Underdeveloped embryos and kinds of dormancy in seeds of two gymnosperms: Podocarpus costalis and Nageia nagi (Podocarpaceae)

2013 ◽  
Vol 23 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Shun-Ying Chen ◽  
Carol C. Baskin ◽  
Jerry M. Baskin ◽  
Ching-Te Chien
Keyword(s):  
Seed Plants ◽  
Cold Stratification ◽  
Morphophysiological Dormancy ◽  
Seed Maturity ◽  
Basal Clade ◽  
Radicle Emergence ◽  
Primitive Condition ◽  
Morphological Dormancy

AbstractAlthough it has been speculated that seeds of the gymnosperm family Podocarpaceae have an underdeveloped embryo, no detailed studies have been done to definitively answer this question. Our purpose was to determine if embryos in seeds of two species of Podocarpaceae, Podocarpus costalis and Nageia nagi, from Taiwan are underdeveloped and to examine the kind of dormancy the seeds have. Embryos in fresh seeds of P. costalis were 4.6 ± 0.5 mm long, and they increased in length by about 54% before radicle emergence (germination), demonstrating that the embryo is underdeveloped at seed maturity. Seeds germinated to >90% at 30/20, 25/15 and 25°C in light in ≤ 4 weeks, without any cold stratification pretreatment. Thus, seeds of P. costalis have morphological dormancy (MD). Embryos in fresh seeds of N. nagi were 7.4 ± 0.8 mm long and they increased in length by about 39% before radicle emergence (germination) occurred, indicating that the embryo is underdeveloped at seed maturity. Seeds germinated to < 25% at 30/20 and 25°C in light in 4 weeks but to >90% at the same temperatures in 12 weeks. Thus, most seeds of N. nagi have morphophysiological dormancy (MPD). Although underdeveloped embryos are considered to be a primitive condition in seed plants, they also occur in the most advanced orders. The occurrence of underdeveloped embryos in Podocarpaceae documents that they are not restricted to a basal clade in gymnosperms.

Seed dormancy in the early diverging eudicot Trochodendron aralioides (Trochodendraceae)

2006 ◽  
Vol 16 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin ◽  
Ching-Te Chien ◽  
Shun-Ying Chen
Keyword(s):  
Seed Dormancy ◽  
Seed Plants ◽  
Seed Length ◽  
Seed Maturity ◽  
Early Tertiary ◽  
Radicle Emergence ◽  
Primitive Condition ◽  
Embryo Length ◽  
Morphological Dormancy

The embryo length/seed length (E/S) ratio of the early diverging eudicot Trochodendron aralioides is 0.34. Embryos in fresh seeds were 0.36±0.01 mm long, and they increased in length by about 250% (in 20 d) before radicle emergence (germination) occurred, demonstrating that the embryo is underdeveloped at seed maturity. Seeds germinated to 95–100% at 20/10, 25/15 and 30/15°C in light in ≤4 weeks, without any pretreatment, but no seeds germinated in darkness. Thus, seeds of T. aralioides have morphological dormancy (MD), which is considered to be the primitive condition in seed plants, and MD probably has existed in the genus Trochodendron since its origin in the early Tertiary.

Germination of Viburnum odoratissimum seeds: a new level of morphophysiological dormancy

2008 ◽  
Vol 18 (3) ◽  
pp. 179-184 ◽  
Author(s):  
Carol C. Baskin ◽  
Ching-Te Chien ◽  
Shun-Ying Chen ◽  
Jerry M. Baskin
Keyword(s):  
Incubation Temperature ◽  
Cold Stratification ◽  
Morphophysiological Dormancy ◽  
Physiological Dormancy ◽  
Radicle Emergence ◽  
Viburnum Odoratissimum

