Soaking, Temperature, and Seed Placement Affect Seed Germination and Seedling Emergence of Litchi chinensis

To find efficient ways to increase the percentage of seed germination and seedling emergence in litchi (Litchi chinensis Sonn.), we investigated the effects of soaking and high temperature on seed germination, as well as the influence of seed placement (orientation and burial depth) on seedling emergence. Seeds of most tested litchi cultivars soaked in water had a better germination performance than seeds without soaking. More than 90% germination of tested litchi seeds was obtained when the soaking times were 26–54 hours. During presprouting, short-term high temperatures (37–44 °C) exerted a negative effect on seed germination rate, but did not influence the germination percentage. In addition, high temperatures (>42 °C) compromised the further growth of sprouted litchi seeds. Burial depth and seed orientation both significantly influenced the seedling recruitment. There was a reduction in seedling emergence with an increase in burial depth. Seeds at the depth of 2 cm showed the best seedling emergence with an average percentage of 90%. Litchi seedling emergence was greatest and most rapid when seeds were sown 2 cm deep, positioned flat, on their sides, and with the radicle oriented downward.

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Effect of Environmental Factors on the Germination and Emergence of Drunken Horse Grass (Achnatherum inebrians)

Weed Science ◽

10.1017/wsc.2020.81 ◽

2020 ◽

pp. 1-29

Author(s):

Yonghuan Yue ◽

Guili Jin ◽

Weihua Lu ◽

Ke Gong ◽

Wanqiang Han ◽

...

Keyword(s):

Seed Germination ◽

Environmental Factors ◽

Abiotic Factors ◽

Seedling Emergence ◽

Management Strategies ◽

Germination Percentage ◽

Western China ◽

Burial Depth ◽

Achnatherum Inebrians ◽

Water Ph

Abstract Drunken horse grass [Achnatherum inebrians (Hance) Keng] is a perennial poisonous weed in western China. A comprehensive understanding of the ecological response of A. inebrians germination to environmental factors would facilitate the formulation of better management strategies for this weed. Experiments were conducted under laboratory conditions to assess the effects of various abiotic factors, including temperature, light, water, pH and burial depth, on the seed germination and seedling emergence of A. inebrians. The seeds germinated at constant temperatures of 15, 20, 25, 30, 35°C and in alternating-temperature regimes of 15/5, 20/10, 25/15, 30/20, 35/25, 40/30°C, and the seed germination percentages under constant and alternating temperatures ranged from 51% to 94% and 15% to 93%, respectively. Maximum germination occurred at a constant temperature of 25°C, and germination was prevented at 45/35°C. Light did not appear to affect seed germination. The germination percentage of seeds was more than 75% in the pH range of 5 to 10, with the highest germination percentage at pH 6. The seeds germinated at osmotic potentials of 0 MPa to -1.0 MPa, but decreasing osmotic potential inhibited germination, with no germination at -1.2MPa. After 21 d of low osmotic stress, the seeds that did not germinate after rehydration had not lost their vitality. The seedling emergence percentage was highest (90%) when seeds were buried at 1 cm but declined with increasing burial depth and no emergence at 9 cm. Deep tillage may be effective in limiting the seed germination and emergence of this species. The results of this study provide useful information on the conditions necessary for A. inebrians germination and provide a theoretical basis for science-based prediction, prevention and control of this species.

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Effect of Environmental Factors on Germination and Emergence of Shortawn Foxtail (Alopecurus aequalis)

Weed Science ◽

10.1017/wsc.2017.42 ◽

2017 ◽

Vol 66 (1) ◽

pp. 47-56 ◽

Cited By ~ 12

Author(s):

Ning Zhao ◽

Qi Li ◽

Wenlei Guo ◽

Lele Zhang ◽

Lu’an Ge ◽

...

