Dormancy Induction and Release in Buds and Seeds

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings grown in two different container cavities that received four different dormancy induction treatments, short (SD) or long days (LD) in combination with moisture stress (D) or no stress (W) in the greenhouse, and lifted and placed in cold storage (November, January, or March), were planted on two adjacent coastal reforestation sites in British Columbia and monitored for survival and morphological development. Survival was greatest in seedlings grown in the larger cavities in the greenhouse, in seedlings lifted in March, and in seedlings not treated to moisture stress. Seedling shoots had more stem units on the southeast than the northwest site, but the amount varied with nursery treatment. Seedlings from the LD treatments produced more stem units during free growth and lammas growth than those from the SD treatment. Nevertheless, most shoot growth was predetermined in the buds during nursery culture, accounting for a minimum of 67% of the final number of stem units. Stem unit length (SUL) was longer in seedlings on the southeast site than on the northwest site for those treated to LD in the nursery. Seedlings treated to short days showed the reverse pattern (SDW) to this, or were unaffected by site (SDD). Shoots and needles were shortest for seedlings from the SDD treatment and for those lifted in November. Shoot growth was greatest for seedlings lifted in March and for those treated with LD, mainly owing to their longer SUL. Lammas growth was most frequent in seedlings from the smaller cavities, and in those from the November and March lifts.

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Induction of Dormancy in Nondormant Seeds

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.119.3.408 ◽

1994 ◽

Vol 119 (3) ◽

pp. 408-413 ◽

Cited By ~ 9

Author(s):

Anwar A. Khan

Keyword(s):

Abscisic Acid ◽

Lycopersicon Esculentum ◽

Gibberellic Acid ◽

Lactuca Sativa ◽

Daucus Carota ◽

Apium Graveolens ◽

Lettuce Seeds ◽

Moist Chilling ◽

Dormancy Induction ◽

Ga Biosynthesis

A gibberellic acid (GA) biosynthesis inhibitor, tetcyclacis, induced dormancy in nondormant seeds of lettuce (Lactuca sativa L.), tomato (Lycopersicon esculentum Mill.), pepper (Capsicum annuum L.), carrot [Daucus carota var. sativus (Hoffn.)], onion (Allium cepa L.), celery (Apium graveolens L.), and impatiens (Impatiens novette), as most of the seeds failed to germinate after washing under conditions that permitted germination before dormancy induction. In lettuce seeds, tetcyclacis and paclobutrazol were more effective in inhibiting germination in light than in darkness. A 16- to 24-h soak treatment with tetcyclacis was sufficient to induce dormancy in nearly all seeds. Tetcyclacis failed to induce dormancy if applied after 6 h presoak in water. Dormancy induced by tetcyclacis was released by GA4+7 (a mixture of gibberellin A4 and A7), light, and moist-chilling treatments. When GA4+7 was applied with tetcyclacis, dormancy induction was prevented under both favorable, e.g., 25C, and unfavorable, e.g., 5C, or low water potential (Ψ), germination conditions. Unlike tetcyclacis, abscisic acid (ABA) failed to induce dormancy in lettuce seeds. Thermodormancy induction in lettuce seeds at 35C was prevented by fluridone. However, neither ABA nor tetcyclacis countered its effect. Dormancy was also induced in lettuce seeds by ancymidol, flurprimidol, or paclobutrazol. Dormancy induced by tetcyclacis in pepper, tomato, carrot, and onion seeds was released by GA4+7, but not by irradiation or moist-chilling. Chemical names used: 5-(4-chlorophenyl)-3, 4, 5, 9, 10-pentaazatetracyclo [5.4.102,6.08,11]-dodeca-3, 9-diene (tetcyclacis); 1-(4-chlorophenyl)-4, 4-dimethyl-2-(1H-1, 2, 4-triazole-1-yl)-3-pentanol (paclobutrazol); α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidine methanol (ancymidol); α-(1-methyl)-α-[4-(trifluoromethoxy) phenyl]-5-pyrimidine-methanol (flurprimidol); 1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4 (1H)-pyridinone (fluridone).