AbstractPrevious studies indicated that seeds of Viburnum odoratissimum had only physiological dormancy (PD), but no measurements of embryos were made during the dormancy-break treatments. Thus, we investigated embryo growth and radicle and cotyledon emergence over a range of temperatures. Seeds have underdeveloped embryos, and their length increased about 300% before radicle emergence. Embryos also had PD, as evidenced by delays in beginning of embryo growth (2–3 weeks) and of germination after embryos were elongated (4 weeks). After radicle emergence, epicotyl emergence was delayed 1–8 weeks, depending on incubation temperature, but cold stratification was not required to break PD of the epicotyl. Unlike seeds of many previously studied Viburnum spp., epicotyls of V. odoratissimum have non-deep, rather than deep, PD. Hence, a new level of MPD called non-deep, simple, epicotyl MPD has been identified.

scholarly journals Seed dormancy in Camellia sinensis L. (Theaceae): effects of cold-stratification and exogenous gibberellic acid application on germination

Botany ◽  
2017 ◽  
Vol 95 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Danping Song ◽  
Ganesh K. Jaganathan ◽  
Yingying Han ◽  
Baolin Liu
Keyword(s):  
Gibberellic Acid ◽  
Camellia Sinensis ◽  
Summer Temperature ◽  
Cold Stratification ◽  
Morphophysiological Dormancy ◽  
Temperature Regimes ◽  
Physiological Dormancy ◽  
Radicle Emergence ◽  
Persistent Seed Bank ◽  
Natural Dispersal

There are several different opinions regarding dormancy in tea (Camellia sinensis L.), but there is no strong evidence available to conclude whether or not these seeds are dormant. Freshly matured tea seeds collected from Hangzhou, China, at the natural dispersal time did not germinate in light at daily alternative temperature regimes of 10/15, 15/20, 20/25, or 25/35 °C, or at a constant temperature of 25 °C. Seeds were permeable to water and the embryos did not grow prior to radicle emergence, thus, the seeds have no physical, morphological, or morphophysiological dormancy. When cold-stratified at 4 °C for 1, 2, and 3 months, 64%, 88%, and 93% of the seeds germinated, respectively. Intact fresh seeds failed to germinate after treatment with 0, 10, 500, and 1000 ppm GA3, whereas 3%, 4%, 61%, and 86% of cracked seeds germinated, respectively. Thus, the seeds have nondeep and intermediate physiological dormancy. Seeds cold-stratified for 2 months that were buried at soil depths of 0, 1, and 5 cm in pots showed that seeds at 1 cm depth established significantly higher number of seedlings (P < 0.05) than at other two depths. Because tea seeds are susceptible to summer temperature drying, these seeds do not establish a persistent seed bank.

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).

Intermediate complex morphophysiological dormancy in the endemic Iberian Aconitum napellus subsp. castellanum (Ranunculaceae)

2010 ◽  
Vol 20 (2) ◽  
pp. 109-121 ◽  
Author(s):  
José M. Herranz ◽  
Miguel Á. Copete ◽  
Pablo Ferrandis ◽  
Elena Copete
Keyword(s):  
Seed Germination ◽  
Population Level ◽  
Intermediate Complex ◽  
Cold Stratification ◽  
Morphophysiological Dormancy ◽  
Seed Age ◽  
Aconitum Napellus ◽  
Radicle Emergence ◽  
The Mean ◽  
Embryo Length

AbstractSeeds of Aconitum napellus subsp. castellanum were physiologically dormant at maturity in early autumn, with underdeveloped embryos. Thus they have morphophysiological dormancy (MPD). Embryos in fresh seeds were on average 1.01 mm long, and they had to grow to 3.60 mm before radicle emergence. Cold stratification at 5°C for 5 months with light enhanced the mean embryo length to 2.73 mm (SE = 0.13) and seed germination to 20%. However, with higher temperatures (15/4, 20/7, 25/10, 28/14 and 32/18°C) embryo growth was small, with no seeds germinating. Optimal germination was achieved after 4 months of cold stratification at 5°C followed by incubation at 20/7°C for 1 month with light, when germination ranged between 70 and 79%, depending on seed age, locality and year of collection. Cold stratification could be substituted by the application of GA3 solution, since mean embryo length in seeds incubated at 25/10°C for 1 month with light was 3.52 mm and the germination was 80%. Since cold stratification was the only requirement for the loss of MPD, the longest embryo growth occurred during this treatment, and GA3 promoted MPD loss, we concluded that A. napellus seeds have intermediate complex MPD. Germination was higher in 4-month stored than in freshly matured seeds. A pronounced variability in germinative patterns at inter-annual and inter-population level was recorded.

