scholarly journals Germination Responses to GA3 and Stratification of Threatened Festuca L. Species from Eastern Mediterranean

2006 ◽  
Vol 61 (5-6) ◽  
pp. 372-376 ◽  
Author(s):  
Serap Çelikler ◽  
Gürcan Güleryüz ◽  
Rahmi Bilaloğlu
Keyword(s):  
Seed Germination ◽  
Eastern Mediterranean ◽  
Germination Percentage ◽  
Cold Stratification ◽  
Combined Treatments ◽  
Alpine Belt ◽  
Germination Characteristics ◽  
The Mean ◽  
Different Doses

The seed germination characteristics of three threatened Festuca sp. [F. punctoria Sm., F. cyllenica Boiss. et Heldr. subsp. uluana Markgr.-Dannenb., F. paphlagonica (St.-Yves) Markgr.-Dannenb. subsp. paphlagonica] were investigated. These species are endemic and spread on alpine belt. The study was carried out with wet-cold and dry-cold stratification throughout 15 days, different doses of GA3 (50, 100 and 150 ppm) and hormone-stratification combined treatments, and non-treatment series. We found that the germination rates of three fescue seeds for various treatment series were different. The mean germination percentage of F. cyllenica was higher (80%) than that of F. punctoria and F. paphlagonica which were fairly low (50-60%). Germination rates increased by wet-stratification treatment in F. punctoria and also increased with 100 ppm GA3 application to the seeds of F. paphlagonica. When taken into consideration the germination percentages of all fescue species, the seeds of F. punctoria and F. paphlagonica can be dormant, but the seeds of F. cyllenica are non-dormant.

scholarly journals Physical characterization of Rhipsalis (Cactaceae) fruits and seeds germination in different temperatures and light regimes

2016 ◽  
Vol 76 (2) ◽  
pp. 367-373 ◽  
Author(s):  
A. B. Lone ◽  
R. C. Colombo ◽  
B. L. G. Andrade ◽  
L. S. A. Takahashi ◽  
R. T. Faria
Keyword(s):  
Seed Germination ◽  
Germination Percentage ◽  
Light Regimes ◽  
Total Absence ◽  
Germination Characteristics ◽  
Different Temperatures ◽  
Medium Time ◽  
Seeds Germination

Abstract The germination characteristics of the native cactus species are poorly known, being the temperature and the light the factors that the most interferes in that process. Thus, the objective of the present work was to characterize the fruits and evaluate the influence of the temperature and the light in the seed germination of Rhipsalis floccosa, Rhipsalis pilocarpa and Rhipsalis teres. The tested constant temperatures were 15, 20, 25, 30 and 35 °C and the alternate of 20-30 °C and 25-35 °C in a photoperiod of 10 hours, and with determination of the most appropriate temperature, the germination was tested in light absence. The germination percentage, the index of germination speed and medium time of germination were evaluated. For R. floccosa, the highest germination percentage was at 20 °C. For R. pilocarpa and R. teres, the highest germination percentages occurred in 15 °C and 20 °C. There was correlation to germination percentage between the three species, indicating that they had similar germination behavior. Total absence of germination was verified for the three species in condition of light absence. In conclusion, the temperature of 20 °C is the most suitable for the seed germination of R. floccosa. For the species R. pilocarpa and R. teres, the temperatures of 15 and 20 °C are the most suitable.

scholarly journals Temperature Requirements for Seed Germination of Three Penstemon Species'

HortScience ◽  
1990 ◽  
Vol 25 (2) ◽  
pp. 191-193 ◽  
Author(s):  
Phil S. Allen ◽  
Susan E. Meyer
Keyword(s):  
Seed Germination ◽  
Incubation Temperature ◽  
Marked Decrease ◽  
Rocky Mountain ◽  
Germination Percentage ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Primary Dormancy ◽  
Temperature Requirements ◽  
Seed Propagation

To determine optimum germination temperatures and effective dormancy-breaking procedures, field-grown (1983-85) seeds of `Bandera' Rocky Mountain penstemon (Penstemon strictus Benth), `Cedar' Palmer penstemon (Penstemon palmeri Gray), and firecracker penstemon (Penstemon eatonii Gray) were subjected to various cold stratification and incubation temperature treatments. Increased germination following an 8-week stratification occurred in seed lots containing dormant seeds, but a 2-week stratification generally failed to break dormancy. Older (1983) seeds of `Bandera' and `Cedar' penstemon germinated to full viability without stratification. All species showed a marked decrease in germination percentage above 20C; 15C consistently produced maximum germination after 4 weeks. At 15C, mean times to 90% of total germination were 11, 22, and 29 days for `Bandera', `Cedar', and firecracker penstemon, respectively. Transfer of seeds failing to germinate at warm temperatures (25 and 30C) to 15C and applying 720 μm gibberellic acid (GA3) solution was effective in breaking primary dormancy of firecracker penstemon and secondary dormancy of `Bandera' penstemon. Our findings suggest that incubation below 20C, combined with 8 weeks of stratification or the use of after-ripened seed, may improve seed propagation efforts for these species.

