scholarly journals Germination ecology of Rhynchosia capitata: an emerging summer weed in Asia

2013 ◽  
Vol 31 (2) ◽  
pp. 249-257 ◽  
Author(s):  
H.H. Ali ◽  
A. Tanveer ◽  
M.A. Nadeem ◽  
H.N. Asghar ◽  
M.M. Javaid
Keyword(s):  
Seed Germination ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Ecological Factors ◽  
Moisture Stress ◽  
Burial Depth ◽  
Seed Burial ◽  
Germination Ability ◽  
Wide Range ◽  
The One

Rhynchosia capitata is becoming an increasing problem in summer crops, such as cotton, soybean, pearl millet and mungbean in many Asian countries. Laboratory and greenhouse studies have been conducted to determine the effects of several environmental factors on seed germination patterns and seedling emergence of R. capitata. We investigated whether the diverse ecological factors such as temperature, light, salinity, moisture stress, pH, and soil depth affected germination and seedling emergence of R. capitata. Germination increased as temperature increased from 25ºC and significantly reduced at 45ºC. Presence or absence of light did not influence germination. Germination of R. capitata was sensitive to increased salt and moisture stress, as well as to seed burial depth. Only 48% of seeds germinated at 150 mM salt concentration compared to 100% in control (distilled water). Similarly, 15% of seeds germinated at an osmotic potential of ‑0.8 MPa compared to 88% at ‑0.2 MPa. The optimum pH for seed germination of R. capitata was 7 (98% germination), but the seeds also germinated at lower level of pH 5 (85%) and at higher level of pH 10 (75%). In seed burial trial, maximum seedling emergence of 93% occurred at 2 cm depth, and seedling did not emerge from a depth of 12 cm. The high germination ability of R. capitata under a wide range of ecological factors suggests that this species is likely to be the one to cause more problems in a near future, if not managed appropriately.

scholarly journals Germination Ecology of Two Troublesome Weeds of Arid Chickpea: Euphorbia dracunculoides and Astragalus Species

2019 ◽  
Vol 37 ◽  
Author(s):  
R.M. IKRAM ◽  
A. TANVEER ◽  
H.H. ALI ◽  
M.E. SAFDAR ◽  
M.M. JAVAID ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Chloride Concentration ◽  
Ecological Factors ◽  
Cropping System ◽  
Soil Surface ◽  
Growth Patterns ◽  
Burial Depth ◽  
Germination Ecology ◽  
Wide Range

ABSTRACT: The species Euphorbia dracunculoides and Astragalus are problematic weeds of arid chickpea in the chickpea mono-cropping system in Pakistan. The influence of various ecological factors on germination and seedling emergence characteristics of these weeds was determined under laboratory conditions. The results suggested that seed germination of both species was 50% at 15 oC under light conditions, and germination decreased when the temperature was increased. The increase in drought stress from 2.5 to 15% significantly decreased germination of E. dracunculoides and Astragalus spp. Both species failed to germinate at the osmotic potential of -3.02 MPa. The increase in field capacity from 25 to 100% increased emergence percentage and emergence index of both weeds. A pH range of 6 to 9 did not influence seed germination of both species and they were able to germinate at a wide range of pH conditions. Both weeds were very sensitive to salinity; however, a few seeds (10%) of Astragalusspp. germinated even at a 150 mM sodium chloride concentration. To check the effect of burial depth, seeds were placed in pots under seeding depths of 0 to 6 cm at an interval of 1 cm, respectively. Maximum emergence was attained at the soil surface and emergence declined with increasing depths. Seedling emergence of E. dracunculoides was higher than that of Astragalusspp. at all burial depths. Studies on germination ecology of these two weeds will offer insights into their behavior under different environmental conditions. Their germination responses and growth patterns under different ecological factors will help us to design an efficient management strategy to control these two troublesome weeds.

