Alternating temperature requirements in Leucospermum R.Br. seed germination and ecological correlates in fynbos

Abstract: Phytelephas macrocarpa (ivory palm) is an Amazonian palm vulnerable to exploitation pressure, as its seeds are widely used in regional handicrafts. The aims of this study were to evaluate the effectiveness of different stratification temperatures in overcoming seed dormancy and to analyze the seedling development stages of this species. In germination under stratification, the seeds were placed in plastic bags containing moistened vermiculite, and maintained at the constant temperatures of 25, 30, 35 and 40 °C, and an alternating temperature from 26 to 40 °C. In the study about the development of seedlings, seeds were sown in vermiculite under plastic cover (growing house), and the evolution of the seedling was evaluated, from the formation of germinative button to the complete blade expansion of the first eophyll. Stratification at alternating temperatures (26 to 40 °C) helped overcoming seed dormancy. Stratification at 25 °C kept the seed viability for nine months. Germination, characterized by the formation of the germinative button took an average of 114 ± 24 days, and the seedling development until the first extended eophyll lasted 244 ± 57 days.

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Opportunistic Germination Behaviour of Gypsophila (Caryophyllaceae) in Two Priority Habitats from Semi-arid Mediterranean Steppes

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha3916078 ◽

2011 ◽

Vol 39 (1) ◽

pp. 18 ◽

Cited By ~ 6

Author(s):

Felix MORUNO ◽

Pilar SORIANO ◽

Oscar VICENTE ◽

Monica BOSCAIU ◽

Elena ESTRELLES

Keyword(s):

Seed Germination ◽

Climatic Conditions ◽

Thermal Time ◽

Distribution Area ◽

Base Temperature ◽

Additional Information ◽

High Viability ◽

Germination Behaviour ◽

Alternating Temperature

Gypsophila tomentosa and G. struthium are closely related species, characteristic of two European priority habitats, salt and gypsum inland steppes, respectively. Germination strategies of the two taxa were investigated in plants from two nearby populations, growing under the same climatic conditions but on different types of soil, and belonging to different plant communities. Their germination patterns were studied at five constant temperatures in darkness: 5oC, 10oC, 15oC, 20oC and 25oC, and the base temperature and the thermal time requirement were calculated. As the distribution area of both species is subjected to a Mediterranean continental climate with significant differences between day and night, the possible preferences for an alternating temperature regime (25/10oC) were contrasted, as well as the influence of cold stratification and freezing. The effects on seed germination of light at constant 20oC and a 12/12 h photoperiod were also compared in the two species. The main conclusions of the work are the similarity of behaviour of both species, with an absence of seed dormancy, their opportunistic germination strategy, and water availability as the principal limitation to seed germination and plant establishment. The base temperature and thermal time indicate higher competitiveness of G. struthium at low temperatures, but seed germination of G. tomentosa is the most efficient at temperatures higher than 13.3oC. Optimal temperature and illumination conditions for nursery propagation depend on the species. The high viability of seeds observed after freezing prove the orthodox character of these seeds, providing additional information for long term seed conservation procedures.

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Effects of Environmental Factors on Seed Germination and Emergence of Velvetleaf (Abutilon theophrasti)

Planta Daninha ◽

10.1590/s0100-83582018360100122 ◽

2018 ◽

Vol 36 (0) ◽

Cited By ~ 2

Author(s):

RC. XIONG ◽

Y. MA ◽

HW. WU ◽

WL. JIANG ◽

XY. MA

Keyword(s):

