SEASONAL CHANGES IN THE GERMINATION RESPONSES OF FALL PANICUM TO TEMPERATURE AND LIGHT

1983 ◽  
Vol 63 (4) ◽  
pp. 973-979 ◽  
Author(s):  
JERRY M. BASKIN ◽  
CAROL C. BASKIN
Keyword(s):  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Temperature Cycle ◽  
Late Autumn ◽  
Fine Mesh ◽  
Temperature Regimes ◽  
June July ◽  
Panicum Dichotomiflorum ◽  
Autumn And Winter

Seeds of fall panicum (Panicum dichotomiflorum Michx.) were buried in fine-mesh nylon bags in soil and exposed to the annual temperature cycle. Fresh seeds and seeds exhumed after 1–15 mo were tested in light and darkness at five temperature regimes simulating those in the field from early spring through late autumn. Freshly matured seeds were dormant, but they came out of dormancy during late autumn and winter. Thus, by spring (April) seeds germinated to near 100% in light at 20/10, 25/15, 30/15 and 35/20 °C. However, except at 35/20 °C during June, July and August, the majority of the seeds required light for germination. In the field, germination does not begin until April when temperatures come within the range of those required for germination. Seeds retained the ability to germinate to a high percentage at 30/15 and 35/20 °C throughout the summer, but they lost this ability at 20/10 °C in early summer and at 25/15 °C in late summer. Thus, seeds stop germinating in early autumn when diurnal field temperatures decrease below about 20–25 °C maximum and 10–15 °C minimum. In autumn, seeds lost the ability to germinate even at the high temperatures, but they regained it by the following January.Key words: Germination, dormancy, after-ripening, fall panicum, summer annual, buried seeds

scholarly journals Cereal rye to extend the grazing season

1995 ◽  
pp. 115-118
Author(s):  
David H. Sample' ◽  
Henry M. Bartholomew ◽  
R.Marc Sulc
Keyword(s):  
Crude Protein ◽  
Late Summer ◽  
Early Spring ◽  
Grazing Season ◽  
Cereal Rye ◽  
Late Autumn ◽  
Protein Levels ◽  
Winter Grazing ◽  
Autumn And Winter ◽  
Made In

Eleven cereal rye (&cafe cereale) cultivars, one triticale (Triticum secale) and one winter wheat (Triticum aestivum) cultivar were evaluated in 2 studies for their ability to extend the grazing season into the autumn and winter in southern Ohio. The cultivars, 5 in 1993 and 9 in 1994, were randomly assigned to replicated plots and planted in late summer. Plots were harvested in late autumn to determine dry matter (DM) yield and forage quality. Results from the two years indicate significant differences (P=O.O5) between cultivars for DM yield, crude protein(CP) and NDF levels. DM yields ranged from 1389 to 2470 kg/ha (1993) and 1018 to 2 124 kg/ha (1994). Crude protein levels ranged from 25.2 to 27.9% (1993) and 28.8 to 33.7% (1994). A second harvest of the 1994 plots was made in early spring 1995 for continued evaluation. Statistically significant differences again existed between the stockpiled cultivars. DM yields ranged from 1979 to 2980 kg/ha while crude protein levels ranged between 21.5 and 27.0% of DM. Results support the conclusion that selected cereal rye cultivars can produce excellent yields of high quality forage for late autumn and winter grazing in the Ohio climate. Keywords: cereal rye, extended grazing season, Secale cereale, triticale, wheat

scholarly journals Spatial and temporal distribution of phytoplankton in Lake Skadar

2012 ◽  
Vol 64 (2) ◽  
pp. 585-595 ◽  
Author(s):  
Jelena Rakocevic
Keyword(s):  
Spatial Heterogeneity ◽  
Phytoplankton Community ◽  
General Pattern ◽  
Seasonal Succession ◽  
Temporal Distribution ◽  
Late Summer ◽  
Early Summer ◽  
Quantitative Composition ◽  
Autumn And Winter ◽  
Lake Skadar

Phytoplankton seasonal succession and spatial heterogeneity were studied in Lake Skadar from February to December 2004. A total of 167 taxa from 6 algal divisions were observed, with Bacillariophyta being best represented (52.8%). The general pattern of phytoplankton seasonal succession in Lake Skadar was: Bacillariophyta in the spring, Chlorophyta in early summer, Cyanobacteria and Chlorophyta in late summer and Bacillariophyta and Chlorophyta in autumn and winter. Distinct spatial heterogeneity was observed. The central, open part of the lake (pelagic zone) was characterized by dominant euplanktonic species, mostly diatoms, whereas the western and northwestern parts (more isolated and shallower) had higher abundance of greens and blue-greens and a higher percentage of resuspended benthic-epiphytic forms in the phytoplankton community. Comparison with former phytoplankton data showed distinct differences in terms of the qualitative and quantitative composition of the phytoplankton community of Lake Skadar, which indicates lake deterioration.

