Environmental factors affecting the germination and seedling emergence of two populations of an emerging agricultural weed: wild lettuce (Lactuca serriola)

2019 ◽  
Vol 70 (8) ◽  
pp. 709 ◽  
Author(s):  
Aakansha Chadha ◽  
Singarayer Florentine ◽  
Bhagirath S. Chauhan ◽  
Benjamin Long ◽  
Mithila Jayasundera ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Crop Residues ◽  
Seedling Emergence ◽  
Detailed Knowledge ◽  
Burial Depth ◽  
Factors Affecting ◽  
Wild Lettuce ◽  
Lactuca Serriola ◽  
Environmental Weed ◽  
Two Populations

Wild lettuce (Lactuca serriola L.) is a significant emerging agricultural and environmental weed in many countries. This invasive species is now naturalised in Australia and is claimed to cause significant losses within the agricultural industry. Sustainable management of wild lettuce has been hampered by a lack of detailed knowledge of its seed ecology. Laboratory-based studies were performed to examine the potential influence of environmental factors including temperature and light conditions, salinity, pH, moisture availability and burial depth on the germination and emergence of two spatially distant populations of wild lettuce. Results suggested that the germination of wild lettuce seeds occurred across a broad range of temperature conditions (12-h cycle: 30°C/20°C, 25°C/15°C and 17°C/7°C) for both populations. We also found that these seeds are non-photoblastic; germination was not affected by darkness, with >80% germination in darkness for both populations at all tested temperature ranges. Germination significantly declined as salinity and osmotic stress increased for both populations, with seeds from the Tempy population were more affected by NaCl >100 mM than seeds from Werribee, but in neither population was there any observed effect of pH on germination (>80% germination in both populations at all tested pH ranges). For both populations, germination significantly decreased as burial depth increased; however, the two populations differed with regard to response to burial depth treatment, whereby seeds from the Tempy population had higher emergence than those from Werribee at 0.5 cm burial depth. These results suggest that light-reducing management techniques such as mulching or use of crop residues will be unsuccessful for preventing germination of wild lettuce. By contrast, burial of seeds at a depth of at least 4 cm will significantly reduce their emergence.

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.

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

Weed Science ◽  
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.

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.

Factors Affecting Seed Germination and Seedling Emergence of Asia Minor Bluegrass (Polypogon fugax)

Weed Science ◽  
2015 ◽  
Vol 63 (2) ◽  
pp. 440-447 ◽  
Author(s):  
Xian Wu ◽  
Jun Li ◽  
Hongle Xu ◽  
Liyao Dong
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Late Summer ◽  
Asia Minor ◽  
Burial Depth ◽  
Optimum Temperature ◽  
Large Area ◽  
Factors Affecting ◽  
Temperature Regimes ◽  
Grass Weed

Little published information is available related to seed germination and seedling establishment of Asia Minor bluegrass, a problematic grass weed in some regions of China. The objective of this study was to examine the effects of different environmental factors on Asia Minor bluegrass seed germination. The optimum temperature for germination was around 10 to 20 C, and more than 90% of seeds germinated under 20/10 and 25/15 C temperature regimes. Also, light and pH did not appear to have any effect on seed germination. Asia Minor bluegrass was sensitive to osmotic stress, but tolerant of NaCl. No seedlings emerged when seeds were buried 4 cm deep. The result suggested that Asia Minor bluegrass has the potential to spread into a large area in China. To prevent its spreading, measures such as soil cultivation can be used to limit seed germination from increased burial depth and/or nonselective herbicides can be applied to kill early-germinating weed seedlings in late summer.

scholarly journals Factors Affecting Seed Dormancy and Germination of Greater Bur-Parsley (Turgenia latifolia)

2018 ◽  
Vol 36 ◽  
Author(s):  
M. REZVANI ◽  
S.A. SADATIAN ◽  
H. NIKKHAHKOUCHAKSARAEI
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Seed Dormancy ◽  
Seedling Emergence ◽  
Potassium Nitrate ◽  
Germination Percentage ◽  
Dormancy Breaking ◽  
Planting Depth ◽  
Factors Affecting ◽  
Drought And Salt Stresses

ABSTRACT: Our knowledge about seed dormancy breaking and environmental factors affecting seed germination of greater bur-parsley (Turgenia latifolia) is restricted. This study has addressed some seed dormancy breaking techniques, including different concentrations of gibberellic acid (GA3) and potassium nitrate (KNO3), leaching duration, physical scarification as well as some environmental factors effective on seed germination such as salt and drought stresses, pH and seed planting depth. Seed germination was promoted with lower concentrations of KNO3 (0.01 to 0.02 g L-1), while higher concentrations reduced germination percentage. Seed dormancy was declined by low concentrations of GA3 up to 100 ppm. Seeds of greater bur-parsley germinated in a range of pH from 3 to 7. With enhancement of drought and salt stresses, seed germination decreased. Also, there was no seed germination in a high level of stresses. Seedling emergence reduced as planting depth increased. Use of GA3, KNO3, leaching and physical scarification had a positive effect on seed dormancy breaking of greater bur-parsley. The information from the study increases our knowledge about seed dormancy breaking techniques, response of germination to drought and salt stresses and also determination of distribution regions of greater bur-parsley in the future.