Germination Biology of Sesbania (Sesbania cannabina): An Emerging Weed in the Australian Cotton Agro-environment

Weed Science ◽  
2018 ◽  
Vol 67 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Nadeem Iqbal ◽  
Sudheesh Manalil ◽  
Bhagirath S. Chauhan ◽  
Steve W. Adkins
Keyword(s):  
Seed Germination ◽  
Management Strategies ◽  
Moisture Stress ◽  
Integrated Weed Management ◽  
Burial Depth ◽  
Weed Species ◽  
Physical Dormancy ◽  
Sesbania Cannabina ◽  
Wide Range ◽  
The Impact

AbstractSesbania [Sesbania cannabina(Retz.) Pers.] is a problematic emerging weed species in Australian cotton-farming systems. However, globally, no information is available regarding its seed germination biology, and better understanding will help in devising superior management strategies to prevent further infestations. Laboratory and glasshouse studies were conducted to evaluate the impact of various environmental factors such as light, temperature, salt, osmotic and pH stress, and burial depth on germination and emergence of two Australian biotypes ofS. cannabina. Freshly harvested seeds of both biotypes possessed physical dormancy. A boiling-water scarification treatment (100±2 C) of 5-min duration was the optimum treatment to overcome this dormancy. Once dormancy was broken, the Dalby biotype exhibited a greater germination (93%) compared with the St George biotype (87%). The nondormant seeds of both biotypes showed a neutral photoblastic response to light and dark conditions, with germination marginally improved (6%) under illumination. Maximum germination of both biotypes occurred under an alternating temperature regime of 30/20 and 35/25 C and under constant temperatures of 32 or 35 C, with no germination at 8 or 11 C. Seed germination of both biotypes decreased linearly from 87% to 14% with an increase in moisture stress from 0.0 to −0.8 MPa, with no germination possible at −1.0 MPa. There was a gradual decline in germination for both biotypes when imbibed in a range of salt solutions of 25 to 250 mM, with a 50% reduction in germination occurring at 150 mM. Both biotypes germinated well under a wide range of pH values (4.0 to 10.0), with maximum germination (94%) at pH 9.0. The greatest emergence rate of the Dalby (87%) and St George (78%) biotypes was recorded at a burial depth of 1.0 cm, with no emergence at 16.0 cm. Deep tillage seems to be the best management strategy to stopS. cannabina’s emergence and further infestation of cotton (Gossypium hirsutumL.) fields. The findings of this study will be helpful to cotton agronomists in devising effective, sustainable, and efficient integrated weed management strategies for the control ofS. cannabinain cotton cropping lands.

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.

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.

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 three Artemisia species (Asteraceae) inhabiting desert sand dunes in China

2006 ◽  
Vol 16 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Kazuo Tobe ◽  
Liping Zhang ◽  
Kenji Omasa
Keyword(s):  
Seed Germination ◽  
Sand Dunes ◽  
Seedling Emergence ◽  
Light Sensitivity ◽  
Burial Depth ◽  
Secondary Effects ◽  
Seed Burial ◽  
Desert Sand ◽  
Light Fluence ◽  
Artemisia Species

Artemisia ordosica,A. arenariaandA. sphaerocephalaare semi-shrubs inhabiting desert sand dunes in China and often used to rehabilitate desertified areas. Improvement of dune rehabilitation success by sowing requires better understanding of the processes involved in the control of seed germination and seedling emergence in these species. Thus, (1) effects of temperature, light and osmotica (polyethylene glycol-6000) on seed germination, and (2) effects of seed burial depth in sand and irrigation regime on seedling emergence, were studied under controlled conditions. Seeds of the three species required light for germination, and the light fluence needed for germination was dependent on temperature. Seedling emergence of the three species was maximal (70–94%) for seeds sown at a depth of 2.5 mm, and decreased with increasing seed burial depth when the pots were initially and subsequently treated with 16 mm and 3 mm irrigation at 1-d intervals. However, when the pots were initially and subsequently treated with 8 mm and 3 mm irrigation at 2-d intervals, seedling emergence was almost completely suppressed due to water deficiency in sand. It is suggested that the probability of seed germination and seedling emergence of the three species in the field is very limited, because the light requirement restricts seed germination to shallow sand layers where water is lost rapidly due to evaporation. Temperature appeared to have secondary effects on seed germination, by modifying the light sensitivity of seeds.