Keyword(s):

Seed Germination ◽

Osmotic Potential ◽

Control Strategies ◽

Abiotic Factors ◽

Germination Rate ◽

Seedling Emergence ◽

Soil Surface ◽

Burial Depth ◽

Effective Measure ◽

Wide Range

Shortawn foxtail is an invasive grass weed infesting winter wheat and canola production in China. A better understanding of the germination ecology of shortawn foxtail would help to develop better control strategies for this weed. Experiments were conducted under laboratory conditions to evaluate the effects of various abiotic factors, including temperature, light, pH, osmotic stress, salt concentration, and planting depth, on seed germination and seedling emergence of shortawn foxtail. The results showed that the seed germination rate was greater than 90% over a wide range of constant (5 to 25C) and alternating (15/5 to 35/25C) temperatures. Maximum germination occurred at 20C or 25/15C, and no germination occurred at 35C. Light did not appear to have any effect on seed germination. Shortawn foxtail germination was 27% to 99% over a pH range of 4 to 10, and higher germination was obtained at alkaline pH values ranging from 7 to 10. Seed germination was sensitive to osmotic potential and completely inhibited at an osmotic potential of −0.6 MPa, but it was tolerant to salinity: germination even occurred at 200 mM NaCl (5%). Seedling emergence was highest (98%) when seeds were placed on the soil surface but declined with the increasing burial depth. No seedlings emerged when seeds were buried 6-cm deep. Deep tillage could be an effective measure to limit seed germination from increased burial depth. The results of this study will lead to a better understanding of the requirements for shortawn foxtail germination and emergence and will provide information that could contribute to its control.

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Seed germination at different temperatures and seedling emergence at different depths of Rhamnus spp

Open Life Sciences ◽

10.2478/s11535-014-0291-4 ◽

2014 ◽

Vol 9 (5) ◽

pp. 569-578 ◽

Cited By ~ 1

Author(s):

Hanan Aou-ouad ◽

Hipólito Medrano ◽

Ahmed Lamarti ◽

Javier Gulías

Keyword(s):

Seed Germination ◽

Seedling Recruitment ◽

Seedling Emergence ◽

Burial Depth ◽

Temperature Regimes ◽

Mediterranean Shrubs ◽

Different Temperatures ◽

Temperature Ranges ◽

Different Depths ◽

Rhamnus Alaternus

AbstractRhamnus alaternus and R. ludovici-salvatoris, two Mediterranean shrubs with different geographic distributions, have shown important differences in seedling recruitment capacity. The objectives of this work were to determine the ability of these species to germinate seeds under different temperature ranges, as well as the capacity of seedlings to emerge from different burial depths, in order to better understand their regeneration processes. Two different experiments were performed. In the first one, seed germination was studied in Petri dishes and in the dark at different temperature regimes: a) 5–15°C, b) 10–20°C and c) 15–25°C (12h/12h). In the second experiment, seedling emergence capacity from different burial depths (0.5, 2 and 5 cm) was tested. R. ludovici-salvatoris showed a significantly higher final germination rates, a lower dormancy period, and average time response at 10–20°C than at other temperature ranges, although differences were much greater when seeds were subjected to the 5–15°C temperature regime. By contrast, R. alaternus did not show significant differences between treatments (5–15°C and 10–20°C) in germination behavior. Seedling emergence of both species was lower and slower when seeds were buried at 5 cm. However, R. ludovici-salvatoris always showed a lower seedling emergence capacity than R. alaternus at any burial depth. The low ability of R. ludovici-salvatoris to germinate seeds and emerge between 5–15°C, even from shallow depths, is discussed in relation to its low regeneration capacity and declining geographic distribution.

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Influence of Winter Seed Position and Recovery Date on Hairy Nightshade (Solanum sarrachoides) Recruitment and Seed Germination, Dormancy, and Mortality

Weed Science ◽

10.1614/ws-06-051.1 ◽

2007 ◽

Vol 55 (1) ◽

pp. 49-59 ◽

Cited By ~ 6

Author(s):

