Dormancy breakage and germination are tightly controlled by hypoxic submergence water on Echinochloa crus-galli seeds from an accession resistant to anaerobic germination

2020 ◽  
pp. 1-6 ◽  
Author(s):  
Juliana Echeverry Holguín ◽  
María Crepy ◽  
Gustavo G. Striker ◽  
Federico P.O. Mollard
Keyword(s):  
Light Pulse ◽  
Seedling Establishment ◽  
Inhibitory Action ◽  
Seedling Emergence ◽  
Red Light ◽  
Functional Trait ◽  
Dormancy Breaking ◽  
Temporal Window ◽  
Resistant Accession ◽  
Anaerobic Germination

Abstract In wetlands, dormancy may be a key functional trait enabling seeds to avoid underwater germination, which could be lethal for seedling establishment. Our objectives were to find out (i) if shallow dormant (i.e. conditionally dormant) Echinochloa crus-galli seeds from an anaerobic germination resistant accession can break dormancy under hypoxic submergence and (ii) if underwater germination can be restored in scarified, non-dormant seeds. Shallow dormant E. crus-galli seeds perceived diurnally alternating temperatures (AT) and red light (R) pulses (i.e. dormancy-breaking cues) under hypoxic submergence; however, an inhibitory far-red light pulse given at the end of the 4-d inundation period demonstrated that most of the seeds (85%) were unable to break dormancy. Scarified E. crus-galli seeds, which did not express dormancy under drained conditions, were unable to germinate under hypoxic submergence, despite being exposed to dormancy-breaking cues (AT + R). Lastly, the temporal window for germination sensitivity to the inhibitory action of hypoxia, once dormancy-breaking signals have been applied, is progressively lost and bounded to approximately 18 h for half of the seed lot. These results highlight the importance of dormancy as a trait enabling E. crus-galli seeds to avoid underwater germination, a risky scenario for seedling emergence and establishment in this facultative hydrophyte.

scholarly journals The counteracting effect of potassium cyanide in sodium azide-inhibited germination of Paulownia tomentosa  Steud. seeds

2005 ◽  
Vol 57 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Suzana Zivkovic ◽  
Dragoljub Grubisic ◽  
Zlatko Giba ◽  
Radomir Konjevic
Keyword(s):  
Seed Germination ◽  
Light Pulse ◽  
Sodium Azide ◽  
Incubation Medium ◽  
Red Light ◽  
Potassium Cyanide ◽  
Inhibitory Effect ◽  
Escape Time ◽  
Paulownia Tomentosa ◽  
Respiratory Inhibitors

The effect of some respiratory inhibitors on light-induced Paulownia tomentosa Steud. seed germination was studied. Millimolar solution of sodium azide was sufficient to completely prevent germination induced by a 5-min red light pulse. The inhibitory effect of azide was absent if seeds were rinsed before phytochrome activation by light. Sodium azide was effective only if present in the period of Pfr activity. The escape time from azide inhibition compared to the escape from far-red light action, was delayed for about 24 hours. When azide was applied after phytochrome activation, its effect depended on how long it was present in the incubation medium. The removal of azide allowed full restoration of germination by another red light pulse and the far-red escape time did not differ from the escape of untreated, i.e. water-imbibed seeds. Potassium cyanide alone did not produce any effect in light-stimulated germination of these seeds. However, it counteracted the inhibitory effect of azide in light-stimulated germination, if applied simultaneously at a concentration three times higher.

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.

scholarly journals Seedling recruitment in subalpine grassland forbs: Predicting field regeneration behaviour from lab germination responses

Botany ◽  
2017 ◽  
Vol 95 (1) ◽  
pp. 73-88 ◽  
Author(s):  
Vigdis Vandvik ◽  
Reidar Elven ◽  
Joachim Töpper
Keyword(s):  
Predictive Power ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
Selective Advantage ◽  
Dormancy Breaking ◽  
Bare Ground ◽  
Seasonal Timing ◽  
Moist Chilling ◽  
Germination Behaviour ◽  
Carry Over

