Floral initiation in wheat

1976 ◽  
Vol 192 (1108) ◽  
pp. 273-298 ◽  
Keyword(s):  
Genetic Control ◽  
Genetic System ◽  
Sensitive Period ◽  
Floral Initiation ◽  
Physiological Processes ◽  
Environmental Treatment ◽  
Floral Differentiation ◽  
Developmental Gradient ◽  
The Stability ◽  
Short Days

The gap in understanding between genetic control and physiological processes of differentiation is far from being bridged; but it is being narrowed by a coordinated approach from both directions. The genetic system controlling the stability of floral differentiation in a series of wheat genotypes with progressively disturbed floral morphogenesis provides an experimental means of investigating the elements of the physiological system controlling floral initiation and development. Selected genotypes were exposed to an environmental treatment of short days with high temperatures, starting at precise intervals during early spikelet and floret differentiation. The effects were ascertained at ear emergence and corroborated by histological examination throughout and after treatment. A sensitive period for each floret was detected between the initiation of the subtending lemma and the initiation of the floret itself. Over the inflorescence as a whole, sterility gradients were recognized which were characteristic of the respective genotypes and clearly under genetic control. These gradients are explained on the basis of an activator substance interacting with, but distinct from the developmental gradient of the spike. It is suggested that the same elements - sensitive stage of floral initiation and activator gradient - play a major role in the floral differentiation of normal genotypes.

scholarly journals Current Practices for Reference Gene Selection in RT-qPCR of Aspergillus: Outlook and Recommendations for the Future

Genes ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 960
Author(s):  
Meagan Archer ◽  
Jianping Xu
Keyword(s):  
Gene Expression ◽  
Reference Gene ◽  
Reference Genes ◽  
Gene Selection ◽  
Quantitative Polymerase Chain Reaction ◽  
Specific Method ◽  
Experimental Conditions ◽  
Reference Gene Selection ◽  
Physiological Processes ◽  
The Stability

Aspergillus is a genus of filamentous fungi with vast geographic and ecological distributions. Species within this genus are clinically, agriculturally and biotechnologically relevant, leading to increasing interest in elucidating gene expression dynamics of key metabolic and physiological processes. Reverse-transcription quantitative Polymerase Chain Reaction (RT-qPCR) is a sensitive and specific method of quantifying gene expression. A crucial step for comparing RT-qPCR results between strains and experimental conditions is normalisation to experimentally validated reference gene(s). In this review, we provide a critical analysis of current reference gene selection and validation practices for RT-qPCR gene expression analyses of Aspergillus. Of 90 primary research articles obtained through our PubMed query, 17 experimentally validated the reference gene(s) used. Twenty reference genes were used across the 90 studies, with beta-tubulin being the most used reference gene, followed by actin, 18S rRNA and glyceraldehyde 3-phosphate dehydrogenase. Sixteen of the 90 studies used multiple reference genes for normalisation. Failing to experimentally validate the stability of reference genes can lead to conflicting results, as was the case for four studies. Overall, our review highlights the need to experimentally validate reference genes in RT-qPCR studies of Aspergillus.

Responses of Some Turkish Wheat Cultivars to Vernalization and Photoperiod

1988 ◽  
Vol 24 (2) ◽  
pp. 237-245
Author(s):  
Serpil Terzioğlu
Keyword(s):  
Bread Wheat ◽  
Normal Development ◽  
Photoperiodic Response ◽  
Reliable Information ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Primary Shoot ◽  
Time Of Year ◽  
Short Days

SUMMARYThe vernalization and photoperiodic response of six locally adapted bread wheat cultivars grown under natural daylength conditions during the summer or winter months was examined in glasshouse experiments. The wheat was vernalized by chilling imbibed grains at 2 ± 1°C for 0, 15 or 45 days. Vernalization for 45 days followed by long summer days led to floral initiation in all cultivars within 28 days but vernalization for 0 or 15 days only led to floral initiation in one cultivar. Vernalization followed by long days reduced the time from transplanting to anthesis, resulting in early ear emergence. Vernalization followed by short days accelerated the development of all the cultivars, but normal development could also occur without vernalization at this time of year. Apical differentiation of the primary shoot and its length and development gave the most reliable information on the period of vernalization required.

