A quantitative requirement for long day in the induction of staminate strobili by gibberellin in the conifer Cupressus arizonica

1970 ◽  
Vol 48 (3) ◽  
pp. 653-658 ◽  
Author(s):  
R. P. Pharis ◽  
M. D. E. Ruddat ◽  
J. L. Glenn ◽  
W. Morf
Keyword(s):  
Steady State ◽  
Indeterminate Growth ◽  
Photoperiodic Control ◽  
Short Day ◽  
Long Day ◽  
Exogenous Gibberellin ◽  
Absolute Requirement ◽  
Cupressus Arizonica ◽  
Male Strobili

Induction of male strobili in Arizona cypress (Cupressus arizonica Greene) by exogenous gibberellin A3 (GA3) appears to have an absolute requirement for light, a quantitative requirement for long day (LD), and as shown by interruption of the dark periods, is in part under photoperiodic control. Under LD conditions the total number of new meristems produced is 10-fold greater than under short day (SD) even though this species exhibits indeterminate growth and does not set dormant buds under SD. Hence the total number of strobili resulting from GA3 application is higher under LD than under SD. However, strobili produced by GA3, when expressed as a percentage of the total number of meristems, is the same under both LD and SD, provided the GA3 concentration under SD is increased, and a longer period of time is allowed under SD. The factor(s) responsible for the enhanced meristem production under LD decrease(s) to an apparent steady state within the first 10 days after transfer of the plant to SD.

Development of the gibberellin-induced ovulate strobilus of western red cedar: quantitative requirement for long-day → short-day → long-day

1969 ◽  
Vol 47 (3) ◽  
pp. 415-420 ◽  
Author(s):  
R. P. Pharis ◽  
W. Morf ◽  
J. N. Owens
Keyword(s):  
Initial Period ◽  
Thuja Plicata ◽  
Short Day ◽  
Red Cedar ◽  
Long Day ◽  
Full Development ◽  
Western Red Cedar ◽  
Cupressus Arizonica ◽  
Thuja Plicata Donn ◽  
Short Days

The induction of flowering in western red cedar (Thuja plicata Donn.) by gibberellin (GA3) has a quantitative requirement for long-day (LD). However, the strobilus does not develop fully under LD. Full development does occur though, if the photoperiod sequence of short-day (SD) → LD is given after an initial period of 3+ months under LD for induction. For the male, continued development entails a slight expansion and the shedding of pollen. For the female, it involves expansion from a tight 2-mm bud to a 15-mm cone, even without pollination. Cold increased the number of developing strobili, although it did not affect the date of first expansion. GA3 concentration had little effect on continued strobilus development under SD or LD. The present study indicates that continued development of the strobilus has a photoperiodic requirement that can be likened to the requirement of SD → LD of some flowers for anthesis. The requirement for SD is quantitative rather than qualitative, an increasing number of short-days will increase the number of expanding strobili, and eventually (18 to 30 months) some strobili will develop even under continuous LD. Continued development of the strobilus will not take place under SD alone, LD must follow. Therefore, the LD requirement in the sequence SD → LD appears to be qualitative in nature. This does not appear to be true for another conifer, Arizona cypress (Cupressus arizonica Greene). These strobili will develop under SD, but their development is enhanced by the sequence SD → LD.

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)

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

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.

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