scholarly journals TEMPERATURE IS A KEY REGULATOR OF GROWTH AND FLOWERING IN PROTEA NERIIFOLIA AND PROTEA CYNAROIDES

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 649g-649
Author(s):  
Steven Dupee ◽  
Peter Goodwin
Keyword(s):  
Field Data ◽  
Floral Development ◽  
Important Determinant ◽  
Stem Diameter ◽  
Flower Initiation ◽  
Cool Temperature ◽  
Floral Initiation ◽  
Vegetative Phase ◽  
Reproductive Phase ◽  
Temperature Regimes

The strategy of this study was to determine the period of floral initiation for both species and then to determine the critical regulator(s) of flower initiation and floral development. Plants grown under different temperature regimes gave best shoot extension and flower initiation at temperatures with 10°C night and 15 to 25°C day. Field data from four locations showed a correlation of time of flower initiation and temperatures over the same range. Temperature is an important determinant of the vegetative flush period of both species. The stem diameter of all shoots is a consequence of the vegetative flush growth and in turn is well correlated with flower initiation. Plants given day temperatures of 20°C or above remain in the vegetative phase. Flower abortions in Protea neriifolia and reversions from floral to vegetative shoots in Protea cynaroidesresult from high day temperatures. Daylength was not found to be critical for flower initiation. A cool temperature period acts as a control to change shoots from the vegetative to reproductive phase.

LEAFY expression and flower initiation in Arabidopsis

Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3835-3844 ◽  
Author(s):  
M.A. Blazquez ◽  
L.N. Soowal ◽  
I. Lee ◽  
D. Weigel
Keyword(s):  
Life Cycle ◽  
Floral Induction ◽  
Shoot Meristem ◽  
Flower Initiation ◽  
Gradual Change ◽  
Vegetative Phase ◽  
Flower Meristem ◽  
Reproductive Phase ◽  
Plant Life Cycle ◽  
Short Days

During the initial vegetative phase, the Arabidopsis shoot meristem produces leaves with associated lateral shoots at its flanks, while the later reproductive phase is characterized by the formation of flowers. The LEAFY gene is an important element of the transition from the vegetative to the reproductive phase, as LEAFY is both necessary and sufficient for the initiation of individual flowers. We have analyzed in detail the expression of LEAFY during the plant life cycle, and found that LEAFY is extensively expressed during the vegetative phase. In long days, Arabidopsis plants flower soon after germination, and this is paralleled by rapid upregulation of LEAFY. In short days, Arabidopsis plants flower several weeks later than in long days, but LEAFY expression increases gradually before flowering commences. Application of the plant hormone gibberellin, which hastens flowering in short days, enhances the gradual change in LEAFY expression observed in short days. Changes in LEAFY expression before the transition to flowering suggest that the time point of this transition is at least partly controlled by the levels of LEAFY activity that are prevalent at a given time of the life cycle. This assumption is borne out by the finding that increasing the copy number of endogenous LEAFY reduces the number of leaves produced before the first flower is formed. Thus, LEAFY combines properties of flowering-time and flower-meristem-identity genes, indicating that LEAFY is a direct link between the global process of floral induction and the regional events associated with the initiation of individual flowers.

Photoperiod and Temperature Influence on Flower Initiation and Development for Euphorbia pulcherrima Grown Under Florida Conditions

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 509a-509
Author(s):  
C.E. Wieland ◽  
J.E. Barrett ◽  
D.G. Clark ◽  
G. J. Wilfret
Keyword(s):  
Subsequent Development ◽  
Flower Initiation ◽  
Euphorbia Pulcherrima ◽  
Floral Initiation ◽  
Temperature Influence ◽  
Average Temperature ◽  
Long Day ◽  
Time To Initiation ◽  
Growth Room ◽  
Maximum Temperatures

Four poinsettia cultivars were grown in glass greenhouses in Gainesville, Fla., in the Fall 1997 to evaluate differences in floral initiation and subsequent development. Three means of regulating photoperiod were 1) natural days 2) long-day lighting to 6 Oct. and then natural days (lights out) 3) long-day lighting to 6 Oct., and then short-day conditions by black cloth for 15 h (black cloth). At 2-day intervals, sample meristems were collected and examined for initiation of reproductive development. Average minimum and maximum temperatures during the first two weeks of October were 22 and 29 °C, respectively, with an average temperature of 25.3 °C. The overall average temperature was 23.2 °C from planting to anthesis. Differences in anthesis dates among cultivars were primarily due to time to initiation vs. rate of development. Under natural days, `Lilo' initiated first on 8 Oct. and `Freedom', `Peterstar', and `Success', followed by 6, 8, and 18 days, respectively. Lights out resulted in `Lilo' initiating 17 Oct., followed by `Freedom', `Peterstar', and `Success' initiating 7, 12, and 15 days later, respectively. Differences between cultivars in time of initiation was reduced under black cloth, where `Lilo' initiated 14 Oct., followed by `Freedom' 2 days later, and `Peterstar' and `Success' 7 days afterward. Initiation was positively correlated to visible bud and anthesis. First color was positively correlated to initiation and visible bud, with the exception of `Lilo'. Growth room studies conducted using various high temperatures and photoperiods indicated similar trends.