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.

scholarly journals FLORAL INITIATION IN THE LONG-DAY PLANT Rudbeckia hirta

HortScience ◽  
1991 ◽  
Vol 26 (6) ◽  
pp. 719A-719
Author(s):  
Richard L. Harkess ◽  
Robert E. Lyons
Keyword(s):  
Methyl Green ◽  
Floral Initiation ◽  
Serial Sections ◽  
Sodium Cacodylate ◽  
Rudbeckia Hirta ◽  
Long Day ◽  
Cacodylate Buffer ◽  
Ethanol Series ◽  
Inductive Photoperiod ◽  
Short Days

A study was undertaken to determine the rate of floral initiation in Rudbeckia hirta. R. hirta plants were grown to maturity, 14-16 leaves, under short days (SD). Paired controls were established by placing half of the plants under long days (LD) with the remainder left under SD. Beginning at the start of LD (day 0), five plants were harvested daily from each photoperiod group for twenty days. Harvested meristems were fixed in 2% paraformaldehyde - 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.0) for 24 hrs, dehydrated in an ethanol series, embedded in paraffin and sectioned at 8 μm. Serial sections were stained with Methyl-green Pyronin, with adjacent sections treated with RNase for nucleic acid comparison. All events of floral initiation were identified, The results of limited inductive photoperiod indicate that 16-18 LD were required for flowering.

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 INFLUENCE OF THE RATIO OF INCANDESCENT TO FLUORESCENT LIGHT ON THE FLOWERING RESPONSE OF MARQUIS WHEAT GROWN UNDER CONTROLLED CONDITIONS

1961 ◽  
Vol 41 (2) ◽  
pp. 418-427 ◽  
Author(s):  
D. J. C. Friend ◽  
V. A. Helson ◽  
J. E. Fisher
Keyword(s):  
Stem Elongation ◽  
High Light ◽  
Light Energy ◽  
Fluorescent Light ◽  
Floral Initiation ◽  
Incandescent Light ◽  
Flowering Response ◽  
Controlled Conditions ◽  
Floral Differentiation ◽  
Plant Level

When Marquis wheat is grown under artificial conditions, the main light energy (lamp watts) supplied by fluorescent light should be supplemented by at least 35 per cent of incandescent light in order to have a photoperiodic effect close to the maximal. Increasing the percentage up to 100 per cent resulted in slightly earlier flowering. This effect of incandescent light was caused, not by earlier floral initiation, but by an increase in the rate of stem elongation and a hastening of the later stages of floral differentiation. This action of incandescent light could not be replaced by substituting pink fluorescent for one-third of the white fluorescent lights.To obtain a photoperiodic effect equal to that of high light energy from combined fluorescent and incandescent bulbs, it is recommended that the daylength be extended by sufficient incandescent light to give an intensity of at least 50 ft.-c. at plant level.

scholarly journals Dual functions of Rack1 in regulating Hedgehog pathway

2020 ◽  
Vol 27 (11) ◽  
pp. 3082-3096 ◽  
Author(s):  
Yan Li ◽  
Xiaohan Sun ◽  
Dongqing Gao ◽  
Yan Ding ◽  
Jinxiao Liu ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Cellular Localization ◽  
Multiple Roles ◽  
Dual Roles ◽  
Cubitus Interruptus ◽  
Trimeric Complex ◽  
Physiological Processes ◽  
Underlying Mechanisms ◽  
The Stability ◽  
Fine Tune

Abstract Hedgehog (Hh) pathway plays multiple roles in many physiological processes and its dysregulation leads to congenital disorders and cancers. Hh regulates the cellular localization of Smoothened (Smo) and the stability of Cubitus interruptus (Ci) to fine-tune the signal outputs. However, the underlying mechanisms are still unclear. Here, we show that the scaffold protein Rack1 plays dual roles in Hh signaling. In the absence of Hh, Rack1 promotes Ci and Cos2 to form a Ci–Rack1–Cos2 complex, culminating in Slimb-mediated Ci proteolysis. In the presence of Hh, Rack1 dissociates from Ci–Rack1–Cos2 complex and forms a trimeric complex with Smo and Usp8, leading to Smo deubiquitination and cell surface accumulation. Furthermore, we find the regulation of Rack1 on Hh pathway is conserved from Drosophila to mammalian cells. Our findings demonstrate that Rack1 plays dual roles during Hh signal transduction and provide Rack1 as a potential drug target for Hh-related diseases.

