DISCOVERY OF PHYTOHORMONES-AUXIN, GIBBERILIN, CYTOKININ

                 DISCOVERY OF PHYTOHORMONES-AUXIN, GIBBERILIN, CYTOKININ

                                                                    AUXIN

S.NO	SCIENTISTS	YEAR OF IDENTIFICATION	DISCOVERY
1	Charles Darwin	1880	The unilateral growth and curvature of Canary  grass (Phalaris canariensis) coleoptile to light.
2	F. W. Went	1926	The term auxin (Greek: Auxin – to Grow)  was first used by him .
3	F. W. Went	1928	Avena curvature test – he  using  Oats (Avena) coleoptile and isolated the auxin.
4	F. W. Went	1928	He collected auxin in agar jelly.
5	Kogl and Haugen Smith	(1931)	He isolated Auxin from human urine, and called it as Auxin A.
6	Kogl and Haugen Smith	1934	An active  substances was isolated from corn grain oil and was named  as Auxin B.
7	Kogl et al.,and Thimann	1934	He found heteroauxin in the plant and chemically called it as Indole-3 Acetic Acid (IAA)
8	Paal	1919	He concluded that large amount of auxin on the shaded side cause that side to grow more and the coleoptile to bend towards unilateral light.
9	Boysen- jensen	1910	It was evident from his experiment that the ‘stimulus’ mentioned by Darwin was in fact  a ‘material substance’ which was in control of growth.
10	Skoog and Thimann	1934	They pointed out that apical dominance might be under the control of auxin produced at the terminal bud.
11	French and Beevers	1953	The auxin may increase the rate of respiration.

 

                                                                  GIBBERELLIN

  

S.NO	SCIENTISTS	YEAR OF IDENTIFICATION	DISCOVERY
1	Kurosawa	1926	This disease was found by to be caused by a fungus Gibberella  fujikuroi.
2	Yabuta	1935	The active substance was separated from fungus and named as gibberellin . These are more than 100 gibberellins reported from both fungi and higher plants. They are noted as GA1, GA2, GA3 and so on. GA3 is the first discovered gibberellin.
3	Yabuta and Sumiki	1938	He isolated gibberellin in  crystalline form.
4	Brain et al.,	1955	He  gave the name gibberellic acid.
5	Cross et al.,	1961	He established its structure.

                                                                      

                                                                   CYTOKININ

 

S.NO	SCIENTISTS	YEAR OF IDENTIFICATION	DISCOVERY
1	Haberlandt	1913	The presence of cell division inducing substances in plants was first demonstrated by him. In Coconut milk (liquid endosperm of coconut) which contains cell division inducing substances.
2	Skoog and Miller	1954	They discovered that autoclaved DNA from herring sperm stimulated cell division in tobacco pith cells. They called this cell division inducing principle as kinetin (chemical structure: 6-Furfuryl Amino Acid). This does not occur in plants.
3	Lethan	1963	He introduced the term cytokinin.
4	Lethan and Miller	1964	They  isolated and identified a new cytokinin called Zeatin from unripe grains of maize. The most  widely occurring cytokinin in plants is Iso Pentenyl adenine (IPA).
5	Zachau et al.,	1966	He identified a cytokinin 2ipa*
6	Sorokin et al.,	1962	In pea stem section, kinetin can induce formation of interfascicular cambium.
7	Wickson and Thimann	1958	He concluded that apical dominance might be under the control of a balance of concentration between kinetin like substance (cytokinins) and IAA.
8	Richmond and Lang	1957	Richmond-lang effect = the effect of kinetin in delaying the senescence.
9	Mothes	1960	The delay of senescence at some part due to kinetin treatment may result in senescence in other part of the plant.
10	Osborne	1962	He suggest that the high protein content in kinetin treated tissue is probably due to more synthesis of protein.