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

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.

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

Canadian Journal of Botany ◽

10.1139/b73-065 ◽

1973 ◽

Vol 51 (3) ◽

pp. 535-551 ◽

Cited By ~ 11

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.

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

Acta Societatis Botanicorum Poloniae ◽

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.

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Neurotrophic control of events in injured forelimbs of larval urodeles

Development ◽

10.1242/dev.69.1.183 ◽

1982 ◽

Vol 69 (1) ◽

pp. 183-192

Author(s):

Anthony L. Mescher

Keyword(s):

Cell Cycle ◽

Dna Synthesis ◽

Mitotic Activity ◽

Mitotic Index ◽

Elevated Level ◽

Labelling Index ◽

Neurotrophic Control ◽

Epimorphic Regeneration ◽

Baseline Levels

Denervated forelimbs and contralateral innervated forelimbs of Ambystoma larvae were injured internally distal to the elbow by compression with watchmaker's forceps. Innervated controls completely repaired the crush injury within one week; denervated limbs failed to repair the injury and exhibited varying degrees of limb regression. Histological examination revealed that the process of tissue dedifferentiation initiated by injury was more extensive in denervated, regressing limbs than in controls. In innervated limbs, both the DNA labelling index and the mitotic index peaked approximately 4–6 days after the injury and returned to baseline levels by 10 days. In denervated limbs, the DNA labelling index also increased and remained at an elevated level for at least 2 weeks after the injury, but significant mitotic activity was not observed. The data indicate that intact nerves are not needed for cellular dedifferentiation, cell cycle re-entry, and DNA synthesis in injured limbs, but are required for the cells to proliferate and repair the injury. These results are discussed together with those of similar experiments on the role of nerves during the initiation of epimorphic regeneration in amputated limbs.

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In Vitro Evaluation of Anti-Mitotic Activity of Green Synthesized Silver Nanoparticles from Ethanolic Extract of Chromolaena odorata, Caesalpinia coriaria (Bark and Leaves) using Allium cepa Roots

Research Journal of Pharmacy and Technology ◽

10.52711/0974-360x.2021.00711 ◽

2021 ◽

pp. 4107-4110

Author(s):

Nishita Gogia ◽

Anandhi D ◽

Kanaga G ◽

Revathi K

Keyword(s):

Silver Nanoparticles ◽

Mitotic Activity ◽

Mitotic Index ◽

Allium Cepa ◽

Chromolaena Odorata ◽

Root Tips ◽

Antimitotic Activity ◽

Biological Potential ◽

Green Synthesized Silver Nanoparticles

The scope of the present study was to evaluate the In-vitro biological potential of Green synthesized silver nanoparticles from Chromolaena odorata, Caesalpinia coriaria (Bark) and Caesalpinia coriaria (Leaf). We investigated the effect of green synthesized silver nanoparticles from Chromolaena odorata, Caesalpinia coriaria (Bark) and Caesalpinia coriaria (Leaf) by studying anti-mitotic activity An attempt has been made to evaluate the anti-mitotic activity of silver nanoparticles using Allium cepa roots. The mitotic index of the root tips meristem was calculated and compared with the standard methotrexate. Antimitotic activity results shows the mitotic index was ranged from 30-40%. Green synthesized silver nanoparticles from Chromolaena odorato, Caesalpinia coriaria (Bark) and Caesalpinia coriaria (Leaf) possess significant anti-mitotic activity.

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Volume-Corrected Mitotic Index and Mitotic Activity Index in Transitional Cell Bladder Cancer

European Urology ◽

10.1159/000463925 ◽

1990 ◽

Vol 18 (4) ◽

pp. 258-262 ◽

Cited By ~ 11

Author(s):

Pertti K. Lipponen ◽

Matti J. Eskelinen

Keyword(s):

Bladder Cancer ◽

Mitotic Activity ◽

Mitotic Index ◽

Activity Index ◽

Transitional Cell ◽

Cell Bladder Cancer ◽

Mitotic Activity Index ◽

Transitional Cell Bladder Cancer

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Seasonal studies of vegetative buds of Helianthus tuberosus: concentration of nuclei in phase G1 during winter dormancy

