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.

Vegetative and reproductive development of shoot apices of Pharbitis nil as influenced by photoperiodism

1969 ◽  
Vol 47 (9) ◽  
pp. 1403-1406 ◽  
Author(s):  
D. S. Bhar ◽  
N. W. Radforth
Keyword(s):  
Mitotic Activity ◽  
Dark Period ◽  
Pollen Grains ◽  
Reproductive Development ◽  
Epidermal Cells ◽  
Floral Transition ◽  
Pharbitis Nil ◽  
Shoot Apices ◽  
The Third

In shoot apices of Pharbitis nil, cytohistological zonation is not clearly delineated at germination. With increase in age, zonation develops and the granular appearance of the cytoplasm disappears. After induction by a single 16-hour dark period the first recognizable sign of floral transition becomes evident on the second day, with increase in the mitotic activity of the apex. On the third and fourth days, the sepals are initiated and the petals and stamens are initiated simultaneously on the fifth day. On the sixth day the carpel primordia originate. Between the 11th and 12th days after the inductive dark period, the pollen grains develop and the style extends. Between the 19th and 20th days the epidermal cells of the stigma become secretory.

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.

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.

Ontogeny and histochemistry of the vegetative apex of Cosmos bipinnatus "Sensation"

1972 ◽  
Vol 50 (6) ◽  
pp. 1171-1184 ◽  
Author(s):  
Marje Molder ◽  
John N. Owens
Keyword(s):  
Mitotic Activity ◽  
Mitotic Index ◽  
Vegetative State ◽  
Zonation Pattern ◽  
Short Day ◽  
Rna Content ◽  
Cosmos Bipinnatus ◽  
Leaf Arrangement ◽  
Nucleolar Volume ◽  
Initial Present

Plants of Cosmos bipinnatus Cav. "Sensation" (a quantitative short-day plant) were grown under continuous conditions of long days to maintain the vegetative state. The vegetative apex shows a cytohistological zonation pattern superimposed upon a tunica–corpus organization. The biseriate tunica is separated into two zones: axial and lateral; while the corpus is separated into three zones: the peripheral, central, and rib meristem. Based on mitotic activity (both frequency and index) there is neither a "méristème d'attente" nor an "anneau initial" present. A double plastochron cycle is present because of the decussate leaf arrangement and the presence of prominent leaf bases. Cytohistological zonation, nucleolar volume, RNA content, and mitotic index vary in a cyclic manner with the phase of plastochron. Although the degree of zonation decreases just after leaf buttress initiation, zonation does not disappear at any time during a plastochron.

In vitro studies of floral shoot apices of Pharbitis nil

1970 ◽  
Vol 48 (7) ◽  
pp. 1355-1358 ◽  
Author(s):  
D. S. Bhar
Keyword(s):  
Dark Period ◽  
Floral Organ ◽  
In Vitro Studies ◽  
Pharbitis Nil ◽  
Shoot Apices ◽  
Intact Plants ◽  
Full Complement

Shoot apices of Pharbitis nil were excised and cultured in vitro at different intervals after the intact plants were photoperiodically induced. The induced apices excised immediately after and up to 24 h after an inductive dark period, grew vegetatively for at least 4 weeks in culture. The apices excised and cultured from intact plants at 36 and 48 h after induction initiated a full complement of floral-organ primordia when observed after 4 weeks of growth.

scholarly journals The level of phyA in Pharbitis nil Chois during the photoperiodic flower induction

2014 ◽  
Vol 69 (4) ◽  
pp. 269-272 ◽  
Author(s):  
Adriana Szmidt-Jaworska ◽  
Krzysztof Jaworski ◽  
Jan Kopcewicz
Keyword(s):  
Dark Period ◽  
Polyclonal Antibodies ◽  
Flower Induction ◽  
Pharbitis Nil ◽  
Light Illumination ◽  
Direct Control ◽  
Short Day ◽  
Rapid Destruction ◽  
Photoperiodic Flower Induction

The aim of this work was to determine if there is any relationship between an endogenous phyA level and photoperiodic flower induction. The level of phyA was characterised with polyclonal antibodies directed to phyA from pea. At first it was detected that phyA level is predominant in cotyledons, whereas in roots and stems the concentration of labile phytochrome is rather low. So cotyledons were used for later experiments. In these cotyledons exposed to light illumination a rapid destruction of phyA has been observed. The loss of extractable phyA chromoprotein occurs already after 60 min of irradiation. <em>Pharbitis nil</em> is a short-day plant and a single 16-hours-long dark period is fully inductive. We assessed that phyA level is extremely low during a long inductive night and an immunodetectable phytochrome appears only after 24 hours of darkness. The obtained results suggest that labile phytochrome is not taking part in the direct control of the photoperiodic flower induction.

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.

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