Changes with time in the germination of buried scentless chamomile (Matricaria perforata Mérat) seeds

1995 ◽  
Vol 75 (1) ◽  
pp. 277-281 ◽  
Author(s):  
G. G. Bowes ◽  
A. G. Thomas ◽  
L. P. Lefkovitch
Keyword(s):  
Seed Bank ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Growing Season ◽  
Early Spring ◽  
First Year ◽  
Temperature Regimes ◽  
Buried Seed ◽  
Second Year ◽  
Persistent Seed Bank

Change with time in the germination of scentless chamomile (Matricaria perforata Mérat) seeds was investigated. Seeds were placed in nylon net bags, buried 7 cm deep in soil, exhumed at monthly intervals for 2 yr and allowed to germinate in temperature regimes of 10/2 °C, 20/5 °C, 25/10 °C and 35/20 °C (16/8 h), simulating temperatures found during early spring or late fall, spring or fall, summer and mid-summer on the soil surface, respectively. Exhumed and refrigerator-stored (2 °C) check seeds exhibited no yearly dormancy/nondormancy germination cycle, but mortality of buried seed increased to 36%, after 10 mo in contrast with that of the check seeds which remained low for two years. Light was required for germination during the first year but was not required for a portion of the seed during the second year. The retention of viability in buried seed explains the persistent seed bank and seedling emergence throughout the growing season when moisture and temperature are nonlimiting. Key words: Seed burial, germination, Matricaria perforata Mérat

Effects of Soil Texture and Seed Placement on Emergence of Four Subshrubs

Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 380-384 ◽  
Author(s):  
H. S. Mayeux
Keyword(s):  
Seed Bank ◽  
Soil Texture ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Seed Burial ◽  
Seed Placement ◽  
Buried Seed ◽  
Rate Of Emergence ◽  
Gutierrezia Sarothrae

Seedling emergence of broom snakeweed [Gutierrezia sarothrae(Pursh) Britt. & Rusby], threadleaf snakeweed [G. microcephala(DC.) Gray], common goldenweed [Isocoma coronopifolia(Gray) Greene], and false broomweed (Ericameria austrotexanaM.C. Johnston) was studied in the glasshouse. Germination of these species is known to be light-stimulated. Seed of all four subshrubs germinated readily if placed on the surface or partially pressed into the soil. Emergence was reduced by covering seed with soil to a depth of less than 1 mm. Few seedlings emerged from a depth of 1 cm, and none emerged from a depth of 2 cm. Rate of emergence also decreased with increasing depth of placement. Soil texture had little effect on emergence. Rapid germination on the soil surface is consistent with other aspects of the regenerative strategy of common goldenweed and false broomweed, which do not depend upon a buried seed bank for regeneration. Seed burial probably provides a form of enforced dormancy in the small, long-lived seeds of the two snakeweed species.

Seedbank Dynamics of Two Swallowwort (Vincetoxicum) Species

2017 ◽  
Vol 10 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Antonio DiTommaso ◽  
Lindsey R. Milbrath ◽  
Scott H. Morris ◽  
Charles L. Mohler ◽  
Jeromy Biazzo
Keyword(s):  
United States ◽  
Management Strategy ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Growing Season ◽  
First Year ◽  
Northeastern United States ◽  
The Third ◽  
Viable Seeds ◽  
Filled Seeds

Pale swallowwort and black swallowwort are European viny milkweeds that have become invasive in many habitats in the northeastern United States and southeastern Canada. A multiyear seedbank study was initiated in fall 2011 to assess annual emergence of seedlings and longevity of seeds of pale swallowwort and black swallowwort at four different burial depths (0, 1, 5, and 10 cm) over 4 yr. One hundred swallowwort seeds were sown in seed pans buried in individual pots, and emerged seedlings were counted and removed from May through September each year. A subset of seed pans was retrieved annually in October, and recovered seeds were counted and tested for viability. The majority of seedling emergence occurred during the first year (92% in 2012), and no new seedlings emerged in the third (2014) or fourth (2015) years. Pale swallowwort had relatively poor emergence at sowing depths of 0 cm (11%), 5 cm (6%), and 10 cm (0.05%—only one seedling), while 37% of pale swallowwort seeds emerged at 1 cm. The larger-seeded black swallowwort was more successful, with two-thirds of all sown seeds emerging at depths of 1 cm (71%) and 5 cm (66%), and 26% emerging at 10 cm. Only 16% of the surface-sown black swallowwort emerged. A large portion of the seeds that germinated at 10 cm, as well as at 5 cm for pale swallowwort, died before reaching the soil surface. Of filled seeds that were recovered in 2012 (black swallowwort at the 0-cm depth), 66% were viable. No viable seeds were recovered after the second growing season. Seeds recovered following the third year had become too deteriorated to accurately assess. Swallowwort seeds do not appear to survive more than 2 yr in the soil, at least in our experiment, suggesting that the elimination of seed production over 3 yr will exhaust the local seedbank. Seeds would need to be buried at least 10 cm for pale swallowwort but more than 10 cm for black swallowwort to prevent seedling emergence. Burial of swallowwort seeds as a management strategy may, however, only be practical in natural areas where high swallowwort densities occur.