Sucrose accumulation in sugarcane is influenced by temperature and genotype through the carbon source - sink balance

2010 ◽  
Vol 61 (2) ◽  
pp. 111 ◽  
Author(s):  
N. G. Inman-Bamber ◽  
G. D. Bonnett ◽  
M. F. Spillman ◽  
M. H. Hewitt ◽  
D. Glassop
Keyword(s):  
Water Stress ◽  
Molecular Techniques ◽  
Clonal Variation ◽  
Sink Strength ◽  
Extension Rate ◽  
Cool Temperature ◽  
Sucrose Accumulation ◽  
Temperature Regimes ◽  
New Research ◽  
Source Sink

While substantial effort has been expended on molecular techniques in an attempt to break through the apparent ceiling for sucrose content (SC) in sugarcane stalks, molecular processes and genetics limiting sucrose accumulation remain unclear. Our own studies indicate that limiting expansive growth with water stress will enhance sucrose accumulation in both low- and high-sucrose clones. Sucrose accumulation was largely explained (72%) by an equation with terms for photosynthesis, plant extension rate (PER), and plant number. New research was conducted to determine if this simple model stands when using temperature rather than water stress to perturb the source–sink balance. We also applied a thinning treatment to test the proposal implicit in this equation that SC will increase if competition between plants for photo-assimilate is reduced. Four clones from a segregating population representing extremes in SC were planted in pots and subjected to warm and cool temperature regimes in a glasshouse facility. A thinning treatment was imposed on half the pots by removing all but 6 shoots per pot. Temperature as a means of reducing sink strength seemed initially to be more successful than water regime because PER was 43% lower in the cool than in the hot regime while photosynthesis was only 14% less. PER was a good indicator of dry matter allocation to expansive growth, limited by water stress but not by temperature, because stalks tended to thicken in low temperature. Thinning had little effect on any of the attributes measured. Nevertheless the clonal variation in plant numbers and the response of PER to temperature helped to explain at least 69% of the variation in sucrose accumulation observed in this experiment. Thus the earlier model for sucrose accumulation appeared to be valid for the effect on sucrose accumulation of both temperature and water stress on the source–sink balance. The next step is to include internodes in models of assimilate partitioning to help understand the limiting steps in sucrose accumulation from the basics of source–sink dynamics.

The effect of temperature stress on grain development in wheat

1965 ◽  
Vol 16 (1) ◽  
pp. 1 ◽  
Author(s):  
RD Asana ◽  
RF Williams
Keyword(s):  
Growth Analysis ◽  
Important Determinant ◽  
Effect Of Temperature ◽  
Synthetic Activity ◽  
Grain Development ◽  
Night Temperature ◽  
Complex Interactions ◽  
Temperature Regimes ◽  
Controlled Environments ◽  
Stable Characteristic

Experiments were conducted in controlled environments to determine the effects of high temperatures on grain development and yield in wheat. Two Australian and three Indian cultivars of wheat were exposed, from a week after anthesis until maturity, to "day" temperatures of 25, 28, and 3l°C, and "night" temperatures of 9 and 12°C. There was a mean reduction in yield of 16%' for the 6° rise in day temperature, but the cultivars did not differ significantly in their response to these temperatures. There were no significant effects of night temperature on grain weight, but stem weight was less at 12°C. Senescence was hastened only slightly by high day temperature, and there were no differential effects between cultivars in this respect.In a subsidiary experiment one Indian and five Australian cultivars were subjected to three day-night temperature regimes (24/19°, 27/22°, and 30/25°C). Highly significant but complex interactions were established between temperature regime and cultivar. A growth analysis for the Australian cultivars Ridley and Diadem indicated that the developing grain of Ridley had a greater capacity for growth than that of Diadem from the earliest stage. This, together with the confirmation of grain size as a very stable characteristic for all the varieties, points to the developmental and synthetic activity of the grain as an important determinant of grain yield. The relevance of this study to the production of wheat in India is briefly discussed.