R. Edward Peachey ◽

Carol Mallory-Smith

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Weed Management ◽

Seedling Recruitment ◽

Germination Rate ◽

Burial Depth ◽

Undisturbed Soil ◽

Linear Temperature ◽

Hairy Nightshade ◽

Seed Position

Understanding the factors regulating recruitment in diverse tillage systems will improve the efficacy of weed-management strategies. Experiments measured the effect of hairy nightshade winter seed position (burial depth) on seedling recruitment and seed germination, dormancy, and mortality. Hairy nightshade seeds were placed in soil tubes at 1 cm below the soil line and buried in the fall so that seeds were positioned in the soil at 1, 6, 13, and 25 cm below the soil surface. Tubes with undisturbed soil and seeds were removed from the field in March, April, and May of 2004 and 2005 and placed in wells in a heated, aluminum block with a linear temperature gradient from 22.7 to 36.0 C at 2.7 C intervals, and recruitment was measured. Seeds were also recovered from the soil tubes to determine effects of seed position on germination rate, mortality, and seed dormancy. Hairy nightshade seedling recruitment was greater for seeds positioned at 6, 13, and 25 cm during the winter than at 1 cm. Seed dormancy and mortality were greatest for seeds positioned at 1 cm, but that did not adequately account for the significant decrease in recruitment at 1 cm compared to seeds buried at 6, 13, or 25 cm. Protecting the seeds buried at 1 cm from rainfall during the winter increased seedling recruitment from 0 to 20% of buried seeds but had a negligible effect on seed mortality and dormancy. Soil density was negatively correlated with recruitment.

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Solution pH and Papaya Seed Germination and Seedling Emergence

HortScience ◽

10.21273/hortsci.32.3.486e ◽

1997 ◽

Vol 32 (3) ◽

pp. 486E-486

Author(s):

Robin A. DeMeo ◽

Thomas E. Marler

Keyword(s):

Seed Germination ◽

Germination Rate ◽

Seedling Emergence ◽

Germination Percentage ◽

Growth Chamber ◽

Sand Culture ◽

Solution Ph ◽

Wide Range ◽

Substrate Ph ◽

Papaya Seed

Two studies were conducted to determine the influence of pH on papaya seed germination and seedling emergence. The germination test was conducted with `Waimanalo' and `Tainung 1' seeds, using a double layer of filter paper disks in plastic petri dishes placed within a growth chamber. Each dish received 40 seeds, and germination was defined as when the radicle was visible. Disks were wetted daily with nutrient solution adjusted to pH of 3, 4, 5, 6, 7, 8, or 9. Germination began on day 5, and the study was terminated on day 23. Solution pH did not influence germination rate or ultimate germination percentage. `Waimanalo' exhibited 58% germination and `Tainung 1' exhibited 64% germination in this test. The seedling emergence study was conducted with `Waimanalo' seeds using sand culture within a growth chamber. Thirty seeds were planted in 10-cm containers, and the sand was irrigated daily with the solutions from the first study. Emergence was defined as when the hypocotyl hook was visible above the sand. Emergence began on day 10, and the study was terminated on day 30. Solution pH did not influence seedling emergence, and mean emergence was 69% in this study. The results indicate that the seed germination and seedling emergence stages of papaya seedling growth are adapted to a wide range of substrate pH.

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Factors effecting the germination and emergence of a rangeland weed; European heliotrope (Heliotropium europaeum L.)

The Rangeland Journal ◽

10.1071/rj18048 ◽

2018 ◽

Vol 40 (6) ◽

pp. 583

Author(s):

Talia Humphries ◽

Friedrich F. Graz ◽

Singarayer K. Florentine

Keyword(s):

