Delayed germination in seeds of Phacelia dubia var. dubia

1973 ◽  
Vol 51 (12) ◽  
pp. 2481-2486 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Life Cycle ◽  
Seedling Establishment ◽  
Winter Temperature ◽  
Seed Crop ◽  
Temperature Conditions ◽  
Secondary Dormancy ◽  
Winter Temperatures ◽  
Winter Annual ◽  
Delayed Germination ◽  
Germinating Seeds

Not all seeds of a particular seed crop of the winter annual Phacelia dubia var. dubia germinate the first autumn after their dispersal in spring, and germination of a given seed crop is spread over several years. Nondormant seeds that do not germinate in autumn are induced into secondary dormancy by low winter temperatures and must afterripen again during summer before they are capable of germinating. Seeds that do not afterripen the first summer after dispersal are prevented from doing so until at least the next summer because winter temperature conditions prevent afterripening. These responses of the seeds to the environment insure that germination will occur only in autumn, the only season of the year that is suitable for seedling establishment and eventual completion of the life cycle.

An update on the hydroxyl airglow temperature record from the Auroral Station in Adventdalen, Svalbard (1980–2005)

2007 ◽  
Vol 85 (2) ◽  
pp. 143-151 ◽  
Author(s):  
M E Dyrland ◽  
F Sigernes
Keyword(s):  
Solar Rotation ◽  
Temperature Fluctuations ◽  
Winter Temperature ◽  
Temperature Record ◽  
Positive Temperature ◽  
Spectral Measurements ◽  
Daily Average ◽  
Winter Temperatures ◽  
Hydroxyl Airglow ◽  
Average Winter Temperature

This paper reports on the daily mesospheric winter temperature series derived from ground-based spectral measurements of the hydroxyl airglow layer from the Auroral Station in Adventdalen near Longyearbyen, Svalbard (78°N, 15°E). Temperature estimates from the four latest seasons (2001–2002 to 2004–2005) have been added to the series reported by Sigernes et al. J. Geophys. Res. 108(A9), 1342 (2003). Lomb–Scargle periodogram analyses were performed on both hourly and daily average temperatures to look for significant periods. From the daily means, ∼24 and ∼26 d oscillations that are consistent with a solar rotation modulation of the atmosphere were identified. Analyses of the hourly averaged data did not reveal any considerable diurnal and semidiurnal periods in the temperatures. The 2003–2004 mesopause winter was one of the warmest reported over Svalbard during the last 25 years. It is common to observe within a few days temperature fluctuations in the range 20–40 K. Some years show far less variation than others. The overall daily average winter temperature is 209 K. The annual mean winter temperatures show a slightly positive temperature trend (+0.2 ± 0.1 K/year), on the verge of being a statistically significant change in the winter mesospheric temperatures over Svalbard.PACS Nos.: 92.60.hc, 07.20.Dt, 93.30.Sq, 92.60.hw

scholarly journals Mid-winter temperatures, not spring temperatures, predict breeding phenology in the European starling Sturnus vulgaris

2015 ◽  
Vol 2 (1) ◽  
pp. 140301 ◽  
Author(s):  
Tony D. Williams ◽  
Sophie Bourgeon ◽  
Allison Cornell ◽  
Laramie Ferguson ◽  
Melinda Fowler ◽  
...  
Keyword(s):  
Clutch Size ◽  
Prey Availability ◽  
Sturnus Vulgaris ◽  
Winter Temperature ◽  
Laying Date ◽  
Breeding Phenology ◽  
European Starlings ◽  
Winter Temperatures ◽  
Lag Times ◽  
High Degree

In many species, empirical data suggest that temperatures less than 1 month before breeding strongly influence laying date, consistent with predictions that short lag times between cue and response are more reliable, decreasing the chance of mismatch with prey. Here we show in European starlings ( Sturnus vulgaris ) that mid-winter temperature ca 50–90 days before laying (8 January–22 February) strongly ( r 2 = 0.89) predicts annual variation in laying date. Mid-winter temperature also correlated highly with relative clutch size: birds laid later, but laid larger clutches, in years when mid-winter temperatures were lower. Despite a high degree of breeding synchrony (mean laying date 5–13 April = ±4 days; 80% of nests laid within 4.8 days within year), European starlings show strong date-dependent variation in clutch size and productivity, but this appears to be mediated by a different temporal mechanism for integration of supplemental cue (temperature) information. We suggest the relationship between mid-winter temperature and breeding phenology might be indirect with both components correlating with a third factor: temperature-dependent development of the starling's insect (tipulid) prey. Mid-winter temperatures might set the trajectory of growth and final biomass of tipulid larvae, with this temperature cue providing starlings with information on breeding season prey availability (though exactly how remains unknown).