Effect of phosphorus applied as superphosphate on rate of development and spikelet number per ear of different cultivars of wheat

1977 ◽  
Vol 28 (2) ◽  
pp. 183 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson
Keyword(s):  
Constant Temperature ◽  
Leaf Number ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Main Shoot ◽  
Spikelet Number ◽  
Vegetative Phase ◽  
Rate Of Development ◽  
Elongation Phase

The effects of adding phosphorus (40 kg of phosphorus ha-1) at sowing on rate of development, spikelet number per ear, rate of spikelet initiation, apex length at floral initiation, and leaf number at ear emergence of the main shoot of seven wheat cultivars were studied under a 16 hr photoperiod at a constant temperature of 20°C. Phosphorus additions increased the spikelet number per ear, rate of spikelet initiation, and apex length significantly in all wheats, but had no effect on the duration of the vegetative phase, spikelet phase or elongation phase, or on leaf number. The increase in spikelet number was due to an increase of spikelet initiation. All wheats responded similarly to addition of phosphorus.

Floral development and anatomy of Macarthuria australis (Macarthuriaceae): key to understanding the unusual initiation sequence of Caryophyllales

2019 ◽  
Author(s):  
Louis P. Ronse De Craene ◽  
Lai Wei
Keyword(s):  
Floral Development ◽  
Floral Anatomy ◽  
Floral Evolution ◽  
Flower Initiation ◽  
Developmental Sequence ◽  
Petal Development ◽  
Initiation Sequence ◽  
Rapid Emergence

We investigated the floral anatomy and development of Macarthuria australis Hügel ex Endl., an unusual genus endemic to Australia, in the context of floral evolution of core Caryophyllales. Flower initiation is spiral, with sepals developing quincuncially. The first two petals continue the sequence of sepal initiation, but the remaining petals arise from common stamen–petal primordia. The androecium develops sequentially as three inner antesepalous and five outer antepetalous stamens. The globular ovary is trimerous with a short symplicate zone and two arillate ovules per locule. The rapid emergence of the androecium leads to a partial absorption of the petal primordia within the androecial tissue. The two first-formed petals have more room for development and precede the androecium, supporting the fact that petals are not staminodial in origin. This heterochronic shift correlates with an inversed developmental sequence of the antesepalous stamens. The constraint caused by the spatial occupation of sepals and carpels leads to the loss of two stamens, and the re-arrangement of stamens and petals along the flanks of the carpels. The floral development of Macarthuria anticipates a syndrome of stamen and petal development in other core Caryophyllales and culminating in the Caryophyllaceae.

Agronomic studies on Vigna spp. in south-eastern Queensland. I. Phenological response of cultivars to sowing date

1979 ◽  
Vol 30 (5) ◽  
pp. 855 ◽  
Author(s):  
RJ Lawn
Keyword(s):  
Sowing Date ◽  
Reproductive Period ◽  
Day Length ◽  
Rate Of Development ◽  
South Eastern ◽  
Vigna Species ◽  
Reproductive Phase ◽  
Temperature Regimes ◽  
Sowing Dates ◽  
Maximum Temperatures

Phenological development of 16 cultivars from four Vigna species (V. radiata, green gram; V. mungo, black gram; V. angularis, adzuki bean; V. umbellata, rice bean) was studied over a range of 17 weekly sowing dates at Lawes in south-eastern Queensland. Cultivar and sowing date effects on phenology were large. In all cultivars, the rate of development during pre-flowering was associated negatively with mean day length and positively with mean maximum and/or mean minimum temperature. Cultivars differed in sensitivity to both photoperiod and temperature. Genetic lateness of flowering among cultivars was associated positively with increasing sensitivity to day length and negatively with the latitude of cultivar source. In the grams, early-flowering cultivars showed response to maximum temperatures, while the later-flowering lines responded to minimum temperatures. Rate of development in all four species during the reproductive phase was largely independent of cultivar and sowing date, per se, but rather appeared to depend on the day length and temperature regimes prevailing subsequent to the onset of flowering. The reproductive period in all species was shortest for those cultivar x sowing date combinations which commenced flowering in early autumn. Where flowering occurred in midsummer, i.e. for early sowings and for early cultivars, the reproductive period was extended as a consequence of prolonged flowering in response to the longer prevailing day lengths. As the date of flowering was delayed into mid or late autumn, the reproductive phase was extended owing to slower pod maturation rates in response to cooler prevailing temperatures. The implications of these responses on adaptation and agronomic utilization of these species are discussed.

