Flowering in Pisum: Does Gibberellic Acid Directly Influence the Flowering Process?

1977 ◽  
Vol 4 (4) ◽  
pp. 479 ◽  
Author(s):  
JB Reid ◽  
PJ Dalton ◽  
IC Murfet
Keyword(s):  
Gibberellic Acid ◽  
Direct Effect ◽  
Continuous Light ◽  
Flower Initiation ◽  
Small Delay ◽  
Effect Of Age ◽  
Flowering Process

Gibberellic acid is shown to cause a substantial delay in the flowering node, time of flower initiation and leaf requirement for flowering in the late pea cultivar line 24, grown under an 8-h photoperiod. In continuous light, gibberellic acid caused only a small delay in the flowering node and leaf require- ment. As the plants became older the effect of applied gibberellic acid decreased. This was not due to initiation having already occurred or to the gibberellic acid not penetrating the plant. It is suggested that gibberellic acid has a direct effect on the flowering process in line 24 plants grown under an 8-h photoperiod and that it may act by reducing the effect of age on the gene Sn.

Betacyanin accumulation, chlorophyll content, and flower initiation in Chenopodium rubrum as related to endogenous rhythmicity and phytochrome action

1970 ◽  
Vol 48 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Edgar Wagner ◽  
Bruce G. Cumming
Keyword(s):  
Gibberellic Acid ◽  
Chlorophyll Content ◽  
Dark Period ◽  
Continuous Light ◽  
High Energy ◽  
Hypocotyl Elongation ◽  
Chenopodium Rubrum ◽  
Physiological Status ◽  
Flower Initiation ◽  
Endogenous Rhythmicity

In Chenopodium rubrum seedlings (ecotypes 50°10′ N and 49°58′ N) betacyanin synthesis is light dependent (completely dark-grown seedlings contain no betacyanin) and is under phytochrome control via both the low energy and the high-energy (HER) reactions of photomorphogenesis. In continuous light, accumulation of betacyanin is linear with time. However, when a single dark period interrupts continuous light, the amount of both betacyanin and chlorophyll synthesized during a given period of time after the dark interruption shows a rhythm reflecting differences in the rate of, and (or) the capacity for, pigment accumulation that are dependent on the duration of the dark period. The rhythm in chlorophyll content was higher in frequency than circadian, with a period of about 15 h, while rhythmicity in the rate of synthesis of betacyanin was circadian. These results suggest that there is endogenous rhythmicity in the metabolic state of the system in darkness. The imposition of light after darkness apparently stabilizes the specific physiological status attained at that respective time of darkness and thus determines the metabolic activity of the seedlings.When glucose was supplied throughout darkness interrupting continuous light, the phasing of the rhythm of betacyanin synthesis was positively correlated with the rhythm of flower initiation, but this was not so when phenylalanine was supplied during darkness. In contrast, when glucose was supplied for a varied length of time in continuous light, there was rhythmicity in the rate of betacyanin accumulation, with a periodicity of about 15 h, that was dependent on the duration of the glucose application.When seedlings were supplied with 10−6 M gibberellic acid during darkness there was a rhythm in the amount of hypocotyl elongation that depended on the length of a single dark period interrupting continuous light. Other evidence has suggested that there is a rhythm in the stability of the cellular membranes; this rhythm was assayed (non-physiologically) by the time of onset of betacyanin leakage from seedlings into an extraction medium and was apparent only after application of 10−10 M gibberellic acid. The rhythms in hypocotyl elongation and in membrane stability that were revealed after the application of gibberellic acid suggest that there may be a rhythm in the rate of differentiation and (or) development of the system.It is postulated that endogenous rhythmicity is due to the spatial separation of energy production and use in different cell particulates, with phytochrome acting as a membrane operator.

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.

