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.

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.

Non-deep simple morphophysiological dormancy in seeds of Cheirodendron trigynum (Araliaceae) from the montane zone of Hawaii

2015 ◽  
Vol 25 (2) ◽  
pp. 203-209 ◽  
Author(s):  
Carol C. Baskin ◽  
Jerry M. Baskin ◽  
Alvin Yoshinaga
Keyword(s):  
Low Temperature ◽  
Woody Species ◽  
First Report ◽  
Morphophysiological Dormancy ◽  
Temperature Regimes ◽  
Physiological Dormancy ◽  
Montane Zone ◽  
Radicle Emergence ◽  
Shoot Emergence

AbstractThe Araliaceae is known to have seeds with underdeveloped embryos that must grow prior to radicle emergence, and thus they have morphological (MD) or morphophysiological (MPD) dormancy. Araliaceae is one of about 15 families with woody species in the tropical montane zone, and in Hawaii 15 species occur in the montane. Our purpose was to determine if seeds of the Hawaiian Araliaceae species Cheirodendron trigynum subsp. trigynum have MD or MPD and, if MPD, what level. In a move-along experiment, some seeds were incubated continuously at 15/6, 20/10 or 25/15°C, while others were moved sequentially from low to high or from high to low temperature regimes. Germination percentages and embryo growth were monitored. Also, the effects of cold and warm stratification on dormancy break were determined. Seeds had physiological dormancy (PD) in addition to small embryos that grew prior to germination, and thus MPD. PD was broken slowly ( ≥ 12 weeks), after which embryos grew rapidly, followed by root and shoot emergence. Embryos grew at temperatures suitable for warm stratification; thus, seeds have Type 1 non-deep simple MPD; the dormancy formula is C1bBb. Seeds from Oahu germinated to 94–100% at 15/6, 20/10 and 25/15°C, while those from the Big Island germinated to high percentages only at 15/6 and 20/10°C. Temperature shifts improved germination of seeds from the Big Island, and movement from either low to high or from high to low temperature regimes was effective in promoting germination. This is the first report of non-deep simple MPD in the Araliaceae.

Seeds of Thalictrum mirabile (Ranunculaceae) require cold stratification for loss of nondeep simple morphophysiological dormancy

2000 ◽  
Vol 77 (12) ◽  
pp. 1769-1776 ◽  
Author(s):  
Jeffrey L Walck ◽  
Carol C Baskin ◽  
Jerry M Baskin
Keyword(s):  
Gibberellic Acid ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Early Spring ◽  
Late Winter ◽  
Cold Stratification ◽  
Morphophysiological Dormancy ◽  
Physiological Dormancy ◽  
Buried Seeds ◽  
Persistent Soil Seed Bank

Seeds of the eastern North American herbaceous polycarpic perennial Thalictrum mirabile Small have differentiated but underdeveloped (small) embryos that are physiologically dormant at maturity in September. Physiological dormancy was broken effectively by cold stratification at 1°C, but embryos required temperatures [Formula: see text]15:6°C for growth after physiological dormancy was broken. Gibberellic acid substituted for cold stratification. Breaking of physiological dormancy in seeds exposed to natural temperatures in a greenhouse occurred during winter, and embryo growth and germination occurred in late winter - early spring. Furthermore, seeds in the greenhouse remained viable until the second and third (spring) germination seasons. Thus, T. mirabile seeds have the capacity to form a short-lived persistent soil seed bank. Buried seeds of T. mirabile apparently go through an annual dormancy-nondormancy cycle. Seeds buried in September 1994 were nondormant when exhumed in April 1995 and April 1996 and incubated in light at 25:15°C for 2 weeks, but they were dormant in June 1995 and September 1995. Seeds of T. mirabile have nondeep simple morphophysiogical dormancy. This is the first report of nondeep simple morphophysiological dormancy being broken by cold, and not by warm, stratification.

