scholarly journals Ecology of Musk Thistle (Carduus nutans) Seed Germination for Grasslands of Temperate Climates

Weed Science ◽  
2013 ◽  
Vol 61 (4) ◽  
pp. 549-556 ◽  
Author(s):  
Chengchou Han ◽  
Stephen L. Young
Keyword(s):  
Seed Germination ◽  
Perennial Grass ◽  
Management Strategies ◽  
Temperate Grasslands ◽  
Invasive Weed ◽  
Light Levels ◽  
Temperature Regimes ◽  
Alternating Temperature ◽  
Reduced Light ◽  
Temperate Climates

Musk thistle is an invasive weed that is widely distributed throughout much of North America, including grasslands in temperate climates of the midwest USA. A series of laboratory and greenhouse experiments were conducted to determine the effect of various environmental factors on germination of musk thistle seeds. In temperature-fluctuation experiments, seed germination was greater than 65% in both alternating (30/20 C) and constant (20 or 25 C) temperature regimes with an 8-h day but less (33%) in warmer regimes (35/20 C). Germination of musk thistle seeds was 37% in alternating temperature regimes of 30/20 C in total darkness, but less than 67% in pots in the greenhouse. Differences of 10 and 15 C between day and night temperatures resulted in 91 and 75% maximum germination of musk thistle, respectively. Increasingly dryer soils reduced germination of musk thistle seeds from 35% (−0.03 MPa) to 0% (−1.2 MPa), whereas saline soils (> 80 mM) reduced maximum germination to less than 10%. Musk thistle seeds collected from populations in a bare-ground area had 96% germination, which was greater than that of seeds collected from populations growing in a perennial grass pasture (71%). A residence time (i.e., period that seeds remained on the parent plant) of 9 to 12 wk after capitulum maturity resulted in seeds germinating more quickly than those dispersed earlier. Overall, reduced light levels, cool and fluctuating temperatures, and amount of time seeds remained in residence are some of the most important factors that contribute to germination of musk thistle seeds. Information on germination dynamics of musk thistle seeds provides an understanding of the interactions that affect this process and underscores the importance of timely management strategies in temperate grasslands.

Comparison of germination responses of cultivated wheat ( Triticum ) and its wild relative ( Aegilops ) species under salinity, temperature and light

2007 ◽  
Vol 55 (4) ◽  
pp. 407-415 ◽  
Author(s):  
M. Yildiz ◽  
E. Kasap
Keyword(s):  
Seed Germination ◽  
Inhibitory Effect ◽  
Wild Relative ◽  
Wheat Cultivars ◽  
Wheat Species ◽  
Wild Wheat ◽  
Light Levels ◽  
Temperature Regimes ◽  
Salinity Levels ◽  
Alternating Temperature

The seed germination of bread ( Triticum aestivum cv. Bezostaya 1 and Ceyhan 99) and durum ( Triticum durum cv. Diyarbakır 81 and Fırat 93) wheat species and their wild relative species ( Aegilops biuncialis and Ae. triuncialis ) was compared at two light levels, nine NaCl concentrations and three alternating temperature regimes. No seeds germinated at 675 mmol/L NaCl. The highest seed germination (100%) of cultivated wheat cultivars was noted in the control at 15/25°C and 20/30°C, and that of wild wheat species in both the control and the 150 mmol/L NaCl treatment under all temperature regimes. The seed germination of bread and durum wheat cultivars was completely inhibited at or above 450 and 375 mmol/L NaCl, respectively. No Ae. biuncialis seeds germinated at 600 mmol/L NaCl, while seeds of Ae. triuncialis germinated at this concentration (38.9%) only at 20/30°C in darkness. The inhibitory effect of light on germination in all genotypes was determined in some salinity levels at 15/25°C. The optimal germination treatment for all genotypes was 15/25°C temperature regime and darkness. The inhibitory effect of high salinity on germination was greater at 25/35°C than at 15/25°C or 20/30°C. In salinity and temperature interactions, the seeds of wild wheat species were found to be more tolerant than those of wheat cultivars.