Investigation of flowering in Banksia baxteri R. Br. and B. hookeriana Meissner for improving pruning practices

1994 ◽  
Vol 34 (8) ◽  
pp. 1209 ◽  
Author(s):  
LJ Rohl ◽  
AM Fuss ◽  
JA Dhaliwal ◽  
MG Webb ◽  
BB Lamont
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Floral Development ◽  
Early Summer ◽  
Stem Length ◽  
First Year ◽  
Floral Initiation ◽  
Scanning Electron

Floral initiation and development in relation to time of flowering were investigated in Banksia baxteri and B. hookeriana with the aid of scanning electron microscopy. Floral initiation occurred in spring in B. baxteri and in early summer in B. hookeriana. Floral development was rapid in B. baxteri (3 months to reach anthesis in summer). In B. hookeriana, development took 5 months, with anthesis occurring in winter. Most B. hookeriana blooms were produced on 2-year-old shoots, while B. baxteri produced about half of its blooms on 2-year-old shoots and almost as many on 3-year-old shoots. In both species, shoots that flowered within 2 years were longer and thicker in their first year than other shoots. A critical minimum stem length was determined for the first year's growth, to be used as a criterion for determining which shoots to remove during pruning. Details are provided for the timing of pruning to achieve maximum bloom production in B. baxteri and B. hookeriana.

Some Effects of Temperature and Light on Floral Initiation and Development in Acacia pycnantha

1985 ◽  
Vol 12 (2) ◽  
pp. 109 ◽  
Author(s):  
M Sedgley
Keyword(s):  
Light Intensity ◽  
Floral Development ◽  
Early Stage ◽  
The Other ◽  
Floral Initiation ◽  
Ambient Conditions ◽  
Low Light ◽  
Floral Primordia ◽  
Effects Of Temperature ◽  
Normal Light

Floral initiation and development in Acacia pycnantha were studied under three environments. Two had ambient southern Australian temperatures of warm summer (mean max. 32°C, mean min. 16°C) and cool winter (mean max. 19°C, mean min. 8°C), one with full sunlight (outside) and the other with 30% light intensity (shadehouse). The other environment (glasshouse) had slightly lower than normal light intensity and a relatively constant year round temperature of mean 28°C maximum and 16°C minimum. Plants were scored for microscopic and macroscopic evidence of floral initiation and development. Floral primordia were initiated all year round under all environments. Floral development proceeded normally under ambient conditions of temperature and light, and anthesis occurred between August and October. Under low light intensity, floral development did not progress beyond a very early stage and macroscopically visible racemes were rare. Under the constant temperatures, floral development proceeded normally up to the stage of microsporogenesis and megasporogenesis. Meiosis did not occur and inflorescence buds ceased growth and were shed from the plant. Plants were transferred between the outside and glasshouse conditions in June, at around the stage of meiosis. Those transferred from outside to the glasshouse did not flower whereas some of those transferred from the glasshouse to outside flowered, but later and for a shorter period than plants maintained outside throughout. It appears that a 70% reduction in sunlight inhibits floral development at an early stage and that temperatures of approximately mean maximum 19°C and minimum 8°C are required for meiosis in Acacia pycnantha.

Interrelations in the growth and development of Lolium. I. Some effects of vernalization on growth and development

1965 ◽  
Vol 16 (6) ◽  
pp. 903 ◽  
Author(s):  
JH Silsbury
Keyword(s):  
Low Temperature ◽  
Growth Rates ◽  
Growth And Development ◽  
Growth Curves ◽  
High Growth ◽  
Reproductive Development ◽  
Controlled Environment ◽  
Lolium Rigidum ◽  
Vegetative Phase ◽  
Reproductive Phase

The responses of Lolium rigidum Gaud. and L. perenne L. to low temperature seed vernalization were determined by comparing the growth and development of vernalized and unvernalized plants raised in the field and in a controlled environment cabinet. Vernalization did not appear to influence growth in the vegetative phase, but usually induced earlier heading and a greater proportion of reproductive tillers. Comparisons of vernalized (reproductive) and unvernalized (vegetative) plants show increased reproductive development to be associated with higher growth rates, lower tillering, and greater weight per tiller. High growth rates during the reproductive phase are considered to be due to the ability of reproductive tillers to grow more rapidly than vegetative tillers through the growth of true stem functioning as a "sink" for assimilate. Generalized growth curves for vernalized and unvernalized ryegrass grown under long days are presented and discussed.

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