Seed Germination Ecophysiology of Meadow Salsify (Tragopogon pratensis) and Western Salsify (T. dubius)

Weed Science ◽  
1993 ◽  
Vol 41 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Meiqin Qi ◽  
Mahesh K. Upadhyaya
Keyword(s):  
Seed Germination ◽  
Storage Temperature ◽  
Seedling Emergence ◽  
Separate Study ◽  
Optimum Temperature ◽  
Seedling Mortality ◽  
Secondary Dormancy ◽  
Persistence Strategies

To understand persistence strategies of meadow and western salsify, ecophysiological characteristics of their seed germination were studied. Anaerobiosis (immersion in deoxygenated water) induced secondary dormancy in seeds of both species. Dormancy could be induced in 86% of meadow salsify seeds and in 65% of western salsify seeds by a 1-d anaerobiosis treatment. The induced dormancy was gradually released during storage of air-dried secondary dormant meadow salsify seeds, and the rate of this release was influenced by storage temperature; 30 C was more effective than 10 or 20 C in releasing secondary dormancy. These results suggest that the two species may rely on induced dormancy as an option in their persistence strategy. The optimum temperature for germination of nondormant seeds of both species was 15 C. Maximum germination percentages for both species were established within 4 to 6 d of incubation at 15 C and within 14 to 28 d of incubation at 25 C. Nondormant seeds did not germinate below 10 or above 30 C. Stratification (at 5 C for 2 to 10 wk) stimulated germination of secondary dormant seeds of meadow salsify. This stratification requirement can be important in preventing germination of dormant salsify seeds in the fall, thereby avoiding high seedling mortality in the winter. Light (red and far-red) had no effect on germination of seeds in secondary dormancy. In a separate study, seeds of both species were planted in pots at depths of 2 to 14 cm and seedling emergence was observed. Maximum emergence occurred when seeds were buried 2 cm deep. Seeds planted 8 cm or deeper germinated but did not emerge.

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 Caracterization of seed germination of Zephyranthes sylvatica (Mart.) Baker (Amarilidacea)

2014 ◽  
Vol 36 (2) ◽  
pp. 178-185
Author(s):  
Mayara Wesley da Silva ◽  
Laise Guerra Barbosa ◽  
José Eduardo Santos Barboza da Silva ◽  
Keylan Silva Guirra ◽  
Diego Rangel da Silva Gama ◽  
...  
Keyword(s):  
Salt Stress ◽  
Seed Germination ◽  
Seedling Emergence ◽  
Primary Root ◽  
Seed Vigor ◽  
Optimum Temperature ◽  
Salt Stress Tolerance ◽  
Germination Process ◽  
The Ideal

Zephyranthes sylvatica is a beautiful lily, endemic from the Brazilian Caatinga. Although it has a great ornamental potential, little is known about this species, especially regarding its seeds germination process. Aiming to characterize the germination of Z. sylvatica seeds, we studied its imbibition curve, optimum temperature and substrate for germination and seedling emergence, osmotic and salt stress tolerance, as well as the tolerance to frosting/ defrosting, which indicates long term cryostorage potential. The germination of Z. sylvatica presents a triphasic model of imbibition, in which the primary root protrusion occurs after 72 hours of imbibition. The ideal conditions for evaluating seed germination of Z. sylvatica is 25 ºC, in paper rolls. These seeds are highly tolerant to osmotic stress, but not to salt stress. Z. sylvatica seeds can be cryopreservated without loss of germination and seed vigor.

Seed germination, seedling emergence, and seed bank ecology of sweet fern (Comptonia peregrina(L.) Coult.)

1999 ◽  
Vol 77 (9) ◽  
pp. 1378-1386
Author(s):  
Melissa A Dow ◽  
Christa R Schwintzer
Keyword(s):  
Seed Germination ◽  
Seed Bank ◽  
Temperature Fluctuation ◽  
Seedling Emergence ◽  
Chilling Temperature ◽  
Secondary Dormancy ◽  
Forest Sites ◽  
Moist Chilling ◽  
Adjacent Field ◽  
Dormancy Cycles

We examined seed-bank seeds of sweet fern (Comptonia peregrina (L.) Coult.), an actinorhizal nitrogen-fixing shrub, to determine their distribution in the soil and to identify the factors that stimulate them to germinate following removal of the vegetation. Seeds were extracted from the soil of adjacent field and forest sites currently lacking sweet fern in Orono, Maine. Both sites contained approximately 2000 seeds·m-2with the greatest concentration at a depth of 60-80 mm. The seeds were 4.0-5.5 mm long, enclosed by a pitted, woody pericarp, and 8% contained embryos. Many seedlings emerged in disturbed plots (vegetation removed and upper soil mixed) in May and June 1997, but none appeared after 24 July. Seeds collected in May and June germinated readily in a growth chamber (30-45% germination) whereas only 2-5% of July- and August-collected seeds germinated indicating induction of secondary dormancy. August-collected seeds showed strong germination after >=15 days of moist chilling at 4°C indicating relief of secondary dormancy by chilling. Temperature fluctuation with an amplitude of 10°C strongly stimulated germination. Presence of annual secondary dormancy cycles and stimulation by strong temperature fluctuation assures that seed-bank seeds germinate under conditions that allow the seedlings to become established.Key words: actinorhizal plants, Comptonia peregrina, germination ecophysiology, secondary dormancy, seed bank, seedling emergence.

scholarly journals FACTORS INFLUENCING PREEMERGENCE DAMPING-OFF AND SEEDLING BLIGHT OF SH-2 SWEET CORN CAUSED BY PENICILLIUM OXALICUM

