VIABLE SEED POPULATIONS IN ALBERTA PRAIRIE TOPSOILS

1969 ◽  
Vol 49 (1) ◽  
pp. 75-82 ◽  
Author(s):  
A. Johnston ◽  
S. Smoliak ◽  
P. W. Stringer
Keyword(s):  
Constant Temperature ◽  
Plant Succession ◽  
Viable Seed ◽  
Soil Temperatures ◽  
Viable Seeds ◽  
Number Of Seeds ◽  
Secondary Plant

Naturally disseminated seeds in soil obtained from native and cultivated grass stands were permitted to germinate and grow in pots at different soil temperatures or in greenhouse flats at a constant temperature. There were differences in numbers of seeds of various species germinating at various temperatures, but greatest differences were among sites. Grazing affected number of seeds of a species that germinated, with grasses decreasing and weeds increasing as intensity of grazing increased. Viable seeds ranged in number from 204 to 12,342/m2, Distribution of numbers of seeds in topsoils was skewed, with the mode at 780/m2. The presence of viable seeds of many species on or in the topsoil would, upon its disturbance, assure secondary plant succession.

scholarly journals Self fertility of pear varieties conditioned by natural self pollination (autogamy)

2000 ◽  
Vol 6 (1) ◽  
Author(s):  
J. Nyéki ◽  
M. Soltész ◽  
J. Iváncsics
Keyword(s):  
Fruit Set ◽  
Experimental Period ◽  
Gene Bank ◽  
Viable Seed ◽  
Ecological Conditions ◽  
Self Pollination ◽  
Seed Content ◽  
Viable Seeds ◽  
Number Of Seeds

Authors studied the autofertility depending on natural self pollination (autogamy) in 59 pear cultivars during 4 seasons at three locations with different ecological conditions (Helvetia, Kecskemet-Kisfai, Keszthely). The aim of the experiments was to determine the autogamous tendencies of varieties hitherto unexplored in the Hungarien gene bank, or to check data found in the literature. A total of 42616 isolated pear flowers produced 1.2% fruits with at least one viable seed in each. The 59 varieties observed did not set fruit by autogamy on either of the three sites during the four years of the study. The triploid (3n=51) varieties were entirely self-sterile. According to the highest autogamous fruit set, during the experimental period, the varieties have been assigned to four groups: (1) Entirely auto-incompatible (0% fruit set), (2) auto-incompatible (0.1 to 0.9%), slightly self fertile (1.1 to 5%) and (4) self fertile (5.1 to 10%). According to the number of viable seeds per fruit resulting from autogamy, the varieties are assigned to three groups as (1) low seed content (less than 3 seeds per fruit), medium (3.1 to 5) and (3) high (more than 5 seeds). Thus, the assessment of the number of seeds per fruit resulting from autogamy is indispensable as a proof of the absence of parthenocarpy.

Comparative effects of three seasons on seed population and viability of cattle, sheep and goat dungs in South-West Nigeria

2021 ◽  
Vol 32 (1) ◽  
pp. 94-101
Author(s):  
A. O. Jolaosho ◽  
J. A. Olanite ◽  
B. O. Oduguwa ◽  
E. A. O. Adekunle
Keyword(s):  
Rainy Season ◽  
Dry Season ◽  
Sheep And Goats ◽  
South West ◽  
Three Samples ◽  
Seed Population ◽  
Higher Weights ◽  
Ruminant Animals ◽  
Viable Seeds ◽  
Number Of Seeds

