Floral initiation under continuous light in Pharbitis nil, a typical short-day plant

1974 ◽  
Keyword(s):  
Continuous Light ◽  
Pharbitis Nil ◽  
Floral Initiation ◽  
Short Day

Magnesium localization in shoot apices during flower induction in Pharbitis nil

2006 ◽  
Vol 84 (12) ◽  
pp. 1908-1916
Author(s):  
Natsuko I. Kobayashi ◽  
Keitaro Tanoi ◽  
Tomoko M. Nakanishi
Keyword(s):  
Day Treatment ◽  
Continuous Light ◽  
Flower Induction ◽  
Pharbitis Nil ◽  
Elemental Distribution ◽  
Short Day ◽  
Induction Process ◽  
Staining Methods ◽  
First Time ◽  
Flowering Process

We present the potential involvement of Mg2+ in the flowering mechanism in the shoot apex of the short-day plant Pharbitis nil (L.). To analyze elemental distribution in shoot apical meristems, fluorescence staining methods with Mag-fluo-4 AM and Fluo-3 AM were used. The former is sensitive to both Mg2+ and Ca2+, and the latter is a specific Ca2+ indicator. When plants were grown under continuous light conditions, some cells with intensive fluorescence of Mg2+ appeared in the top layers of the shoot apical meristem. During growth in the vegetative phase, cells in the center of the top layers accumulated large amounts of Mg2+. Exposure to a single 16 h short-day treatment induced the flowering process and dramatically reduced the fluorescence associated with Mg2+ accumulation in the top layers, suggesting that Mg2+ contributes to the flower induction process. The fluorescence associated with Ca2+ did not show this distribution difference between growth phases. A night-break treatment also influenced the fluorescence pattern. It was suggested for the first time that Mg2+ plays an important role in flower induction.

Changes in Catecholamine Levels in Short Day-Induced Cotyledons of Pharbitis nil

2003 ◽  
Vol 58 (3-4) ◽  
pp. 220-224 ◽  
Author(s):  
Masayuki Suzuki ◽  
Masaya Mizoguchi ◽  
Fumihiko Yano ◽  
Utako Hara ◽  
Mineyuki Yokoyama ◽  
...  
Keyword(s):  
Continuous Light ◽  
Flower Induction ◽  
Pharbitis Nil ◽  
Fresh Weight ◽  
Dark Treatment ◽  
Short Day ◽  
Dopamine Content ◽  
Significant Change ◽  
First Time ◽  
Catecholamine Levels

We investigated the effects of catecholamine on flower-induction in P. nil (cv. Violet). GCSIM analysis identified dopamine for the first time in P. nil seedlings. Dopamine levels in the cotyledons did not show a significant change during the inducing dark treatment. The dopamine content of cotyledons exposed to various durations of darkness were 0.1-0.2 nmol/ g fresh weight. The same content was found when cotyledons were exposed to continuous light.

scholarly journals The effect of photoperiodic treatments on mitotic activity in Pharbitic nil Chois

10.5586/1201 ◽  
2014 ◽  
Vol 60 (1-2) ◽  
pp. 133-138
Author(s):  
Joanna Czaplewska ◽  
Jan Kopcewicz
Keyword(s):  
Mitotic Activity ◽  
Mitotic Index ◽  
Dark Period ◽  
Continuous Light ◽  
The State ◽  
Pharbitis Nil ◽  
Shoot Apices ◽  
Inductive Cycle ◽  
Short Day ◽  
Inductive Photoperiod

The short-day plant, <i>Pharbitis nil</i>, requires only a single inductive cycle with a 16-hour dark period for flowering. The mitotic activity in the shoot apices was studied directly after the termination of the inductive photoperiod. A pronounced rise in the mitotic index was found in the 2nd and the 8th-14th hours. Control plants grown under noninductive conditions (continuous light, a light interruption in the middle of the dark period) did not flower and did not show an increased mitotic index. The increased mitotic activity in the shoot apices of <i>Pharbitis</i> seems to be causally connected with the phytochrome-controlled entry of the plants into the state of generative induction.

Semidian rhythmicity in the flowering response of Pharbitis nil to changes in temperature

1998 ◽  
Vol 25 (2) ◽  
pp. 183 ◽  
Author(s):  
O.M. Heide ◽  
R.W. King ◽  
L.T Evans
Keyword(s):  
Circadian Rhythm ◽  
Constant Temperature ◽  
Opposite Effect ◽  
Dark Period ◽  
Floral Induction ◽  
Continuous Light ◽  
The Other ◽  
Pharbitis Nil ◽  
Flowering Response ◽  
Short Day

