Environmental factors affecting the germination and emergence of white horehound (Marrubium vulgare L.): a weed of arid-zone areas

2018 ◽  
Vol 40 (1) ◽  
pp. 47 ◽  
Author(s):  
Muhammad M. Javaid ◽  
Singarayer K. Florentine ◽  
Hafiz H. Ali ◽  
Bhagirath S. Chauhan

White horehound (Marrubium vulgare L.), is a troublesome weed of arid zones, particularly in cropping and grazing areas. Understanding the seed ecology of white horehound is relevant to its management. The present study investigated the effects of temperature, light, osmotic potential, salinity, pH, and seeding depth on seed germination and seedling emergence of white horehound. Seeds germinated over a wide range of temperatures, with highest germination (100%) occurring at 25/20°C in either 12-h alternating light/dark or complete darkness. Germination decreased from 92% to 10% as the osmotic potential decreased from 0 to minus 0.6 MPa and germination was completely inhibited at minus 0.8 MPa. Increasing concentration of sodium chloride (salinity) from 50 to 150 mM reduced germination from 68% to 11% but was completely inhibited at 200 mM. Germination was not limited by variation of pH in solutions of pH 5 to pH 10. Maximum germination (99%) occurred at pH 7, but slightly decreased (90%) in acidic or alkaline media. Surface located seeds were highly germinable (87%) where seedling emergence significantly declined as seeding depth increased from 0.5 to 3 cm. Nil seedling emergence was occurred at 4 cm burial depth. Light significantly affected germination, time to 50% germination, mean germination time and germination index. Increasing osmotic and salinity stress both significantly increased the time to start germination, time to 50% germination, mean germination time, but decreased germination index. Burial depth adversely affected seedling emergence with surface located seedlings emerging earlier (4.2 days) compared with 20 days for seeds buried at 3 cm. Results suggest that effective management of white horehound should consider targeting surface located seeds in combination with tools that induce minimal soil disturbance, particularly in relatively non-saline environments.

Weed Science ◽  
2017 ◽  
Vol 66 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Ning Zhao ◽  
Qi Li ◽  
Wenlei Guo ◽  
Lele Zhang ◽  
Lu’an Ge ◽  
...  

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.


2014 ◽  
Vol 39 (1) ◽  
pp. 143-150 ◽  
Author(s):  
KU Ahammad ◽  
MM Rahman ◽  
MR Ali

The research work was carried out at the Seed Laboratory of Agronomy Department of Bangladesh Agricultural University, Mymensingh during the period from February to April in 2008 to find out the effect of hydropriming methods on maize seedling emergence. The hydropriming methods were- T1 (Non-priming), T2 (14 hours soaking + drying + storing), T3 (18 hours soaking + drying + storing), T4 (22 hours soaking + drying + storing), T5 (14 hours soaking + surface drying), T6 (18 hours soaking + surface drying), and T7 (22 hours soaking + surface drying). Effect of different hydropriming methods on seedling emergence performance of maize was evaluated at two moisture levels viz., 30% and 60% moisture of saturated sand in the experiment. Germination percentage, germination index and mean germination time were influenced significantly by hydropriming methods. The highest germination percentage, germination index, and lowest mean germination time were recorded with T6 (18 hours soaking + surface drying). DOI: http://dx.doi.org/10.3329/bjar.v39i1.20164 Bangladesh J. Agril. Res. 39(1): 143-150, March 2014


2013 ◽  
Vol 31 (1) ◽  
pp. 39-51 ◽  
Author(s):  
A Tanveer ◽  
M Tasneem ◽  
A Khaliq ◽  
M.M Javaid ◽  
M.N Chaudhry