The influence of different daylengths on ear emergence and seed setting in oats

1961 ◽  
Vol 57 (2) ◽  
pp. 279-288 ◽  
Author(s):  
D. J. Griffiths
Keyword(s):  
Genetic Control ◽  
Geographical Distribution ◽  
Geographic Origin ◽  
Seed Setting ◽  
Region Of Origin ◽  
Short Day ◽  
Selection Experiments ◽  
Close Relationship ◽  
Floral Differentiation ◽  
Photoperiodic Responses

1. The study of the photoperiodic responses of varieties and forms of the genus Avena has revealed considerable diversity within the group.2. The investigation of a number of forms differing in geographical distribution confirms the close relationship between photoperiodism and region of origin. There appears to exist a definite relationship between the geographic origin of a given form and the limits of its tolerance to short day. The forms from the more southerly latitudes suffered less from short day than those of northern origin.3. Panicle exsertion was entirely suppressed under photoperiods of 12 hr. and less in A. sativa varieties Victory, S. 84 and Black Supreme, which have been selected for high yielding ability in more northerly latitudes.4. Plants which failed to produce exserted panicles in varietal tests were dissected, and it was found that floral differentiation had not been inhibited by the shortened photoperiods, but that the full elongation of the internodes, especially the upper internodes, had been suppressed.5. Selection experiments with progenies of the cross Wintok × A.fatna form Cc 3872 grown under different photoperiods confirmed a highly selective response to daylength, thus indicating that this response is under genetic control.

scholarly journals Influence of Environmental Parameters on the Stability of the DNA Molecule

Entropy ◽  
2021 ◽  
Vol 23 (11) ◽  
pp. 1446
Author(s):  
Alexander Svidlov ◽  
Mikhail Drobotenko ◽  
Alexander Basov ◽  
Eugeny Gerasimenko ◽  
Anna Elkina ◽  
...  
Keyword(s):  
External Environment ◽  
Environmental Parameters ◽  
High Viscosity ◽  
Rate Of Change ◽  
Dna Molecule ◽  
Twisted State ◽  
Physiological Processes ◽  
Dna Strands ◽  
The Stability ◽  
Open States

Fluctuations in viscosity within the cell nucleus have wide limits. When a DNA molecule passes from the region of high viscosity values to the region of low values, open states, denaturation bubbles, and unweaving of DNA strands can occur. Stabilization of the molecule is provided by energy dissipation—dissipation due to interaction with the environment. Separate sections of a DNA molecule in a twisted state can experience supercoiling stress, which, among other things, is due to complex entropic effects caused by interaction with a solvent. In this work, based on the numerical solution of a mechanical mathematical model for the interferon alpha 17 gene and a fragment of the Drosophila gene, an analysis of the external environment viscosity influence on the dynamics of the DNA molecule and its stability was carried out. It has been shown that an increase in viscosity leads to a rapid stabilization of the angular vibrations of nitrogenous bases, while a decrease in viscosity changes the dynamics of DNA: the rate of change in the angular deviations of nitrogenous bases increases and the angular deformations of the DNA strands increase at each moment of time. These processes lead to DNA instability, which increases with time. Thus, the paper considers the influence of the external environment viscosity on the dissipation of the DNA nitrogenous bases’ vibrational motion energy. Additionally, the study on the basis of the described model of the molecular dynamics of physiological processes at different indicators of the rheological behavior of nucleoplasm will allow a deeper understanding of the processes of nonequilibrium physics of an active substance in a living cell to be obtained.

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