scholarly journals Gibberellic Acid Stimulation of Cucumber Hypocotyl Elongation

1989 ◽  
Vol 90 (4) ◽  
pp. 1335-1340 ◽  
Author(s):  
Anne Taylor ◽  
Daniel J. Cosgrove
Keyword(s):  
Gibberellic Acid ◽  
Hypocotyl Elongation ◽  
Cucumber Hypocotyl ◽  
Stimulation Of

Effects of Kaurane Diterpene Derivatives on Germination and Growth of Lactuca sativa Seedlings

2005 ◽  
Vol 60 (1-2) ◽  
pp. 72-78 ◽  
Author(s):  
Henriete S. Vieira ◽  
Jacqueline A. Takahashi ◽  
Lúcia P. S. Pimenta ◽  
Maria Amélia D. Boaventura
Keyword(s):  
Gibberellic Acid ◽  
Lactuca Sativa ◽  
Naturally Occurring ◽  
Germination And Growth ◽  
Stimulation Of

Kaurenoic and grandiflorenic acid, isolated from Wedelia paludosa (Asteraceae), some derivatives from these acids (alcohols, esters, amides, lactones, oximes) and other naturally occurring kaurane diterpenes were tested for their action on the growth of radical and shoot of Lactuca sativa. Gibberellic acid, GA3, a commercially available phytohormone, belonging to the same class of diterpenes, was also tested. Some of the tested substances showed a remarkable activity either in the inhibition or in stimulation of L. sativa growth. The activity, in some cases, was even higher than that of GA3.

Gibberellic acid and the growth of crop plants

1958 ◽  
Vol 50 (1) ◽  
pp. 49-59 ◽  
Author(s):  
D. G. Morgan ◽  
G. C. Mees
Keyword(s):  
Growth Rate ◽  
Gibberellic Acid ◽  
Crude Protein ◽  
Dry Matter ◽  
Field Trials ◽  
Natural Growth ◽  
Nitrogenous Fertilizer ◽  
Sodium Calcium ◽  
Normal Green ◽  
Stimulation Of

1. Field trials with gibberellic acid on grass, wheat, potatoes, turnips, carrots, peas, runner beans, lettuce, celery, blackcurrants, kale and maize are described. The effects on plant growth and crop yield were determined.2. The experiments on grassland were carried out between July 1953 and June 1956, and included trials at four different centres. They all gave essentially similar results.3. 2 oz. per acre of gibberellic acid sprayed at 100 gal. per acre stimulated the growth of all components of the swards. The stimulation was most clearly seen in spring and autumn when the natural growth rate was slow. At these times gibberellic acid was able to produce a grazeable growth of grass more rapidly than nitrogenous fertilizers. The stimulation of growth was accompanied by yellowing of the grass, but recovery to a normal green colour was speeded up by applying a nitrogenous fertilizer at the same time as the gibberellic acid spray.4. The dry-matter yields at the first cut following a treatment with gibberellic acid were increased by 0·6–10·8 cwt. per acre. The crude protein yields were also increased by the treatment, but to a relatively smaller degree, and the protein content of the grass was reduced by between ½ and 2%. The contents of phosphorus, potassium, sodium, calcium, barium, magnesium, manganese, copper, aluminium and tin were not altered.

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.

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