Environmental cueing that restricts seed germination to times and places where mortality risk is relatively low may have considerable selective advantage. The predictive power of lab germination responses for field regeneration behaviour is rarely tested. We screened 11 alpine grassland forbs for germination behaviour predictive of microsite and seasonal selectivity, and seed carry-over across years. The predictions were tested in a field experiment. Germination in the lab ranged from 0.05% to 67.9%, and was affected by light (5 species), temperature (6 species), fluctuating temperatures (4 species), moist chilling prior to germination (cold-stratification) (6 species), and dormancy-breaking by means of gibberellic acid (8 species). Seedling emergence in the field varied from 0.1% to 14.1%, and increased in low-competition microsites (bare-ground gaps and cut vegetation; 7 species), and showed seasonal timing (1 species in autumn and 1 species in spring), and seed carry-over across years (7 species). Lab germination responses successfully predicted microsite selectivity in the field and to some extent seed carry-over across years but not seasonal timing of germination. Gap-detecting species were generally small-seeded, low-growing, and found in unproductive habitats. Larger-seeded species germinated in all of the microsites but experienced increased mortality in high-competition microsites. Seed carry-over across years was lower for alpine specialists than for more widely-distributed species.

Effect of soil water content and temperature on dormancy breaking and germination of three weeds

Weed Science ◽  
1997 ◽  
Vol 45 (6) ◽  
pp. 791-797 ◽  
Author(s):  
Maria A. Martinez-Ghersa ◽  
Emilio H. Satorre ◽  
Claudio M. Ghersa
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Seed Dormancy ◽  
Seedling Establishment ◽  
Germination Rate ◽  
High Rate ◽  
Dormancy Breaking ◽  
Species Response ◽  
Redroot Pigweed

In laboratory experiments, we studied barnyardgrass, common lambsquarters, and redroot pigweed seed dormancy release by alternating temperatures under different soil water regimes, to determine whether that response serves as a mechanism for assuring seedling establishment. Alternating temperatures were important in breaking seed dormancy in the three weeds, but the species' response to alternating temperatures differed with soil water content. For redroot pigweed and newly dispersed seeds of barnyardgrass, dormancy breaking by alternating temperatures occurred only when soil water content was high enough for germination. Moreover, adverse incubation conditions (constant temperature and low water content) induced secondary dormancy in these seeds. Seventy percent of seeds incubated in open boxes emerged before the soil reached wilting point, when seeds were incubated at temperatures high enough for a high germination rate. A dormancy breaking mechanism that triggers a high rate of germination may be important in assuring success of seedling establishment where rainfall patterns result in wetting and drying cycles of the soil, especially in soil types that lose water rapidly from the surface layers.

Establishment of Jeffrey Pine Seedlings from Animal Caches

1992 ◽  
Vol 7 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Stephen B. Vander Wall
Keyword(s):  
Sierra Nevada ◽  
Seedling Establishment ◽  
Seedling Emergence ◽  
Pinus Jeffreyi ◽  
Jeffrey Pine ◽  
Pine Seedlings

Abstract Jeffrey pine (Pinus jeffreyi) seeds have large wings and are effectively dispersed by wind, but 37% of the seedling emergence sites in spring 1989 in the Sierra Nevada of western Nevada consisted of tight clumps of seedlings. By fall 1989, 41% of all emergence sites where seedlings survived had resulted from what were originally clumps of seedlings. As Jeffrey pines aged, clumps became smaller, and the frequency of clumps decreased. These seedling clumps and many single seedlings emerged from the scattered caches of seed-hoarding rodents and corvids, and the activities of these animals in the study area were sufficient to account for most of the Jeffrey pine seedling establishment observed. Cached seeds may gain important advantages over uncached seeds in the semiarid habitat occupied by this pine. West. J. Appl. For. 7(1):14-20

scholarly journals Factors Affecting Seed Dormancy and Germination of Greater Bur-Parsley (Turgenia latifolia)

2018 ◽  
Vol 36 ◽  
Author(s):  
M. REZVANI ◽  
S.A. SADATIAN ◽  
H. NIKKHAHKOUCHAKSARAEI
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Seed Dormancy ◽  
Seedling Emergence ◽  
Potassium Nitrate ◽  
Germination Percentage ◽  
Dormancy Breaking ◽  
Planting Depth ◽  
Factors Affecting ◽  
Drought And Salt Stresses

