Question

gibberelli defination and its commercial application?

Answer 1

Gibberellins (GAs) are plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction, and leaf and fruit senescence.[1]

Gibberellin was first recognized in 1926 by a Japanese scientist, Eiichi Kurosawa, studying bakanae, the "foolish seedling" disease in rice.[1][2] It was first isolated in 1935 by Teijiro Yabuta and Sumuki, from fungal strain (Gibberella fujikuroi) provided by Kurosawa.[1] Yabuta named the isolate as gibberellin.[1]

Interest in gibberellins outside Japan began after World War II. In the United States, the first research was undertaken by a unit at Camp Detrick in Maryland, via studying seedlings of the bean Vicia faba.[1] In the United Kingdom, work on isolating new types of gibberellin was undertaken at Imperial Chemical Industries.[1] Interest in gibberellins spread around the world as the potential for its use on various commercially important plants became more obvious. For example, research that started at the University of California, Davis in the mid-1960s led to its commercial use on Thompson seedless table grapes throughout California by 1962.[3][clarification needed] A known gibberellin biosynthesis inhibitor is paclobutrazol (PBZ), which in turn inhibits growth and induces early fruitset as well as seedset.

Contents

ChemistryEdit



Effect of gibberellic acid on cannabis sprout

All known gibberellins are diterpenoid acids that are synthesized by the terpenoid pathway in plastids and then modified in the endoplasmic reticulum and cytosol until they reach their biologically-active form.[4] All gibberellins are derived via the ent-gibberellane skeleton, but are synthesised via ent-kaurene. The gibberellins are named GA1 through GAn in order of discovery. Gibberellic acid, which was the first gibberellin to be structurally characterized, is GA3.

As of 2003, there were 126 GAs identified from plants, fungi, and bacteria.[1]

Gibberellins are tetracyclic diterpene acids. There are two classes based on the presence of either 19 or 20 carbons. The 19-carbon gibberellins, such as gibberellic acid, have lost carbon 20 and, in place, possess a five-member lactone bridge that links carbons 4 and 10. The 19-carbon forms are, in general, the biologically active forms of gibberellins. Hydroxylation also has a great effect on the biological activity of the gibberellin. In general, the most biologically active compounds are dihydroxylated gibberellins, which possess hydroxyl groups on both carbon 3 and carbon 13. Gibberellic acid is a dihydroxylated gibberellin.[5]



Gibberellin A1 (GA1)

 



Gibberellic acid (GA3)

 



ent-Gibberellane

 



ent-Kaurene

Bioactive GAsEdit

The bioactive GAs are GA1, GA3, GA4, and GA7.[6] There are three common structural traits between these GAs: 1) a hydroxyl group on C-3β, 2) a carboxyl group on C-6, and 3) a lactone between C-4 and C-10.[6] The 3β-hydroxyl group can be exchanged for other functional groups at C-2 and/or C-3 positions.[6] GA5 and GA6 are examples of bioactive GAs that do not have a hydroxyl group on C-3β.[6] The presence of GA1 in various plant species suggests that it is a common bioactive GA.[7]

Answer 2

Gibberellin. From Wikipedia, the free encyclopedia. Jump to: navigation, search. Gibberellins (GAs) are plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction, and leaf and fruit senescence