scholarly journals Differences in the Sterility of Japanese Rice Varieties under Short-day Conditions and Seasonal Changes

2021 ◽  
Vol 90 (3) ◽  
pp. 317-323
Author(s):  
Masahiro Okamoto ◽  
Takahiro Hara
Keyword(s):  
Seasonal Changes ◽  
Rice Varieties ◽  
Short Day

Seasonal changes in concentrations of plasma hormones in the male ring dove (Streptopelia risoria)

1986 ◽  
Vol 108 (3) ◽  
pp. 385-391 ◽  
Author(s):  
R. W. Lea ◽  
P. J. Sharp ◽  
H. Klandorf ◽  
S. Harvey ◽  
I. C. Dunn ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Plasma Corticosterone ◽  
Early Spring ◽  
Energy Requirements ◽  
Breeding Cycle ◽  
Plasma Prolactin ◽  
Winter Solstice ◽  
Natural Lighting ◽  
Short Day ◽  
Ring Dove

ABSTRACT Seasonal changes in concentrations of plasma LH, prolactin, thyroxine (T4), GH and corticosterone were measured in captive male ring doves exposed to natural lighting at latitude 56 °N. Plasma LH levels decreased steeply in autumn when the daylength fell below about 12·5 h but increased in November as the birds became short-day refractory. In comparison with plasma LH concentrations in a group of short-day refractory birds exposed to 6 h light/day from the winter solstice, plasma LH levels in birds exposed to natural lighting increased further in spring after the natural daylength reached about 12·5 h. There were no seasonal changes in plasma prolactin concentrations and plasma T4 concentrations were at their highest during December, January and February, the coldest months of the year. The seasonal fall in plasma LH levels in September was associated with a transitory increase in plasma T4, a transitory decrease in plasma corticosterone and a sustained increase in plasma GH. It is suggested that in the ring dove, short-day refractoriness develops rapidly in November to allow the bird to breed when the opportunity arises, during the winter and early spring. The annual breeding cycle is synchronized by a short-day induced regression of the reproductive system in the autumn, the primary function of which may be to enable the birds to meet the energy requirements for the annual moult. The changes in plasma T4, corticosterone and especially of GH at this time of year are probably concerned with the control of moult or the associated changes in energy requirements. J. Endocr. (1986) 108, 385–391

scholarly journals Photoperiodic regulation of dopamine signaling regulates seasonal changes in retinal photosensitivity in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kousuke Okimura ◽  
Yusuke Nakane ◽  
Taeko Nishiwaki-Ohkawa ◽  
Takashi Yoshimura
Keyword(s):  
Seasonal Changes ◽  
Molecular Basis ◽  
Seasonal Affective Disorder ◽  
Winter Season ◽  
Light Therapy ◽  
Therapeutic Interventions ◽  
Pharmacological Intervention ◽  
Short Day ◽  
Photoperiodic Regulation ◽  
Dopamine Signaling

AbstractAt high latitudes, approximately 10% of people suffer from depression during the winter season, a phenomenon known as seasonal affective disorder (SAD). Shortened photoperiod and/or light intensity during winter season are risk factors for SAD, and bright light therapy is an effective treatment. Interestingly, reduced retinal photosensitivity along with the mood is observed in SAD patients in winter. However, the molecular basis underlying seasonal changes in retinal photosensitivity remains unclear, and pharmacological intervention is required. Here we show photoperiodic regulation of dopamine signaling and improvement of short day–attenuated photosensitivity by its pharmacological intervention in mice. Electroretinograms revealed dynamic seasonal changes in retinal photosensitivity. Transcriptome analysis identified short day-mediated suppression of the Th gene, which encodes tyrosine hydroxylase, a rate-limiting enzyme for dopamine biosynthesis. Furthermore, pharmacological intervention in dopamine signaling through activation of the cAMP signaling pathway rescued short day–attenuated photosensitivity, whereas dopamine receptor antagonists decreased photosensitivity under long-day conditions. Our results reveal molecular basis of seasonal changes in retinal photosensitivity in mammals. In addition, our findings provide important insights into the pathogenesis of SAD and offer potential therapeutic interventions.

Response of rice varieties to short-day treatment

Euphytica ◽  
1954 ◽  
Vol 3 (3) ◽  
pp. 221-228 ◽  
Author(s):  
R. L. M. Ghose ◽  
S. V. S. Shastry
Keyword(s):  
Day Treatment ◽  
Rice Varieties ◽  
Short Day

Control of cambial activity and dormancy in Picea sitchensis by indol-3-ylacetic and abscisic acids

1981 ◽  
Vol 59 (8) ◽  
pp. 1480-1493 ◽  
Author(s):  
C. H. A. Little ◽  
P. F. Wareing
Keyword(s):  
Water Stress ◽  
Seasonal Changes ◽  
Cambial Activity ◽  
Picea Sitchensis ◽  
Gas Chromatography Mass Spectrometry ◽  
Short Day ◽  
Internal Water ◽  
Tracheid Production ◽  
Cambial Dormancy ◽  
Exogenous Iaa