Heat Shock ◽

Seed Germination ◽

Osmotic Stress ◽

Germination Rate ◽

Seedling Emergence ◽

Control Treatment ◽

Research Station ◽

Burial Depth ◽

South Wales ◽

Heliotropium Europaeum

European heliotrope (Heliotropium europaeum L.) is an important weed in semiarid and arid Australia, due to its toxicity to livestock and its ability to out-compete crops for water and soil nutrients. It is an ephemeral species; populations appear in high densities when conditions are favourable, but seeds remain dormant in the soil seedbank for extended periods of time. This study aimed to identify environmental factors that promoted the germination of this weed and factors that de-vitalise seeds. Seeds were collected from the Australian semiarid zone, at Nanya Research Station, New South Wales. The effects on seed germination and seedling emergence of H. europaeum of alternating temperature, photoperiod, drought, salinity, pH range, heat shock combined with smoke exposure, and burial depth were investigated. The highest germination rate was observed under the highest temperature regime, 30/20°C, under a photoperiod of 12h light and 12h dark. The weed germinated under moderate osmotic stress, but the highest germination occurred in the control treatment (no osmotic stress). The effect of salinity and pH on percentage germination was not significant. The effect of the heat shock and smoke treatment significantly reduced seed germination, with germination inhibited when seeds were exposed to 100°C for 3min. Burial depth had a significant effect on seedling emergence, with a burial depth of 0.5cm reducing the germination by ~20%. It is recommended that further research into using fire and tillage interventions for H. europaeum be explored, as these may be used to reduce the viable seedbank of this weed, allowing long-term control to be achieved.

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Germination Ecology of Brachiaria eruciformis in Australia and Its Implications for Weed Management

Agronomy ◽

10.3390/agronomy10010030 ◽

2019 ◽

Vol 10 (1) ◽

pp. 30

Author(s):

Ahmadreza Mobli ◽

Mahboobeh Mollaee ◽

Sudheesh Manalil ◽

Bhagirath Singh Chauhan

Keyword(s):

Sodium Chloride ◽

Seed Germination ◽

Weed Management ◽

Cropping Systems ◽

Germination Rate ◽

Seedling Emergence ◽

Soil Surface ◽

Burial Depth ◽

The World ◽

Noxious Weed

Brachiaria eruciformis (Sm.) Griseb. is a noxious weed of Australia and other parts of the world. The effects of different environmental conditions on the seed germination and seedling emergence of three biotypes sourced from different cropping systems (mungbean field, sorghum field, and fenceline) of this weed were evaluated. There were no differences in the response of biotypes to the evaluated factors; therefore, the data was pooled across the biotypes. The highest germination rate was observed at 30/20 °C, and seeds germinated both in light and dark conditions. Seed germination was influenced by different sodium chloride (NaCl) concentrations and water potentials, and no seeds germinated at 200 mM NaCl and −0.8 MPa water potential. Seeds germinated (>70%) at a broad range of pH, from 4 to 10. Compared with seeds sown on the soil surface, a burial depth of 4 cm reduced the seedling emergence by 84%. Similarly, a sorghum residue amount of 4 t ha−1 on the soil surface reduced the seedling emergence by 65%, compared with no sorghum residue cover. No seedlings emerged from seeds buried at 8 cm depth and >4 t ha−1 sorghum residue. This study suggests that burying seeds deep into the soil through tillage or employing a residue cover on the soil surface can reduce B. eruciformis emergence.

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Evaluation of Lettuce Genotypes for Seed Thermotolerance

HortScience ◽

10.21273/hortsci.48.6.708 ◽

2013 ◽

Vol 48 (6) ◽

pp. 708-714 ◽

Cited By ~ 6

Author(s):

Abbas Lafta ◽

Beiquan Mou

Keyword(s):

