Bromus tectorum seed germination: between-population and between-year variation

1996 ◽  
Vol 74 (6) ◽  
pp. 875-882 ◽  
Author(s):  
Julie Beckstead ◽  
Susan E. Meyer ◽  
Phil S. Allen
Keyword(s):  
Seed Germination ◽  
Bromus Tectorum ◽  
Incubation Temperature ◽  
Weather Conditions ◽  
Germination Percentage ◽  
Maximum Temperature ◽  
Germination Time ◽  
Germination Response ◽  
Mean Germination Time ◽  
Contrasting Habitats

Cheatgrass (Bromus tectorum L., Poaceae), an introduced winter annual, has invaded a variety of habitats in western North America. This study examines variation in cheatgrass germination response and after-ripening patterns that are related to differences in habitat and to yearly differences in weather conditions during seed maturation. Seeds collected from five contrasting populations in 1992 and 1993 were subjected to controlled dry storage and then incubated across a range of temperatures. Recently harvested seeds were dormant and germinated slowly, while fully after-ripened seeds were nondormant and germinated rapidly. The optimal incubation temperature for mean germination time shifted from 5:15 to 20:30 °C as a result of after-ripening. Between-population differences in germination response appear to be related to the potential risk of precocious summer germination. The results from this 2-year study suggest that the more extreme yet predictable environments select for seed germination and after-ripening patterns that are genetically fixed, while populations from more favorable environments tended to show more between-year variations, suggesting more phenotypic plasticity. Germination percentage showed greater between-year variation than mean germination time. Between-year differences could not be explained simply by differences in maximum temperature or total precipitation during maturation. Adaptive germination responses in cheatgrass populations from contrasting habitats may have both genetic and environmental components, thus explaining why this species can become established in such a variety of habitats. Keywords: after-ripening, invading species, dormancy, mean germination time, cheatgrass, downy brome.

scholarly journals Can Bulk and Nanosized Titanium Dioxide Particles Improve Seed Germination Features of Wheatgrass (Agropyron desertorum)

2013 ◽  
Vol 5 (3) ◽  
pp. 325-331 ◽  
Author(s):  
Reyhaneh AZIMI ◽  
Hassan FEIZI ◽  
Mohammad KHAJEH HOSSEINI
Keyword(s):  
Seed Germination ◽  
Germination Percentage ◽  
Germination Time ◽  
Positive Effects ◽  
Tio2 Particles ◽  
Nanosized Titanium Dioxide ◽  
Mean Germination Time ◽  
Germination Value ◽  
Improve Seed Germination ◽  
Nanosized Tio2

The goal of this study was to evaluate concentrations of nanosized TiO2 at 0, 5, 20, 40, 60 and 80 mg L-1 with bulk TiO2 for possible stimulatory effects on wheatgrass seed germination and early growth stage. After 14 days of seed incubation, germination percentage improved by 9% following exposure to 5 ppm nanosized TiO2 treatment comparing to control. Similar positive effects occurred in terms of germination value and mean daily germination. Application of bulk TiO2 particles in 80 ppm concentration greatly decreased the majority of studied traits. Therefore phytotoxicity effect observed on wheatgrass seedling by application of bulk TiO2 particles in 80 ppm concentration. Exposure of wheatgrass seeds to 5 ppm nanosized TiO2 and bulk and nanosized TiO2 at 60 ppm obtained the lowest mean germination time but higher concentrations did not improve mean germination time. In general, there was a positive response by wheatgrass seed to some concentrations of nanosized TiO2. Usage of nanoparicles in order to improve germination and establishment of range plant in adverse environments similar to rangeland could be possible.

scholarly journals Sensitivity of Seed Germination to Temperature and Light in Helichrysum amorginum