Morphophysiological seed dormancy inHeptacodium

2018 ◽  
Vol 28 (3) ◽  
pp. 192-196 ◽  
Author(s):  
Robert L. Geneve ◽  
Sharon T. Kester
Keyword(s):  
Cell Walls ◽  
Germination Percentage ◽  
Cold Stratification ◽  
Seed Length ◽  
Morphophysiological Dormancy ◽  
Storage Vesicles ◽  
Dissolution Zone ◽  
Radicle Emergence ◽  
Hydrolysis Of ◽  
Storage Reserves

AbstractHeptacodium miconiodesis an endangered, monotypic genus in the Caprifoliaceae endemic to China. Species within the Caprifoliaceae have been shown to have morphological or morphophysiological dormancy.Heptacodiumseeds had an underdeveloped embryo at the time of fruit dispersal with an embryo that occupied approximately 12% of the seed length. Cold (8 weeks at 5°C) and warm (8 weeks at 20°C) stratification was effective for dormancy release, but embryo growth prior to germination only occurred at warm temperatures (20°C). Gibberellic acid treatment partially substituted for cold stratification. Final seed germination percentage was not different after warm or cold stratification; however, seeds initially exposed to cold stratification germinated faster and more uniformly. Cold stratified seeds reached 50% final germination approximately 55 days sooner than warm stratified seeds. Prior to radicle emergence, embryos grew to fill approximately 60% of the seed through an endosperm channel that occupied the centre portion of the endosperm. Cells in the endosperm channel had thinner cell walls and fewer storage vesicles compared with other endosperm cells. Channel cells formed a dissolution zone ahead of embryo elongation assumed to be involved with enzymatic hydrolysis of storage reserves. Based on these results, it was concluded thatHeptacodiumdisplays the characteristics of seeds with non-deep simple morphophysiological dormancy.

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.

Seed dormancy and germination of the subalpine geophyte Crocus alatavicus (Iridaceae)

2013 ◽  
Vol 61 (5) ◽  
pp. 376 ◽  
Author(s):  
Ziyan Fu ◽  
Dunyan Tan ◽  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Central Asia ◽  
Seed Dormancy ◽  
Natural Habitat ◽  
Early Summer ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Morphophysiological Dormancy ◽  
Radicle Emergence ◽  
Germination Requirements ◽  
Seed Dormancy And Germination

Crocus alatavicus Regel et Sem. is a cormous perennial primarily distributed in central Asia that may have potential in horticulture; however, relatively little is known about seed dormancy in the genus Crocus. The primary aim of the present study was to identify the dormancy breaking and germination requirements of seeds of C. alatvicus and to assign them to a dormancy category. In its natural habitat, the underdeveloped embryo in C. alatavicus seeds grows in early summer, and radicles emerge in early autumn. However, cotyledon emergence is delayed until the following spring. Radicle emergence was promoted by warm stratification and cotyledon emergence by cold stratification. GA3 was ineffective in promoting either radicle or epicotyl emergence. We conclude that seeds of C. alatavicus have deep simple epicotyl morphophysiological dormancy of the type C1bB(root) – C3(shoot). To our knowledge, this is the first detailed study on the ecophysiology of seed dormancy and germination in the genus Crocus.