Dormancy, germination, and sensitivity to salinity stress in five species of Potentilla (Rosaceae)

Botany ◽  
2019 ◽  
Vol 97 (8) ◽  
pp. 452-462 ◽  
Author(s):  
Jeremi Kołodziejek ◽  
Jacek Patykowski ◽  
Mateusz Wala
Keyword(s):  
Environmental Factors ◽  
Seed Bank ◽  
Salt Concentration ◽  
Soil Surface ◽  
Growing Season ◽  
Limiting Factors ◽  
Cold Stratification ◽  
Alkaline Soils ◽  
Persistent Seed Bank ◽  
Germination Requirements

Laboratory and greenhouse experiments were conducted to determine the effect of environmental factors on the germination and emergence of five species of Potentilla L. All of the species we studied differed in their germination requirements, and these could be related to their habitat/ecology. For all species, completion of germination was the highest at 25/15 °C with a 14 h photoperiod. Seeds of Potentilla argentea L. and P. inclinata Vill. completed germination immediately after ripening while seeds of P. aurea Borkh., P. incana P.Gaertn., B.Mey. & Scherb., and P. reptans L. needed a 16-week period of cold stratification to break dormancy. GA3 treatment did not substitute for cold stratification. The seeds of all species did not complete germination in darkness and showed maximal emergence on the soil surface, which suggests the formation of a persistent seed bank. Completion of germination was inhibited by decreasing osmotic potential and increasing salt concentration. The seeds of all species we studied can complete germination in both acidic and alkaline soils. These results suggest that under field conditions, if moisture and (or) salinity are not limiting factors and a seed is located on the soil surface, completion of germination of nondormant species (P. argentea and P. inclinata) is possible any month of the growing season.

scholarly journals PRODUCTIVITY OF PERENNIAL GRASSES AND MIXTURES WITH DIFFERENT SOWING DATES IN WESTERN SIBERIA

2020 ◽  
pp. 24-32
Author(s):  
V. A. Petruk
Keyword(s):  
Dry Matter ◽  
Crop Yields ◽  
Growing Season ◽  
Single Species ◽  
Field Studies ◽  
Perennial Grasses ◽  
First Year ◽  
Sowing Dates ◽  
Second Year ◽  
Sowing Period

The results of field studies for 2017 - 2019 are presented. yields of perennial grasses sown at different times of the growing season. Spring, summer, and winter sowing periods were compared. Alfalfa, clover, rump, and also their mixtures were sown in 2017 under the cover of barley. The value of the cover crop yield of spring and summer sowing periods did not differ significantly and amounted to 4-5 t / ha of absolutely dry matter. Winter barley crops have not formed. On average, over 2 years of use, the highest yields were observed in alfalfa-crust grass mixtures - 3.4 t / ha of absolutely dry matter. The lowest yield was obtained in the single-species seeding of the rump. Correspondingly, in the spring, summer and winter periods of sowing, the yield of rump was 1.6; 1.1 and 1.3 t / ha. With a late sowing period, the yield of perennial grasses is significantly lower compared to spring and summer. With winter sowing periods, the yield was the highest for grass stands of alfalfa and alfalfacrust grass mixture - 2.3 and 2.4 t / ha. It should be noted that in the second year of use, the yield by the sowing dates in single-species crops and grass mixtures is leveled. The winter crops of perennial grasses in the first year of use formed a low yield. Only in the second year (third year of life) the productivity of perennial grasses of winter sowing began to increase. Consequently, in the area under perennial grasses of the winter sowing period, during one growing season (the next year after sowing), the crop was not actually formed. Based on the data obtained, production can be recommended for spring and summer planting of perennial grasses under the cover of barley. The winter sowing period provides economically valuable crop yields only by the third year of life.