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

2018 ◽  
Vol 36 (0) ◽  
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.

scholarly journals Seed Germination and Seedling Growth of the Endangered Azorean Cherry Prunus azorica

HortScience ◽  
2012 ◽  
Vol 47 (9) ◽  
pp. 1222-1227 ◽  
Author(s):  
Orlanda Cristina Barros Moreira ◽  
José Martins ◽  
Luís Silva ◽  
Mónica Moura
Keyword(s):  
Seed Germination ◽  
Growth Regulator ◽  
Incubation Temperature ◽  
Seed Morphology ◽  
Laurel Forest ◽  
Life Project ◽  
Temperature Regimes ◽  
Physiological Dormancy ◽  
Priority Species ◽  
Alternating Temperature

Prunus azorica is an Azorean endemic tree considered as a priority species for conservation. It is important as a laurel forest component, particularly at medium altitude, and as a food source for the endangered bird Pyrrhula murina. The best conditions for seed germination were investigated after removal of the outer layers of the fruit by determining the effect of 1) using stones or seeds; 2) stratification regime (six treatments and a control); 3) incubation temperature (four alternating temperature regimes); and 4) gibberellic acid concentration (three levels). This resulted in a fully factorial design with 168 (2 × 7 × 4 × 3) treatments with three replicates per treatment and 25 seeds per replicate. Cumulative germination percentages were determined at the end of the trial. Globally, there was a significant effect of endocarp removal (49% germination with seeds and 15% with stones). Both for stones and seeds, there was a significant effect of incubation temperature, stratification regime, and growth regulator concentration. Stones attained a maximum germination of ≈80% under several stratification treatments including cold (4 °C) or warm (20 °C) followed by cold and at 10/5 °C without the addition of a growth regulator. Seeds attained a maximum germination of greater than 90% without stratification at 10/5 or 15/10 °C without the addition of a growth regulator. During the stratification process, germination occurred only for seeds, particularly for longer treatments, for example, those corresponding to 3 or more months of stratification, including warm followed by cold (75% to 80%) or cold alone (77%). According to seed morphology and germination results, the seed appears to have a non-deep physiological dormancy. Seeds of P. azorica can thus be efficiently germinated after endocarp removal at temperatures of 10/5 or 15/10 °C with a daily light period of 12 hours. This protocol allowed producing hundreds of viable seedlings that were used in the reforestation of a laurel forest stand in a LIFE project.

Environmental factors affect seed germination and seedling emergence of invasive Centaurea balsamita

2017 ◽  
Vol 68 (6) ◽  
pp. 583 ◽  
Author(s):  
Iraj Nosratti ◽  
Samira Soltanabadi ◽  
Saeid J. Honarmand ◽  
Bhagirath S. Chauhan
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Osmotic Potential ◽  
Seedling Emergence ◽  
Potassium Nitrate ◽  
Weed Species ◽  
Invasive Weed ◽  
Western Iran ◽  
Temperature Regimes ◽  
Wide Range

Centaurea balsamita is a problematic and invasive weed of agricultural fields in western Iran. This study was conducted to determine the effect of different environmental factors on germination and seedling emergence of this weed species. Results revealed that seed germination occurred over a wide range of temperatures (from 5°C to 35°C) with the highest germination at 25°C. Seed germination of C. balsamita was similar between light and dark conditions. Germination decreased with increased in water stress levels, but some seeds were capable of germinating at –1.4 MPa osmotic potential. Seed germination was sensitive to salt stress and complete inhibition occurred at 150 mM sodium chloride. Seed germination of C. balsamita occurred over a pH range of 4–10 with lowest seed germination at pH 4. Seed germination was inhibited by increasing concentrations of potassium nitrate. No seedlings emerged when seeds were buried in the soil at depths greater than 6 cm, suggesting that using a sweep cultivator in crops and deep tillage would be beneficial in managing C. balsamita. The ability of C. balsamita to germinate under a wide range of temperature regimes and high levels of osmotic potential shows that this weed is well adapted to invade other cropping regions, especially rain-fed fields in western Iran.

Germination, emergence, and growth of giant foxtail (Setaria faberi) and fall panicum (Panicum dichotomiflorum)

Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 423-425 ◽  
Author(s):  
Jason C. Fausey ◽  
Karen A. Renner
Keyword(s):  
Seed Germination ◽  
Temperature Regime ◽  
Weed Management ◽  
Management Strategies ◽  
Effect Of Temperature ◽  
Setaria Faberi ◽  
Giant Foxtail ◽  
The Hours ◽  
Alternating Temperature ◽  
H 20

Controlled environment experiments were completed to determine the effect of temperature on giant foxtail and fall panicum germination, emergence, and growth. Giant foxtail seed germination decreased when exposed to a constant 30 C compared to 20 C. Germination also decreased in the alternating 20/30 C temperature regime when the hours of exposure to 30 C as compared to 20 C increased. Fall panicum required alternating temperatures of 14 C (9 h)/28 C (15 h) to germinate. Giant foxtail seed germination exceeded 60% 4 d after exposure to an alternating temperature of 7 C (9.4 h)/20 C (14.6 h). Conversely, fall panicum seed did not germinate at the 7 C (9.4 h)/20 C (14.6 h) temperature regime and required a minimum of 7 d exposure to alternating temperatures of 13 C (8.7 h)/26 C (15.3 h) for 88% of the seed to germinate. The greatest emergence of giant foxtail and fall panicum was from 1 cm and 1 to 2.5 cm, respectively. Less than 5% of the giant foxtail and fall panicum seed emerged from 7.5 cm. The growth of giant foxtail seedlings was five times greater than that of fall panicum at each temperature regime tested. Incorporation of this information into bioeconomic models could result in accurate predictions of weed germination for effective weed management strategies.

