Seasonal distribution of loline alkaloid concentration in meadow fescue infected with Neotyphodium uncinatum

2011 ◽  
Vol 62 (7) ◽  
pp. 603 ◽  
Author(s):  
Brian Patchett ◽  
Ravi Gooneratne ◽  
Lester Fletcher ◽  
Bruce Chapman
Keyword(s):  
Late Summer ◽  
Seasonal Distribution ◽  
Late Spring ◽  
Selected Lines ◽  
Meadow Fescue ◽  
Late Autumn ◽  
Early Autumn ◽  
Harvest Dates ◽  
Loline Alkaloids ◽  
First Time

Loline alkaloids are present in meadow fescue containing the endophyte (Neotyphodium uncinatum Gams, Petrini and Schmidt) (Clavicipitacae). Root, crown and shoot loline alkaloid concentrations in 10 selected lines from meadow fescue ecotypes are reported for the first time, from a Canterbury farm during 2004–05. The concentrations of four loline alkaloid derivatives, N-formyl loline (NFL), N-acetyl loline (NAL), N-acetyl norloline (NANL) and N-methyl loline (NML), in these lines (each line represented by one genotype) were determined at four harvest dates during late spring, late summer, and early and late autumn. There were marked differences in loline alkaloid concentration between lines and seasons. Maximum shoot loline concentration was recorded in summer (up to 2860 µg/g in Fp408). Root loline alkaloid concentration was substantially higher in late autumn (up to 790 µg/g in Fp408) and the shoot concentration correspondingly lower than in spring, summer and early autumn suggesting loline alkaloid transportation from shoots to roots. In the lines tested at each of the four harvest dates in spring, summer, and autumn, the root, crown, and shoot alkaloid concentration with minor exceptions was NFL > NAL > NANL > NML.

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 Measurement report: characteristics of clear-day convective boundary layer and associated entrainment zone as observed by a ground-based polarization lidar over Wuhan (30.5° N, 114.4° E)

2021 ◽  
Vol 21 (4) ◽  
pp. 2981-2998
Author(s):  
Fuchao Liu ◽  
Fan Yi ◽  
Zhenping Yin ◽  
Yunpeng Zhang ◽  
Yun He ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Growth Stage ◽  
Late Spring ◽  
Atmospheric Measurements ◽  
Convective Boundary ◽  
Late Autumn ◽  
Early Autumn ◽  
Entrainment Zone ◽  
Aerosol Backscatter

Abstract. Knowledge of the convective boundary layer (CBL) and associated entrainment zone (EZ) is important for understanding land–atmosphere interactions and assessing the living conditions in the biosphere. A tilted 532 nm polarization lidar (30∘ off zenith) has been used for the routine atmospheric measurements with 10 s time and 6.5 m height resolution over Wuhan (30.5∘ N, 114.4∘ E). From lidar-retrieved aerosol backscatter, instantaneous atmospheric boundary layer (ABL) depths are obtained using the logarithm gradient method and Harr wavelet transform method, while hourly mean ABL depths are obtained using the variance method. A new approach utilizing the full width at half maximum of the variance profile of aerosol backscatter ratio fluctuations is proposed to determine the entrainment zone thickness (EZT). Four typical clear-day observational cases in different seasons are presented. The CBL evolution is described and studied in four developing stages (formation, growth, quasi-stationary and decay); the instantaneous CBL depths exhibited different fluctuation magnitudes in the four stages and fluctuations at the growth stage were generally larger. The EZT is investigated for the same statistical time interval of 09:00–19:00 LT. It is found that the winter and late autumn cases had an overall smaller mean (mean) and standard deviation (SD) of EZT data compared to those of the late spring and early autumn cases. This statistical conclusion was also true for each of the four developing stages. In addition, compared to those of the late spring and early autumn cases, the winter and late autumn cases had larger percentages of EZT falling into the subranges of 0–50 m but smaller percentages of EZT falling into the subranges of > 150 m. It seems that both the EZT statistics (mean and SD) and percentage of larger EZT values provide measures of entrainment intensity. Common statistical characteristics also existed. All four cases showed moderate variations of the mean of the EZT from stage to stage. The growth stage always had the largest mean and SD of the EZT and the quasi-stationary stage usually the smallest SD of the EZT. For all four stages, most EZT values fell into the 50–150 m subrange; the overall percentage of the EZT falling into the 50–150 m subrange between 09:00 and 19:00 LT was > 67 % for all four cases. We believe that the lidar-derived characteristics of the clear-day CBL and associated EZ can contribute to improving our understanding of the structures and variations of the CBL as well as providing a quantitatively observational basis for EZ parameterization in numerical models.