Seed Germination ◽

High Temperatures ◽

Seedling Emergence ◽

Seed Priming ◽

High Temperature Stress ◽

Germination Percentage ◽

Production Costs ◽

Land Cost ◽

Red Giant ◽

Germplasm Accessions

Thermoinhibition of lettuce (Lactuca sativa L.) seed germination is a common problem associated with lettuce production. Depending on lettuce cultivars, seed germination may be inhibited when temperatures exceed 28 °C. The delay or inhibition of seed germination at high temperatures may reduce seedling emergence and stand establishment of lettuce in the field, leading to a reduction in economic yield. To identify heat-tolerant lettuce genotypes, lettuce varieties and germplasm accessions were screened for the ability to germinate under high-temperature stress. Twenty-four to 26 genotypes were selected from each lettuce types (crisphead, romaine, butterhead, loose leaf, and wild species) and their seeds were placed in petri dishes to test their ability to germinate at high temperatures (29 and 34 °C) as compared with controls at 24 °C. Some lettuce genotypes showed thermotolerance to 34 °C (less than 20% reduction in germination) such as Elizabeth, PI 342533, PI 358025, Florida Buttercrisp, Kordaat, Corsair, FL 50105, PRO 425, PI 278070, Noemie, Picarde, Gaillarde, L. serriola (PI 491112, UC96US23, PI 491147), L. virosa (PI 274378 D), L. saligna (PI 491159), and primitive (PI 187238 A, PI 289063 C). The germination rates were consistent with the germination percentage at the high temperatures. Seed germination in the field was very low and positively correlated with seed germination at 29 and 34 °C. The highest field germination percentages (greater than 40%) were observed in Belluro, Mantilia, Mid Queen, Headmaster, PRO 874, PRO 425, FL 50105, Corsair, Romaine SSC 1148, Romaine Romea, Green Forest, Grenadier, FL 43007, Squadron, Xena, Noemie, Green Wave, Picarde, and Red Giant. The results of this study indicated that lettuce genotypes differ greatly in their ability to germinate at high temperatures as determined by the percentages and the rates of germination. Our research indicates that thermoinsensitive varieties could be used to expand lettuce production seasons in warm and low land cost areas and reduce the need for seed priming, lowering the production costs. The information may also be useful for growers to better choose cultivars for warm environments and for lettuce breeders to improve the crop for adaptation to global warming and climate change.

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Influence of Heat on Seed Germination of Cistus Laurifolius and Cistus Ladanifer

International Journal of Wildland Fire ◽

10.1071/wf9920015 ◽

1992 ◽

Vol 2 (1) ◽

pp. 15 ◽

Cited By ~ 47

Author(s):

L Valbuena ◽

R Tarrega ◽

E Luis

Keyword(s):

Seed Germination ◽

High Temperatures ◽

Exposure Time ◽

Germination Rate ◽

Heat Exposure ◽

Cistus Ladanifer ◽

Different Temperatures ◽

Petri Dishes ◽

Germinated Seeds

The influence of high temperatures on germination of Cistus laurifolius and Cistus ladanifer seeds was analyzed. Seeds were subjected to different temperatures for different times, afterwards they were sowed in plastic petri dishes and monitored for germinated seeds over two months.The germination rate observed in Cistus ldanifer was greater than in Cistus laurifolius. In both species, heat increased germination percentages. For Cistus laurifolius higher temperatures or longer exposure times were needed. Germination percentages of Cistus ladanifer were lower when heat exposure time was 15 minutes.It must be emphasized that germination occurred when seeds were not treated, while seeds exposed to 150�C for 5 minutes or more did not germinate.

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The Effect of High Concentrations of Ethylene on Seed Germination of Douglas Fir (Pseudotsugamenziesii (Mirb.) Franco)

Canadian Journal of Forest Research ◽

10.1139/x75-058 ◽

1975 ◽

Vol 5 (3) ◽

pp. 419-423 ◽

Cited By ~ 4

Author(s):

Carey Borno ◽

Iain E. P. Taylor

Keyword(s):

Seed Germination ◽

Germination Rate ◽

Inhibitory Effect ◽

Germination Percentage ◽

Douglas Fir ◽

Control Treatment ◽

Continuous Exposure ◽

Short Term ◽

Short Term Exposure ◽

High Concentrations

Stratified, imbibed Douglas fir (Pseudotsugamenziesii (Mirb.) Franco) seeds were exposed to 100% ethylene for times between 0 and 366 h. Germination rate and germination percentage were increased by treatments up to 48 h. The 12-h treatment gave largest stimulation; 30% enhancement of final germination percentage over control. Treatment for 96 h caused increased germination rate for the first 5 days but reduced the germination percentage. Germinants were subject to continuous exposure to atmospheres containing 0.1 – 200 000 ppm ethylene in air, but it did not stimulate growth, and the gas was inhibitory above 100 ppm. Although some effects of high concentrations of ethylene may have been due to the lowering of oxygen supplies, this alone was insufficient to account for the full inhibitory effect. The mechanism of stimulation by short-term exposure to ethylene is discussed.

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