An understanding of seed germination ecology of weeds can assist in predicting their potential distribution and developing effective management strategies. Influence of environmental factors and seed size on germination and seedling emergence of Convolvulus arvensis (field bindweed) was studied in laboratory and greenhouse conditions. Germination occurred over a wide range of constant temperatures, between 15 and 40 ºC, with optimum germination between 20 and 25 ºC. Time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased with an increase in temperature from 20 ºC, salinity and osmotic stress. However, germination was tolerant to low salt (25 mM) or osmotic stress (0.2 MPa), but as salinity and osmotic stress increased, germination percentage and germination index decreased. Seeds of C. arvensis placed at soil surface showed maximum emergence and decreased as seeding depth increased. Seeds of C. arvensis germinated over a wide range of pH (4 to 9) but optimum germination occurred at pH 6 to 8. Under highly alkaline and acidic pH, time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased. Increase in field capacity caused decreased time to start germination, time to 50% germination and mean germination time but increased germination percentage and germination index. Bigger seeds had low time to start germination, time to 50% germination and mean germination time but high germination percentage and germination index. Smaller seeds were more sensitive to environmental factors as compared to larger or medium seeds. It can be concluded that except for pH, all environmental factors and seed sizes adversely affect C. arvensis as regards seed germination or emergence and germination or emergence traits, and larger seeds result in improved stand establishment and faster germination than small seeds, regardless of moisture stress or deeper seeding depth.


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1123
Author(s):  
Shahid Farooq ◽  
Huseyin Onen ◽  
Sonnur Tad ◽  
Cumali Ozaslan ◽  
Samy F. Mahmoud ◽  
...  

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.


Weed Science ◽  
2021 ◽  
pp. 1-27
Author(s):  
Aseemjot Singh ◽  
Gulshan Mahajan ◽  
Bhagirath Singh Chauhan

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.


1970 ◽  
pp. 13-20
Author(s):  
A. A. Kandil, A. E. Sharief ◽  
Alkhamsa K. D. Botabaah

To explore the impact of antioxidants types and levels prim on seed germination characters of some bread wheat cultivars under salinity stress. An experiment accompanied in seed science lab during November and December 2016, to study the response of antioxidants seed prim of some bread wheat cultivars to germinate under salinity levels. The highest of final percentages of germination (96.8 %), higher percentages of germination energy (58.11 %), highest values of germination index (0.970) and a smaller amount of germination time (2.29 day) obtained from sown Misr 1 variety. The results showed that maximum of percentages of germination (91.15 %) and germination index (0.951) obtained from soaking in humic acid. The maximum percentages of energy of germination (41.21 %) and the less mean germination time (2.77 day from soaking grains in ascorbic acid compared with without antioxidants. Increasing antioxidant concentrations to 200 ppm produced the highest percentages of germination (91.61 %), energy of germination (37.63 %), germination index (0.953) and the lowermost of mean germination time (2.97 day) compared with without antioxidants and level of 100 ppm. Increasing salinity to 160 mM during germination of wheat cultivars significantly reduced percentages of germination by 18.5 %, energy of germination by 96.7 %, germination index by 18.6 % and mean germination time by 53.5 % compared with without salinity (control). Whereas, for reducing the gap between production and consumption, it could be recommended that soaking bread wheat in humic acid or ascorbic acid at 200 mM under salinity stress enhanced seed viability and advise to sown under saline new reclaimed soil.


2019 ◽  
Vol 48 (3) ◽  
pp. 449-455
Author(s):  
Muneeb Ahmad Wani ◽  
FU Khan ◽  
Imityaz Tahir Nazki ◽  
Ambreena Din ◽  
Shameen Iqbal ◽  
...  

Seeds of China aster cv. Powderpuff were subjected to two conditioning techniques viz, hydroconditioning and halo-conditioning at different levels of concentrations and subjected time durations, constituting a total of 16 treatment combinations (P1 - P15) along with control (P0). Hydro-priming for 12 hrs and the halo-priming with 2 % KNO3 for 12 hrs significantly improved germination, mean germination time, germination index, germination rate index and growth attributes of China aster cv. Powderpuff. Hydropriming being simple economical and eco/subject friendly and safe is recommended for effective germination and growth of China aster cv. Powderpuff.


2013 ◽  
Vol 31 (2) ◽  
pp. 249-257 ◽  
Author(s):  
H.H. Ali ◽  
A. Tanveer ◽  
M.A. Nadeem ◽  
H.N. Asghar ◽  
M.M. Javaid

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.


2017 ◽  
Vol 68 (6) ◽  
pp. 583 ◽  
Author(s):  
Iraj Nosratti ◽  
Samira Soltanabadi ◽  
Saeid J. Honarmand ◽  
Bhagirath S. Chauhan

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.


Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 481-485 ◽  
Author(s):  
Samuel G. L. Kleemann ◽  
Bhagirath S. Chauhan ◽  
Gurjeet S. Gill

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.


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