Dormancy-breaking and germination requirements of seeds of fourLoniceraspecies (Caprifoliaceae) with underdeveloped spatulate embryos

2000 ◽  
Vol 10 (4) ◽  
pp. 459-469 ◽  
Author(s):  
Siti N. Hidayati ◽  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Soil Surface ◽  
The Other ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Morphophysiological Dormancy ◽  
Seed Maturity ◽  
Breaking Dormancy ◽  
Natural Temperature ◽  
To Come ◽  
Germination Requirements

AbstractDormancy-breaking requirements and types of dormancy were determined for seeds ofLonicera fragrantissimaLindl. & Paxt.,L. japonicaThunb.,L. maackii(Rupr.) Maxim. andL. morrowiiA. Gray. Seeds of all four species have underdeveloped spatulate embryos that are about 20–40%fully developed (elongated) when dispersed. Embryos in freshly matured, intact seeds grew better at 25/15°C than at 5°C. Gibberellic acid (GA3) (tested only in the light) was more effective in breaking dormancy inL. maackiiandL. morrowiithan inL. fragrantissimaandL. japonica. Warm- followed by cold stratification was required to break dormancy in seeds ofL. fragrantissima, whereas seeds ofL. japonicarequired cold stratification only. Thus, seeds ofL. fragrantissimahave deep simple morphophysiological dormancy (MPD) and those ofL. japonicanondeep simple MPD. About 50%of the seeds ofL. maackiirequired warm- or cold stratification only to come out of dormancy and 50% of those ofL. morrowiirequired warm stratification only, whereas the other 50% did not require stratification to germinate. Thus, about half of the seeds of the two species has nondeep simple MPD, and the other half has morphological dormancy (MD). In these laboratory tests, seeds ofL. japonica,L. maackii, andL. morrowiigenerally germinated to significantly higher percentages in light than in darkness; seeds ofL. fragrantissimawere not tested in darkness. Peaks of germination for seeds ofL. fragrantissima,L. japonica,L. maackiiandL. morrowiisown on a soil surface and covered withQuercusleaves under near-natural temperature conditions shortly after seed maturity and dispersal in late June 1997, late November 1997, early November 1996 and late June 1998, respectively, occurred in early March 1998, late February 1998, late March 1997 and early October 1998, respectively. The germination phenologies of seeds of the same species and seed lots buried in soil were similar to those of seeds under leaf litter. High percentages of seeds of all four species germinated both under litter (78–96%) and beneath the soil surface (78–97%). These germination patterns correspond closely with the requirements for embryo growth and dormancy break in the fourLoniceraspecies.

Seed germination ecology of poison hemlock, Conium maculatum

1990 ◽  
Vol 68 (9) ◽  
pp. 2018-2024 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Late Winter ◽  
Cold Stratification ◽  
North Central ◽  
Conium Maculatum ◽  
Morphophysiological Dormancy ◽  
Key Words Dispersal ◽  
Embryo Dormancy ◽  
Monocarpic Perennial ◽  
Autumn And Winter ◽  
Morphological Dormancy

In north-central Kentucky, United States, seeds of Conium maculatum are dispersed from mid-September to mid to late February, with up to 95% of them being dispersed by late December. Depending on the year, 40–85% of the freshly matured seeds had morphological dormancy (MD) and thus needed only a moist substrate, 10–15 14-h photoperiod days and 12-h alternating thermoperiods of 30:15 °C for embryo growth and germination. The other seeds had morphophysiological dormancy (MPD), and embryo dormancy had to be broken before embryo growth and germination could occur. MPD was broken in some of the undispersed seeds during summer, and by September 50–85% (depending on the year) germinated at 25:15 °C in light. During late autumn and winter, 35–95% (depending on the year) of the undispersed seeds in MD in autumn entered MPD. Cold stratification at 5 °C induced about half the seeds with MD into MPD. Seeds in MD germinated to higher percentages on soil than on sand, and in light than in darkness. Most of the seeds sown on soil in a nonheated greenhouse in July, August, and September germinated in September. Seeds sown in October and November germinated in autumn, late winter, and the following autumn, and those sown in late winter germinated in spring and autumn. The later seeds were sown, the higher germination percentages were the following autumn. Key words: dispersal, dormancy, germination, morphological dormancy, poison hemlock, Conium maculatum, monocarpic perennial.

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