An experiment to determine the effects of seasonal variations on population and viability of seeds in the faeces of ruminant animals was conducted between April to December 2001 using two breeds of cattle, sheep and goats. Three samples were collected per breed from three animals that were tagged for uniformity of data collection. Sampling took place weekly, in the mornings before the animals were taken out for grazing. The highest (P<0.05) total number of seeds, seeds/g dry weights and total number of viable seeds were recovered from cattle, while the least were from goats, but the reverse was the case for percentage viability. The weights of the faeces were significantly (P<0.05) higher in the rainy season than the dry season. The weights of the faeces reduced gradually as the dry season sets in. Likewise, there were more seeds in the early rain than in the late rain and early dry season, with the percentage viability higher in the late rains and early dry season than the early rainy season. There were more broadleaved weeds and sedges in the early rain than late rain and early dry season but the reverse was the case for grasses. In conclusion, although there were more faeces and consequently more seed production in the rainy season, however, but the viability was lower than in the dry season. Also, seeds of broadleaved plants were more in the rainy season while those of grasses were more in the dry season. More seeds and number of viable seeds were recovered from the faeces of cattle than sheep and goats in all the seasons due to the higher weights of faeces but the percentage viability was higher for sheep and goat than cattle. 

Viable seed populations by soil depth and potential site recolonization after disturbance

1977 ◽  
Vol 55 (18) ◽  
pp. 2408-2412 ◽  
Author(s):  
Janice M. Moore ◽  
Ross W. Wein
Keyword(s):  
Soil Depth ◽  
Seedling Emergence ◽  
Mineral Soil ◽  
Organic Soil ◽  
Viable Seed ◽  
Soil Layers ◽  
Forest Experiment Station ◽  
Viable Seeds ◽  
Study Sites ◽  
Germination Experiment

Seedling emergence from organic and mineral soil layers was measured for nine study sites at the Acadia Forest Experiment Station near Fredericton, New Brunswick. The number of viable seeds showed a decrease from deciduous-dominated forest, to conifer-dominated forest, to organic soil study sites. Viable seed number varied from 3400/m2 for a deciduous-dominated forest study site to zero for a bog study site. Most seeds germinated from the upper organic soil layers of all study sites and were predominantly Rubus strigosus Michx. After the germination experiment, ungerminated seeds, which showed no viability by the tetrazolium test, were separated from the soil. These seeds were almost entirely Betula spp. and seed numbers were as high as 4200–9400/m2 for a deciduous-dominated forest. The applicability of the results to differing types of postdisturbance revegetation is discussed.

The impact of increased temperatures on germination patterns of semi-aquatic plants

2019 ◽  
Vol 29 (3) ◽  
pp. 204-209
Author(s):  
Jade Dessent ◽  
Susan Lawler ◽  
Daryl Nielsen
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Soil Seed Bank ◽  
Ambient Air ◽  
Future Climate Change ◽  
Ambient Air Temperature ◽  
Threshold Temperatures ◽  
Soil Temperatures ◽  
The Impact ◽  
Number Of Seeds

AbstractFuture climate change predictions indicate that there will be an increase in ambient air temperature. Increases in ambient air temperature will result in a corresponding increase in soil temperature. The consequences of further increases in soil temperature will potentially be detrimental for the soil seed bank of plants in terms of length of dormancy and viability of seeds. This experiment investigated the effect of different exposure temperatures and duration of exposure on the germination of semi-aquatic plant species. Seeds of four species (Alternanthera denticulata, Juncus usitatus, Persicaria lapathifolia and Persicaria prostrata) were exposed to temperatures ranging from 25 to 100°C for durations between 1 and 14 days, before being germinated in an incubator for 6 weeks. Germination occurred in all four species after exposure to temperatures ranging from 25 to 60°C. These temperatures appeared to promote germination as the temperature and duration of exposure increased. However, in P. lapathifolia and P. prostrata, the number of seeds germinating declined when exposed to 70°C and there was no germination for temperatures exceeding this. In contrast, A. denticulata and J. usitatus only began to decline when exposed to 80°C, with no germination at higher temperatures. These results suggest that soil temperatures exceeding potential threshold temperatures of 70 and 80°C will result in a decline in the number of seeds germinating and may potentially see a change in species distributions. As such soil temperatures are already being experienced throughout Australia, some species may already be close to their thermal threshold.