ABSTRACT: Our knowledge about seed dormancy breaking and environmental factors affecting seed germination of greater bur-parsley (Turgenia latifolia) is restricted. This study has addressed some seed dormancy breaking techniques, including different concentrations of gibberellic acid (GA3) and potassium nitrate (KNO3), leaching duration, physical scarification as well as some environmental factors effective on seed germination such as salt and drought stresses, pH and seed planting depth. Seed germination was promoted with lower concentrations of KNO3 (0.01 to 0.02 g L-1), while higher concentrations reduced germination percentage. Seed dormancy was declined by low concentrations of GA3 up to 100 ppm. Seeds of greater bur-parsley germinated in a range of pH from 3 to 7. With enhancement of drought and salt stresses, seed germination decreased. Also, there was no seed germination in a high level of stresses. Seedling emergence reduced as planting depth increased. Use of GA3, KNO3, leaching and physical scarification had a positive effect on seed dormancy breaking of greater bur-parsley. The information from the study increases our knowledge about seed dormancy breaking techniques, response of germination to drought and salt stresses and also determination of distribution regions of greater bur-parsley in the future.

scholarly journals Dormancy and germination of the trimorphic achenes of a cold desert annual: spreading the risk over time

AoB Plants ◽  
2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Juanjuan Lu ◽  
Wenjing Dong ◽  
Dunyan Tan ◽  
Carol C Baskin ◽  
Jerry M Baskin
Keyword(s):  
Seedling Emergence ◽  
Dispersal Ability ◽  
Dormancy Breaking ◽  
Cold Desert ◽  
Standard Procedures ◽  
Emergence Percentage ◽  
Desert Annual ◽  
The Relationship ◽  
Over Time ◽  
Temporal Dispersal

Abstract Many studies have been done on the relationship between variation in morphology, dispersal ability and degree of dormancy of heterocarpic species with dimorphic diaspores. However, there are far fewer such studies on species that produce trimorphic diaspores. Our aim was to compare dormancy and germination of achenes from peripheral, intermediate and central positions in the capitulum of the diaspore-trimorphic cold desert annual Asteraceae species Heteracia szovitsii, an important component of plant communities in the cold deserts of NW China. Dormancy breaking/germination responses of the three achene morphs and of seeds isolated from the pericarp were tested in the laboratory using standard procedures, and seedling emergence phenology of the achene morphs was monitored under natural cold desert temperature conditions in an experimental garden with and without supplemental watering. Depth of dormancy of the three achene morphs was peripheral > intermediate > central. Seedlings from the three morphs emerged in spring and in autumn. Cumulative seedling emergence percentage from achenes during 47 months of burial was central > intermediate > peripheral. Central achene morphs emerged over a period of ~12 months after sowing, while intermediate and peripheral achene morphs did so for ~40 and 47 months, respectively. Thus, H. szovitsii exhibits a temporal dispersal strategy. No viable central or intermediate achene morphs were present after 16 and 40 months, respectively, but ~60 % of the non-emerged peripheral achenes morphs were viable after 47 months. Based on our results on diaspore dormancy and those of a previous study of diaspore spatial dispersal of H. szovitsii, we conclude that this species has a high–intermediate–low risk diaspore dispersal/dormancy strategy that likely increases the chances for population persistence over time and space.

Germination response to phytochrome depends on specific dormancy states in wild oat (Avena fatua)

1993 ◽  
Vol 71 (11) ◽  
pp. 1528-1532 ◽  
Author(s):  
J. Q. Hou ◽  
G. M. Simpson
Keyword(s):  
Relative Humidity ◽  
Gibberellic Acid ◽  
Red Light ◽  
Avena Fatua ◽  
Mechanical Injury ◽  
Wild Oat ◽  
Dormancy Breaking ◽  
Negative Effects ◽  
Germination Response ◽  
Genetic Origins

Effects of brief red and far-red light on germination of seeds from dormant lines of wild oat (Avena fatua L.) were studied in combination with mechanical injury to the seed coat, application of gibberellin A3, or changes in relative humidity during afterripening. Aberrant germination responses to phytochrome action were observed in the mechanically injured seeds in some of the lines, i.e., brief red light inhibited or delayed germination induced by injury, and immediately following far-red light cancelled the negative effects. Phytochrome action influenced germination of the gibberellin-treated seeds in a normal fashion, although effects of the gibberellic acid and brief red light on germination were not additive. Brief red light inhibited germination of seeds afterripened in zero relative humidity; the same light promoted germination of those in 30 and 60% relative humidity. Germination response to phytochrome in wild oat depends on specific seed dormancy states, illustrated by genetic origins, dormancy-breaking methods and afterripening conditions. Key words: Avena fatua, dormancy, mechanical injury, gibberellin A3, phytochrome, relative humidity.

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