Trait stasis versus adaptation in disjunct relict species: evolutionary changes in seed dormancy-breaking and germination requirements in a subclade of Aristolochia subgenus Siphisia (Piperales)

2005 ◽  
Vol 15 (2) ◽  
pp. 161-173 ◽  
Author(s):  
Christopher A. Adams ◽  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seed Dormancy ◽  
Considerable Change ◽  
The Other ◽  
Temperate Species ◽  
Dormancy Breaking ◽  
Geological Time ◽  
Relict Species ◽  
Morphophysiological Dormancy ◽  
Eastern Usa ◽  
Germination Requirements

There are two ideas regarding changes in the physiological and ecological tolerances and requirements within plant lineages through geological time. One is that these attributes have changed very little, or not at all (trait stasis), and the other is that they have undergone considerable change (adaptation), as plants shifted to new climatic and vegetation zones. We tested these ideas for seed dormancy-breaking and germination requirements of four species in a subclade ofAristolochiasubgenusSiphisia: the three temperate species,A. macrophyllaandA. tomentosa(the basal species in the subclade) of eastern USA andA. manshuriensisof East Asia, and the Mediterranean-climate speciesA. californica endemic to California, USA. A long period at cold-stratifying temperatures was required for growth of the underdeveloped embryo and seed germination inA. californica, whereas embryos grew and seeds germinated in the other three species at warm temperatures, either before or after they were cold stratified. Thus, seeds ofA. californicahave either intermediate or deep complex morphophysiological dormancy (MPD), whereas those of the three temperate species have either morphological dormancy or non-deep simple MPD. Further, there were quantitative differences in temperature requirements for dormancy-break and germination between the AppalachianA. macrophylla, which did not differ from its sister speciesA. manshuriensis, and the lowlandA. tomentosa. Thus, within this lineage there has been both trait stasis and divergence (adaptation) in the physiology and ecology of seed dormancy and germination.

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.

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

Horticulturae ◽  
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.

scholarly journals Seed dormancy and germination in Cardiocrinum giganteum var. yunnanense, a perennial herb in China with post-dispersal embryo growth

2020 ◽  
Vol 48 (2) ◽  
pp. 303-314
Author(s):  
Ye-Fang Li ◽  
Jie Song ◽  
Wen-Ling Guan ◽  
Feng-Rong Li
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Practical Knowledge ◽  
Perennial Herb ◽  
Late Winter ◽  
Dormancy Breaking ◽  
Morphophysiological Dormancy ◽  
Summer Temperatures ◽  
Autumn And Winter ◽  
Seed Dormancy And Germination

Seeds of Cardiocrinum giganteum var. yunnanense, which is native to China, has underdeveloped embryos when dispersed from parent plants that did not grow until the second autumn and winter after exposure to summer temperatures. Radicles and cotyledons emerged in late winter and spring. Thus, a 15–16 month period was required from dispersal to seed germination. Under laboratory conditions, this period could be shortened to 5–6 months in a 25°C/15°C (60 days) → 15°C/5°C (60 days) → 5°C (60 days) temperature sequence. Based on dormancy-breaking requirements, the seeds have deep simple morphophysiological dormancy (MPD). This is practical knowledge for propagation of the species from seeds.

A comparative study of the seed germination biology of a narrow endemic and two geographically-widespread species ofSolidago(Asteraceae). 1. Germination phenology and effect of cold stratification on germination

1997 ◽  
Vol 7 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Jeffrey L. Walck ◽  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Small Area ◽  
Geographic Range ◽  
The Other ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Widespread Species ◽  
Narrow Endemic ◽  
Germination Phenology ◽  
Primary Difference ◽  
Germination Requirements

AbstractSolidago shortiiis endemic to a small area in northcentral Kentucky (USA), whereas two of its sympatric congeners,S. altissimaandS. nemoralis, are geographically widespread. Seeds (achenes) ofS. shortii(0.370 mg) are significantly larger (PLSD,P=0.05) than those ofS. altissima(0.070 mg) andS. nemoralis(0.068 mg). Germination percentages of freshly-matured seeds of the threeSolidagospecies collected in November 1991, 1992 and 1994 were 0–2% in light at 15/6°C, 1–37% at 20/10°C, 9–56% at 25/15°C and 10–85% at 30/15 and 35/20°C. Stratification increased the percentage and rate of germination and decreased the time to the onset of germination (measured by Timson's index only at 20/10°C in light) in the three species. Following 12 weeks of cold stratification in light, seeds of the three species germinated to 72–100% in the light and to 22–100% in darkness over the range of thermoperiods; those cold-stratified in darkness germinated to 39–100% in light. Freshly-matured seeds ofS. altissimaand ofS. nemoralisgerminated to 0–4% in darkness, whereas those cold-stratified for 12 weeks in darkness germinated to 0–28% in darkness. On the other hand, freshly-matured and cold-stratified (in darkness) seeds ofS. shortiigerminated to 0–13 and 13–73%, respectively, in darkness. Under near-natural temperatures in a glasshouse without temperature control, germination of the three species peaked in March. Thus, the primary difference in dormancy-breaking and germination requirements of the three species is that the endemic germinates to a much higher percentage in darkness than its two congeners. Seeds ofS. shortiido not have any special dormancy-breaking or germination requirements that could not be fulfilled outside its present-day geographic range.

