scholarly journals Germination biology of three populations of Navua sedge (Cyperus aromaticus)

Weed Science ◽  
2020 ◽  
pp. 1-13
Author(s):  
Aakansha Chadha ◽  
Singarayer K. Florentine ◽  
Kunjithapatham Dhileepan ◽  
Kim Dowling ◽  
Christopher Turville
Keyword(s):  
Pacific Islands ◽  
Early Stage ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Radiant Heat ◽  
Saccharum Officinarum ◽  
Livestock Grazing ◽  
Burial Depth ◽  
Equatorial Africa ◽  
Cyperus Aromaticus

Abstract Navua sedge [Cyperus aromaticus (Ridley) Mattf. & Kük.] is an aggressive perennial sedge native to equatorial Africa that has become problematic in many Pacific islands and wet, tropical Queensland, Australia. It has had a significant impact on the livestock-grazing industry, sugarcane (Saccharum officinarum L.) and banana (Musa acuminata Colla) plantations, and various other ecosystems. A laboratory-based research investigation was conducted to understand germination and emergence requirements under various environmental conditions of three geographically varied populations sourced from South Johnstone (SJ), Mackay (M) and Nyleta Creek (NC) in Queensland. Germination was identified to be stimulated by light, with no germination recorded under darkness. Populations SJ and NC had optimal germination at alternating temperatures of 25/15, 30/20, and 35/25 C, whereas population M had optimal germination at 25/15 and 30/20 C. All populations recorded greater than 85% germination at all pH levels tested. Seeds of population SJ were more sensitive to salinity compared with populations M and NC, with SJ showing no germination at 100 mM, whereas populations M and NC had 23% and 9% germination, respectively. An inverse relationship was observed between osmotic potential and germination, with no germination recorded at osmotic potentials below −0.8 MPa in any population, indicating moisture availability is a critical requirement for germination. Exposing seeds to 120 C radiant heat completely inhibited germination in populations M and NC, whereas 3% of population SJ germinated following a 180-s exposure at 120 C. Seedling emergence decreased as planting depth increased. Emergence was greatest for seeds on the soil surface or at 0.5-cm burial depth, consistent with germination being stimulated by light. Knowledge of these biological characteristics of C. aromaticus seed germination will assist in investigation of suitable control actions for this species, particularly in the early stage of its invasion into new areas, and will contribute to significant reduction in the soil seedbank.

Seasonal cycles in germination and seedling emergence of summer and winter populations of catchweed bedstraw (Galium aparine) and wild mustard (Brassica kaber)

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 114-120 ◽  
Author(s):  
Husrev Mennan ◽  
Mathieu Ngouajio
Keyword(s):  
Soil Depth ◽  
Cropping Systems ◽  
Seedling Emergence ◽  
Seed Mass ◽  
Soil Surface ◽  
Burial Depth ◽  
Galium Aparine ◽  
Wild Mustard ◽  
Seed Population ◽  
Brassica Kaber

Catchweed bedstraw and wild mustard each produce two populations per year: a winter population (WP) in June, and a summer population (SP) in September. Experiments were conducted to determine whether the WP and SP differ in seed mass and seasonal germination. Seeds of both weeds were buried at 0, 5, 10, and 20 cm in cultivated fields, and retrieved at monthly intervals for 24 mo for germination tests in the laboratory. Additionally, seedling emergence from seeds buried at 0, 5, and 10 cm in the field was evaluated for 1 yr. Seeds from the WP were heavier than those from the SP for both species. Germination of exhumed seeds was affected by burial depth and by seed population. It was highest for seeds that remained on the soil surface and declined with increasing depth of burial. The WP of catchweed bedstraw produced two germination peaks per year, whereas the SP and all populations of wild mustard had only one peak. The WP of both weeds germinated earlier than the SP. Seedling emergence for both species in the field was greater for the WP than for the SP. Increasing soil depth reduced seedling emergence of both the WP and SP of wild mustard and affected only the WP of catchweed bedstraw. We conclude that the WP and SP of catchweed bedstraw and wild mustard seeds used in this study differed in seed mass, seasonal germination, and seedling emergence. The ability of a WP to produce large seeds that germinate early and have two germination peaks per year could make these populations a serious problem in cropping systems.

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

Weed Science ◽  
2017 ◽  
Vol 66 (1) ◽  
pp. 47-56 ◽  
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.