Seasonal Changes in the Germination Responses of Buried Witchgrass (Panicum capillare) Seeds

Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 22-24 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seasonal Changes ◽  
Late Summer ◽  
Late Spring ◽  
Seasonal Temperature ◽  
Temperature Changes ◽  
Late Autumn ◽  
Buried Seeds ◽  
Autumn And Winter

Buried seeds of witchgrass (Panicum capillare L., # PANCA) exposed to natural seasonal temperature changes in Lexington, KY, for 0 to 35 months exhibited annual dormancy/nondormancy cycles. Seeds were dormant at maturity in early October. During burial in late autumn and winter, fresh seeds and those that had been buried for 1 and 2 years became nondormant. Nondormant seeds germinated from 76 to 100% in light at daily thermoperiods of 15/6, 20/10, 25/15, 30/15, and 35/20 C, while in darkness they germinated from 1 to 24%. In late spring, seeds lost the ability to germinate in darkness, and by late summer 63 to 100% of them had lost the ability to germinate in light. As seeds became nondormant, they germinated (in light) at high (35/20, 30/15 C) and then at lower (25/15, 20/10, and 15/6 C) temperatures. As seeds reentered dormancy, they lost the ability to germinate (in light) at 15/6 C and at higher thermoperiods 2 to 3 months later.

scholarly journals Influence of a Municipal Solid Waste Landfill on the Surrounding Environment: Landfill Vegetation as a Potential Risk of Allergenic Pollen

2019 ◽  
Vol 16 (24) ◽  
pp. 5064 ◽  
Author(s):  
Magdalena Daria Vaverková ◽  
Dana Adamcová ◽  
Jan Winkler ◽  
Eugeniusz Koda ◽  
Jana Červenková ◽  
...  
Keyword(s):  
Plant Species ◽  
Low Cost ◽  
Late Summer ◽  
Cost Effective ◽  
Early Spring ◽  
Early Summer ◽  
Allergenic Pollen ◽  
Grass Species ◽  
Vegetation Monitoring ◽  
Growing Seasons

When the landfill use comes to end, important subsequent steps include aftercare, safety assurance, and ecological regeneration. Landfill revegetation is cost-effective and eco-friendly approach in the management of landfill areas, which serves the purpose of stabilization and provides a pleasant landscape. There are various vegetation types that can be planted, yet grass species are often used for low-cost reasons. Plants can be important sources of air pollution, particularly by grass pollen. The main goal of our study was to identify plant species that produce allergenic pollen. Long-term vegetation monitoring took place on three sites in the growing seasons of years 2008–2018. Studied objects were landfills located in the Czech Republic. The vegetation was assessed using a floristic survey of identified plant species. Plant species that produced allergens were recorded. During the monitoring, 298 plant species were determined. Plant species with allergenic pollen have a considerable share in the landfill vegetation. Thus, landfills are potential sources of various kinds of allergenic pollen. Moreover, our results indicated that there are three periods of pollen production: early spring, late spring, and early summer; late summer; and autumn. The second period is typical for the production of highly allergenic pollen by grasses. Most detected plant species with allergenic pollen are common for all monitored sites, which demonstrates that the vegetation of landfills is a significant source of allergenic pollen.

Reproduction of paua, Haliotis iris Gmelin 1791 (Mollusca:Gastropoda), in north-eastern New Zealand

1995 ◽  
Vol 46 (3) ◽  
pp. 617 ◽  
Author(s):  
SH Hooker ◽  
RG Creese
Keyword(s):  
New Zealand ◽  
Gonad Index ◽  
Sharp Decrease ◽  
Late Summer ◽  
Early Spring ◽  
Reproductive Pattern ◽  
Marine Gastropods ◽  
North Eastern ◽  
Males And Females ◽  
Autumn And Winter

An examination of the reproductive condition of a population of paua, H. iris, at Leigh in north-eastern New Zealand during 1986-87 revealed a long breeding season extending from late summer through autumn and winter and into early spring. Within this period, a sharp decrease of over 60% in the gonad index for both males and females indicated major spawning events in July and October. A smaller decrease in the gonad index in March suggested a third, minor spawning. These spawning events were confirmed by regular examination of histological sections of gonadal material. This breeding pattern is different from that previously described for southern localities in New Zealand, where spawning activity is limited to a four-month period from late summer into autumn. Paua in this northern population had a sex ratio slightly biased towards males (1 female to every 1.3 males) and achieved reproductive maturity between the sizes of 48 and 60 mm shell length. These features are also different from those described for southern populations of H. iris. These findings highlight the need to take regional differences in reproductive pattern into account when describing the population dynamics of marine gastropods.