Seed Germination Ecology of Junglerice (Echinochloa colona): A Major Weed of Rice

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 235-240 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
David E. Johnson
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Moisture Stress ◽  
The Philippines ◽  
Reduced Tillage ◽  
Burial Depth ◽  
Tillage Systems ◽  
Ph Range ◽  
The Tropics

Junglerice is one of the most serious grass weeds of rice in the tropics. Experiments were conducted in the laboratory and screenhouse to determine the influence of environmental factors on seed germination and seedling emergence of junglerice in the Philippines. In the laboratory, germination was stimulated by light, suggesting that seeds of this species are positively photoblastic. The tested temperatures (35/25, 30/20, and 25/15 C alternating day/night temperatures), however, did not influence germination. Germination in the laboratory was not affected by a soil pH range of 4 to 9, but was decreased by salinity (> 50 mM NaCl) and moisture stress (< −0.2 MPa osmotic potential). In the screenhouse, germination of junglerice was greatest (97%) for seeds at the soil surface, but emergence declined exponentially with increasing seed burial depth, and no seedlings emerged from seeds buried at 6 cm. In pots, seedling emergence declined markedly with the addition of rice residue to the soil surface at rates equivalent to 4 to 6 tonnes (t) ha−1. As germination of junglerice was strongly stimulated by light, and seedling emergence was optimal at shallow burial depths, this species is likely to be problematic in reduced tillage systems.

Germination Ecology of Four African mustard (Brassica tournefortii Gouan.) Populations in the Eastern Region of Australia

Weed Science ◽  
2021 ◽  
pp. 1-28
Author(s):  
Sohraab Singh ◽  
Gulshan Mahajan ◽  
Rajandeep Singh ◽  
Bhagirath S. Chauhan
Keyword(s):  
Temperature Regime ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Chloride Concentration ◽  
Burial Depth ◽  
Eastern Region ◽  
Germination Ecology ◽  
Wide Range ◽  
Brassica Tournefortii ◽  
Winter Annual

Abstract African mustard (Brassica tournefortii Gouan) is a problematic winter annual weed in Australia. Germination ecology of B. tournefortii may change in response to the maternal environments or habitats in which they grow. A study was conducted to evaluate the effect of environmental factors on germination and emergence of four populations of B. tournefortii that were collected from different fields. Averaged over populations, germination was stimulated by dark and was higher at 25/15 C (92%) as compared with 15/5 C (76%) and 35/25 C (45%). Averaged over light/dark regimes, at the lowest temperature regime (15/5 C), population A had higher germination than population D ; however, at the highest temperature regime (35/25 C), population D had higher germination than population A. Population B and C had higher germination in the temperature range of 25/15 C and 30/20 C compared with 15/5 C, 20/10 C, and 35/25 C. Seeds germinated at a wide range of alternating day/night temperatures (15/5 to 35/25 C), suggesting that seeds can germinate throughout the year if other optimum conditions are available. Population A was more tolerant to water and salt stress than population D. The sodium chloride concentration and osmotic potential required to inhibit 50% germination of population A was 68 mM and -0.60 MPa, respectively. Averaged over populations, seeds placed at 1cm soil depth had the highest emergence (54%), and burial depth of 8 cm resulted in 28% seedling emergence. Averaged over populations, wheat residue retention at 6000 kg ha-1 resulted in greater seedling emergence than the residue amount of 1000 kg ha-1. The results suggest that B. tournefortii will be favored in no-till systems and the seed bank of B. tournefortii could be managed by tillage regimes that bury its seeds below 8 cm depths and restrict seedling emergence and growth of new plants.

scholarly journals The Influence of Environmental Factors on Seed Germination of Polygonum perfoliatum L.: Implications for Management