Recovery of 15N-labelled fertilizers applied to bromegrass on a Thin Black Chernozem soil

1995 ◽  
Vol 75 (4) ◽  
pp. 539-542 ◽  
Author(s):  
S. S. Malhi ◽  
M. Nyborg ◽  
J. T. Harapiak
Keyword(s):  
Ammonium Nitrate ◽  
Early Spring ◽  
Late Spring ◽  
N Recovery ◽  
Chernozem Soil ◽  
Band Placement ◽  
Late Autumn ◽  
Time Of Application ◽  
Broadcast Application ◽  
Early Autumn

The availability of N fertilizers on established grass stands is a function of such processes as immobilization, gaseous loss, leaching and position of applied N. A field experiment was conducted on a Thin Black Chernozem soil at Crossfield, Alberta to determine the effect of source, time and method of application on the recovery of 15N-labelled fertilizers applied to smooth bromegrass (Bromus inermis Leyss.). The treatments included two sources of N [urea and ammonium nitrate (AN)], four application times (early autumn, late autumn, early spring and late spring) and two methods of placement (surface-broadcast and subsurface banding). In most cases the 15N recovery in soil did not differ much between urea and AN. However, when urea was surface-broadcast, there was, on average, 10.2% less 15N recovery in plants than AN. The N recovery for late spring > early spring > late autumn = early autumn. When urea was banded 4 cm deep into the soil, N recovery in plants increased significantly compared with its surface-broadcast application. However, this was not observed when the source of N was AN. Banding generally increased the amount of immobilized N present in the soil and N recovery. We concluded that the N recovery in plants and in plants plus soil was less for urea than for AN and was less with autumn broadcast N application than with spring broadcast application. Key words: Ammonium nitrate, band placement, bromegrass, recovery of N, surface-broadcast, time of application, urea

Seasonal changes in leaf and stem loline alkaloids in meadow fescue

2011 ◽  
Vol 62 (3) ◽  
pp. 261 ◽  
Author(s):  
Brian Patchett ◽  
Ravi Gooneratne ◽  
Lester Fletcher ◽  
Bruce Chapman
Keyword(s):  
Seasonal Changes ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Sharp Decline ◽  
Meadow Fescue ◽  
Accumulation Pattern ◽  
Loline Alkaloids

Leaf and stem loline alkaloid concentration in 10 European meadow fescue (Festuca pratensis Huds.) lines grown in a field in Canterbury, New Zealand, were determined in samples collected six times between early spring 2004 and late autumn 2005. Significant differences in loline alkaloid concentrations were noted between lines and between harvest times. Higher total loline alkaloid concentrations (up to 4990 µg g–1) were found in stems compared to leaf (up to 1770 µg g–1). However, the seasonal accumulation pattern of different loline alkaloid concentrations in leaf and stem varied. In most lines, stem loline concentration peaked sharply in late spring and declined during early summer and autumn. The seasonal pattern of leaf loline alkaloid concentration followed the stem concentration except for a sharp decline in early summer followed by an increase in late summer. In most instances, the concentration of N-formyl loline was the highest > N-acetyl loline > N-acetyl norloline > N-methyl loline. The possible role of stem and leaf loline alkaloids to deter pasture-feeding insects is briefly discussed.