Seed Germination Ecology of Itchgrass (Rottboellia cochinchinensis)

Weed Science ◽  
2011 ◽  
Vol 59 (2) ◽  
pp. 182-187 ◽  
Author(s):  
Grace E-K. Bolfrey-Arku ◽  
Bhagirath S. Chauhan ◽  
David E. Johnson
Keyword(s):  
High Temperature ◽  
Seed Germination ◽  
Seedling Emergence ◽  
Soil Surface ◽  
The Philippines ◽  
Integrated Weed Management ◽  
Burial Depth ◽  
Soil Burial ◽  
Dark Regime ◽  
Temperature Pretreatment

Itchgrass is a weed of many crops throughout the tropics and one of the most important grass weeds of rainfed rice. Experiments were conducted in the laboratory and screenhouse to determine the effects of light, alternating day/night temperatures, high temperature pretreatment, water stress, seed burial depth, and rice residue on seed germination and seedling emergence of itchgrass in the Philippines. Two populations were evaluated and the results were consistent for both populations. Germination in the light/dark regime was greater at alternating day/night temperatures of 25/15 C than at 35/25, 30/20, or 20/10 C. Light was not a requirement for germination, but a light/dark regime increased germination by 96%, across temperature and population. A 5-min high temperature pretreatment for 50% inhibition of maximum itchgrass germination ranged from 145 to 151 C with no germination when seeds were exposed to ≥ 180 C. The osmotic potential required for 50% inhibition of maximum germination was −0.6 MPa for itchgrass, although some seeds germinated at −0.8 MPa. Seedling emergence was greatest for seeds placed on the soil surface, and emergence declined with increasing soil burial depth; no seedlings emerged from seeds buried at 10 cm. The addition of rice residue to soil surface in pots at rates equivalent to 4 to 6 Mg ha−1reduced itchgrass seedling emergence. Since seedling emergence was greatest at shallow depths and germination was stimulated by light, itchgrass may become a problem in systems where soil is cultivated at shallow depths. Knowledge gained in this study could contribute to developing components of integrated weed management strategies for itchgrass.

Germination ecology of wild mustard (Sinapis arvensis) and its implications for weed management

Weed Science ◽  
2021 ◽  
pp. 1-27
Author(s):  
Aseemjot Singh ◽  
Gulshan Mahajan ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Salt Stress ◽  
Seed Germination ◽  
Seedling Emergence ◽  
Radiant Heat ◽  
Burial Depth ◽  
Sinapis Arvensis ◽  
Germination Ecology ◽  
Wild Mustard ◽  
Differential Adaptation ◽  
Wide Range

Abstract Wild mustard (Sinapis arvensis L.) is a widespread weed of the southeastern cropping region of Australia. Seed germination ecology of S. arvensis populations selected from different climatic regions may differ due to adaptative traits. Experiments were conducted to evaluate the effects of temperature, light, radiant heat, soil moisture, salt concentration, and burial depth on seed germination and seedling emergence of two [Queensland (Qld) population: tropical region; and Victoria (Vic) population: temperate region] populations of S. arvensis. Both populations germinated over a wide range of day/night (12 h/12 h) temperatures (15/5 to 35/25 C), and had the highest germination at 30/20 C. Under complete darkness, the Qld population (61%) had higher germination than the Vic population (21%); however, under the light/dark regime, both populations had similar germination (78 to 86%). At 100 C pretreatment for 5 min, the Qld population (44%) had higher germination than the Vic population (13%). Germination of both populations was nil when given pretreatment at 150 and 200 C. The Vic population was found tolerant to high osmotic and salt stress compared with the Qld population. At an osmotic potential of −0.4 MPa, germination of Qld and Vic populations was reduced by 85% and 42%, respectively, compared with their respective control. At 40, 80, and 160 mM sodium chloride, germination of the Qld population was lower than the Vic population. Averaged over the populations, seedling emergence was highest (52%) from a burial depth of 1 cm and was nil from 8 cm depth. Differential germination behaviors of both populations to temperature, light, radiant heat, water stress, and salt stress suggests that populations of S. arvensis may have undergone differential adaptation. Knowledge gained from this study will assist in developing suitable control measures for this weed species to reduce the soil seedbank.

The Effects of Depth and Duration of Seed Burial on Viability, Dormancy, Germination, and Emergence of Ivyleaf Speedwell (Veronica hederifolia)

2006 ◽  
Vol 20 (2) ◽  
pp. 438-444 ◽  
Author(s):  
Husrev Mennan ◽  
Bernard H. Zandstra
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
Burial Depth ◽  
Triphenyltetrazolium Chloride ◽  
Primary Dormancy ◽  
Dry Storage ◽  
Winter Annual ◽  
High Level ◽  
Depth Of Burial ◽  
Over Time