Morphological and physiological dormancy in seeds of Aegopodium podagraria (Apiaceae) broken successively during cold stratification

2009 ◽  
Vol 19 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Filip Vandelook ◽  
Nele Bolle ◽  
Jozef A. Van Assche
Keyword(s):  
Low Temperature ◽  
Seedling Emergence ◽  
Early Spring ◽  
Temperate Climate ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Morphophysiological Dormancy ◽  
Temperature Requirement ◽  
Physiological Dormancy ◽  
Chilling Period

AbstractA low-temperature requirement for dormancy break has been observed frequently in temperate-climate Apiaceae species, resulting in spring emergence of seedlings. A series of experiments was performed to identify dormancy-breaking requirements of Aegopodium podagraria, a nitrophilous perennial growing mainly in mildly shaded places. In natural conditions, the embryos in seeds of A. podagraria grow in early winter. Seedlings were first observed in early spring and seedling emergence peaked in March and April. Experiments using temperature-controlled incubators revealed that embryos in seeds of A. podagraria grow only at low temperatures (5°C), irrespective of a pretreatment at higher temperatures. Seeds did not germinate immediately after embryo growth was completed, instead an additional cold stratification period was required to break dormancy completely. Once dormancy was broken, seeds germinated at a range of temperatures. Addition of gibberellic acid (GA3) had a positive effect on embryo growth in seeds incubated at 10°C and at 23°C, but it did not promote germination. Since seeds of A. podagraria have a low-temperature requirement for embryo growth and require an additional chilling period after completion of embryo growth, they exhibit characteristics of deep complex morphophysiological dormancy.

Dormancy break and germination requirements in acorns of two bottomland Quercus species (Sect. Lobatae) of the eastern United States with references to ecology and phylogeny

2020 ◽  
Vol 30 (3) ◽  
pp. 199-205
Author(s):  
Tracy S. Hawkins
Keyword(s):  
United States ◽  
Cold Stratification ◽  
Eastern United States ◽  
Closely Related Species ◽  
Temperature Regimes ◽  
Quercus Species ◽  
Physiological Dormancy ◽  
Alternating Temperature ◽  
Incubation Temperatures ◽  
Germination Requirements

AbstractQuercus species are ecologically and economically important components of deciduous forests of the eastern United States. However, knowledge pertinent to a thorough understanding of acorn germination dynamics for these species is lacking. The objectives of this research were to determine dormancy break and germination requirements for acorns of two eastern United States bottomland species, Quercus nigra and Quercus phellos (Section Lobatae), and to present results within ecological and phylogenetic contexts. Three replicates of 50 acorns of each species received 0 (control), 6, 12 or 18 weeks of cold stratification, followed by incubation in alternating temperature regimes of 15/6, 20/10, 25/15 and 30/20°C. Eighteen weeks of cold stratification were not sufficient for dormancy break in Q. nigra acorns. Cumulative germination percentages at 4 weeks of incubation were ≥77%, but only in incubation temperatures of 25/15 and 30/20°C. Dormancy break in Q. phellos acorns was achieved with 18 weeks of cold stratification, and cumulative germination percentages were ≥87% at 4 weeks of incubation in all test temperature regimes. Gibberellic acid solutions were not an effective substitute for cold stratification in either species. Phylogenetically, Q. nigra and Q. phellos are closely related species and, ecologically, both grow in the same habitat. Acorns of both species possess deep physiological dormancy (PD), but dormancy break and germination requirements differ in acorns of these two Quercus species.

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.

scholarly journals Effect of stratification and gibberellic acid on epicotyl dormancy release in seeds of Yunnanopilia longistaminea (Opiliaceae)

2016 ◽  
Author(s):  
Guan-song Yang ◽  
Liu Yang ◽  
Yue-hua Wang ◽  
Shi-kang Shen
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Economic Value ◽  
Cold Stratification ◽  
Dormancy Release ◽  
Spring Temperature ◽  
Edible Plant ◽  
Seed Moisture Content ◽  
Radicle Emergence ◽  
Shoot Emergence

Yunnanopilia longistaminea is an endangered monotypic species belonging to Opiliaceae. This edible plant is an important germplasm source with a high economic value in China. The seed dormancy and germination of Opiliaceae species have been rarely investigated. This study examined the effects of scarification, soaking in gibberellic acid, and dehydration on the seed germination of Y. longistaminea. Results indicated that the seed germination of this species involves two stages: radicle emergence and epicotyls (shoot) emergence. During radicle emergence, the optimum temperatures were 28 °C and 28 °C/20 °C. Seed moisture content and viability decreased as dehydration occurred. Thus, the seeds may be recalcitrant. The optimum GA3 solution for the seeds undergoing shoot emergence was 100 mg·L−1. The percentages of shoot emergence in 7 and 14 days of stratification at 5 °C were slightly higher than those in other groups. This study is the first to describe epicotyl dormancy in Y. longistaminea seeds. From the seed grow to the seedling of Y. longistaminea subjected to a autumn→winter→spring temperature process in nature conditions. Warm and cold stratification can alleviate radicle and epicotyl dormancy, respectively. The duration of cold stratification also significantly affects the epicotyl dormancy release of Y. longistaminea. The researches on the seeds breaking methods: warm(28°C/20°C)→cold(5°C)→GA3(100mg·L−1)→warm(28°C/20°C).