2020 ◽  
Vol 77 (1) ◽  
pp. 7
Author(s):  
Sofia ARGYRIOU ◽  
Panayiota PAPASTYLIANOU ◽  
George STAVROPOULOS ◽  
Angeliki KOUSTA ◽  
Ioanna KAKABOUKI ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Survival ◽  
Germination Percentage ◽  
Effect Of Temperature ◽  
Germination Time ◽  
Randomized Design ◽  
Perennial Shrub ◽  
Mean Germination Time ◽  
Lower Temperature ◽  
Seed Propagation

Helichrysum amorginum is a perennial shrub, endemic on the Greek island of Amorgos and used for medicinal, cosmetic and ornamental purposes. Information concerning germination behavior and seedling survival is considered essential for the establishment and cultivation of wild species. The objective of this study was to investigate the effect of temperature and light on germination of Helichrysum amorginum seeds. A set of experiments was conducted under completely randomized design with four replications of 200 seeds at three different suboptimal germination temperatures (15, 20 and 25°C) in light and dark conditions for 10 days. Seed material was collected from two different fields of the island (Aegiali and Katapola). The germination performance was evaluated by final germination percentage and mean germination time. The effect of temperature on seed germination percentage and mean germination time was significant in all cases. The presence of light enhanced germination, especially at the optimum temperature of 20°C. In most cases the mean germination time increased at the lower temperature of 15°C. Seeds from Aegiali exhibited higher germination ability than the seed lot from Katapola. Knowledge of seed germination behaviour is of major importance in order to establish effective protocols for seed propagation in Helichrysum amorginum.

scholarly journals Germination Response of MR 219 Rice Variety to Different Exposure Times and Periods of 2450 MHz Microwave Frequency

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Daryush Talei ◽  
Alireza Valdiani ◽  
Mahmood Maziah ◽  
Mohammad Mohsenkhah
Keyword(s):  
Seed Germination ◽  
Root Length ◽  
Germination Rate ◽  
Rice Variety ◽  
Microwave Frequency ◽  
Germination Percentage ◽  
Rice Seed ◽  
Germination Time ◽  
Primary Shoot ◽  
Mean Germination Time

Germination is a key process in plants' phenological cycles. Accelerating this process could lead to improvment of the seedling growth as well as the cultivation efficiency. To achieve this, the effect of microwave frequency on the germination of rice seeds was examined. The physiological feedbacks of the MR 219 rice variety in terms of seed germination rate (GR), germination percentage (GP), and mean germination time (MGT) were analyzed by exposing its seeds to 2450 MHz of microwave frequency for one, four, seven, and ten hours. It was revealed that exposing the seeds to the microwave frequency for 10 hours resulted in the highest GP. This treatment led to 100% of germination after three days with a mean germination time of 2.1 days. Although the other exposure times of microwave frequency caused the moderate effects on germination with aGPa3ranged from 93% to 98%, they failed to reduce theMGTa3. The results showed that ten-hour exposure times of microwave frequency for six days significantly facilitated and improved the germination indices (primary shoot and root length). Therefore, the technique is expected to benefit the improvement of rice seed germination considering its simplicity and efficacy in increasing the germination percentage and rate as well as the primary shoot and root length without causing any environmental toxicity.

scholarly journals Seed germination and seedling growth of two Pseudobombax species (Malvaceae) with contrasting habitats from Brazilian Cerrado

2018 ◽  
pp. 1915-1925
Author(s):  
Clesnan Mendes-Rodrigues ◽  
Paulo Eugênio Oliveira ◽  
Marli Aparecida Ranal
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Underground Structure ◽  
Seedling Emergence ◽  
Dry Mass ◽  
Underground Structures ◽  
Germination Time ◽  
Central Brazil ◽  
Mean Germination Time ◽  
Contrasting Habitats

