Chemical Regulators of Gibberellin Status and Their Application in Plant Production

Abstract

Gibberellins and inhibitors of their biosynthesis are widely used in modern agriculture, horticulture and viticulture. Their global market is in the range of US$ 500 million. The gibberellins GA 3 , GA 4 and GA 7 are primarily used to increase fruit yield and/or quality in fruit trees and table and wine grapes. Distinct steps of the gibberellin biosynthetic pathway can be inhibited by growth retardants: chlormequat and mepiquat chloride, ancymidol, flurprimidol, paclobutrazol, uniconazole, and the fungicides tebuconazole and metconazole and daminozide, trinexapac-ethyl and prohexadione-calcium are currently used in crop production. Growth retardants reduce shoot elongation, thereby lowering the risk of lodging in cereals, rice and oilseed rape, and making ornamentals more compact. A better canopy structure with improved formation of reproductive structures is induced in cotton and peanuts. In fruit and nut trees, less pruning is required and increases in crop yield and quality are obtained.

Effects of Gibberellin and Gibberellin Biosynthesis Inhibitor (Paclobutrazol) Applications on Radish (Raphanus sativus) Taproot Expansion and the Presence of Authentic Hormones

“…As presented in Fig. 9, paclobutrazol inhibition of gibberellins occurs through the competitive binding block of ent-kaurene oxidation from forming the GA12-aldehyde (Rademacher, 2016). This blockage is achieved, because of the structural similarities between the PBZ and ent-kaurene, which is clearly demonstrated by computer-assisted molecular modelling method (Katagi et al, 1987).…”

“…Growth retardants were employed to reduce the shoot system, thereby lowering the risk of lodging in cereal crops, also used in making ornamental plants more compact with better canopy structure as well as improving the formation of reproductive structures in many other crops. (Liangjiu et al, 1990;Sridharan et al, 2009Sridharan et al, , 2015Rademacher, 2016). Expansion in xylem area is essential for growth of radish primary root (Cavusoglu et al, 2009).…”

Dynamic of accumulation and redistribution of various carbohydrate forms and nitrogen in organs of tomatoes under treatment with retardants

“…Вплив антигіберелінових препаратів пов'язаний із двома фізіологічними ефектами. Вони або інгібують синтез гіберелінутриазолпохідні та онієві препарати (Rademacher, 2016), або ж блокують утворення гормон-рецепторного комплексу, тобто нівелюють вплив уже синтезованого гібереліну,етиленпродуценти та гідразинпохідні сполуки (Zemlyanskaya et al, 2016).…”

Gibberellic Acid Production by Fusarium moniliforme and Aspergillus niger Using Submerged Fermentation of Banana Peel

“…Among the gibberellins, the most predominant is gibberellic acid (gibberellin A3 or GA), because of its frequency and high-level occurrence in microbial fermentations as well as its high biological activity in plants (Rademacher, 2016). The gibberellic acid is a naturally occurring plant growth regulator which may produce a variety of effects including stem elongation, sex expression, enzyme induction, leaf and fruit senescence, growth regulation, seed germination and flowering (Rangaswamy, 2012;Kwon and Paek, 2016).…”

“…In addition, GA has also been applied in activities relating to scientific research pursuits and pharmacological purposes (Kumar and Lonsane, 1989). GA has an annual global production estimated at 25 tonnes and a global market of about US$ 500 million per year and price about $25 /g (Avinash et al, 2003;Rademacher, 2016).There are three reported ways of producing GA which are: plant extraction, chemical synthesis and microbial fermentation, the latter being the most common method due to the very low amounts of GA produced by plants and the costly undertakings of chemical synthesis (Mander, 2003;Sleem, 2013). In addition, chemical synthesis of GA may lead to the production of large amount of toxic effluents with potentially lethal effects to the environment (Dsikowitzky and Schwarzbauer, 2013).…”