Climatic determinants of introduced Sitka spruce in Hiiumaa Island, Estonia

2019 ◽  
Vol 25 (1) ◽  
pp. 161-167
Author(s):  
Alar Läänelaid ◽  
Samuli Helama
Keyword(s):  
Norway Spruce ◽  
Tree Ring ◽  
Sitka Spruce ◽  
Early Summer ◽  
Winter Temperature ◽  
Moisture Regime ◽  
Growth Responses ◽  
Growth Variability ◽  
Tree Ring Data ◽  
Winter Temperatures

Tree-ring records of Sitka spruce growing in Hiiumaa (Estonia) were investigated to illustrate their growth variability and its climatic determinants. A chronology comprising ring-width series of eight big individuals from the Suuremõisa forest park was correlated with local climatic records. The growth variability of this species introduced to Hiiumaa was statistically explained profoundly by winter temperature and early-spring precipitation. Comparisons were also made with local tree-ring data of Norway spruce. Interestingly, both the native and non-native species responded positively to precipitation in June and negatively to precipitation in April. Previous studies have shown that the winter temperature response, demonstrated here for Sitka spruce, is found as Norway spruce growth responses in eastern Estonia, whereas in western Estonia the growth of the latter species is more clearly connected, similar to our findings, to early-summer precipitation. These findings indicate that while the both spruce species remain sensitive to spring/summer moisture regime, the growth of Sitka spruce may actually be less tolerate to winter temperatures, as evident here in western Estonia where the winters may likely be milder than in eastern Estonia. Common to Sitka spruce results from Hiiumaa, tree-ring data representing conspecific native populations from north-west North American sites indicated positive responses to mid-winter temperatures. Based on these results, low winter temperatures and early-summer droughts may both threaten the survival of the remnant individuals of this species in Hiiumaa.

Temperature conditions of development juvenile NEA cod in the Barents sea for 1998-2015 on the basis of satellite data

2020 ◽  
Author(s):  
George Vanyushin ◽  
Tatyana Bulatova
Keyword(s):  
Life Cycle ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Satellite Data ◽  
Barents Sea ◽  
Sea Surface ◽  
Arctic Cod ◽  
Norwegian Sea ◽  
Temperature Conditions ◽  
The Barents Sea

<p><strong>Temperature conditions of development juvenile NEA cod in the Barents sea for 1998-2015 on the basis of satellite data</strong></p><p>Vanyushin G. P., Bulatova T. V.</p><p>Russian Federal Research Institute of Fisheries and Oceanography (VNIRO)</p><p>107140 17, V. Krasnoselskaya str., Moscow</p><p>tel: 8(499)264-01-33, fax: 8(499)264-91-87,</p><p>e-mail: [email protected]</p><p> </p><p><strong>Abstract</strong></p><p>The paper considers the real temperature conditions in the main spawning area of North-East Arctic cod in the Norwegian sea and the development of its juveniles in the Barents sea in the periods from March to October 1998-2015. Here was taken as a principle the analysis of materials Bank mean weekly maps of sea surface temperature (SST) built on complex process: infrared digital data from metrological satellites of the series "NOAA" and quasisynchronous temperature data "in situ" from ships, buoys and coastal stations. A continuous series of indicators on temperature variability in the surface layer of sea water in coastal zone of the Norwegian sea during spawning periods and later on during the early ontogenesis of juvenile cod in the Barents sea  allowed to establish the dynamics of interannual seasonal temperature trends on a mesoscale period of time (1998-2015). This made it possible to assess the indirect impact of temperature conditions on the prospect of survival and, accordingly, the number of juvenile cod in the first year of its life after spawning – the most important stage in the life cycle of a new generation of cod. The paper presents calculations of monthly and seasonal average values of SST and SST anomalies in the Norwegian and Barents seas, shows the interannual seasonal dynamics of these characteristics. Given for these years, the results of the comparative analysis between: seasonal values of temperature in the water surrounding the Lofoten Islands (March-April – time of the main spawning) and in the water of the Barents sea (May-October - time of the early onthogenesis of juvenile cod) and professional expert estimates the number of yearlings cod. The relationship between these statistical data was positive and about equal to R= + 0,67. Information on the number of generations of cod at different stages of its life cycle was taken from the annual reports of the Arctic Fisheries Working Group ICES.</p><p>Keywords: satellite monitoring, sea surface temperature (SST), the  Northeast Arctic cod, main spawning and habitat waters, yearlings of the cod.</p>

Long-term effects of 2,4-D application on plants. II. Herbicide avoidance by Chenopodium album and Thlaspi arvense

1988 ◽  
Vol 66 (2) ◽  
pp. 230-235 ◽  
Author(s):  
Larry Hume
Keyword(s):  
Life Cycle ◽  
Chenopodium Album ◽  
Herbicide Tolerance ◽  
Long Term Effects ◽  
Annual Life Cycle ◽  
Thlaspi Arvense ◽  
Immature Seeds ◽  
Winter Annual ◽  
Dichlorophenoxy Acetic Acid

Research plots in a wheat–wheat–fallow rotation at Indian Head, Sask., were sprayed annually with 2,4-dichlorophenoxy-acetic acid (2,4-D) for 36 consecutive years. Two species susceptible to 2,4-D, Chenopodium album L. and Thlaspi arvense L., were dominant in these plots. From 1981 to 1983, C. album and T. arvense seedlings that emerged during four periods of the growing season were marked and their mortality, seed production, and size recorded. From these data and other studies, 10 ways in which C. album and T. arvense managed to survive herbicide application were identified. These are intermittent germination, herbicide tolerance, small size of late-emerging seedlings, short life cycle, hardiness, failure of control practices, long-term dormancy, seed dispersal, viability of immature seeds, and winter annual life cycle of T. arvense.

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