Organogenesis from cultured floral meristems of a male sterile tobacco hybrid

1981 ◽  
Vol 59 (9) ◽  
pp. 1665-1670 ◽  
Author(s):  
G. S. Hicks ◽  
Robin Browne ◽  
S. A. Sand
Keyword(s):  
Gibberellic Acid ◽  
Basal Medium ◽  
Continuous Light ◽  
Direct Influence ◽  
Male Sterile ◽  
Normal Sequence ◽  
Skoog Medium ◽  
Tobacco Hybrid ◽  
Floral Meristems

Very young floral meristems of a male-sterile tobacco hybrid were excised and cultured on Linsmaier and Skoog medium in continuous light. Basal medium was supplemented with kinetin and gibberellic acid, singly and in combinations. On medium with kinetin, all four types of floral organs arose in the normal sequence and pattern and the male sterile phenotype was expressed, GA3 suppressed the formation of these organs. The data show that male sterile organs may form and begin differentiation in vitro without direct influence from the plant.

scholarly journals Photopreiodic and Temperature Control of Flower Initiation in the Late Pea Cultivar Greenfeast

1968 ◽  
Vol 21 (4) ◽  
pp. 609 ◽  
Author(s):  
DM Paton
Keyword(s):  
Temperature Control ◽  
Low Temperatures ◽  
Continuous Light ◽  
Flower Initiation ◽  
Temperature Responses

The number of green foliage leaves at initiation is related to a quantitative leaf requirement for flowering in the late pea cultivar Greenfeast. When grown in various temperature and photoperiod regimes the leaf requirement is least in continuous light and low temperatures. The additive nature of the photoperiodic and temperature responses suggests that photoperiod and temperature probably act independently.

Flower initiation in pasture legumes. IV. Flower initiation in Trifolium pratense L.

1964 ◽  
Vol 15 (1) ◽  
pp. 21 ◽  
Author(s):  
Y Aitiken
Keyword(s):  
Trifolium Pratense ◽  
Continuous Light ◽  
Red Clover ◽  
Flower Initiation ◽  
Pasture Legumes ◽  
Flowering Season ◽  
Short Period ◽  
Trifolium Pratense L ◽  
Long Photoperiod ◽  
Early Strain

An early strain (Cowgrass) and a late-maturing strain (Montgomery) of red clover (Trifolium pratense L.) were grown at Melbourne, lat. 38°S., to study flower initiation and the relationship between initiation and flowering, because of the importance of flowering to the use of the species as a source of hay. The terminal inflorescence in red clover arises from a lateral bulge at the shoot apex, and the main shoot of the plant is strongly vegetative, only becoming reproductive in a proportion of plants under long photoperiod, particularly continuous light. In both strains, whether first-year or older plants, flower initiation and therefore flowering were confined to a short period of the year, the early strain having the longer period. Sowing the two strains at intervals through the year in the field, under natural and long photoperiods, showed the importance of both photoperiod and temperature to initiation. Both strains were hastened by a long photoperiod whatever the temperature, and initiated at a similar low leaf number, but the early strain was able to initiate at a shorter photoperiod than the late one. Seed vernalization had almost no effect; but at photoperiods of 14 to 11 hr, high temperatures strongly retarded Cowgrass and appeared to prevent initiation in Montgomery. The capacity of Cowgrass to initiate at a shorter photoperiod and at higher temperatures than Montgomery explains its longer flowering season in temperate latitudes. These genetic differences suggest that an appropriate environment can be used to differentiate early and late-flowering strains for seed certification, and that late strains would stay vegetative at low latitudes and would therefore be less useful as a source of hay than early ones.

FLORAL INITIATION IN STRAWBERRY AND SOME EFFECTS OF RED AND FAR-RED RADIATION AS COMPONENTS OF CONTINUOUS WHITE LIGHT

1966 ◽  
Vol 44 (5) ◽  
pp. 663-668 ◽  
Author(s):  
W. B. Collins
Keyword(s):  
White Light ◽  
Concentration Gradient ◽  
Red Light ◽  
Continuous Light ◽  
High Energy ◽  
Clear Distinction ◽  
Flower Initiation ◽  
Floral Initiation ◽  
Mother Plants ◽  
Red Radiation