Population structure of two dominant gypsophyte shrubs through a secondary plant succession

2012 ◽  
Vol 76 ◽  
pp. 30-35 ◽  
Author(s):  
M. Eugenio ◽  
J.M. Olano ◽  
P. Ferrandis ◽  
E. Martínez-Duro ◽  
A. Escudero
Keyword(s):  
Population Structure ◽  
Plant Succession ◽  
Secondary Plant

Hard-seed content of alfalfa grown in Canada

1991 ◽  
Vol 71 (2) ◽  
pp. 437-444 ◽  
Author(s):  
D. T. Fairey ◽  
L. P. Lefkovitch
Keyword(s):  
British Columbia ◽  
Geographic Location ◽  
Viable Seed ◽  
Hard Seed ◽  
Peace River ◽  
Seed Content ◽  
River Region ◽  
Hard Seeds ◽  
Viable Seeds ◽  
Production Areas

The hard-seed content of alfalfa (Medicago spp.) grown in Canada in relation to genotype and geographic location of production was surveyed for the commercial growing regions in Manitoba, Saskatchewan, Alberta and British Columbia. The average hard-seed content of all pedigreed production over a 5-yr period, ranged from 22 to 37% and that in nonpedigreed production was between 14 and 30%. A database of the five widely grown cultivars revealed that the hard-seed content of alfalfa in the most northerly growing areas in the Peace River region of Alberta and British Columbia ranged from 31 to 51%, while hard seed content of alfalfa produced elsewhere varied from 22 to 38%. There was no apparent effect of latitude on the proportion of hard seeds, while there was a small increase for two of the five cultivars in production areas further west. Of particular interest was the trend in viable seed production. There was consistent evidence suggesting that the proportion of viable seeds decreased in production areas further north, but increased in production areas further west. However, the minimum viability was always in excess of 85%. There was no correlation between hard and viable seed. Key words: Medicago spp., alfalfa, lucerne, hard seeds, viable seeds

Crossability of naturalized and cultivated Lythrum taxa

1994 ◽  
Vol 72 (3) ◽  
pp. 337-341 ◽  
Author(s):  
Kimberly A. Ottenbreit ◽  
Richard J. Staniforth
Keyword(s):  
Key Words ◽  
Wild Population ◽  
Lythrum Salicaria ◽  
Purple Loosestrife ◽  
Wild Plants ◽  
High Fertility ◽  
Viable Seed ◽  
Viable Seeds ◽  
Pollination And Fertilization

Lythrum cultivars Morden Pink, Morden Gleam, and Dropmore Purple, and a wild population of Lythrum salicaria from Lockport, Manitoba were artificially self- and cross-pollinated. Success of pollination and fertilization was measured in terms of the percentage of resulting capsules and the average numbers of viable seeds per capsule. Germination tests were used to measure the viability of seeds produced as a result of successful crosses. Cultivars rarely produced seeds as a result of selfing but many crosses with wild plants or with other cultivars were fertile. As expected, legitimate (i.e., different style morphs) wild crosses were highly fertile, but other crosses gave high fertility, especially those in which 'Morden Gleam' was the provider of pollen or ovules. Although some sterility was indicated in 'Dropmore Purple' and perhaps 'Morden Pink', neither are sufficiently sterile to be considered safe for ornamental flower gardens. Most illegitimate crosses yielded greatly reduced seed outputs in comparison to legitimate crosses, but there were some exceptions. Germinability of ripe seeds from any cross was high and averaged 98%. Cultivars of Lythrum are capable of contributing viable seed and (or) pollen to the spread of purple loosestrife. The sale of cultivars, regardless of parentage, should be prohibited. Key words: purple loosestrife, Lythrum spp., interfertility, hybridization.