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Regulation of seed dormancy by abscisic acid and DELAY OF GERMINATION 1

Seed Science Research ◽

10.1017/s0960258514000415 ◽

2015 ◽

Vol 25 (2) ◽

pp. 82-98 ◽

Cited By ~ 19

Author(s):

Bas J.W. Dekkers ◽

Leónie Bentsink

Keyword(s):

Abscisic Acid ◽

Seed Dormancy ◽

Plant Hormone ◽

Complex Trait ◽

Hormone Interactions ◽

Physiological Dormancy ◽

Recent Developments ◽

Radicle Emergence ◽

Dormancy Induction

AbstractPhysiological dormancy has been described as a physiological inhibiting mechanism that prevents radicle emergence. It can be caused by the embryo (embryo dormancy) as well as by the structures that cover the embryo. One of its functions is to time plant growth and reproduction to the most optimal season and therefore, in nature, dormancy is an important adaptive trait that is under selective pressure. Dormancy is a complex trait that is affected by many loci, as well as by an intricate web of plant hormone interactions. Moreover, it is strongly affected by a multitude of environmental factors. Its induction, maintenance, cycling and loss come down to the central paradigm, which is the balance between two key hormonal regulators, i.e. the plant hormone abscisic acid (ABA), which is required for dormancy induction, and gibberellins (GA), which are required for germination. In this review we will summarize recent developments in dormancy research (mainly) in the model plant Arabidopsis thaliana, focusing on two key players for dormancy induction, i.e. the plant hormone ABA and the DELAY OF GERMINATION 1 (DOG1) gene. We will address the role of ABA and DOG1 in relation to various aspects of seed dormancy, i.e. induction during seed maturation, loss during dry seed afterripening, the rehydrated state (including dormancy cycling) and the switch to germination.

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Dormancy cycling is accompanied by changes in ABA sensitivity in Polygonum aviculare seeds

Journal of Experimental Botany ◽

10.1093/jxb/eraa340 ◽

2020 ◽

Vol 71 (19) ◽

pp. 5924-5934 ◽

Cited By ~ 1

Author(s):

Natalia Verónica Laspina ◽

Diego Batlla ◽

Roberto Luis Benech-Arnold

Keyword(s):

Molecular Mechanisms ◽

Hormone Metabolism ◽

Polygonum Aviculare ◽

Primary Dormancy ◽

Aba Sensitivity ◽

Winter Temperatures ◽

Spring Temperatures ◽

Aba Content ◽

Dormancy Induction ◽

Endogenous Aba

Abstract Polygonum aviculare seeds show high levels of primary dormancy (PD). Low winter temperatures alleviate dormancy and high spring temperatures induce seeds into secondary dormancy (SD), naturally establishing stable seedbanks cycling through years. The objective of this work was to elucidate the mechanism(s) involved in PD expression and release, and in SD induction in these seeds, and the extent to which abscisic acid (ABA) and gibberellins (GAs) are part of these mechanisms. Quantification of endogenous ABA both prior to and during incubation, and sensitivity to ABA and GAs, were assessed in seeds with contrasting dormancy. Expression analysis was performed for candidate genes involved in hormone metabolism and signaling. It was found that endogenous ABA content does not explain either dormancy release or dormancy induction; moreover, it does not seem to play a role in dormancy maintenance. However, dormancy modifications were commonly accompanied by changes in ABA sensitivity. Concomitantly, induction into SD, but not PD, was characterized by a increased PaABI-5 and PaPYL transcription, and a rise in GA sensitivity as a possible counterbalance effect. These results suggest that dormancy cycling in this species is related to changes in embryo sensitivity to ABA; however, this sensitivity appears to be controlled by different molecular mechanisms in primary and secondary dormant seeds.