The effects of different ratios of red to far-red radiation in continuous light on flower initiation in strawberry are described. A correlation was found between flower promotion and the content of far-red light in the supplied radiation which may be related to the red/far-red ratio of light and therefore to the level of phytochrome-Pfr in the plants. However, since relatively high energy (white) light was the only radiation used, a clear distinction between photosynthetic and red/far-red photoreversible effects is not possible. Flowering did not occur on all runner plants. Where flowering was promoted it invariably occurred first on the second- or third-formed runner plants on the stolon. Flowering was delayed on the proximal runner plants and never occurred on the mother plants. The results support the premise that a flower-inhibiting system was present along a concentration gradient in the runner.

scholarly journals Germination and Storage of Vinca Seed Is Influenced by Light, Temperature, and Relative Humidity

HortScience ◽  
1992 ◽  
Vol 27 (9) ◽  
pp. 993-996 ◽  
Author(s):  
William J. Carpenter ◽  
Joseph F. Boucher
Keyword(s):  
Relative Humidity ◽  
Gibberellic Acid ◽  
Catharanthus Roseus ◽  
Continuous Light ◽  
Seed Storage ◽  
Germination Percentage ◽  
Seed Moisture ◽  
And Storage ◽  
Storage Temperatures

Light, temperature, relative humidity (RH), and GA3 affect vinca [Catharanthus roseus (L.) G. Don] seed storage and/or germination. GA3 failed to increase the germination percentage in darkness but significantly increased the percentage in continuous light. Similarly, GA3 treatment reduced both the number of days required to achieve 50% of the final germination percentage (T50) and the span between 10% and 90% germination (T90 — T10) for seeds in light, but not in darkness. Germination percentages were maximal and about equal at 25, 30, or 35C in darkness; germination was lowest below 25C. Germination T50 and T90 — T10 required the fewest days between 25 and 35C. Reducing seed moisture from 9.9% to 3.9% increased the T50 from 2.4 to 3.0 days but failed to change germination percentages. Germination percentage declined linearly as seed storage temperatures were reduced from 5 to — 20C, whereas days to T50 increased. Seed storage for 12 months without reduction in germination percentage was possible at 5C and 11%, 33%, or 52% RH, but storage at 75% or 95% RH for periods exceeding 1 month reduced germination. Seeds stored at 33% or 52% RH required fewer days to T50 than did seeds stored at 11%, 75%, or 95% RH. Chemical name used: gibberellic acid (GA3).

scholarly journals Effects of Cold and Photoperiod on Flowering of Several Herbaceous Perennial Species

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 581b-581
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins ◽  
Arthur C. Cameron ◽  
William H. Carlson
Keyword(s):  
Cold Treatment ◽  
Continuous Light ◽  
Flower Initiation ◽  
Perennial Species ◽  
Cold Response ◽  
Long Day ◽  
Before And After ◽  
Cold Requirement ◽  
Incandescent Lamps ◽  
Herbaceous Perennial

Thirty herbaceous perennial species were treated at 5°C for 0 or 15 weeks. Critical photoperiods for flower initiation and development with and without a cold treatment were determined. Photoperiods were 10, 12, 13, 14, 16, or 24 hours of continuous light or 9 hours plus a 4-hour night interruption. Continuous photo-periodic treatments consisted of 9-hour natural days extended with light from incandescent lamps. Species were categorized into nine response types based on the effects of cold and photoperiod on flowering. Plants had three flowering responses to cold treatment: obligate, facultative, or none. The perennials were obligate long-day, facultative long-day, or day-neutral plants. For example, Campanula carpatica `Blue Clips' had no response to cold and was an obligate long-day plant requiring photoperiods of 16 hours or longer or night interruption for flowering. Rudbeckia fulgida `Goldsturm' had a facultative response to cold and required photoperiods of 14 hours or longer or night interruption for flowering. Veronica longifolia `Sunny Border Blue' had an obligate cold requirement and was day-neutral. Some species responded differently to photoperiod before and after cold. Leucanthemum ×superbum `Snow Cap' flowered as an obligate long-day plant without cold and as a facultative long-day plant after cold. Response categories are discussed.

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