Facts and Myths about Seasonal Variation in Suicide

2007 ◽  
Vol 100 (3) ◽  
pp. 810-814 ◽  
Author(s):  
Martin Voracek ◽  
Ulrich S. Tran ◽  
Gernot Sonneck
Keyword(s):  
Seasonal Variation ◽  
Northern Hemisphere ◽  
Seasonal Pattern ◽  
Early Summer ◽  
Seasonal Distribution ◽  
Late Spring ◽  
Early Winter ◽  
Late Autumn ◽  
Everyday Reasoning

The prevalence of suicide presents a universal seasonal pattern. In the Northern hemisphere, suicides peak during spring and early summer and the trough occurs during winter. This peculiar pattern might be counterintuitive for everyday reasoning. Data from 1,093 medical and psychology undergraduates from Austria (382 men and 711 women; M age 25.0 yr., SD = 6.6) indicated an almost perfectly reversed pattern of beliefs about suicide seasonality compared with the actual seasonal distribution. The vast majority of respondents believed the peak to be located in late autumn and early winter and the trough occurring in late spring and the summer months. Implications for education and practice are discussed.

Ecology of lice on sheep. VII. Population dynamics of Damalinia ovis (Schrank)

1969 ◽  
Vol 17 (2) ◽  
pp. 179 ◽  
Author(s):  
MD Murray ◽  
G Gordon
Keyword(s):  
Population Dynamics ◽  
Matrix Model ◽  
Direct Relationship ◽  
Early Spring ◽  
Late Spring ◽  
Winter Period ◽  
Late Autumn ◽  
Early Autumn ◽  
Deterministic Matrix

The numbers of D. ovis decline in the spring, remain low during the summer, and increase during the winter. A density of two lice per square inch is necessary in the autumn if numbers are to increase during the winter to 200 per square inch, the density found on heavily infested sheep in the early spring. The time needed for this increase has been calculated using the deterministic matrix model ofpopulation increase described by Leslie (1945), and 4-5 months are required when there is only a small mortality. Thus, when the favourable winter period lasts only 3 months, the increase in louse numbers may be insufficient to sustain the losses which occur in late spring, summer, and early autumn. The factors responsible for these losses determine the density of the louse population at the commencement of winter. Should the winter period last c. 6 months there is usually a direct relationship between the number of lice on a sheep in the late autumn and in the following spring. However, should winter last 9 months it is suggested that other factors become increasingly significant, and determine the eventual size of the louse population.

Seasonal changes in abundance of Gammarus oceanicus (Crustacea, Amphipoda) in Newfoundland

1976 ◽  
Vol 54 (11) ◽  
pp. 2019-2022 ◽  
Author(s):  
D. H. Steele
Keyword(s):  
Seasonal Changes ◽  
Environmental Temperature ◽  
Late Summer ◽  
Stone Size ◽  
Late Autumn ◽  
Early Autumn

Abundance of Gammarus oceanicus reaches a peak in late summer – early autumn and declines to a low in the spring just before the young are produced. G. oceanicus disappears from the upper beach in late autumn, but is found permanently at lower levels. At low tide the numbers found under stones vary directly with stone size and inversely with the level of the stone on the beach. This, in turn, is related to environmental temperature. In the microhabitat under the stones, temperature varies inversely with stone size and directly with the level on the beach.

Two late-spring braconid genera of the subfamily Alysiinae (Hymenoptera: Braconidae) new for the fauna of Russia

2011 ◽  
Vol 20 (1) ◽  
pp. 85-95 ◽  
Author(s):  
S.A. Belokobylskij ◽  
T.S. Kostromina
Keyword(s):  
New Species ◽  
Morphological Characters ◽  
Late Spring ◽  
Key To Species ◽  
The Urals ◽  
Asian Continent ◽  
First Time ◽  
A New Species