Our earlier experiments on flowering in the short day plant Pharbitis nil involved far- red/dark (FR/D) interruptions of 90 min duration at various times during a continuous light, constant temperature period before a single inductive dark period. They revealed a rhythm with a period of 12 h, hence semidian. We concluded that the phasing of this semidian rhythm determined the length of darkness required for floral induction. This conclusion has since been challenged so we sought other pretreatments which reveal the semidian rhythm. Interruptions at 12°C–17°C for 45–90 min at various times prior to the inductive dark period were as effective as FR/D in eliciting the semidian rhythm, with significant effects on flowering persisting for at least three cycles in constant conditions in continuous light. The rhythmic response to 12°C pretreatments was 3 h out of phase with that to FR/D pretreatments. Flowering responses to the semidian rhythm exposed by 12°C pretreatments were additive to and independent of those to a circadian rhythm. Some evidence was obtained of reversal of the inhibition or promotion of flowering by FR/D or 12°C by exposure immediately afterwards to the other pretreatment at times of their opposite effect. Pretreatments at 12°C, like those with FR/D, either reduced (if promotive) or extended (if inhibitory) the length of the dark period required for floral induction in this short day plant.

Effects of continuous light and short-day photoperiod on smolting, seawater survival and growth in Atlantic salmon (Salmo salar)

Aquaculture ◽  
1995 ◽  
Vol 130 (4) ◽  
pp. 373-388 ◽  
Author(s):  
Trygve Sigholt ◽  
Magne Staurnes ◽  
Hans J. Jakobsen ◽  
Torbjørn Åsgård
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Continuous Light ◽  
Atlantic Salmon Salmo Salar ◽  
Short Day ◽  
Survival And Growth

Effects of carbon dioxide on Pharbitis, Xanthium, and Silene in short days

1974 ◽  
Vol 52 (6) ◽  
pp. 1283-1291 ◽  
Author(s):  
A. N. Purohit ◽  
E. B. Tregunna
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Concentration ◽  
Dry Weight ◽  
Morphological Characters ◽  
Photoperiodic Response ◽  
Pharbitis Nil ◽  
Light Sources ◽  
Short Day ◽  
Unit Leaf ◽  
Silene Armeria

The flowering response and other morphological characters of Pharbitis nil, Xanthium pennsylvanicum, and Silene armeria were studied in environments with different levels of carbon dioxide and oxygen under short-day conditions. Different light sources and intensities were also tested. Irrespective of the light source and intensity used, higher levels of carbon dioxide delayed or inhibited flowering as well as other morphological characters of the short-day plants but induced flowering in the long-day plant. Dry weight per unit leaf area as well as total chlorophyll increased with carbon dioxide concentration. The results are discussed in relation to some other recent reports, and it is proposed that large variations in photosynthetic rates of plants probably alter their photoperiodic response.

Ontogeny and histochemistry of the intermediate and reproductive apices of Cosmos bipinnatus var. Sensation in response to gibberellin A3 and photoperiod

1973 ◽  
Vol 51 (3) ◽  
pp. 535-551 ◽  
Author(s):  
Marje Molder ◽  
John N. Owens
Keyword(s):  
Gibberellic Acid ◽  
Response Rate ◽  
Intermediate Stage ◽  
Floral Initiation ◽  
Transitional Stage ◽  
Zonation Pattern ◽  
Short Day ◽  
Cosmos Bipinnatus ◽  
Cytological Features ◽  
Short Days

Plants of Cosmos bipinnatus Cav. ‘Sensation’ (a quantitative short-day plant) were grown under continuous conditions favorable or unfavorable for flowering, and some plants in each group were treated with gibberellic acid (GA3). Floral apices of Cosmos are formed by the transition of previously vegetative apices. The vegetative apex shows a cytohistological zonation pattern superimposed upon a tunica–corpus organization. The vegetative apex passes into an intermediate stage presumed typical of many plants held under non-inductive conditions. This stage is marked by many cytological features characteristic of both reproductive and vegetative apices but leaves continue to be produced. The presence of the intermediate stage accounts for conflicting results obtained in physiological studies since there is great variation in response rate depending on age of plant and the stage of the apex at the start of an experiment. This stage is followed by a typical transitional stage marked by an increase in RNA content, increased mitotic activity, and a change in zonation. Elongation of the apex and internodes occurs followed by initiation of the involucral bracts and floret primordia, marking the beginning of the prefloral and inflorescence stages respectively.GA3 specifically induces Cosmos to flower under non-inductive conditions thereby influencing floral initiation in a facultative short-day plant. Microscopic examination of the rate of apical transition revealed that GA3 substituted effectively for short days but was not as efficient an inducer as were short days.

Reduction in the critical dark length for flower induction during aging in the short-day plant Pharbitis nil var. Kidachi

2010 ◽  
Vol 23 (4) ◽  
pp. 291-300 ◽  
Author(s):  
Hiroshi Hasegawa ◽  
Mizuki Yamada ◽  
Yuiko Iwase ◽  
Kaede C. Wada ◽  
Kiyotoshi Takeno
Keyword(s):  
Flower Induction ◽  
Pharbitis Nil ◽  
Short Day

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.

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