Experiments were conducted to investigate the effects of depth and duration of burial on seasonal germination, primary and secondary dormancy, viability, and seedling emergence of ivyleaf speedwell (Veronica hederifoliaL.) seeds. The seeds were buried at 0, 5, 10, or 20 cm and retrieved from the field at monthly intervals. The exhumed seeds were germinated at 5 C. In the second experiment, seeds were stored in the laboratory after harvest and tested for germination at monthly intervals. In each experiment, nongerminated seeds were treated with triphenyltetrazolium chloride at monthly intervals to test their viability. The effects of stratification and burial depth on seedling emergence were observed for 1 yr. The seeds exhumed from the soil were dormant at the beginning of the experiment and exhibited dormancy/nondormancy/conditional dormancy cycling throughout the experiment. Depth of burial and time affected seed germination. Seeds retrieved from the soil surface germinated well initially, but germination decreased as depth of burial increased. In the dry storage experiment, seeds had a high level of primary dormancy, and viability decreased over time. Seedling emergence decreased when depth of burial increased. Seedlings emerged nonuniformly throughout the year and demonstrated typical winter annual characteristics.

scholarly journals Seed Germination, Seedling Emergence, and Response to Herbicides of Triquetrous Murdannia (Murdannia triquetra) in Rice

Weed Science ◽  
2016 ◽  
Vol 65 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Wei Tang ◽  
Jie Chen ◽  
Jianping Zhang ◽  
Yongliang Lu
Keyword(s):  
Seed Germination ◽  
Weed Management ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Soil Surface ◽  
Rice Fields ◽  
Integrated Weed Management ◽  
Burial Depth ◽  
Nacl Concentration ◽  
Dark Regime

Triquetrous murdannia is an annual weed commonly found in rice fields in China. Laboratory and screenhouse experiments were carried out to determine the effect of light, temperature, osmotic and salt stress, seed burial depth, amount of rice residue, and depth of flooding on seed germination and seedling emergence of triquetrous murdannia and to evaluate the response of this weed to commonly available POST herbicides in China. Germination was greater than 93% under a wide day/night temperature range of 20/10 to 30/20 C in the light/dark regime. The time to onset of germination decreased as temperature increased. Germination was slightly stimulated when seeds were placed in light/dark conditions compared with seeds placed in the dark. The osmotic potential and NaCl concentration required for 50% inhibition of maximum germination were −0.5 MPa and 122 mM, respectively. The highest germination (68%) was observed from seeds sown on the soil surface, but decreased with increasing burial depth. Only 7% of seedlings emerged from a depth of 4 cm, and no seedlings emerged from seeds buried deeper than 6 cm. Seedling emergence decreased from 93 to 35% with increasing quantity of rice residue (1 to 6 103kg ha−1) applied on the soil surface. Seedling emergence was reduced by 40, 48, 64, and 70% at flooding depths of 1, 2, 4, and 6 cm, respectively, for the seeds sown on the soil surface. Fluroxypyr and MCPA herbicides provided 100% control of triquetrous murdannia at the 2- to 6-leaf stages; however, to achieve 100% control with bispyribac-sodium, MCPA+bentazone or MCPA+fluroxypyr, herbicides had to be applied by the 4-leaf stage. The results of this study could help in developing more sustainable and effective integrated weed management strategies for the control of triquetrous murdannia in rice fields in China.

Factors Affecting Buffalobur (Solanum rostratum) Seed Germination and Seedling Emergence

Weed Science ◽  
2009 ◽  
Vol 57 (5) ◽  
pp. 521-525 ◽  
Author(s):  
Shouhui Wei ◽  
Chaoxian Zhang ◽  
Xiangju Li ◽  
Hailan Cui ◽  
Hongjuan Huang ◽  
...  
Keyword(s):  
Seed Germination ◽  
Light Exposure ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Distribution Area ◽  
Burial Depth ◽  
Weed Species ◽  
Continuous Darkness ◽  
Invasive Weed

Buffalobur is a noxious and invasive weed species native to North America. The influence of environmental factors on seed germination and seedling emergence of buffalobur were evaluated in laboratory and greenhouse experiments. The germination of buffalobur seeds occurred at temperatures ranging from 12.5 to 45 C, with optimum germination attained between 25 and 35 C. Buffalobur seeds germinated equally well under both a 14-h photoperiod and continuous darkness; however, prolonged light exposure (≥ 16 h) significantly inhibited the seed germination. Buffalobur seed is rather tolerant to low water potential and high salt stress, as germination was 28 and 52% at osmotic potentials of −1.1 MPa and salinity level of 160 mM, respectively. Medium pH has no significant effect on seed germination; germination was greater than 95% over a broad pH range from 3 to 10. Seedling emergence was higher (85%) for seeds buried at a soil depth of 2 cm than for those placed on the soil surface (32%), but no seedlings emerged when burial depth reached 8 cm. Knowledge of germination biology of buffalobur obtained in this study will be useful in predicting the potential distribution area and developing effective management strategies for this species.

