Cessation of Long Day Melatonin Rhythms Time Puberty in a Short Day Breeder*

Endocrinology ◽  
1988 ◽  
Vol 123 (3) ◽  
pp. 1636-1641 ◽  
Author(s):  
DOUGLAS L. FOSTER ◽  
FRANCIS J. P. EBLING ◽  
LEE E. CLAYPOOL ◽  
CELIA J. I. WOODFILL
Keyword(s):  
Short Day ◽  
Long Day

Control of torpor and body weight patterns by a seasonal timer in Siberian hamsters

1989 ◽  
Vol 257 (1) ◽  
pp. R142-R149 ◽  
Author(s):  
T. J. Bartness ◽  
J. A. Elliott ◽  
B. D. Goldman
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Implant Removal ◽  
Daily Torpor ◽  
Short Day ◽  
Siberian Hamsters ◽  
Long Day ◽  
Preparatory Phase ◽  
Pelage Color ◽  
Seasonal Responses

Two experiments were designed to assess whether the short-day-induced patterns of shallow daily torpor, body weight, and other seasonal responses (food intake and pelage pigmentation) exhibited by Siberian hamsters (Phodopus sungorus sungorus) are under the control of a "seasonal timekeeping mechanism" that is independent of reproductive status [testosterone, (T)]. We examined whether the patterning and expression of these seasonal responses were altered by decreases in serum T that accompany gonadal regression during the first 8 wk of short-day exposure (i.e., the "preparatory phase" of the torpor season) or by experimental increases in serum T after this phase. Short-day-housed, castrated hamsters bearing T implants had long-day levels of the hormone and did not exhibit torpor. Appropriate seasonal patterns and levels of torpor, body weight, pelage color stage, and food intake were exhibited after T implant removal although serum T was clamped to long-day levels during the preparatory phase. In animals that were gonad intact during the preparatory phase and were subsequently castrated and given T implants, torpor did not occur as long as the implants were in place. However, the patterns and levels of daily torpor, food intake, and body weight rapidly returned to appropriate seasonal values compared with the castrated, blank-implanted controls on T implant removal; these effects occurred whether the T implants were removed when torpor frequency was increasing, at its peak, or decreasing across the torpor season. T did not affect pelage color stage under any condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcriptomic analysis of Allium sativum uncovers putative genes involved in photoperiodic pathway and hormone signaling under long day and short day conditions

Plant Science ◽  
2021 ◽  
pp. 111095
Author(s):  
Muhammad Jawaad Atif ◽  
Bakht Amin ◽  
Muhammad Imran Ghani ◽  
Muhammad Ali ◽  
Somia Khursheed ◽  
...  
Keyword(s):  
Allium Sativum ◽  
Transcriptomic Analysis ◽  
Hormone Signaling ◽  
Short Day ◽  
Long Day

scholarly journals Agronomic Performance and Flowering Behavior in Response to Photoperiod and Vernalization in Barley (Hordeum vulgare L.) Genotypes with Contrasting Drought Tolerance Behavior

2021 ◽  
Author(s):  
Jamal Abu-Elenein ◽  
Rabea Al-Sayaydeh ◽  
Zahera Akkeh ◽  
Zakaria Al-Ajlouni ◽  
AbdRaheem A. Al-Bawalize ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Agronomic Performance ◽  
Short Day ◽  
Drought Tolerant ◽  
Long Day ◽  
Meristem Development ◽  
Rainfed Conditions ◽  
Barley Genotypes

Abstract Background In barley, flowering behavior is a highly regulated and complex process where the appropriate matching of reproductive development with seasonal variation in water availability confer barley adaptation to different environments. In this study, the role of variation in flowering time and drought tolerance in four selected barley genotypes was studied under field and controlled conditions. For this purpose, field trials were conducted for two consecutive seasons at three diverse environments where the studied genotypes were subjected to either rainfed conditions or rainfed plus supplementary irrigation under two different sowing dates. Furthermore, reproductive meristem development in two selected barley genotypes, Rum (drought tolerant) and Steptoe (drought-sensitive) was also assessed in response to both vernalization and water stress under two different photoperiod conditions.Results Variation in the number of days to heading was more pronounced under rainfed conditions than under well water conditions. For agronomic performance, Rum was superior under all tested environments, which assure its general adaptability to multiple environments, while Steptoe was the poorest. The transition to reproductive meristem was faster under vernalized long-day conditions as compared to vernalized short-day conditions. The progress of shoot apical meristem development and heading under long-day conditions was significantly faster in Rum than that of Steptoe. A clear effect of drought stress was observed on shoot apical meristem development in Steptoe. Under short-day conditions, vernalized Rum plants subjected to water deficit showed an advanced meristem development stage a significant earlier HD when compared with non-stressed plants. This early flowering behavior in stressed Rum plants under short-day conditions was accompanied by higher gene expression of the Vrn-H1 gene. Conclusion In conclusion, the integration of vernalization and photoperiod signals in drought-tolerant barley genotypes is associated with early flowering behavior and higher productivity in dry environments.

scholarly journals Photocontrol of Flowering and Extension Growth in the Long-day Plant Pansy

2003 ◽  
Vol 128 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins
Keyword(s):  
Flower Development ◽  
Red Light ◽  
Reproductive Development ◽  
Extension Growth ◽  
Separate Experiment ◽  
Flower Initiation ◽  
Minimal Extension ◽  
Short Day ◽  
Long Day ◽  
Light Duration