scholarly journals Environmental Factors Affecting the Mineralization of Crop Residues

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1951
Author(s):  
Aleksandra Grzyb ◽  
Agnieszka Wolna-Maruwka ◽  
Alicja Niewiadomska
Keyword(s):  
Environmental Factors ◽  
Crop Production ◽  
Crop Residues ◽  
Management Strategies ◽  
C:N Ratio ◽  
Environment Friendly ◽  
Factors Affecting ◽  
Plant Matter ◽  
High Yields

The aim of this article is to present the issues related to the significance of microorganisms in the mineralization of crop residues and the influence of environmental factors on the rate of this process. Crop residues play a very important role in agriculture because they can be used both as an environment-friendly waste management strategy and as a means of improving soil organic matter. The inclusion of crop residues in the soil requires appropriate management strategies that support crop production and protect the quality of surface water and groundwater. Crops need nutrients for high yields; however, they can only absorb ionic forms of elements. At this point, the microorganisms that convert organically bound nitrogen, phosphorus, and sulfur into soluble NH4+, NO3−, H2PO4−, HPO42−, and SO42− ions are helpful. Mineralization is the transformation of organic compounds into inorganic ones, which is a biological process that depends on temperature, rainfall, soil properties, the chemical composition of crop residues, the structure and composition of microbial communities, and the C:N ratio in soil after the application of plant matter. An adjustment of the values of these factors enables us to determine the rate and direction of the mineralization of crop residues in soil.

Influence of Various Environmental Factors on Seed Germination and Seedling Emergence of a Noxious Environmental Weed: Green Galenia (Galenia pubescens)

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 486-494 ◽  
Author(s):  
Ako H. Mahmood ◽  
Singarayer K. Florentine ◽  
Bhagirath S. Chauhan ◽  
David A McLaren ◽  
Grant C. Palmer ◽  
...  
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
South African ◽  
Seedling Emergence ◽  
Temperate Grasslands ◽  
Low Levels ◽  
Noxious Weed ◽  
Environmental Weed ◽  
Agricultural Areas

Green galenia is a South African woody prostrate perennial that was first recorded in Australia in the early 1900s and has since become a serious threat to indigenous temperate grasslands and surrounding agricultural areas. Laboratory and field based experiments were conducted to examine the effect of environmental factors on the germination and viability of green galenia seed. It was shown that green galenia was able to germinate over a broad range of temperatures, but short bursts (5 min) of high temperatures (80 C to 120 C replicating possible exposures to a fire) reduced seed germination. Seed germination was positively favored by light, declined rapidly in darkness, and decreased by > 80% at a depth of only 0.5 cm in soil. Water stress greatly reduced seed germination (45% germination at osmotic potentials below −0.2 MPa). Germination was completely inhibited at water potentials of −0.4 to −1.0 MPa. This species is moderately tolerant to salinity, with over 50% of seeds germinating at low levels of salinity (60 mM NaCl), and moderate germination (49%) occurring at 120 mM NaCl, it can germinate well in both alkaline (pH 10–83%) and acidic (pH 4–80%) conditions. The results of this study have contributed to our understanding of the germination and emergence of green galenia, and this will assist in developing tools and strategies for the long term management of this noxious weed in Victoria and other parts of Australia.

Environmental factors affecting 17th–19th century whaling in the Greenland Sea

Polar Record ◽  
1991 ◽  
Vol 27 (161) ◽  
pp. 77-86 ◽  
Author(s):  
Chesley W. Sanger
Keyword(s):  
Environmental Factors ◽  
19Th Century ◽  
Environmental Conditions ◽  
Detailed Knowledge ◽  
Greenland Sea ◽  
Factors Affecting ◽  
Whale Oil ◽  
Unique Character ◽  
Ice Edge ◽  
Sea Wind

AbstractCommercial pelagic whaling of the 17th–19th centuries in the Greenland Sea was heavily influenced by environmental factors. Much of the fishery took place along a constantly shifting ice-edge, variations in which stamped a unique character on each season's operation. Environmental conditions required expert interpretation, both to procure paying cargoes of whale oil and bone and to survive hazards posed by sea, wind and ice. Detailed knowledge of currents, temperatures and winds enhanced greatly the chance that a master would have a successful voyage.

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