502. The vitamin A potency of New Zealand butter

1953 ◽  
Vol 20 (1) ◽  
pp. 76-100 ◽  
Author(s):  
A. K. R. McDowell ◽  
F. H. McDowall
Keyword(s):  
New Zealand ◽  
Vitamin A ◽  
Northern Hemisphere ◽  
Seasonal Variations ◽  
Late Summer ◽  
Early Spring ◽  
Seasonal Trends ◽  
Late Autumn ◽  
Grazing Period ◽  
Summer Grazing

Results of a survey of the carotene and vitamin A contents, and of the vitamin A potency, of New Zealand butterfat and butter, are presented. The butter samples were drawn from twenty representative commercial factories at fortnightly intervals over three successive years (1946–8). The survey covers the analysis of 1517 samples of fresh butter and 670 samples of stored butter.There were uniform and regularly recurring seasonal variations in both carotene and vitamin A contents of butterfats from all North Island districts. Maximum values were found in the late-autumn/winter/early-spring, and minimum values in the late-summer/early-autumn butterfats. The seasonal trends were thus distinctly different from those which have been reported for northern hemisphere butterfats, for which the maximum values are commonly found during the summer grazing period.The seasonal variations in carotene and vitamin A contents of South Island butterfat were less marked and less consistent than those in the corresponding values for North Island butterfat.

Sub-seasonal streamflow predictions by combining numerical weather models and re-analysis data in alpine catchments

2021 ◽  
Author(s):  
Mattia Zaramella ◽  
Susen Shtrestha ◽  
Mattia Callegari ◽  
Alice Crespi ◽  
Felix Greifeneder ◽  
...  
Keyword(s):  
Model Simulation ◽  
Late Summer ◽  
Analysis Data ◽  
Early Spring ◽  
Early Summer ◽  
Lead Times ◽  
Streamflow Prediction ◽  
Reanalysis Dataset ◽  
Numerical Weather ◽  
Basin Scale

<p>The European Center for Medium-Range Weather Forecasts (ECMWF) has presented in 2017 its latest seasonal forecasting system, SEAS5, available at 1° spatial resolution and daily timestep. More recently, in 2019, the ERA5 reanalysis dataset was released, replacing ERA Interim in providing climatic variables at a finer spatial and temporal resolution (30 km and hourly respectively). The use of such numerical weather predictions and re-analysis data has increased following the need for skills in planning water resources and preventing hydrogeological risk, as demanded by policy makers, energy stakeholders and public authorities. In this work, we apply at a sub-seasonal timescale the ECMWF-SEAS5 hindcast dataset to assess its prediction skills in the upper Adige river basin in the Eastern Italian Alps. The classical Extended Streamflow Prediction (ESP) framework was designated as a benchmark to assess ECMWF scores over the reference, a model simulation calibrated and validated on the runoff observed from 16 sub-basins and size spanning from 50 to 6900 km<sup>2</sup>. Before application, ECMWF was downscaled and adjusted to the ERA5 re-analysis data by means of a Quantile Mapping (QM) technique. The analysis was conducted over 23 hindcast years from 1993 to 2016 exploiting the semi-distributed basin-scale hydrological model (ICHYMOD). We showed that the sub seasonal QPF-based forecasts have advantages over the ESP, although, generally their skill deteriorates in lead times after day 15. Moreover, ECMWF predictions better perform during early-spring snowmelt and late summer. During late spring and early summer, the forecast skills of the two frameworks vary from basin to basin depending on specific features and lead times.  </p>

scholarly journals Population biology of eyeflukes in fish from a large fluvial ecosystem: the importance of gulls and habitat characteristics

2001 ◽  
Vol 79 (6) ◽  
pp. 1102-1113 ◽  
Author(s):  
D J Marcogliese ◽  
S Compagna ◽  
E Bergeron ◽  
J D McLaughlin
Keyword(s):  
Population Biology ◽  
Yellow Perch ◽  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Habitat Characteristics ◽  
Vitreous Humour ◽  
Late Fall ◽  
Golden Shiners ◽  
St Lawrence River