Seed Germination ◽

Environmental Factors ◽

Field Experiments ◽

Cropping Systems ◽

Control Strategies ◽

Seedling Emergence ◽

Central China ◽

Burial Depth ◽

Temperature Regimes ◽

Alternating Temperature

ABSTRACT: Velvetleaf, an annual broadleaf weed, is a common and troublesome weed of cropping systems worldwide. Laboratory and field experiments were conducted to determine the effects of environmental factors on germination and emergence of velvetleaf. Seeds germinated over a range of constant temperatures from 10 to 40 oC regardless of light conditions, but no germination occurred at temperature below 5 oC and beyond 50 oC. Seeds germinated at alternating temperature regimes of 15/5 to 40/30 oC, with maximum germination (>90%) at alternating temperatures of 40/30 oC. Germination was sensitive to water stress, and only 0.4% of the seeds germinated at the osmotic potential of -0.4 MPa. There was no germination at ? 0.6 MPa. Moreover, germination was reduced by saline and alkaline stresses and no germination occurred at ³ 150 mM NaCl or ³ 200 mM NaHCO3 concentrations. However, pH values from 5 to 9 had no effect on seed germination. Seedling emergence was significantly affected by burial depth and maximum emergence (78.1-85.6%) occurred at the 1-4 cm depth. The results of this study have contributed to our understanding of the germination and emergence of velvetleaf and should enhance our ability to improve control strategies in cropping systems in central China.

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Seed germination of Brazilian Aldama species (Asteraceae)

Journal of Seed Science ◽

10.1590/2317-1545v37n3146138 ◽

2015 ◽

Vol 37 (3) ◽

pp. 185-191 ◽

Cited By ~ 2

Author(s):

Aline Bertolosi Bombo ◽

Tuane Santos de Oliveira ◽

Beatriz Appezzato-da-Glória ◽

Ana Dionísia da Luz Coelho Novembre

Keyword(s):

Seed Germination ◽

Reproductive Strategies ◽

Fluorescent Lamp ◽

Optimal Temperature ◽

Embryo Viability ◽

Seed Health ◽

Sexual Propagation ◽

Alternating Temperature ◽

Underground System ◽

Germinating Seeds

Brazilian samples from the Aldama genus (Asteraceae) could not propagate vegetatively despite their thickened underground system; thus, this study on sexual propagation is critical given the lack of data on reproductive strategies for such species. The aim for this research was to assess the optimal temperature for Aldama arenaria, A. filifolia, A. linearifolia, A. robustaand A. trichophylla seed germination. Seed germination was evaluated at the constant temperatures 20, 25 and 30 °C and the alternating temperatures 15-35, 20-30 and 20-35 °C with an 8-h daily photoperiod, using fluorescent-lamp. The ungerminated seeds were evaluated for embryo viability. The A. filifolia seed health was also evaluated. The optimal temperatures for germination are 20 and 25 °C for Aldama arenaria, A. filifolia, A. robusta and A. trichophylla seeds and 20 °C for A. linearifoliaseeds. The alternating temperature 15-35 °C is not recommended for germinating seeds from these species. The six fungi taxa studied herein did not affect A. filifolia seed germination.

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Afterripening and germination of seeds of American highbush cranberry (Viburnum trilobum)

Canadian Journal of Botany ◽

10.1139/b73-228 ◽

1973 ◽

Vol 51 (10) ◽

pp. 1761-1764 ◽

Cited By ~ 9

Author(s):

Paul Fedec ◽

R. H. Knowles

Keyword(s):

Seed Germination ◽

Gibberellic Acid ◽

Prolonged Exposure ◽

Inductive Effect ◽

Polar Lipids ◽

Lipid Degradation ◽

Lipid Reserve ◽

High Lipid ◽

Alternating Temperature

Seed of the American highbush cranberry, Viburnum trilobum Marsh., kept at germinative conditions of 20 °C, required 328 days to reach 92% germination. Initially, about one-half the seed germinated within 120 days. After a 120-day lag, the balance germinated. Afterripening, with as little as one cycle of alternating temperature (1 week at 20 °C and 1 week at 2 °C) shortened the time to total germination by [Formula: see text] months. The inductive effect of afterripening was studied in relation to utilization of the high lipid reserve present in the endosperm. No appreciable changes in polar and non-polar lipids occurred during prolonged exposure to either afterripening or germinative conditions, indicating that afterripening is not associated with lipid degradation. Gibberellic acid (GA3) had little effect on seed germination but successfully overcame epicotyl dormancy of the seedling.