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1123
Author(s):  
Shahid Farooq ◽  
Huseyin Onen ◽  
Sonnur Tad ◽  
Cumali Ozaslan ◽  
Samy F. Mahmoud ◽  
...  
Keyword(s):  
Seed Germination ◽  
Osmotic Potential ◽  
Seedling Emergence ◽  
Management Strategies ◽  
The Black Sea ◽  
Burial Depth ◽  
Weed Species ◽  
Black Sea Region ◽  
Wide Range ◽  
Polygonum Perfoliatum

Polygonum perfoliatum L. is an aggressive vine, currently invading the Black Sea region, Turkey. However, information about the seed germination biology of this species is scanty. The objective of the current study was to determine the seed germination biology of three naturalized populations of this species. Chemical scarification with 98% sulfuric acid for 30 min followed by cold-wet stratification at 4 °C for 4 weeks effectively released seed dormancy in tested populations. Seeds of all populations required a 12 h photoperiod for the highest germination, while germination under continuous dark and light remained similar. The seeds were able to germinate under a wide range of constant (5–40 °C) and alternating temperatures, pH (3–11), osmotic potential (0 to −1.4 MPa) and salinity (0–500 mM NaCl). However, the peak germination was observed under 20 °C constant and 20/15 °C alternating day/night temperature, and pH 6.8. Seeds of all populations were able to withstand 200 mM salinity and −0.6 MPa osmotic potential. Increasing seed burial depth initially stimulated seedling emergence and then a sharp decline was observed for the seeds buried below >2 cm depth. More than 90% of the seeds were unable to emerge when buried >6 cm depth. Polygonum perfoliatum has a large potential for range expansion; therefore, immediate management of the naturalized populations is warranted. This weed species in agricultural fields can be managed by burying the seeds in deeper soil layers (6 cm), while post-emergence management strategies need to be developed for roadside populations.

Germination of Fresh Horse Purslane (Trianthema portulacastrum) Seeds in Response to Different Environmental Factors

Weed Science ◽  
2011 ◽  
Vol 59 (4) ◽  
pp. 495-499 ◽  
Author(s):  
Jihyun Lee ◽  
Bhagirath S. Chauhan ◽  
David E. Johnson
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Seedling Emergence ◽  
Soil Surface ◽  
The Philippines ◽  
Integrated Weed Management ◽  
Burial Depth ◽  
Seed Burial ◽  
Soil Burial ◽  
Two Populations

Horse purslane, a C4 species, is a branched, prostrate, and annual weed of upland field crops throughout the tropics. Experiments were conducted to determine the influence of various environmental factors on seed germination and seedling emergence of two populations of horse purslane. Seeds were collected from rice fields of the International Rice Research Institute (the IR population) and from sorghum fields of the University of the Philippines (the UP population); the two sites were 5 km apart in Los Baños, Philippines. Germination response of both populations was greater at 30/20 C and35/25 C day/night temperatures than they were at 25/15 C alternating day/night temperatures. Germination of both populations was greater in the light/dark regime than in darkness. In dark, depending on the temperature, seed germination of the UP population ranged from 37 to 62%, whereas seed germination of the IR population was < 20%. Exposure to 5 min at 117 and 119 C for the IR and UP populations, respectively, reduced germination to 50% of maximum germination. Osmotic potential of −0.26 MPa inhibited germination to 50% of the maximum for the UP population, whereas the corresponding value for the IR population was −0.37 MPa. Seeds placed on or near the soil surface had maximum emergence, and emergence declined with increase in seed burial depth. Seedling emergence of the UP and IR populations was 74% and 13%, respectively, for seeds placed on the soil surface. For both populations, no seedlings emerged from a soil burial depth of 6 cm or more. Germination and emergence responses to light and seed burial depth differed between the two populations of horse purslane. Residues on the soil surface of up to 6 Mg ha−1 did not influence seedling emergence of either populations. Knowledge gained in this study could contribute to developing components of integrated weed management strategies for horse purslane.

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