Spottail shiners (Notropis hudsonius) were monitored for eyeflukes monthly at four sites in the St. Lawrence River, Quebec, from spring through autumn in 1997 and 1998. In general, mean abundance of Diplostomum spp. in the lens of spottail shiners was highest at sites near large ring-billed gull (Larus delawarensis) colonies and was higher in 1998 than in 1997. Population studies demonstrated a major period of recruitment in the late summer – early autumn. Mean abundance increased between November and May, when sampling was logistically not possible, reflecting late-fall or early-spring recruitment. Golden shiners (Notemigonus crysoleucas) and small yellow perch (Perca flavescens) were monitored at a single site (Île aux Ours) in 1997 and 1998. Mean abundance of Diplostomum spp. in the lens of golden shiners at Île aux Ours was higher in 1998 than in 1997. Recruitment occurred in the early summer and between November and May, suggesting late-fall or early-spring transmission. Mean abundance decreased between August and October in both years. Yellow perch at Île aux Ours were infected with four different parasite species in their eyes. Mean abundance of Diplostomum spp. in the vitreous humour or retina increased during the summer and fall and then decreased between the fall and following spring. Diplostomum spp. in the lens increased in abundance in the early summer, and then decreased during the fall. Both Tylodelphys scheuringi and Neascus spp. in the vitreous humour were more abundant in 0+ than in 1+ perch. Mean abundance of T. scheuringi increased over the summer in 1997 and then dropped to zero in the same cohort over winter, suggesting that the parasite lives for only 1 year. Neascus spp. only were found in 1998. Distributional data, together with seasonal information, suggest that habitat characteristics contribute significantly to the abundance of Diplostomum spp. along the St. Lawrence River. Proximity to gull colonies enhances abundance, but higher rates of predation at wetland sites depress abundance and restrict the accumulation of parasites.

Seasonal changes in the germination responses of seeds of Veronica peregrina during burial, and ecological implications

1983 ◽  
Vol 61 (12) ◽  
pp. 3332-3336 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seasonal Changes ◽  
Natural Habitat ◽  
General Pattern ◽  
Late Summer ◽  
Early Spring ◽  
Late Winter ◽  
Seasonal Temperature ◽  
Light In August ◽  
Late Autumn ◽  
Response To Temperature

Seeds of Veronica peregrina collected from a field population in central Kentucky were buried in soil and exposed to seasonal temperature changes. Fresh seeds and those exhumed after 1–26 months were tested in light and darkness at five thermoperiods simulating those in the natural habitat from early spring through late autumn. Freshly matured seeds were dormant, but they came out of dormancy in June and July and germinated to 98–100% in light in August at thermoperiods of 20:10, 25:15, 30:15, and 35:20 °C. Seeds retained the ability to germinate to high percentages at these temperatures until late winter and spring, but they never germinated to high percentages in darkness. Thus, in the natural habitat in July and August germination is prevented only by darkness and (or) insufficient soil moisture. At simulated habitat temperatures, seeds germinated to 88–100% in March and April but to only 21–69% in May and June. Seeds incubated at 15:6 °C showed a decline in germination percentages in late summer and autumn and an increase during late autumn and winter. The same general pattern of seasonal changes in germination response to temperature occurred during the 2nd year of burial.

Oribatida (Acari) associated with three species of Sphagnum at Spruce Hole Bog, New Hampshire, U.S.A.

1996 ◽  
Vol 74 (9) ◽  
pp. 1706-1712 ◽  
Author(s):  
Gay M. Donaldson
Keyword(s):  
New Hampshire ◽  
Water Surface ◽  
New Records ◽  
Oribatid Mite ◽  
Late Summer ◽  
Mite Species ◽  
Early Spring ◽  
Early Summer ◽  
Order Four ◽  
Oribatid Mite Species

In a topogenous, pond-border, moat bog in New Hampshire, 19 220 adult oribatid mites from 47 species were collected from 3 species of Sphagnum in the early spring, early summer, and late summer. The Sphagnum species were distributed along a gradient of increasing height above the water surface and decreasing shade in the order S. cuspidatum, S. recurvum, and S. magellanicum. Oribatid mite species diversity increased along this gradient in the same order. Four species of the genus Limnozetes were associated with Sphagnum spp. in this bog; they differed in habitat preference among the Sphagnum species. New records for New Hampshire were established for 19 oribatid mite species.

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