Seed Germination and Seedling Emergence of Synedrella (Synedrella nodiflora) in a Tropical Environment

Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
David E. Johnson
Keyword(s):  
Seed Germination ◽  
Crop Residue ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Soil Surface ◽  
Burial Depth ◽  
The Family ◽  
Synedrella Nodiflora ◽  
Annual Plant Species ◽  
Osmotic Potentials

Synedrella is a tropical annual plant species of the family Asteraceae that is widely distributed in many crops in nearly 50 countries. Experiments were conducted to determine the influence of various environmental factors on seed germination and seedling emergence of synedrella. Germination response was greater at 30/20 C and 35/25 C than at 25/15 C fluctuating day/night temperatures. Light stimulated germination; however, a small proportion of after-ripened seeds germinated in the dark. Seedling emergence was greatest (96%) for seeds placed on the soil surface but declined with increased seed burial depth. No seedlings emerged from a depth of 4 cm. Seedling emergence and seedling dry matter declined with the addition of crop residue to the soil surface; however, higher quantities of residue than those normally found in low-yield systems were required to result in substantial reductions in emergence. Seed germination was tolerant of moderate salt concentrations (40 to 100 mM sodium chloride) and a broad range of pH (4 to 10) but was sensitive to low osmotic potentials (< −0.8 MPa). The information gained from this study could help predict the invasion potential of this species and could lead to improved management strategies.

Factors Affecting Seed Germination of Perennial Wall Rocket (Diplotaxis tenuifolia) in Southern Australia

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 481-485 ◽  
Author(s):  
Samuel G. L. Kleemann ◽  
Bhagirath S. Chauhan ◽  
Gurjeet S. Gill
Keyword(s):  
Osmotic Potential ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
South Australia ◽  
Soil Surface ◽  
Burial Depth ◽  
Optimal Conditions ◽  
Factors Affecting ◽  
Depth Of Burial ◽  
Osmotic Potentials

Germination response of perennial wall rocket to temperature, light, osmotic potential, and depth of burial emergence was evaluated under controlled environmental conditions. The effect of seed burial depth on seedling recruitment in the field was also investigated at Roseworthy, South Australia. Under optimal conditions (30 C, light/dark) germination of perennial wall rocket was rapid, with 90% of seeds germinating within 48 h of imbibition. Germination was reduced (20%) at lower, suboptimal temperatures (10 to 20 C) when seeds of perennial wall rocket were exposed to light. Germination declined with increasing osmotic potential and was completely inhibited at osmotic potentials of −1.5 MPa. Perennial wall rocket emergence was greatest from seeds placed on the soil surface, but some seedlings (< 10%) emerged from a depth of 0.5 to 2 cm. Under both field and growth-cabinet conditions, the greatest seedling emergence of perennial wall rocket occurred from seed present on the soil surface; however, the level of absolute recruitment from the seed bank was much lower (< 5%). Information gained from this study will further improve our understanding of the germination behavior of perennial wall rocket and contribute to developing sustainable strategies for its control.

Effects of Environmental Factors on Seed Germination and Emergence of Japanese Brome (Bromus japonicus)

Weed Science ◽  
2015 ◽  
Vol 63 (3) ◽  
pp. 641-646 ◽  
Author(s):  
Qi Li ◽  
Jinni Tan ◽  
Wei Li ◽  
Guohui Yuan ◽  
Long Du ◽  
...  
Keyword(s):  
Salt Stress ◽  
Osmotic Stress ◽  
Control Strategies ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Farming Systems ◽  
Effect Of Temperature ◽  
Burial Depth ◽  
Ph Values ◽  
Winter Annual

Japanese brome is a winter annual weed commonly found in wheat fields in China. Laboratory and greenhouse experiments were carried out to determine the effect of temperature, light, pH, osmotic stress, salt stress, and burial depth on the germination and emergence of Japanese brome. Germination was greater than 98% under a wide temperature range of 5 to 30 C and onset of germination was shortened as temperature increased. Light was not required for germination to occur and pH values from 5 to 10 had insignificant effect on germination. Germination was reduced by osmotic stress or salt stress and no germination occurred at −1.3 MPa or 360 mM, suggesting that Japanese brome seed was quite tolerant to osmotic potential and salinity. Seedling emergence was greatest (98%) when seeds were placed on the soil surface but decreased with increasing of burial depth. Only 7% of seedlings emerged at a depth of 5 cm. The results of this study have contributed to our understanding of the germination and emergence of Japanese brome and should enhance our ability to develop better control strategies in wheat farming systems of the Huang-Huai-Hai Plain of China.

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