Temperature effects on jointed goatgrass (Aegilops cylindrica) seed germination

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 594-599 ◽  
Author(s):  
Lynn Fandrich ◽  
Carol Mallory-Smith
Keyword(s):  
Seed Germination ◽  
Winter Wheat ◽  
Weed Management ◽  
Management Strategies ◽  
Wheat Variety ◽  
Wheat Seed ◽  
Aegilops Cylindrica ◽  
Jointed Goatgrass ◽  
Temperature Regimes ◽  
Radicle Protrusion

A better understanding of the persistence of jointed goatgrass seed in soil and its dormancy will lead to the development of more effective weed-management strategies. Three populations of jointed goatgrass were collected from winter wheat fields in Oregon, and grown together with the winter wheat variety ‘Madsen’ in nurseries at Moro and Pendleton, OR. Germination responses of jointed goatgrass and wheat seed were recorded over 14 d at 5/5, 15/10, 15/15, 25/15, 25/25, and 30/20 C day/night temperatures and a 12-h photoperiod. Because jointed goatgrass spikelets often contain two seed, primary and secondary seed germination values were recorded. Secondary seed germination was defined as 3-mm radicle protrusion, and primary seed germination was defined as 5-mm emergence of the second coleoptile. Jointed goatgrass secondary seed germinated when exposed to all temperature regimes. Jointed goatgrass secondary seed germination occurred 3 d earlier in temperature regimes involving 15 C compared to germination at 5/5, 25/25, and 30/20 C. Final germination values for jointed goatgrass secondary seed were greatest when seed were incubated at 25/15 C. Wheat seed germinated at all temperature regimes, although the onset of germination occurred 1 to 1.5 d later at 5/5 C compared to other temperature regimes. Jointed goatgrass primary seed germinated only at 15/10, 15/15, and 25/15 C, and maximum germination occurred at 25/15 C. Dormancy in jointed goatgrass might prevent germination of seed within freshly shattered spikelets until autumn when temperatures are low and moisture is available. Because final germination percentages in jointed goatgrass primary and secondary seed were less than 100%, additional research on factors regulating dormancy is needed.

Can alternating temperature, moist chilling, and gibberellin interchangeably promote the completion of germination in Clematis vitalba seeds?

Botany ◽  
2017 ◽  
Vol 95 (8) ◽  
pp. 847-852 ◽  
Author(s):  
Rosangela Picciau ◽  
Marco Porceddu ◽  
Gianluigi Bacchetta
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Plant Species ◽  
Temperature Regime ◽  
Fluctuating Temperature ◽  
Temperature Regimes ◽  
Moist Chilling ◽  
Clematis Vitalba ◽  
Alternating Temperature ◽  
Positive Effect

Each plant species has particular requirements for seed germination, and some of them respond differently to constant or alternating temperature regimes. In this study, the interchangeable effects of different treatments and temperatures on the completion of seed germination of Clematis vitalba L. were investigated. The seeds were tested with a constant (from 5 °C to 25 °C) or a fluctuating (25/10 °C) temperature regime, and the effect of gibberellic acid (GA3), incubation at warm (W) or cold (C) temperatures while being imbibed, and drying after ripening (DAR) were evaluated. The final germination percentages and the time in days required to reach 50% of germination (T50) were calculated. GA3 and C significantly enhanced completion of seed germination at all of the temperatures tested. A strong positive effect of alternating temperature was observed, which triggered completion of seed germination regardless of treatment. Under the fluctuating temperature, the chilled seeds had the most rapid germination. Low germination rates were observed for both control and DAR treatments. Seeds of C. vitalba display a certain degree of dormancy, which can be broken by moist chilling and GA3 treatments. Moreover, alternating temperature stimulates the completion of seed germination by satisfying certain physiological requirements for germination under constant temperatures.

scholarly journals Seed dormancy and germination characteristics of Acer cinnamomifolium, a plant species endemic to China

2021 ◽  
Author(s):  
Cui-Fang Tang ◽  
Yu-Chen Zhao ◽  
Lin-Feng Ou ◽  
Cai-Hong Zhong ◽  
Song-Quan Song
Keyword(s):  
Seed Germination ◽  
Plant Species ◽  
Seed Dormancy ◽  
Environmental Changes ◽  
Effect Of Temperature ◽  
Cold Stratification ◽  
Dormancy Release ◽  
Temperature Regimes ◽  
Germination Characteristics ◽  
Alternating Temperature