Impact of Clipping Timing on Japanese Hedgeparsley (Torilis japonica) Seed Production and Viability

2014 ◽  
Vol 7 (3) ◽  
pp. 511-516
Author(s):  
Mark J. Renz ◽  
R. Menyon Heflin
Keyword(s):  
United States ◽  
Seed Production ◽  
Management Strategy ◽  
Invasive Plant ◽  
Vegetative Stage ◽  
Effective Management ◽  
Viable Seed ◽  
Torilis Japonica ◽  
Forested Areas ◽  
Viable Seeds

AbstractJapanese hedgeparsley is a biennial plant that invades roadsides, rights-of way, and forested areas in the midwestern United States. Interest in managing populations by mechanical or hand-clipping techniques exists, but no information is available on the appropriate timing to maximize mortality and prevent the production of viable seed. To assess that, we applied clipping treatments at five periods throughout the summer to three Japanese hedgeparsley populations in southern Wisconsin and measured the number and viability of seeds produced by each plant during the year of treatment and the survival of plants clipped. Japanese hedgeparsley plants began producing seed by mid-July, but production was not maximized until early August. Viable seeds were not produced until early or mid-August, coinciding with the presence of ripened brown fruit. Clipping at any timing resulted in > 95% mortality by the fall of the treatment year. All plants that resprouted were in the vegetative stage when clipped, and no plants survived the following year. Results indicate that clipping Japanese hedgeparsley plants when they are in a reproductive phase before fruit turns brown is an effective management strategy for this invasive plant.

A note on the quantitative determination of carbohydrate in exudate from single cotton seeds and its significance

1969 ◽  
Vol 47 (10) ◽  
pp. 1521-1523 ◽  
Author(s):  
D. S. Hayman
Keyword(s):  
Quantitative Determination ◽  
Fungal Infection ◽  
Viable Seed ◽  
Damping Off ◽  
Factors Affecting ◽  
Cotton Seeds ◽  
Single Seeds ◽  
Viable Seeds ◽  
Repeated Samples

A method is described for studying carbohydrate exudation from single seeds. The advantages are that the apparatus for collecting exudates is simple, repeated samples may be obtained without removing or damaging the seeds, and exudation from viable seeds can be determined without including nonviable ones. Different seed lots can be compared on a viable seed basis, and in problems on damping-off diseases, this makes any correlations with susceptibility to preemergence fungal infection more valid. Various factors affecting seed exudation can be readily investigated.

scholarly journals A visual indicator for harvest of immature viable seed of indeterminate soybean genotypes.

1969 ◽  
Vol 77 (1-2) ◽  
pp. 33-43
Author(s):  
Silvia Rodríguez de Cianzio ◽  
Carlos E. Ortiz
Keyword(s):  
Reproductive Stage ◽  
Immature Seed ◽  
Viable Seed ◽  
Ambient Conditions ◽  
Seed Length ◽  
Maximum Width ◽  
General Field ◽  
Soybean Genotypes ◽  
Seed Width ◽  
Viable Seeds

Harvest of immature soybean (Glycine max (I.) Mem] seed is used in breeding nurseries to reduce generation length. Individual pods are harvested and usually dried intact at ambient conditions. Number of days after flowering (DAF) has been shown to be a good criterion to determine the appropriate time to harvest, but the method is time consuming on a large number of genotypes. The objective of this study was to identify a visual indicator of the appropriate stage for harvest of immature viable seeds. Two indeterminate cultivars, Lakota from Maturity Group (MG) I and BSR 301 from MG III, were planted in three environments at Isabela, PR. Harvest of pods began 28 DAF and continued every 3 days until 46 DAF. Field emergence, fresh and dry seed weights, seed width, seed length, seed thickness, pod angle, pod color and reproductive stage of individual plants were recorded. Results pointed out that the best visual indicator for the harvest of immature seed obtained from green pods was a combination of pod angle, seed dimensions, and reproductive stage of the plant. In general, field emergences of 70% or better were obtained with immature seed of green pods that could be bent no more than 30° before rupturing and that contained seeds at or near their maximum width, length, and thickness. These pods were harvested from plants that had reached reproductive stage R6.

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