The combined gas chromatography – mass spectrometry (GCMS) technique of single-ion current monitoring was used to measure indol-3-ylacetic acid (IAA) and abscisic acid (ABA) levels in diffusible, acidic, and conjugated fractions obtained from the cambial region of Sitka spruce (1) during the annual cycle of cambial activity and dormancy in trees reared under natural and controlled environmental conditions, and (2) after debudding, girdling, defoliating, applying exogenous IAA, droughting, or changing the photoperiod. Seasonal changes occurred in the level of IAA and ABA in each fraction, but not obviously and consistently in conjunction with specific changes in cambial activity and dormancy. Debudding and girdling halted tracheid production, decreased the radial enlargement of the last-formed tracheids, and abruptly reduced the content of IAA and ABA in the diffusible and acidic fractions without affecting the ABA level in the conjugated fraction. Applying exogenous IAA to debudded shoots maintained tracheid production and differentiation, and largely prevented the decrease in IAA and ABA content. Elevating the internal water stress inhibited apical and cambial growth, increased the contents of diffusible, acidic, and conjugated ABA, and decreased diffusible and acidic IAA levels; the foliar concentrations of acidic IAA, acidic ABA, and conjugated ABA were similarly altered. Short-day photoperiod induced apical and cambial dormancy and reduced the levels of diffusible and acidic IAA and diffusible, acidic, and conjugated ABA; the decline in hormone content occurred mainly after the cambium ceased activity. Exogenous IAA could not prevent the cambium from ceasing activity under natural field conditions or short-day photoperiod. It is concluded that (1) there is an intrinsic seasonal pattern of change in IAA and ABA levels in the cambial region, governed primarily by seasonal changes in foliar hormone production; (2) this pattern is readily and variously perturbed by changes in the environment, particularly by factors affecting the internal water stress; (3) the evidence accumulated to date casts doubt on a role for ABA in controlling cambial dormancy; (4) cambial activity and the completion of the springtime transition from quiescence to activity depend on a continuous supply of basipetally transported IAA; (5) the changeover from activity to rest at the end of the cambial growing period is due to the development of an inability to respond to IAA, not to a deficiency in IAA supply; and (6) the transition from rest to quiescence during the cambial dormant period involves regaining the ability to respond to IAA.

scholarly journals Yield and grain dimensions of T. Aman rice varieties as influenced by date of transplanting

2016 ◽  
Vol 2 (3) ◽  
pp. 442-450
Author(s):  
Syeda Nuzhat Reza ◽  
Nahid Nadia Tani ◽  
Muhammad Salim ◽  
Ahmed Khairul Hasan ◽  
Mst Arjina Akter
Keyword(s):  
Low Temperature ◽  
Field Experiment ◽  
Grain Yield ◽  
Yield Components ◽  
Day Length ◽  
Rice Varieties ◽  
Short Day ◽  
Yield Parameters ◽  
Two Factors ◽  
Plot Design

A field experiment was carried out at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, during June 2013 to December 2013 to study the yield and grain dimensions of transplant aman rice varieties as influenced by date of transplanting. The experimental factors comprised of two factors namely, date of transplanting and variety. Date of transplanting comprised of 18 July, 19 August and 18 September. The variety comprised of Binadhan-7, BRRI dhan57, BR11 and Bashiraj. The experimental field was laid out in a split plot design. Most of the yield parameters were significantly affected by the date of transplanting. The yield and yield contributing characters were highest at 19 August transplanting and lowest at 18 September transplanting. Variety had significant effect on most of the yield and yield contributing characters. BR11 gave the highest grain yield (4.47 t ha-1) and the lowest value was obtained in BRRI dhan57. Among the grain dimensions, Binadhan-7 with 18 July transplanting gave the highest grain length (9.64 mm) whereas BR11 with 18 September transplanting gave the lowest value (7.82mm). Results showed that yield components were highest at 19 August transplanting and after that the reduction occurred at 18 September may be due to low temperature and short day length at flowering stage.Asian J. Med. Biol. Res. September 2016, 2(3): 442-450

Decreased day length and light intensity as factors inducing reproduction in Gammarus lacustris lacustris Sars

1982 ◽  
Vol 60 (11) ◽  
pp. 2962-2965 ◽  
Author(s):  
B. G. E. de March
Keyword(s):  
Light Intensity ◽  
Seasonal Changes ◽  
Climatic Conditions ◽  
Day Length ◽  
Arctic Ecosystems ◽  
Gammarus Lacustris ◽  
Temperature Conditions ◽  
Short Day ◽  
Dim Light

Gammarus lacustris cultures were maintained in the laboratory under different light and temperature conditions during a 5-year period. Reproduction occurred only in adults which had been held at a short day length (12 h light) or in dim light for several weeks. Changes in photoperiod are the most consistent seasonal changes in temperature and arctic ecosystems, hence the response to light ensures regular annual reproduction in spite of unusual climatic conditions.

Spreading the Word: Seasonal Changes Mean New Opportunities for Media Coverage

ASHA Leader ◽  
2013 ◽  
Vol 18 (7) ◽  
Keyword(s):  
Media Coverage ◽  
Seasonal Changes ◽  
Swimming Pools

Summer kicking into high gear conjures images of swimming pools and barbeques. But before you book your beach house for the weekend, think about what the changing seasons can mean for you professionally.

Seasonal changes in a ultraviolet structural colour signal in blue tits, Parus caeruleus

2002 ◽  
Vol 76 (2) ◽  
pp. 237-245 ◽  
Author(s):  
JONAS ORNBORG ◽  
STAFFAN ANDERSSON ◽  
SIMON C. GRIFFITH ◽  
BEN C. SHELDON
Keyword(s):  
Seasonal Changes ◽  
Parus Caeruleus ◽  
Structural Colour ◽  
Blue Tits ◽  
Colour Signal
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