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Temperature requirements for seed germination of Pereskia aculeata and Pereskia grandifolia

Journal of Thermal Biology ◽

10.1016/j.jtherbio.2016.01.009 ◽

2016 ◽

Vol 57 ◽

pp. 6-10 ◽

Cited By ~ 6

Author(s):

Lucéia F. Souza ◽

Bruno F. Gasparetto ◽

Rodrigo R. Lopes ◽

Ingrid B.I. Barros

Keyword(s):

Seed Germination ◽

Temperature Requirements

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Influence of Light and Temperature on Seed Germination of Flame Azalea

Journal of Environmental Horticulture ◽

10.24266/0738-2898-7.3.109 ◽

1989 ◽

Vol 7 (3) ◽

pp. 109-111 ◽

Cited By ~ 1

Author(s):

Asiah A. Malek ◽

Frank A. Blazich ◽

Stuart L. Warren ◽

James E. Shelton

Keyword(s):

Seed Germination ◽

Continuous Illumination ◽

Light Requirement ◽

Alternating Temperature

Abstract Seeds of flame azalea [Rhododendron calendulaceum (Michx.) Torr.] were germinated at 25°C (77°F) and 25°/15°C (77°/59°F) with daily photoperiods of 0, ½, ½ twice daily, 1, 2, 4, 8, 12 and 24 hr. Seeds exhibited an obligate light requirement. At 25°C (77°F), increasing photoperiods increased germination with maximum germination (85%) occurring by day 12 under continuous illumination. The alternating temperature of 25°/15°C (77°/59°F) enhanced germination when light was limiting. At this temperature, maximum germination of 84 to 91% was reached by day 24 for all photoperiods ≥½ hr although at photoperiods ≥4 hr, comparable germination was noted at day 18.

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Seed Germination of Three Provenances of Rhododendron catawbiense: Influence of Light and Temperature

Journal of Environmental Horticulture ◽

10.24266/0738-2898-12.3.155 ◽

1994 ◽

Vol 12 (3) ◽

pp. 155-158 ◽

Cited By ~ 2

Author(s):

D. Bradley Rowe ◽

Frank A. Blazich ◽

Stuart L. Warren ◽

Thomas G. Ranney

Keyword(s):

United States ◽

Seed Germination ◽

Southeastern United States ◽

Total Darkness ◽

Temperature Requirements ◽

And Storage

Abstract Seeds of three provenances of Rhododendron catawbiense Michx. (Catawba rhododendron) were collected during Fall 1992 from the following localities in the southeastern United States: Cherokee Co., GA [34°20′N, 84°23′W, elev. = 320 m (1050 ft)], Johnston Co., NC [35°45′N, 78°12′W, elev. = 67 m (220 ft)], and Yancey Co., NC [35°45′N, 82°16′W, elev. = 1954 m (6410 ft)]. Following drying for 1 month and storage at 4°C (39°F), seeds were removed from storage in January 1993 and germinated at 25°C (77°F) or an 8/16 hr thermoperiod of 25°/15°C (77°/59°F) with daily photoperiods of 0, ½, 1, 2, 4, 8, 12, or 24 hr. Regardless of temperature and provenance, seeds required light for germination. Negligible germination for all provenances in total darkness was overcome by daily photoperiods as short as ½ hr. All provenances commenced germination earlier at 25°C (77°F) than at 25°/15°C (77°/59°F). Mean germination at day 24 for both temperature treatments and for all photoperiods with the exception of total darkness was 98%, 90%, and 80% for the Yancey, Johnston, and Cherokee Co. provenances respectively. Light and temperature requirements for seed germination of all provenances were similar, although seeds of the higher elevation, Yancey Co. provenance exhibited greater vigor; they germinated at a faster rate with greater cumulative germination.

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