scholarly journals The Alleviation Effect of Silicon on Seed Germination and Seedling Growth of Tomato Under Salinity Stress

2012 ◽  
Vol 76 (1) ◽  
pp. 119-126 ◽  
Author(s):  
Maryam Haghighi ◽  
Zahra Afifipour ◽  
Maryam Mozafarian
Keyword(s):  
Seed Germination ◽  
Salinity Stress ◽  
Seedling Growth ◽  
Germination Rate ◽  
Germination Percentage ◽  
Percentage Germination ◽  
Tomato Seeds ◽  
Germination Characteristics ◽  
Salinity Levels ◽  
Mean Germination Time

The Alleviation Effect of Silicon on Seed Germination and Seedling Growth of Tomato Under Salinity StressThis study was conducted to evaluate the effectiveness of silicon (Si) application under salinity levels on seed germination and growth characteristics of tomato seeds. A laboratory experiment was performed on completely randomized design with two levels of salinity (25 and 50 mM NaCl) and 2 concentration of Si (1 and 2 mM) with 4 replications. Germination percentage, germination rate, seedling shoot and root length, fresh and dry weight of seedling and mean germination time was measured. Seed germination ofLycopersicon esculentumL. was significantly affected by salinity levels, Si and their interaction. Germination characteristics of tomato seeds decreased drastically by increasing NaCl concentrations. However, 1 mM Si had positive effects on seed germination characteristics and improved germination percentage, germination rate and mean germination time. Si alleviated the harmful effect of salinity stress on tomato seed germination at almost all germination characteristics.

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.

Seed-germination response of Leymus chinensis to cold stratification in a range of temperatures, light and low water potentials under salt and drought stresses

2017 ◽  
Vol 68 (2) ◽  
pp. 188 ◽  
Author(s):  
Jixiang Lin ◽  
Yujie Shi ◽  
Shuang Tao ◽  
Xingyang Yu ◽  
Dafu Yu ◽  
...  
Keyword(s):  
Drought Stress ◽  
Seed Germination ◽  
Drought Tolerance ◽  
Northeast China ◽  
Germination Percentage ◽  
Leymus Chinensis ◽  
Grass Species ◽  
Cold Stratification ◽  
Effective Measure ◽  
Salt And Drought Stresses

Leymus chinensis has important forage value and is considered a useful grass species for grassland restoration in Northeast China. However, little information exists concerning the germination responses of this species to interactions of cold stratification, light, temperature and low water potential caused by salinity and drought. Experiments were conducted in growth chambers, and the results showed that in all conditions of light, temperature and water stresses, the germination percentages of cold-stratified seeds were higher than of non-stratified seeds. Light had an inhibitory effect on germination percentage under both non-saline and salt stress conditions; darkness is beneficial for germination of this species. In addition, seeds germinated much better under alternating temperature regimes than under constant temperatures. Both salt and drought stresses decreased the germination percentage of Leymus chinensis, but the reductions under drought stress were much greater. Moreover, after being transferred to distilled water, most non-germinated seeds under drought stress germinated well, and the total percentage reached that of the non-saline condition level. Therefore, cold stratification is an effective measure to increase seed germination and salt or drought tolerance, especially in darkness. We conclude that Leymus chinensis has definite salt and drought tolerance during the germination stage and it is a promising species for the restoration of deteriorated grassland in Northeast China.

Relating germination requirements of timber milkvetch to seral stage in the Interior Douglas-fir zone

2014 ◽  
Vol 94 (4) ◽  
pp. 723-726
Author(s):  
D. J. Thompson
Keyword(s):  
Seed Germination ◽  
Germination Rate ◽  
Germination Percentage ◽  
Douglas Fir ◽  
Native Plant ◽  
Temperature Regimes ◽  
The Mean ◽  
Lower Temperature ◽  
Fluctuating Temperatures ◽  
Germination Requirements

Thompson, D. J. 2014. Relating germination requirements of timber milkvetch to seral stage in the Interior Douglas-fir zone. Can. J. Plant Sci. 94: 723–726. Germination of timber milkvetch (Astragalus miser var. serotinus) seeds was studied to determine if it is an early or late seral species. Seeds were collected from a native plant population and those having a dark seed coat were selected. Germination tests were run in the light or dark and under three temperature regimes: low (constant 10°C), high (constant 25°C), and alternating (25°C day and 10°C night). Germination occurred over a protracted period with new germinants up to 90 d at the lowest temperature. Germination was not affected by light. Germination rate was greater at 25°C than 10°C, while fluctuating temperatures (25 and 10°C alternating every 12 h) reduced germination rate to that at the lower temperature. Days to 50% germination was a more sensitive indicator, with the mean for the fluctuating temperatures falling between those continuous to the high and low temperature. Final germination percentage was reduced at 10°C compared with 25°C, but not with fluctuating temperatures. Timber milkvetch seed germination did not respond to light or fluctuating temperatures, adding to a body of evidence that it is a late seral species.