Uptake by grass and transfer to soil of nitrogen from 15N-labelled legume materials applied to a Rhodes grass pasture

1983 ◽  
Vol 34 (4) ◽  
pp. 367 ◽  
Author(s):  
I Vallis
Keyword(s):  
Linear Relationship ◽  
Dry Matter ◽  
Soil Surface ◽  
First Year ◽  
Rhodes Grass ◽  
Leaf Material ◽  
South Eastern ◽  
Non Linear ◽  
Second Year

Unground legume materials labelled with 15N were applied to the soil surface under a Rhodes grass pasture in south-eastern Queensland and the recovery of the applied 15N was followed over periods of 1-3 years. Comparisons were made between two legumes, Macroptiliurn atropurpureurn cv. Siratro and Desrnodiurn intorturn cv. Greenleaf, between leaf and stem materials of different nitrogen (N) concentrations (0.5-3.8% N), and between fresh and dried materials. After 1 year, 15N in the applied materials had decreased by 25-91%, and 7-25% was recovered in the Rhodes grass. Except for leaf material of Greenleaf, these changes showed a positive, non-linear relationship to the percentage of N (%N) in the applied materials. The changes for leaves of Greenleaf were less than would be predicted from their %N. Drying Siratro leaves and stems before applying them to the soil surface did not significantly affect the above changes. For N-poor materials (0.5-1.8% N) applied at 380-1360 g dry matter m-2, uptake of 15N by Rhodes grass was greater in the second year than in the first year, whereas for N-rich materials (3.8%N) applied at 140 g dry matter m-2 uptake of 15N in the second and third years was only 23 and 12% respectively of that in the first year.

scholarly journals Agronomic performance of sugarcane cultivated under quantities of sugarcane straw on the soil surface

2016 ◽  
Vol 37 (6) ◽  
pp. 3983 ◽  
Author(s):  
Mariana Alves de Oliveira ◽  
Claudemir Zucareli ◽  
Carmen Silvia Vieira Janeiro Neves ◽  
Allan Ricardo Domingues ◽  
Cristiane De Conti Medina ◽  
...  
Keyword(s):  
Crop Yield ◽  
Polynomial Regression ◽  
Soil Surface ◽  
First Year ◽  
Agronomic Performance ◽  
Sugarcane Variety ◽  
Crop Establishment ◽  
Sugarcane Straw ◽  
Second Year ◽  
Plot Design

Mechanized harvesting is increasingly present in the sugarcane production system. The straw removed during harvest can be converted to ethanol or used to generate electricity by burning, it is important to determine the amount of biomass that may be removed without damage to the crop. We evaluated the agronomic performance of sugarcane, variety RB92579, grown under different quantities of sugarcane straw on the soil surface, in the first and second year of cane crop. We used the experimental randomized block in split plot design, with four replications. In the first year the plots received five quantities of straw (0, 4.5, 9.0, 13.5 and 18 Mg ha-1), and six times assessments (60, 120, 180, 240, 300, 360 days after planting) arranged in the subplots. In the second year, the plots received the same quantities of straw and four times assessments (60, 120, 240 and 540 days after the regrowth) in subplots. Biometric indexes, components of production and crop yield were evaluated. The data were submitted to variance analysis and study of polynomial regression (p <0.05). Increasing quantities of sugarcane straw deposited on the soil surface reduces the number and diameter of the stem at the beginning crop establishment, and number of sheets for the first year. The maximum productivity of stems is achieved by maintaining 9,6 Mg ha-1 of straw for first year and 4,7 Mg ha-1 of straw for second year of cane crop.

The role of seed reproduction in the dynamics of established populations of Hieracium floribundum and a comparison with that of vegetative reproduction

1975 ◽  
Vol 53 (24) ◽  
pp. 3022-3031 ◽  
Author(s):  
A. G. Thomas ◽  
H. M. Dale
Keyword(s):  
Population Dynamics ◽  
Seedling Establishment ◽  
Vegetative Reproduction ◽  
Soil Surface ◽  
Growing Season ◽  
Population Based ◽  
Early Spring ◽  
Viable Seed ◽  
Density Patch

In the crowded parts of patches of Hieracium floribundum Wimm. and Grab., which were established for at least a decade in an ungrazed pasture, 7–10% of the population (3700 individuals/m2) flowered. Of the plants that flowered, 94% were alive a year later, but only 5% of these flowered. Abortion of flower heads was common; one half of all those which were initiated in early June had aborted by flowering time in early July. Freshly dispersed seed had a viability of 57%, which was reduced to 17% a year later, after its storage close to the soil surface. Less than 6% of the viable seed was innately dormant. Dry, laboratory-stored seed retained its viability for the year but was slower to germinate than soil-stored seed. In field conditions, germination was temperature inhibited during most of the growing season. Maximum daytime microsite temperatures of less than 32 °C, which is necessary for germination, were found to occur only in early spring and late fall. Successful seedling establishment accounts for 1% of the individuals in a crowded population. Based on the maximum sexual reproduction from plants in crowded populations, a seed has a probability of 1 in 20 000 of becoming an established seedling. A model of population dynamics in a high-density patch traces the fate of seedling establishment, surviving adults, and stolon-derived rosettes for a single year.