Pseudobombax tomentosum and P. longiflorum are common trees in the Cerrado region, but the former species is more common in forest edges while the later is present in open cerrado areas. This work aimed to investigate differences in seed germination and seedling growth in these species, from seed collected from Cerrado areas in Central Brazil. For this, a seed germination experiment was designed and included four replicates with 25 seeds per species; seeds were randomly distributed in the germination chamber. To evaluate initial seedling growth, seedlings height was measured up to 67 days after seedling emergence; besides, some of these seedlings were grown for biomass evaluation during nine months. Results showed that seeds of the two species had the same germinability (near 100%) and mean germination time (ca. 12 days). However, P. longiflorum showed a more spread seed germination through time, with higher values of coefficient of variation in germination time and uncertainty index; and lower values of synchronization than P. tomentosum. The two species showed basically the same growth pattern, but lower values for height of apical meristem, diameter of underground structures (mostly roots), dry mass of shoots, underground structure and total mass of seedlings in P. tomentosum were obtained, compared to P. longiflorum. Both species allocated more dry mass to underground structures in detriment of shoot. This probably allows resprouting behavior which prevents hydric stress and detrimental fire action typical of the open Cerrado areas.

scholarly journals Sugar apple (Annona squamosa L.) seed germination affected by the application of gibberellins

2016 ◽  
Vol 34 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Fabio Ernesto Martínez M. ◽  
Diego Miranda L. ◽  
Stanislav Magnitskiy
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Positive Response ◽  
Germination Rate ◽  
Germination Percentage ◽  
Annona Squamosa ◽  
Germination Time ◽  
Mean Germination Time ◽  
Germinated Seeds

This research sought to establish the response of the germination percentage (PG), synchrony index (E), mean germination time (MGT) and mean germination rate (MGR) of Annona squamosa L. seeds from Apulo (province of Cundinamarca) and Castilla (province of Tolima), Colombia, to treatments with 0, 50, 100, 200, 400, 600, or 800 mg L-1 of gibberellic acid (GA). All of the treatments with GA increased the PG at each point of time of seed incubation. The 600 mg L-1 GA treatment resulted in higher PGs (92.3% at 16 days for Apulo and 95% at 24 days for Castilla) and lower MGTs (8.75 and 5.38 days for Apulo and Castilla, respectively) than those found with the concentration of 0 mg L-1 GA (17.68 and 10.88 days for Apulo and Castilla, respectively). Also, treating the seeds with 600 mg L-1 GA generated higher MGRs (0.18 and 0.12 germinated seeds/day for Castilla and Apulo, respectively) than those obtained with 0 mg L-1 GA (Castilla = 0.09 and Apulo = 0.06 germinated seeds/ day). Likewise, the germination was synchronized with the application of any concentration of GA. The results evidenced a positive response to the GA application, which provided a tool for the characterization of the phenomenon of dormancy in the A. squamosa seeds.

scholarly journals Influence of seed size and ecological factors on the germination and emergence of field bindweed (Convolvulus arvensis)

2013 ◽  
Vol 31 (1) ◽  
pp. 39-51 ◽  
Author(s):  
A Tanveer ◽  
M Tasneem ◽  
A Khaliq ◽  
M.M Javaid ◽  
M.N Chaudhry
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Osmotic Stress ◽  
Germination Percentage ◽  
Germination Index ◽  
Convolvulus Arvensis ◽  
Germination Time ◽  
Wide Range ◽  
Field Bindweed ◽  
Mean Germination Time