Watermelon seed germination. 2. Osmomanipulation of photosensitivity

1992 ◽  
Vol 2 (3) ◽  
pp. 163-168 ◽  
Author(s):  
C. A. Thanos ◽  
K. Mitrakos
Keyword(s):  
Seed Germination ◽  
Prolonged Exposure ◽  
Citrullus Lanatus ◽  
Germination Percentage ◽  
Light Pulses ◽  
Seed Population ◽  
Germination Characteristics ◽  
Dark Interval ◽  
Osmotic Solution ◽  
Negative Exponential

AbstractSeed germination of watermelon (Citrullus lanatus cv. Sugar Baby) was fully suppressed by intermittent far-red (FR) irradiation (1 min every 30 min). When the intervening dark period was increased, a linearly increasing final germination percentage was obtained. However, a 4-day intermittent FR treatment induced phytochrome-controlled dormancy and the longer the dark interval the deeper was the dormancy of the non-germinated seeds. When seeds were soaked in a fully inhibitory osmotic solution, no dormancy was imposed. However, a single FR pulse at the time of transfer induced partial, secondary dormancy; the kinetics of the imposition of dormancy followed a negative exponential curve (half-life 1.5 days; 3 days for the cultivar Crimson Sweet). Seeds osmotreated for 10 days in darkness and subsequently dehydrated (with and without a final FR pulse) acquired germination characteristics similar to those in light-requiring and dark-germinating achenes, respectively, of the lettuce cultivar Grand Rapids. In the light-requiring osmomanipulated seed population, the induction of germination was brought about by the low-energy reaction of phytochrome, chilling, dry storage and decoating. The transformation through osmomanipulation of the dark-germinating watermelon seeds (the inhibition of which required prolonged exposure to light) to positively or negatively photosensitive seeds (that responded to brief light pulses), might be attributed to the slow relaxation of existing meta-Fa and meta-Rb phytochrome intermediates to Pfr upon hydration.

Effects of partial drying on seed germination in the aquatic grasses Zizania palustris L. and Porteresia coarctata (Roxb.) Tateoka

1992 ◽  
Vol 2 (4) ◽  
pp. 199-205 ◽  
Author(s):  
C. D. Aldridge ◽  
R. J. Probert
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Growth Regulators ◽  
Germination Percentage ◽  
Hormonal Status ◽  
Cold Stratification ◽  
Porteresia Coarctata ◽  
Germination Response ◽  
Fold Reduction ◽  
Germination Behaviour

AbstractPartial drying of non-dormant seeds had little effect on germination behaviour compared with undried controls. In contrast, partial drying resulted in a marked increase in the germination response of freshly harvested (dormant) seeds of Z. palustris. Partial drying also resulted in a 100-fold reduction in the concentration of gibberellins (GA4+7) required for maximum germination. Although the concentration range of applied abscisic acid (ABA) that permitted germination was unaltered, partial drying increased the final germination percentage at all concentrations tested. The concentration of ABA above which germination was reduced in freshly harvested (dormant) seeds of Z. palustris was 3.16 × 10−7m compared with 10−4m in fresh (non-dormant) seeds of P. coarctata. Changes in the germination response of Z. palustris seeds to applied growth regulators, following partial drying or cold stratification might be explained by similar changes in hormonal status.

Germination strategies of 20 alpine species with varying seed mass and light availability

2013 ◽  
Vol 61 (5) ◽  
pp. 404 ◽  
Author(s):  
Gao-Lin Wu ◽  
Guo-Zhen Du ◽  
Zhi-Hua Shi
Keyword(s):  
Seed Germination ◽  
Light Availability ◽  
Seed Mass ◽  
Significant Negative Correlation ◽  
Germination Percentage ◽  
Central Component ◽  
Grassland Community ◽  
Germination Characteristics ◽  
Germination Strategy

Seed germination is a central component of plant life history. To investigate the proposed role of seed size on germination strategy in plant communities, a semifield experiment was conducted in alpine meadow of the Qinghai–Tibetan Plateau, China. Interspecies relationships of seed mass and seed germination characteristics were studied under semifield conditions with different light availability. Light availability and seed mass had significant effects on final germination percentage and time to germination for studied species. There was a significant negative correlation between the strength of light required for germination and seed mass. Fifteen study species (e.g. Ligularia przewalskii, Artemisia sieversiana Willd, Tripolium vulgare Ness. and Saussurea morifolia Chen) exhibited a synchronous germination strategy. Seeds from large-seeded species, such as Dracocephalum ruyschiana, Laniophlomis rotate (Benth.) and Salvia przewalskii Maxim., were less likely to require light for germination than those of small-seeded species, such as A. sieversiana Willd, Senecio diversipinnus Ling and Saussurea mongolica (Franch.). We propose that germination strategies of small-seeded species are well suited to unpredictable environmental variation in this alpine grassland community.

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