Seed dormancy is an adaptive response of plants to environmental changes during long-term evolution. It plays an important role in plant survival and propagation. Acer cinnamomifolium, a plant species endemic to China, is an excellent garden and street tree species. However, dormancy and germination characteristics of A. cinnamomifolium seeds are not currently known. In the present paper, the mature seeds were used as experimental materials and we investigated the effect of temperature including alternating temperature, light, after-ripening, stratification and phytohormone on seed dormancy release and germination. After being incubated for 30 days, 0 to 10% of the seeds germinated in constant temperature (10, 15, 20, 25 and 30°C), while in alternating temperature regimes (20/10, 25/15 and 30/20°C), seed germination was < 35%. Dormancy release and germination of seeds can be increased by after-ripening, cold stratification and phytohormone treatments. We concluded that A. cinnamomifolium seeds have a non-deep physiological dormancy. Cold stratification at 4°C for 30 days and incubation thereafter at 20°C were found to be optimal for dormancy release and high seed germination.

Effects of temperature and burial on seed germination and persistence of the restricted invasive Stevia ovata in northern Queensland

2018 ◽  
Vol 66 (5) ◽  
pp. 388
Author(s):  
Faiz F. Bebawi ◽  
Shane D. Campbell ◽  
Robert J. Mayer ◽  
Melissa J. Setter ◽  
Stephen D. Setter
Keyword(s):  
Seed Germination ◽  
Seed Viability ◽  
Seed Longevity ◽  
Burial Depth ◽  
Invasive Weed ◽  
Soil Seed Banks ◽  
Temperature Regimes ◽  
Wide Range ◽  
Wet Tropics ◽  
Rate Of Decline

Stevia ovata Willd. is an invasive weed that has become naturalised in northern Queensland, Australia. To aid management of current infestations, this study evaluated seed germination under a range of constant (13−48°C) and alternating (11/7 to 52/42°C) temperature regimes and quantified the potential longevity of soil seed banks. The effect of different soil types, levels of pasture cover and burial depths on seed longevity was investigated in both the dry- and wet-tropics of North Queensland. Germination of S. ovata occurred under a wide range of both constant (13−39°C) and alternating day/night temperatures (16/12 to 52/42°C), but optimum conditions ranged between 24 and 27°C and 24/20 and 37/31°C respectively. As temperatures declined below the optimum, an increasing proportion of seeds went into a state of enforced dormancy. In contrast, higher than optimum temperatures caused a proportion of seeds to lose viability. Differential responses in seed longevity of S. ovata occurred between the two experimental sites. In the wet-tropics, seed viability was <1% after 12 months and fully expired after 18 months, irrespective of burial depth. In the dry-tropics, seeds persisted for longer (nil viability after 24–42 months) and burial depth had a significant effect. Surface located seeds tended to exhibit a faster rate of decline in viability than seeds buried below ground. These findings have implications for the duration of control/eradication programs and also suggest that S. ovata has the potential to greatly expand its current distribution, particularly into cooler areas of Australia.

scholarly journals Effects of Salinity, Temperature, and Polyethylene Glycol on the Seed Germination of Sunflower (Helianthus annuusL.)

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Zhihui Luan ◽  
Moxin Xiao ◽  
Daowei Zhou ◽  
Hongxiang Zhang ◽  
Yu Tian ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Seed Germination ◽  
Adverse Effects ◽  
Helianthus Annuus ◽  
Salt Tolerant ◽  
Osmotic Effect ◽  
Temperature Regimes ◽  
Salt Tolerant Cultivars ◽  
Alternating Temperature ◽  
Peg Stress

Salinization has severe influences on agriculture in the whole world. The main aims of this work were to evaluate osmotic effect and ion effect of NaCl on seed germination of three sunflower (Helianthus annuusL.) cultivars interacting with three alternating temperature regimes and to select the most salt tolerant cultivars to plant in the saline region. Seeds were germinated in the isotonic NaCl and polyethylene glycol (PEG) solutions of −0.45, −0.90, −1.34, −1.79, and −2.24 MPa at 10 : 20, 15 : 25, and 20 : 30°C temperature regimes. Both NaCl and PEG inhibited germination, but the effects of NaCl were less as compared to that of PEG, which means that adverse effects of PEG on germination were due to osmotic effect rather than specific ion accumulation. For the three cultivars, higher germination occurred at 10 : 20°C in NaCl treatments and at 20 : 30°C in the isotonic PEG treatments. Among the three cultivars, Sandaomei (SDM) is the most tolerant to salt and PEG stress.

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