An understanding of seed germination ecology of weeds can assist in predicting their potential distribution and developing effective management strategies. Influence of environmental factors and seed size on germination and seedling emergence of Convolvulus arvensis (field bindweed) was studied in laboratory and greenhouse conditions. Germination occurred over a wide range of constant temperatures, between 15 and 40 ºC, with optimum germination between 20 and 25 ºC. Time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased with an increase in temperature from 20 ºC, salinity and osmotic stress. However, germination was tolerant to low salt (25 mM) or osmotic stress (0.2 MPa), but as salinity and osmotic stress increased, germination percentage and germination index decreased. Seeds of C. arvensis placed at soil surface showed maximum emergence and decreased as seeding depth increased. Seeds of C. arvensis germinated over a wide range of pH (4 to 9) but optimum germination occurred at pH 6 to 8. Under highly alkaline and acidic pH, time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased. Increase in field capacity caused decreased time to start germination, time to 50% germination and mean germination time but increased germination percentage and germination index. Bigger seeds had low time to start germination, time to 50% germination and mean germination time but high germination percentage and germination index. Smaller seeds were more sensitive to environmental factors as compared to larger or medium seeds. It can be concluded that except for pH, all environmental factors and seed sizes adversely affect C. arvensis as regards seed germination or emergence and germination or emergence traits, and larger seeds result in improved stand establishment and faster germination than small seeds, regardless of moisture stress or deeper seeding depth.

scholarly journals Effects of drought stress on germination and seedling growth of different field pea varieties

2021 ◽  
pp. 59-70
Author(s):  
Gordana Petrovic ◽  
Tomislav Zivanovic ◽  
Radmila Stikic ◽  
Zorica Nikolic ◽  
Dusica Jovicic ◽  
...  
Keyword(s):  
Seed Germination ◽  
Osmotic Stress ◽  
Seedling Growth ◽  
Germination Percentage ◽  
Field Pea ◽  
Tolerance Index ◽  
Germination Time ◽  
Mean Germination Time ◽  
Effects Of Drought ◽  
Osmotic Potentials

Germination and seedling growth of seven genotypes of field pea (Pisum sativum L.) were studied in PEG-6000 solution having osmotic potentials -0.1 and -0.2 MPa. A study was undertaken to evaluate the influence of different osmotic potentials (MPa) on seed germination percentage (GP) and mean germination time (MGT). Results show that the percentage of germination decreased with a decrease in osmotic potential, while mean germination time increased. Variety Javor is much more sensitive than the other varieties at all levels of osmotic stress. By contrast, the lowest sensitivity of germination and MGT was found in varieties Mraz and Trezor. Seed germination tests at -0.1 to -0.2 MPa have the potential to be used as tests in field pea. Osmotic stress exposure and its duration significantly affected the growth of seedlings (shoot and root) and the accumulation of biomass, while its effect was more prominent on the growth of the shoot than on root growth, which was also confirmed by the root tolerance index.

scholarly journals Sensitivity of Seed Germination to Salt Stress in Black Cumin (Nigella sativa L.)

2018 ◽  
Vol 46 (1) ◽  
pp. 202-205 ◽  
Author(s):  
Panayiota PAPASTYLIANOU ◽  
Nikolia-Nonika BAKOGIANNI ◽  
Ilias TRAVLOS ◽  
Ioannis ROUSSIS
Keyword(s):  
Salt Stress ◽  
Seed Germination ◽  
Nigella Sativa ◽  
Germination Percentage ◽  
Oilseed Crop ◽  
Black Cumin ◽  
Germination Time ◽  
Randomized Design ◽  
Mean Germination Time ◽  
Major Factors

Black cumin is an annual oilseed crop, native to the Mediterranean region and widely used for nutritional and medicinal purposes. Reduced seed germination and early seedling growth under saline conditions are considered as major factors limiting the establishment of crops. The objective of this study was to investigate the effect of salinity due to NaCl on germination of black cumin seeds. A set of experiments was conducted under completely randomized design with four replications of 200 seeds at two different suboptimal germination temperatures (15 and 20 °C) in the dark for 16 days. In order to create salt stress conditions during the germination process, five solutions were used (0 as control, 80, 160, 240 and 320 mM NaCl). The germination performance was evaluated by final germination percentage and mean germination time. The effect of salinity on seed germination percentage and mean germination time was significant at p<0.01. Germination of the controls was 96% and 95% at 15 °C and 20 °C, respectively. The presence of NaCl, regardless of temperature, reduced germination. This reduction was more severe at 15 °C (15%, and 19% germination in cases of 80 and 160 mM concentration respectively) than at 20 °C (65% at 80 mM salinity level) and no germination was observed from 240 mM onwards. The mean germination time increased with increased NaCl levels, especially at the lower temperature of 15 °C. The overall results of this experiment showed the inhibitory effects of salt stress on seed germination parameters of black cumin.