Dormancy-breaking and germination requirements of seeds of the Hawaiian endemic Dianella sandwicensis (Xanthorrhoeaceae)

2018 ◽  
Vol 66 (3) ◽  
pp. 213 ◽  
Author(s):  
Dustin Wolkis ◽  
Carol C. Baskin ◽  
Jerry M. Baskin
Keyword(s):  
Plant Species ◽  
Early Summer ◽  
Wild Plant ◽  
Dormancy Breaking ◽  
Seed Length ◽  
Morphophysiological Dormancy ◽  
Wild Plant Species ◽  
Temperature Requirements ◽  
Embryo Length ◽  
Germination Requirements

One problem with including some wild plant species in restoration projects is that seeds are dormant and fail to germinate. Thus, information on the dormancy-breaking and germination requirements facilitates propagation of species, such as the Hawaiian endemic Dianella sandwicensis Hook. & Arn., for conservation. In seeds of this species the embryo is shorter than the endosperm, and seeds sown in early summer in Hawai‘i did not germinate until autumn. Thus, we hypothesised that seeds have morphophysiological dormancy (MPD) and that germination is promoted by low (autumn) temperatures. Studies on embryo growth and the temperature requirements for dormancy-break and germination were conducted on seeds of D. sandwicensis collected on three Hawaiian Islands. Prior to germination the embryo length : seed length ratio increased 16.3 to 17.6%; thus, seeds have MPD. Since both embryo growth and germination occurred at 25/15°C, seeds have a simple level of MPD. Seeds germinated to 90–100% at both 20/10 and 25/15°C, but germination was faster at 20/10°C. However, seeds incubated for 12 weeks at 25/15°C then moved to 20/10°C reached 100% germination as rapidly as seeds kept at 20/10°C. Our results show that exposure of seeds to relatively cool autumn (20/10°C) conditions facilitates propagation of this species from seeds.

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.

Morphophysiological dormancy in seeds of six endemic lobelioid shrubs (Campanulaceae) from the montane zone in Hawaii

2005 ◽  
Vol 83 (12) ◽  
pp. 1630-1637 ◽  
Author(s):  
Carol C. Baskin ◽  
Jerry M. Baskin ◽  
Alvin Yoshinaga
Keyword(s):  
Incubation Period ◽  
Seasonal Temperature ◽  
Dormancy Breaking ◽  
Light Requirement ◽  
Temperature Variations ◽  
Morphophysiological Dormancy ◽  
Temperature Regimes ◽  
Physiological Dormancy ◽  
Montane Zone ◽  
Germination Requirements

The purpose of this study was to investigate seed dormancy breaking and germination requirements of six woody Hawaiian endemic lobelioids (Campanulaceae). Seeds of all species had underdeveloped, physiologically dormant embryos and thus morphophysiological dormancy. Fresh seeds of Clermontia pyrularia Hillebr. and Trematolobelia macrostachys (Hook. & Arnott) A. Zahlbr. did not germinate during 4 weeks of incubation in light at 15/6, 20/10, or 25/15 °C, whereas those of Clermontia fauriei H. Lev., Clermontia hawaiiensis (Hillebr.) Rock, Clermontia kakeana Meyen, and Cyanea angustifolia (Cham.) Hillebr. germinated to 61%–85% but only at 25/15 °C. Since seeds of the latter four species eventually germinated to 84%–100% when incubated for 12–36 weeks at the three temperature regimes, fresh seeds had conditional dormancy; the physiological component of morphophysiological dormancy was nondeep. Seeds of Trematolobelia macrostachys also came out of dormancy (and germinated to 90%) during 18 weeks of incubation at each of the three temperatures regimes, whereas those of Clermontia pyrularia did so only at 15/6 °C. Simulated seasonal temperature variations did not promote dormancy break and germination in any species except Clermontia pyrularia , in which a 12-week incubation period at 25/15 °C resulted in 90% germination after seeds were moved to 20/10 °C. Seeds of all species had an absolute light requirement for germination except those of Clermontia pyrularia, which germinated to 48% in darkness. Since seeds of the six species only require high temperatures for embryo growth and the breaking of physiological dormancy, they have nondeep simple morphophysiological dormancy.

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.

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