Plastics that selectively reduce the transmission of far-red light (FR, 700 to 800 nm) reduce extension growth of many floricultural crops. However, FR-deficient (FRd) environments delay flowering in some long-day plants (LDPs), including `Crystal Bowl Yellow' pansy (Viola ×wittrockiana Gams). Our objective was to determine if FR light could be added to an otherwise FRd environment to facilitate flowering with minimal extension growth. In one experiment, plants were grown under a 16-hour FRd photoperiod, and FR-rich light was added during portions of the day or night. For comparison, plants were also grown with a 9-hour photoperiod [short-day (SD) control] or under a neutral (N) filter with a 16-hour photoperiod (long day control). Flowering was promoted most (i.e., percent of plants that flowered increased and time to flower decreased) when FR-rich light was added during the entire 16-hour photoperiod, during the last 4 hours of the photoperiod, or during the first or second 4 hours after the end of the photoperiod. In a separate experiment, pansy was grown under an FRd or N filter with a 9-hour photoperiod plus 0, 0.5, 1, 2, or 4 hours of night interruption (NI) lighting that delivered a red (R, 600 to 700 nm) to FR ratio of 0.56 (low), 1.28 (moderate), or 7.29 (high). Under the N filter, the minimum NI duration that increased percent flowering was 2 hours with a moderate or low R:FR and 4 hours with a high R:FR. Under the FRd filter, 2 or 4 hours of NI lighting with a moderate or low R:FR, respectively, was required to increase percent flowering, but a 4-hour NI with a high R:FR failed to promote flowering. Pansy appears to be day-neutral with respect to flower initiation and a quantitative LDP with respect to flower development. The promotion of reproductive development was related linearly to the promotion of extension growth. Therefore, it appears that in LDPs such as pansy, light duration and quality concomitantly promote extension growth and flowering, and cannot readily be separated with lighting strategies.

scholarly journals Gibberellic acid flower formation and stem elongation in Silene armeria.

1973 ◽  
Vol 21 (4) ◽  
pp. 245-255
Author(s):  
S.J. Wellensiek
Keyword(s):  
Gibberellic Acid ◽  
Stem Elongation ◽  
Flowering Plants ◽  
Plant Age ◽  
Flower Formation ◽  
High Concentration ◽  
Short Day ◽  
Long Day ◽  
Silene Armeria

Several selected S. armeria lines differing in their reaction to GA3 were treated with GA3 at various concentrations under short-day (SD) or long-day conditions. With SD treatment one application of GA3 at high concentration (10 000 p.p.m. or greater) induced flower formation in certain lines. Stem elongation increased with GA3 concentration and with plant age and was much greater on flowering plants than on non-flowering ones. [For previous related work see HcA 41, 4400.]. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Flowering of Stylosanthes guianensis in controlled temperatures under natural photoperiod

1984 ◽  
Vol 35 (2) ◽  
pp. 219 ◽  
Author(s):  
RL Ison ◽  
LR Humphreys
Keyword(s):  
Floral Initiation ◽  
Minimum Duration ◽  
Stylosanthes Guianensis ◽  
Short Day ◽  
Long Day ◽  
Natural Photoperiod ◽  
Low Levels ◽  
Short Days

Seedlings of Stylosanthes guianensis var. guianensis cv. Cook and cv. Endeavour were grown in naturally lit glasshouses at Brisbane (lat. 27� 30' S.) at 35/30, 30/25 and 25/20�C (day/night), and were sown so as to emerge at 18-day intervals from 18 January to 11 June. Cook behaved as a long day-short day plant, with seedlings emerging after 5 February flowering incompletely or remaining vegetative until the experiment was terminated in mid-October. In the 25/20�C regimen flowering was incomplete in Cook; in Endeavour flowering was delayed but a conventional short-day response was observed. At 35/30�C Endeavour flowering was inhibited in the shortest days of mid-winter, suggesting a stenophotoperiodic response, but short days were confounded with low levels of irradiance. Minimum duration of the phase from emergence to floral initiation was c. 66-70 days in Cook and c. 40-45 days in Endeavour; the duration of the phase floral initiation to flower appearance was linearly and negatively related to temperature.

The role of photoperiod and temperature in the induction and termination of an arrested development in two species of freshwater cyclopia copepods

1971 ◽  
Vol 49 (6) ◽  
pp. 855-862 ◽  
Author(s):  
Nelson H. F. Watson ◽  
B. N. Smallman
Keyword(s):  
Continuous Light ◽  
Temporary Pond ◽  
Environmental Cues ◽  
Complete Darkness ◽  
Arrested Development ◽  
Short Day ◽  
Long Day ◽  
Critical Daylength ◽  
Ecological Implications

Daylength and temperature were shown to be environmental cues which interact to cause an arrest in development at the fourth copepodite instar of two cohabiting, temporary pond species of the genus Diacyclops; D. navus Herrick, and a second species of uncertain specific designation. The first species entered arrest under short-day conditions, the latter under long days. Arrest did not occur in rearings conducted in either continuous light or complete darkness. Cyclopids were sensitive to the photoperiodic stimulus only during the first copepodite instar. Temperature was shown to affect the critical daylength values associated with a transition from a long-day to a short-day response for each species.Similarities with insect diapause and the ecological implications of the response are discussed.

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