Two braconid genera from the subfamily Alysiinae, Lodbrokia Hedqvist, 1962 and Asyntactus Marshall, 1898, are recorded in the fauna of Russia and in the Asian continent for the first time. A new species Lodbrokia uralica sp. nov. is described from the Urals, and a key to species of this genus is provided. Redescriptions of the female and male of Asyntactus rhogaleus Marshall, 1898 with information about the level of variability of its morphological characters are given. Asyntactus sigalphoides Marshall, 1898 is synonymised with A. rhogaleus Marshall, 1898 (syn. nov.).

scholarly journals Aetiology and epidemiology of viral croup in Glasgow, 1966–72

1974 ◽  
Vol 73 (1) ◽  
pp. 143-150 ◽  
Author(s):  
K. A. Buchan ◽  
Karen W. Marten ◽  
D. H. Kennedy
Keyword(s):  
Retrospective Study ◽  
Influenza A ◽  
Seasonal Distribution ◽  
Late Autumn ◽  
Small Peak ◽  
Causative Agents ◽  
Autumn And Winter ◽  
Viral Croup

SUMMARYA retrospective study of 258 children admitted to Ruchill Hospital, Glasgow, with croup between 1966 and 1972 indicated that the viruses most frequently associated with the syndrome were parainfluenza types 1 and 3 and influenza A. Most cases were admitted in the late autumn and winter months, with a small peak in May and June. This seasonal distribution mirrored the circulation of the main causative agents in the community, parainfluenza 1 being principally associated with the autumn cases, influenza A the winter cases and parainfluenza 3 the summer cases. Two of these ‘croup associated’ viruses showed regular periodicity, parainfluenza 1 occurring biennially in even years and influenza A in most years. The periodicity of parainfluenza 3 is as yet undetermined.

scholarly journals First evaluation of coral recruitment in Madagascar

2021 ◽  
Vol 20 (1) ◽  
pp. 47-62
Author(s):  
Gildas G.B. Todinanahary ◽  
Nomeniarivelo Hasintantely ◽  
Igor Eeckhaut ◽  
Thierry Lavitra
Keyword(s):  
Larval Density ◽  
Average Density ◽  
Recruitment Rate ◽  
Seasonal Distribution ◽  
Coral Recruitment ◽  
Significant Difference ◽  
Southwest Region ◽  
The Mean ◽  
First Time ◽  
Very High

The distribution of larvae and recruitment of scleractinians in the southwest region of Madagascar were evaluated for the first time between October 2013 and September 2014 at 3 sites. The presence of coral larvae (planulae) was monitored through weekly sampling using a plankton net and the recruitment rate evaluated by monthly sampling of the newly settled corals (<1 year stage) on recruitment tiles and by a monitoring of the recruitment of juveniles (1< Juveniles < 2 years) using the quadrat method. Planulae were present in the plankton for 9 months during the survey. The recorded mean annual density of planula varied from 0.43 ± 0.41 larvae m-3 to 3.23 ± 5.72 larvae m-3 depending on site, with a peak in larval density towards the end of November and the beginning of December. The variability in the occurrence of planula is very high and implied that the density observed in the year does not present a significant difference between the sites (pKW=0.33). The average density of total recruits was 620.13 ± 621.30 recruits m-2, 40.28 ± 50.97 recruits m-2 and 36.34 ± 33.82 recruits m-2, respectively at the sites of Nosy Tafara, Grande Vasque and Rose Garden. Seasonal distribution of coral recruitment was different between the sites. The mean annual density of newly settled recruits (< 1 month stage) was significantly higher at Nosy Tafara with 94.91±101.08 recruits m-2 compared to Grande Vasque and Rose Garden with 18.75±34.32 recruits m-2 and 11.57±18.47 recruits m-2 (pKW<0.001), respectively. The highest density of newly settled recruits was observed between October to December. Higher density of recruits was also observed in March at Nosy Tafara and in May at all three sites. Results of juvenile monitoring showed high rates (> 10 juveniles m-2) compared to other regions and the threshold, but it revealed high mortality among recruits. Coral recruitment in the southwest region of Madagascar was found to be high and could result in increased resilience of the coral reef assemblages.

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