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

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.

2000 ◽  
Vol 78 (9) ◽  
pp. 1199-1205 ◽  
Author(s):  
Siti N Hidayati ◽  
Jerry M Baskin ◽  
Carol C Baskin

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.


Botany ◽  
2021 ◽  
Author(s):  
Lanlan He ◽  
Ganesh K. Jaganathan ◽  
Baolin Liu

The timing of germination is a crucial event in a plant’s life cycle. Seed dormancy and germination mechanisms are important factors regulating seedling emergence. Since detailed experimental evidence for germination pattern of Phoenix canariensis colonizing sub-tropical climate is scarce, we investigated seed dormancy and germination ecology of P. canariensis. We found that the embryo is underdeveloped at the time of dispersal and doubles in size before the cotyledonary petiole (CP) protrudes through the operculum. The primary root and plumule emerge from the elongated CP outside the seed. In light/dark at 30/25°C, the CP emerged from 8% of the diaspores within 30 days and from 76% within 14 weeks. Thus, 8% of the diaspores have MD and the others MPD. Removal of the pericarp and operculum resulted in 100% germination within 5 days in light/dark at 30/25°C. Cold and warm stratification as well as treatment with GA3 significantly increased the germination speed, but the final germination percentage was not significantly increased. Seed germination was synchronized in early summer when seed dormancy was released by cold stratification in the soil over winter. A remote-tubular germination type and intricate root system provide an ecological advantage to the seedling establishment.


Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 490
Author(s):  
Saeng Geul Baek ◽  
Jin Hyun Im ◽  
Myeong Ja Kwak ◽  
Cho Hee Park ◽  
Mi Hyun Lee ◽  
...  

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.


Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 319
Author(s):  
Yuhan Tang ◽  
Keliang Zhang ◽  
Yin Zhang ◽  
Jun Tao

Sorbus alnifolia (Siebold & Zucc.) K.Koch (Rosaceae) is an economically important tree in the temperate forests of Eastern China. In recent decades, ever-increasing use and modification of forestlands have resulted in major degeneration of the natural habitat of S. alnifolia. Moreover, S. alnifolia seeds germinate in a complicated way, leading to a high cost of propagation. The current study aimed to determine the requirements for breaking seed dormancy and for germination as well as to characterize the type of seed dormancy present in this species. Moreover, the roles of temperature, cold/warm stratification, and gibberellic acid (GA3) in breaking dormancy were tested combined with a study of the soil seed bank. The results showed that intact seeds of S. alnifolia were dormant, requiring 150 days of cold stratification to achieve the maximum germination percentage at 5/15 °C. Exposure of the seeds to ranges of temperatures at 15/25 °C and 20/30 °C resulted in secondary dormancy. Scarifying seed coat and partial removal of the cotyledon promoted germination. Compared with long-term cold stratification, one month of warm stratification plus cold stratification was superior in breaking dormancy. Application of GA3 did not break the dormancy during two months of incubation. Seeds of S. alnifolia formed a transient seed bank. The viability of freshly matured S. alnifolia seeds was 87.65% ± 11.67%, but this declined to 38.25% after 6-months of storage at room temperature. Seeds of S. alnifolia have a deep physiological dormancy; cold stratification will be useful in propagating this species. The long chilling requirements of S. alnifolia seeds would avoid seedling death in winter.


2020 ◽  
Vol 48 (2) ◽  
pp. 303-314
Author(s):  
Ye-Fang Li ◽  
Jie Song ◽  
Wen-Ling Guan ◽  
Feng-Rong Li

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.


2018 ◽  
Vol 66 (3) ◽  
pp. 213 ◽  
Author(s):  
Dustin Wolkis ◽  
Carol C. Baskin ◽  
Jerry M. Baskin

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.


2000 ◽  
Vol 10 (4) ◽  
pp. 459-469 ◽  
Author(s):  
Siti N. Hidayati ◽  
Jerry M. Baskin ◽  
Carol C. Baskin

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.


2005 ◽  
Vol 15 (2) ◽  
pp. 161-173 ◽  
Author(s):  
Christopher A. Adams ◽  
Jerry M. Baskin ◽  
Carol C. Baskin

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.


2018 ◽  
Vol 44 (4) ◽  
pp. 605-611
Author(s):  
Anca Manole ◽  
Cristian Banciu

The phenology of Angelica palustris seeds including maturation, germination requirements, and dormancy class, is still unknown. In opposite to the results reported from other species of Angelica, present findings showed that A. palustris produced seeds with embryo underdeveloped (the ratio between the embryo and the whole seed length was between 0.19 and 0.12) and physiologically dormant which corresponded to Morphophysiological Dormancy class. Dormancy breakdown requires a post maturation period (at least 30 days) at 18 - 20ºC for a complete embryo development, and also up to 30 days of cold stratification at 4°C. The best germination indices were obtained when fruit was removed. Germination energy (Ge) was achieved within 19 days after imbibition and was 25.8 + 0.03 and germination per cent (Gp) was achieved within 28 days and was 64.7 + 0.14. Fruit structure (lateral wings with air cavities) and physiology (essential oil production) are adaptations to facilitate seed dispersal and dormancy/germination balance.


2020 ◽  
Vol 48 (1) ◽  
pp. 37-43
Author(s):  
Maryati Sari ◽  
Satriyas Ilyas ◽  
M. Rahmad Suhartanto ◽  
Abdul Qadir

Bambara groundnut seeds often show unsynchronized and slow germination even though on newly harvested seeds. This might be due to the presence of seed dormancy. Therefore, the objective of this research was to obtain the information on seed dormancy and germination behaviour of bambara groundnut seeds during desiccation. The experiment was arranged in a nested design. Dormancy breaking treatments (untreated, mechanical scarification, soaking in 1% KNO3 for 2 hours, mechanical scarification followed by KNO3 soaking) were nested in each of the desiccation levels (fresh seeds with 54.7% moisture content (mc), desiccated seeds with 44.4%, 18.0%, 15.4%, and 12.1% mc). The results showed that newly harvested seeds were in dormant state. Seed desiccation did not increase the intensity of seed dormancy, even resulted in an increase in field emergence (at 30 days after planting) from 43.9% in fresh seeds to around 70% in dry seed (12-15% mc). Seed desiccation (from 44.4% mc to 12.1% mc) increased the field emergence, although it was inadequate to break the dormancy completely. Meanwhile, seed desiccation tended to increase the GA/ABA ratio, but the seed permeability was decreased. The fact showed that seed desiccation reduced the intensity of dormancy of bambara groundnut seed, therefore, it is suggested to modify the drying method in order to accelerate the increasing of GA/ABA ratio while keeping the testa permeable. Keywords: after-ripening, GA/ABA ratio, hard seed, kacang bogor, permeability


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