Factors affecting seed germination of annual sowthistle (Sonchus oleraceus) in southern Australia

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 854-860 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
Gurjeet Gill ◽  
Christopher Preston
Keyword(s):  
Seed Germination ◽  
Osmotic Potential ◽  
Field Experiments ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Factors Affecting ◽  
Control Programs ◽  
Buried Seed ◽  
Ph Range

Annual sowthistle has become more abundant under no-till systems in southern Australia. Increased knowledge of germination biology of annual sowthistle would facilitate development of effective weed control programs. The effects of environmental factors on germination and emergence of annual sowthistle seeds were examined in laboratory and field experiments. Seeds of annual sowthistle were able to germinate over a broad range of temperatures (25/15, 20/12, and 15/9 C day/night temperatures). Seed germination was favored by light; however, some germination occurred in the dark as well. Greater than 90% of seeds germinated at a low level of salinity (40 mM NaCl), and some seeds germinated even at 160 mM NaCl (7.5%). Germination decreased from 95% to 11% as osmotic potential increased from 0 to −0.6 MPa and was completely inhibited at osmotic potential greater than −0.6 MPa. Seed germination was greater than 90% over a pH range of 5 to 8, but declined to 77% at pH 10. Seedling emergence was the greatest (77%) for seeds present on the soil surface but declined with depth, and no seedlings emerged from a soil depth of 5 cm. In another experiment in which seeds were after-ripened at different depths in a field, seed decay was greater on the soil surface than at 2 or 5 cm depth. At the end of the growing season, there was a much greater persistence of buried seed (32 to 42%) than seeds present on the soil surface (8%). Greater persistence of buried seed could be due to dormancy enforced by dark in this species.

scholarly journals Effects of soil temperature regimes after fire on seed dormancy and germination in six Australian Fabaceae species

2010 ◽  
Vol 58 (7) ◽  
pp. 539 ◽  
Author(s):  
Victor M. Santana ◽  
Ross A. Bradstock ◽  
Mark K. J. Ooi ◽  
Andrew J. Denham ◽  
Tony D. Auld ◽  
...  
Keyword(s):  
Seed Dormancy ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Physical Dormancy ◽  
Temperature Regimes ◽  
Open Canopy ◽  
Eastern Australia ◽  
Soil Temperatures ◽  
Different Depths ◽  
Charred Wood

In addition to direct fire cues such as heat, smoke and charred wood, the passage of fire leads indirectly to changes in environmental conditions which may be able to break physical dormancy in hard-coated seeds. After a fire, the open canopy and the burnt material lying on the surface alter the thermal properties of the soil, resulting in elevated soil temperatures for long periods of time. We simulated daily temperature regimes experienced at different depths of soil profile after a summer fire. Our aim was to determine whether these temperature regimes and the duration of exposure (5, 15 and 30 days) play an important role breaking physical seed dormancy in six legumes from south-eastern Australia. Our results showed that simulated temperature regimes break seed dormancy. This effect is specially pronounced at temperatures that are expected to occur near the soil surface (0–2 cm depth). The duration of exposure interacts with temperature to break dormancy, with the highest germination rates reached after the longest duration and highest temperatures. However, the germination response varied among species. Therefore, this indirect post-fire cue could play a role in the regeneration of plant communities, and could stimulate seedling emergence independent of direct fire cues as well as in interaction with direct cues.

Soil seed bank and growth rates of an invasive species, Piper aduncum, in the lowlands of Papua New Guinea

2000 ◽  
Vol 16 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Howard M. Rogers ◽  
Alfred E. Hartemink
Keyword(s):  
Growth Rate ◽  
Papua New Guinea ◽  
Seed Bank ◽  
Dry Matter ◽  
Soil Seed Bank ◽  
Biomass Accumulation ◽  
New Guinea ◽  
First Year ◽  
Second Year ◽  
Piper Aduncum

Secondary fallow vegetation in parts of the Papua New Guinea lowlands is dominated by the shrub Piper aduncum L. that originates from South America. Here we report on its seed bank, growth rate and biomass accumulation. P. aduncum accounted for 69 % (408 m−2) of the seed bank in the forest and 53 % (1559 m−2) of the seed bank under fallow. About 90 % of the tree seed bank at the fallow site was dominated by P. aduncum whereas this was 78 % in the forest soil. Two-year-old P. aduncum had grown to 4.5 m height and had accumulated 48 Mg dry matter (DM) per ha of above ground biomass. The rate of biomass accumulation increased from 10 Mg DM ha−1 y−1 in the first year to 40 Mg DM ha−1 y−1 in the second year when 76 % of the biomass consisted of mainstems. The highest growth rate of 134 kg DM ha−1 d−1 occurred when P. aduncum was 17-mo-old. Aggressive invasion and monospecific stands of P. aduncum are explained by its dominance in the seed bank, fast growth, and high rates of biomass accumulation. P. aduncum is a major competitor to indigenous tree species and presents a threat to Papua New Guinea's rich biodiversity.

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