Germination ecology of Trachycarpus fortunei (Arecaceae), a species with morphophysiological and shoot dormancy

Botany ◽  
2021 ◽  
Author(s):  
Ganesh K. Jaganathan ◽  
Narangua Bayarkhuu ◽  
LanLan He ◽  
Baolin Liu ◽  
Jiajin Li ◽  
...  
Keyword(s):  
Cold Stratification ◽  
Seed Length ◽  
Morphophysiological Dormancy ◽  
Wide Range ◽  
Cotyledonary Petiole ◽  
Summer Temperatures ◽  
Strong Inference ◽  
Total Seed ◽  
Mature Seeds ◽  
Natural Dispersal

Beyond strong inference that most of the 2600 known species of Arecaceae produce diaspores with an underdeveloped embryo and therefore have morphological (MD) or morphophysiological dormancy (MPD), little is known about the specific dormancy class or sub-class, and how dormancy-break occurs under ecological conditions. Here, we found that mature seeds of Trachycarpus fortunei collected at the time of natural dispersal had an underdeveloped embryo that was 10% of total seed length. No diaspores germinated over a wide range of temperatures in either light or darkness. Cold-stratification at 4 °C for 1, 2, and 3 months or treatment with 100, 500, and 1000 ppm gibberellic acid (GA3) improved germination percentages, with 3 months cold-stratification or 1000 ppm GA3 resulting in highest germination. The embryo grew inside the seeds during cold-stratification. However, warm stratification did not improve germination. Therefore, seeds of T. fortunei have intermediate complex MPD. Cold stratified seeds moved to spring conditions (15/20 °C) had cotyledonary petiole (CP) elongated, but leaves developed only when the CP elongated seeds were moved to summer temperatures (25/30 °C), suggesting the presence of shoot dormancy. The seedlings are remote-tubular type. This is the first report for Arecaceae indicating the presence of complex MPD.

Intermediate morphophysiological dormancy allows for life-cycle diversity in the annual weed, Turgenia latifolia (Apiaceae)

2014 ◽  
Vol 62 (8) ◽  
pp. 630 ◽  
Author(s):  
Miregul Nurulla ◽  
Carol C. Baskin ◽  
Juan J. Lu ◽  
Dun Y. Tan ◽  
Jerry M. Baskin
Keyword(s):  
Life Cycle ◽  
Low Temperatures ◽  
Western China ◽  
Intermediate Complex ◽  
Dormancy Breaking ◽  
Morphophysiological Dormancy ◽  
Temperature Regimes ◽  
Germination Phenology ◽  
Physiological Dormancy ◽  
Winter Annual

Our aim was to determine the seed dormancy-breaking requirements and type of life cycle of Turgenia latifolia in north-western China. At dispersal in July, only 0–9% of the seeds germinated at 5/2°C, 15/2°C, 20/10°C and 25/15°C; thus, 91% of the seeds exhibited physiological dormancy (PD) and 9% were non-dormant. Also, the embryo was underdeveloped and embryo length : seed length ratio increased from 0.38 in fresh seeds to 0.79 at germination. Seeds buried in dry soil at the four temperature regimes for 12 weeks germinated to ≥50% when tested in darkness at 5/2°C, and those buried at 15/2°C and 20/10°C germinated to ≥50% when tested at 15/2°C. Seeds have intermediate complex morphophysiological dormancy (MPD). PD was broken at high and/or low temperatures, but embryo growth was completed only at low temperatures; gibberellic acid (GA3) promoted germination. Seeds buried under natural conditions during summer germinated to ~70% and ~55% at 5/2°C and 15/2°C, respectively, in darkness in autumn. In a germination-phenology study, cumulative germination was ~20% and ~80% in autumn and spring, respectively. Intermediate complex MPD allows the species to behave as a winter annual and as a short-lived summer annual.

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.

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