Gibberellins flower formation

The discovery of the effects of gibberellin on flower formation is closely linked 1 with older studies on the physiology of this process, particularly its regulation by certain external or environmental factors. 

Flower formation is usually obtained only after repeated applications of relatively substantial gibberellin doses. In lettuce, two treatments of 20 / g. each,... 

Most cold-dependent plants also possess a long-day requirement. The gibberellin treatment of these plants was usually conducted under long-day conditions, so that only the temperature-controlled block to flower formation was present. If the treatment was given under short-day conditions, only stem elongation was obtained it is evidently difficult to overcome the simultaneous presence of two blocks to flower formation. 

Can we say anything more precise about the function of gibberellins in flower formation Most plant biologists feel that flower formation is controlled by specific, hormone-like substances, so-called flower hormones. Attempts at ex-... 

The precise function of gibberellin in flower formation is by no means clear and may be indirect in nature. On the other hand, gibberellins are the first... 

Flower sex expression of cucumbers can be modified by treating seedlings with several growthregulating substances With the exception of gibberellin, chemicals tend to reduce the number, or suppress the development, of staminate flowers, and increase the number or accelerate the development of pistillate flowers Gibberellin, in contrast, increases the number of staminate flowers in monoecious cucumbers and results in the formation of staminate flowers on gynoecious cucumbers which otherwise would produce only pistillate flowers In promotive effects on staminate flower formation and vegetative extension, GA4 is approximately tenfold more active than GA3 ... 

Photoperiod enhances the promotive effect of gibberellin on staminate flower formation in the gynoecious cucumber not by increasing the number of nodes which... 

Table V Effect of Gibberellin and Photoperiod on Promotion of Staminate Flower Formation on Gynoecious Cucumber (MSU 713-5)...

The promotion of staminate flower formation in cucumbers by gibberellin is not surprising if one considers the effects of gibberellin as similar to those of a long photoperiod. Extension of the staminate stage in monoecious cucumbers by gibber-... 

Table VI. Comparative Activities of Gibberellin A3 and Butyl Cellosolve Ester of Gibberellin A3 on Promotion of StamSnate Flower Formation on Gynoecious...

Lang, A. (1957). Effect of gibberellin upon flower formation. Proc. Natl. Acad. Sci. USA 43,709-717. 

Michniewicz M, Lang A (1962) Effect of nine different gibberellins on stem elongation and flower formation in cold requiring and photoperiodic plants grown under non-inductive conditions. Planta (Berl) 58 549-563 Milborrow BV (1974) The chemistry and physiology of abscisic acid. Annu Rev Plant Physiol 25 259-307... 

Suttle JC, Zeevaart JAD (1979) Stem growth, flower formation, and endogenous gibberellins in a normal and a dwarf strain of Silene armeria. Planta (Berl) 145 175-180 Torrey JG (1976) Root hormones and plant growth. Annu Rev Plant Physiol 27 435-459 Vince-Prue D (1975) Photoperiodism in plants. McGraw-Hill, London Wareing PF, Saunders PF (1971) Hormones and dormancy. Annu Rev Plant Physiol 22 261-288... 

Induction of Flower Formation. In the case of long day plants and a number of cold-requiring plants gibberellins can induce the formation of flowers under conditions under which this does not normally occur. We shall discuss this phenomenon later (page 304). 

In the case of long day plants that have no requirements for cold, gibberellin treatment can substitute for the long day. That is especially true of those long day plants in which the transition to flower formation is associated with the sprouting of rosettes. 

Studies reported herein are primarily concerned with the effects of gibberellin in extending the staminate stage of monoecious cucumbers and with the formation of staminate flowers on gynoecious cucumbers. 

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