showed that R. alpinum seeds have a nondeep simple MPD while R. uva-crispa seeds have a nondeep complex MPD. Moreover, the different germinative models found for each species help explain their installation in distinct habitats.Keywords: Ribes; seed dormancy break; radicle emergence; seedling emergence; nondeep simple and nondeep complex MPD.Abbreviations used: Morphophysiological dormancy (MPD), morphological dormancy (MD), Gibberellic acid (GA3), months (m).

Classification and ecological relationships of seed dormancy in a seasonal moist tropical forest, Panama, Central America

2007 ◽  
Vol 17 (2) ◽  
pp. 127-140 ◽  
Author(s):  
Adriana Sautu ◽  
Jerry M. Baskin ◽  
Carol C. Baskin ◽  
Jose Deago ◽  
Richard Condit
Keyword(s):  
Tropical Forest ◽  
Seed Dormancy ◽  
Tree Species ◽  
Panama Canal ◽  
Physical Dormancy ◽  
Ecological Relationships ◽  
Morphophysiological Dormancy ◽  
Large Size ◽  
Physiological Dormancy ◽  
Dry Seasons

AbstractThis is the first study to determine the class of seed dormancy (or non-dormancy) of a large number of native tree species in a tropical forest, the seasonal moist tropical forest of the Panama Canal Watershed (PCW), or to test the relationships between class of dormancy (or non-dormancy) and various seed and ecological characteristics of the constituent species. Fresh seeds of 49 of 94 tree species were non-dormant (ND), and 45 were dormant (D). Seeds of 23 species had physiological dormancy (PD), 13 physical dormancy (PY), two morphological dormancy (MD), 7 morphophysiological dormancy (MPD) and none combinational dormancy (PY+PD). Seeds with PY were significantly smaller ( < 0.1 g) and drier (moisture content < 16%) at maturity than those that were ND or in the other D classes. Seeds of 62, 42 and 53% of species dispersed in the early rainy, late rainy (LRS) and dry seasons, respectively, were ND. The majority (61%) of species with PD seeds, but only 17% of those with PY seeds, were dispersed in the LRS. The proportion of species with ND seeds was higher in large-size (63%) than in mid-size (35%) and understorey (17%) trees, but differed only slightly between non-pioneers (58%) and pioneers (54%). The proportion of species with D seeds increased only slightly through a precipitation gradient of about 3100 to 1900 mm in the PCW; however, PY increased from 19 to 32% and PD decreased from 63 to 44%.

A critical update on seed dormancy. I. Primary dormancy

1995 ◽  
Vol 5 (2) ◽  
pp. 61-73 ◽  
Author(s):  
Henk W. M. Hilhorst
Keyword(s):  
Cell Wall ◽  
Abscisic Acid ◽  
Seed Dormancy ◽  
Decisive Role ◽  
Morphological Development ◽  
Primary Dormancy ◽  
Whole Seed ◽  
Aba Content ◽  
Cell Wall Properties

AbstractThe emphasis of modern dormancy research is almost entirely on the form of dormancy that is acquired during seed development, primary dormancy. Abscisic acid (ABA) appears to be intimately involved in its regulation. The action of abscisic acid has also been implied in many other developmental processes. The coincidence of developmental events, such as dehydration and completion of maturation, with the acquisition of primary dormancy suggests that dormancy is influenced by these processes. Germinability, both during development and after maturation, is sometimes directly correlated with ABA content. The lack of such a correlation may be explained by assuming a decisive role for the responsiveness to ABA or other overriding factors. ABA has been detected in all seed components. The different seed tissues may all contribute, to various extents, to the degree of whole seed dormancy. It is concluded that ABA action in dormancy regulation is not restricted to the embryo but is also located in endospermic tissue. In addition, a role of ABA in the morphological development of germination modifying seed tissues is proposed. The mechanism for ABA action appears to be associated with cell wall properties.

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.

Seed dormancy in Campanulaceae: morphological and morphophysiological dormancy in six species of Hawaiian lobelioids

Botany ◽  
2020 ◽  
Vol 98 (6) ◽  
pp. 327-332
Author(s):  
Carol C. Baskin ◽  
Jerry M. Baskin ◽  
Alvin Yoshinaga ◽  
Dustin Wolkis
Keyword(s):  
Seed Dormancy ◽  
The Other ◽  
Morphophysiological Dormancy ◽  
Body Of Knowledge ◽  
Temperature Regimes ◽  
Growing Body ◽  
Radicle Emergence ◽  
The Mean ◽  
Embryo Length ◽  
Morphological Dormancy

We determined the requirements for dormancy break/germination and kind of dormancy in seeds of the Hawaiian lobelioids Cyanea kunthiana, Delissea rhytidoperma, Lobelia grayana, L. hypoleuca, Trematolobelia grandifolia, and T. singularis. Fresh seeds were incubated in light/dark at 15/6, 20/10, and 25/15 °C, and germination monitored at two-week intervals for 14 weeks. For each species, the mean embryo length (E): seed (S) length ratio was determined for freshly matured seeds and for seeds at the time the seed coat split but before radicle emergence (germination). The embryo in seeds of all six species incubated at 25/15 °C grew inside the seed prior to germination (42%–148% increase in E:S ratio, depending on species). Seeds of L. grayana and L. hypoleuca have morphological dormancy (MD); they germinated to 82%–98% at the three temperature regimes in 4 weeks. Seeds of the other species have nondeep simple morphophysiological dormancy (MPD) and require >4 weeks for maximum germination to occur. Our results add to the growing body of knowledge about the kind (class) of seed dormancy in Campanulaceae, which suggests that seeds of members of this family have either MD or MPD and embryos grow at warm (≥15 °C) temperatures.

scholarly journals Promoting Germination in Ornamental Palm Seeds through Dormancy Alleviation

2009 ◽  
Vol 19 (4) ◽  
pp. 682-685 ◽  
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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