A hydrothermal time model of seed after-ripening in Bromus tectorum L.

1996 ◽  
Vol 6 (4) ◽  
pp. 155-164 ◽  
Author(s):  
Maren Christensen ◽  
Susan E. Meyer ◽  
Phil S. Allen
Keyword(s):  
Seed Germination ◽  
Water Potential ◽  
Time Course ◽  
Bromus Tectorum ◽  
Incubation Temperature ◽  
Hydrothermal Time ◽  
Germination Time ◽  
Water Potentials ◽  
Incubation Temperatures ◽  
Base Water Potential

AbstractBromus tectorum L. is an invasive winter annual grass with seeds that lose dormancy through the process of dry after-ripening. This paper proposes a model for after-ripening of B. tectorum seeds based on the concept of hydrothermal time. Seed germination time course curves are modelled using five parameters: a hydrothermal time constant, the fraction of viable seeds in the population, base temperature, mean base water potential and the standard deviation of base water potentials in the population. It is considered that only mean base water potential varies as a function of storage duration and incubation temperature following after-ripening. All other parameters are held constant throughout after-ripening and at all incubation temperatures. Data for model development are from seed germination studies carried out at four water potentials (0, −0.5, −1.0 and −1.5 MPa) at each of two constant incubation temperatures (15 and 25°C) following different storage intervals including recently harvested, partially after-ripened (stored for 4, 9 or 16 weeks at 20°C) and fully after-ripened (stored for 14 weeks at 40°C). The model was fitted using a repeated probit regression method, and for the two seed populations studied gave R2 values of 0.898 and 0.829. Germination time course curves predicted by the model generally had a good fit when compared with observed curves at the incubation temperature/water potential treatment combinations for different after-ripening intervals. Changes in germination time course curves during after-ripening of B. tectorum can largely be explained by decreases in the mean base water potential. The simplicity and good fit of the model give it considerable potential for extension to simulation of after-ripening under field conditions.

scholarly journals Southern highland papaya (Vasconcellea quercifolia A. St.-Hil.): Do fruit ripening and harvesting time affect seed germination?

2019 ◽  
Vol 42 ◽  
pp. e42825 ◽  
Author(s):  
María Manuela Urtasun ◽  
Eugenia Mabel Giamminola ◽  
Marta Leonor de Viana
Keyword(s):  
Seed Germination ◽  
Fruit Ripening ◽  
Storage Period ◽  
Seed Storage ◽  
Potassium Nitrate ◽  
Germination Percentage ◽  
Harvesting Time ◽  
Germination Time ◽  
Light Requirements ◽  
Mean Germination Time

In this work, we report the effects of the harvesting time, the stages in fruit ripening and the influence of potassium nitrate in V. quercifolia seed germination. In addition, information about the storage period and light requirements is provided. Fruits were harvested at the beginning and at the end of the fruiting season, and they were classified into five ripening categories. Seed germination was evaluated with two factorial experiments: 1) harvesting time, fruit ripening, and pre-germination treatment; 2) storage and light requirements. The response variables were germination percentage, mean germination time, and seedling vigor. Seeds harvested at the beginning of the season appeared to be less dormant and they were not influenced by fruit ripening or pre-germination treatments. By contrast, seeds harvested at the end of the season were influenced by fruit ripening and pre-germination treatments. Light and seed storage had a positive effect on germination. Mean germination time varied from 12 to 40 days, and vigor index was positively influenced by potassium nitrate. V.quercifolia seeds are photoblastic positive at constant temperatures and their dormancy can be influenced by harvest time, fruit ripening and a storage period.

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