Canadian Journal of Botany ◽

10.1139/b81-252 ◽

1981 ◽

Vol 59 (10) ◽

pp. 1918-1927 ◽

Cited By ~ 9

Author(s):

S. S. Tepfer ◽

Arlette Nougarède ◽

Pierre Rondet

Keyword(s):

Mitotic Activity ◽

Mitotic Index ◽

Developmental Stages ◽

Central Zone ◽

Winter Period ◽

Helianthus Tuberosus ◽

Winter Dormancy ◽

Feulgen Staining ◽

Vegetative Buds ◽

Terminal Buds

The following vegetative buds were studied at several developmental stages during the course of the year: from November through February dormant terminal buds of subterranean tubers; in March, newly reactivated buds of young shoots; in June, terminal buds of horizontal underground stolons that will form tubers; and in July, the terminal buds of erect aerial shoots. Microdensitometric studies of DNA levels after Feulgen staining showed that during the winter period of dormancy, from November through February, the temporary arrest of growth and morphogenesis is accompanied by a concentration of nuclei in phase G1 (2C level) of a diploid cycle for all nuclei in the terminal meristems of the tubers. In March, reactivation occurs uniformly throughout the meristem without any zonal differences. The G1 phase remains predominant in the cycle and mitotic activity increases uniformly. In the meristems of young underground stolons, beginning in the month of June, signs of concentration at the 2C level again are perceptible. The nuclei of the apical meristems of erect shoots are also diploid at 2C and 4C. In the very large nuclei in the central zone of the tunica where the mitotic index is very low, the distribution of DNA levels shows that nuclei are present at all phases of the cycle. These results are discussed and compared with other species in temporary dormancy and in regard to the concept of nonpolysomatic species.

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Prolonged oestrogen treatment does not correlate with a sustained increase in anterior pituitary mitotic index in ovariectomized Wistar rats

Journal of Endocrinology ◽

10.1677/joe-08-0474 ◽

2008 ◽

Vol 200 (3) ◽

pp. 301-309 ◽

Cited By ~ 9

Author(s):

L A Nolan ◽

A Levy

Keyword(s):

Mitotic Activity ◽

Mitotic Index ◽

Anterior Pituitary ◽

Wistar Rats ◽

High Dose ◽

Oestrogen Treatment ◽

Female Wistar Rats ◽

Continuous Dose ◽

Wet Weight ◽

Dose Dependent

Oestrogen is a powerful mitogen that is believed to exert a continuous, dose-dependent trophic stimulus at the anterior pituitary. This persistent mitotic effect contrasts with corticosterone and testosterone, changes in the levels of which induce only transient, self-limiting fluctuations in pituitary mitotic activity. To further define the putative long-term trophic effects of oestrogen, we have accurately analysed the effects of 7 and 28 days oestrogen treatment on anterior pituitary mitotic activity in ovariectomized 10-week-old Wistar rats using both bromodeoxyuridine (BrdU) and timed colchicine-induced mitotic arrest. An oestrogen dose-dependent increase in mitotic index was seen 7 days after the start of treatment as expected, representing an acceleration in gross mitotic activity from 1.7%/day in ovariectomized animals in the absence of any oestrogen replacement to 3.7%/day in the presence of a pharmacological dose of oestrogen (50 mcg/rat per day: ∼230 mcg/kg per day). Despite continued exposure to high-dose oestrogen and persistence of the increase in pituitary wet weight, the increase in mitotic index was unexpectedly not sustained. After 28 days of high-dose oestrogen treatment, anterior pituitary mitotic index and BrdU-labelling index were not significantly different from baseline. Although a powerful pituitary mitogen in the short term, responsible, presumably, for increased trophic variability in oestrus cycling females, these data indicate that in keeping with other trophic stimuli to the pituitary and in contrast to a much established dogma, the mitotic response to longer-term high-dose oestrogen exposure is transient and is not the driver of persistent pituitary growth, at least in female Wistar rats.

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