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 743b-743
Author(s):  
Nancy W. Callan ◽  
Don E. Mathre ◽  
James B. Miller
Keyword(s):  
Seed Germination ◽  
Sweet Corn ◽  
Seedling Emergence ◽  
Penicillium Oxalicum ◽  
Damping Off ◽  
Seedling Blight ◽  
Seedling Mortality ◽  
Factors Influencing ◽  
Visible Growth ◽  
Soil Temperatures

Penicillium oxalicum is a seed- and soilborne fungal pathogen that causes preemergence damping-off and postemergence seedling blight of sweet corn, While seed infection and infestation by P. oxalicum is common, the amount of injury observed in the field is variable. Our objective was to determine factors influencing the occurrence and severity of disease due to P. oxalicum. Inoculation of sh-2 sweet corn seeds with conidia of P. oxalicum reduced seedling emergence and resulted in seedling mortality. Disease severity in the greenhouse and the field was greater as inoculum density increased from ≈ 102 to 106 conidia per seed. Increasing soil temperatures after planting inoculated seed resulted in more preemergence damping-off. Penicillium oxalicum is capable of growth and sporulation in soil that is too dry for seed germination. Nontreated (naturally infected) sh-2 sweet corn seeds or seeds inoculated with P. oxalicum were incubated in pasteurized soil that had been adjusted to various moisture levels-all too low for seed germination. Increasing soil moisture was associated with visible growth of Penicillium spp. on seed after incubation, and greater levels of damping-off and seedling blight when the seed was planted.

Influence of Environmental Factors on Seed Germination and Seedling Emergence of American Sloughgrass (Beckmannia syzigachne)

Weed Science ◽  
2008 ◽  
Vol 56 (4) ◽  
pp. 529-533 ◽  
Author(s):  
Na Rao ◽  
Liyao Dong ◽  
Jun Li ◽  
Hongjun Zhang
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Osmotic Potential ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Burial Depth ◽  
Optimum Temperature ◽  
Ph Values

The influence of environmental factors on seed germination and seedling emergence of American sloughgrass was studied in laboratory and greenhouse conditions. The optimum temperature for seed germination was 10 C and light was not necessary. Seed germination was sensitive to osmotic potential and completely inhibited at an osmotic potential of −0.6 MPa, but it was quite tolerant to salinity: germination occurred even at 160 mM NaCl (36%). More than 80% of seeds germinated at pH values ranging between 4 and 10. Seedling emergence was highest when seeds were placed on the soil surface (91%) but declined with burial depth. Few (3%) seedlings emerged when seeds were planted at a depth of 5 cm. Information gained in this study will lead to a better understanding of the requirements for American sloughgrass germination and emergence.

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.

ESTIMATION OF GROWTH – TIME TEMPERATURE CHARACTERISTICS FOR ISOLATES OF FOMES PINI, A HEART ROT FUNGUS

1964 ◽  
Vol 42 (12) ◽  
pp. 1635-1652 ◽  
Author(s):  
Lee A. Paine ◽  
Gideon Schwarzbart ◽  
William G. O'Regan
Keyword(s):  
Regression Analysis ◽  
Cross Section ◽  
Growth Pattern ◽  
Storage Temperature ◽  
Three Dimensional ◽  
Douglas Fir ◽  
Growth Time ◽  
Optimum Temperature ◽  
Analysis Techniques ◽  
White Fir

Regression analysis techniques were applied to an estimation of three-dimensional surfaces representing the growth of Fomes pini as a function of time and temperature. These methods were judged to be valuable in their economy of data and in their provision of readily available plotting points for any desired cross section of the surface.The growth pattern of F. pini taken from Douglas fir was distinct from that of the form of F. pini found on nearby white fir. Growth of isolates from Douglas fir was more than twice that of white fir isolates after 18 days at near-optimum temperatures on malt agar. Estimates of growth trends and optimum temperatures were examined both for individual isolates of F. pini and for averages of isolates from the two host species, Douglas fir and white fir. Results suggest that chronological changes in the optimum temperature may be affected by the relation between the storage temperature preceding initial measurements and the terminal optimum temperature.

scholarly journals Factors affecting Cyperus difformis seed germination and seedling emergence

2013 ◽  
Vol 31 (4) ◽  
pp. 823-832 ◽  
Author(s):  
A. Derakhshan ◽  
J. Gherekhloo
Keyword(s):  
Seed Germination ◽  
Integrated Management ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Soil Surface ◽  
Weed Species ◽  
Factors Affecting ◽  
Cyperus Difformis ◽  
Emergence Patterns

Specific knowledge about the dormancy, germination, and emergence patterns of weed species aids the development of integrated management strategies. Laboratory studies were conducted to determine the effect of several environmental factors on seed germination and seedling emergence of Cyperus difformis. Germination of freshly harvested seeds was inhibited by darkness; however, when seeds were subsequently transferred to complete light they germinated readily. Our results showed that 2 wk of cold stratification overcome the light requirement for germination. Seeds of C. difformis were able to germinate over a broad range of temperatures (25/15, 30/20, 35/25, and 40/30 ºC day/night). The response of germination rate to temperature was described as a non-linear function. Based on model outputs, the base, the optimum and the ceiling temperatures were estimated as 14.81, 37.72 and 45 ºC, respectively. A temperature of 120 ºC for a 5 min was required to inhibit 50% of maximum germination. The osmotic potential and salinity required for 50% inhibition of maximum germination were -0.47 MPa and 135.57 mM, respectively. High percentage of seed germination (89%) was observed at pH=6 and decreased to 12% at alkaline medium (pH 9) pH. Seeds sown on the soil surface gave the greatest percentage of seedling emergence, and no seedlings emerged from seeds buried in soil at depths of 1 cm.

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