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Influence of dormancy induction treatments on western hemlock seedlings. I. Seedling development and stock quality assessment

Canadian Journal of Forest Research ◽

10.1139/x91-020 ◽

1991 ◽

Vol 21 (2) ◽

pp. 164-174 ◽

Cited By ~ 19

Author(s):

S. C. Grossnickle ◽

J. T. Arnott ◽

J. E. Major ◽

T. J. Tschaplinski

Keyword(s):

Water Movement ◽

Seedling Development ◽

Western Hemlock ◽

Root Temperature ◽

Turgor Loss Point ◽

Short Day ◽

Long Day ◽

Osmotic Potentials ◽

Dormancy Induction ◽

Needle Primordia

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings were grown in a greenhouse and subjected to four dormancy induction treatments (DIT) (i.e., long-day dry, long-day wet, short-day dry, and short-day wet) during midsummer. In the late summer and fall, seedling development was monitored and it was found that (1) short-day DIT caused a rapid cessation of shoot growth; (2) short-day DIT caused rapid fall development of needle primordia, while long-day DIT took until midwinter to produce the same number of needle primordia; and (3) short-day DIT seedlings had lower saturated and turgor loss point osmotic potentials and greater maximum modulus of elasticity in October than long-day DIT. Seedlings were tested with a comprehensive stock quality assessment procedure just before late winter field planting. These tests showed the following: (1) morphological parameters: short-day DIT reduced shoot to root ratios; (2) pressure–volume analysis: short-day wet seedlings had the lowest osmotic potentials at saturation and turgor loss point; (3) soluble sugar analysis: greater levels of total soluble sugars were found in non water stressed DIT compared with water stressed DIT seedlings; (4) seedling water movement: short-day DIT seedlings had the lowest resistance to water movement at low root temperature (5 °C); (5) low root temperature response: short-day compared with long-day DIT seedlings had greater photosynthesis and stomatal conductance at low root temperatures; (6) root growth capacity: seedlings from all DIT were capable of growing roots at optimum root temperature (22 °C), but short-day compared with long-day DIT had greater root growth at low root temperatures; (7) drought stress response: short-day wet seedlings had the highest photosynthesis and stomatal conductance levels as predawn shoot water potentials decreased; and (8) frost hardiness: short-day wet seedlings had the least needle damage when tested at temperatures of −15 and −18 °C.

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A simple and convenient method for determination of entrance into dormancy in woody plants

Journal of Berry Research ◽

10.3233/jbr-200534 ◽

2020 ◽

Vol 10 (4) ◽

pp. 559-571

Author(s):

Anita Sønsteby ◽

Tomasz L. Woznicki ◽

Ola M. Heide

Keyword(s):

Convenient Method ◽

Woody Plants ◽

Late Summer ◽

Forest Tree ◽

Precise Determination ◽

Black Currant ◽

Lateral Buds ◽

Quantitative Condition ◽

Dormancy Induction

BACKGROUND: Bud dormancy is a quantitative condition that is gradually acquired and lost. Better and more convenient methods for assessment of the time of dormancy entrance of woody plants are highly needed. OBJECTIVE: To demonstrate a simple and convenient method for determination of dormancy in woody plants. METHODS: We employed a seasonal series of soft tipping of vigorously growing annual shoots and used the loss of ability of subtending lateral buds to break and grow as a measure of entrance into dormancy. RESULTS: There was a gradual decline in the ability of the buds to burst and grow during the month of July and early August, culminating with a complete loss of this ability. This coincided with the known time of growth cessation and dormancy induction in shoots of intact plants and occurred in the berry shrubs raspberry and black currant and the forest tree silver birch. CONCLUSIONS: The decline and loss of ability of the buds to grow during late summer is a direct expression of the entrance of buds into the state of endodormancy, rendering the tipping method a simple and convenient method for precise determination of the time of entrance into dormancy in woody plants.

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