Psychoactive Plant Database - Neuroactive Phytochemical Collection

1. Talanta. 2011 Aug 15;85(2):897-905. doi: 10.1016/j.talanta.2011.04.073. Epub 
2011 May 6.

Investigation of plant hormone level changes in shoot tips of longan (Dimocarpus 
longan Lour.) treated with potassium chlorate by liquid 
chromatography-electrospray ionization mass spectrometry.

Susawaengsup C(1), Rayanakorn M, Wongpornchai S, Wangkarn S.

Author information:
(1)Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang 
Mai 50200, Thailand.

The endogenous levels of indole-3-acetic acid (IAA), gibberellins (GAs), 
abscisic acid (ABA) and cytokinins (CKs) and their changes were investigated in 
shoot tips of ten longan (Dimocarpus longan Lour.) trees for off-season 
flowering until 60 days after potassium chlorate treatment in comparison with 
those of ten control (untreated) longan trees. These analytes were extracted and 
interfering matrices removed with a single mixed-mode solid phase extraction 
under optimum conditions. The recoveries at three levels of concentration were 
in the range of 72-112%. The endogenous plant hormones were separated and 
quantified by liquid chromatography-electrospray ionization-mass spectrometry 
(LC-ESI-MS). Detection limits based on the signal-to-noise ratio ranged from 10 
ng mL(-1) for gibberellin A4 (GA4) to 200 ng mL(-1) for IAA. Within the first 
week after potassium chlorate treatment, dry weight (DW) amounts in the treated 
longan shoot tips of four gibberellins, namely: gibberellin A1(GA1), gibberellic 
acid (GA3), gibberellin A19 (GA19) and gibberellin A20 (GA20), were found to 
increase to approximately 25, 50, 20 and 60 ng g(-1) respectively, all of which 
were significantly higher than those of the controls. In contrast, gibberellin 
A8 (GA8) obtained from the treated longan was found to decrease to approximately 
20 ng g(-1)DW while that of the control increased to around 80 ng g(-1)DW. 
Certain CKs which play a role in leaf bud induction, particularly isopentenyl 
adenine (iP), isopentenyl adenosine (iPR) and dihydrozeatin riboside (DHZR), 
were found to be present in amounts of approximately 20, 50 and 60 ng g(-1)DW in 
the shoot tips of the control longan. The analytical results obtained from the 
two-month off-season longan flowering period indicate that high GA1, GA3, GA19 
and GA20 levels in the longan shoot tips contribute to flower bud induction 
while high levels of CKs, IAA and ABA in the control longan contribute more to 
the vegetative development.

Copyright © 2011 Elsevier B.V. All rights reserved.

DOI: 10.1016/j.talanta.2011.04.073
PMID: 21726716 [Indexed for MEDLINE]


2. Planta. 2001 Nov;214(1):153-7. doi: 10.1007/s004250100663.

Auxin promotes gibberellin biosynthesis in decapitated tobacco plants.

Wolbang CM(1), Ross JJ.

Author information:
(1)School of Plant Science, University of Tasmania, GPO Box 252-55, Hobart, 
Tasmania 7001, Australia.

Excision of the apical bud (decapitation) of tobacco (Nicotiana tabacum L.) 
plants reduced the endogenous levels of indole-3-acetic acid (IAA), gibberellin 
A20 (GA20), and GA1 (the bioactive GA), in internode tissue below the excision 
site. Application of IAA to the stump of decapitated plants dramatically 
increased GA20 content, to a level 3-fold greater than in intact plants. 
Gibberellin A1 content was also increased by IAA. Decapitation reduced the 
conversion of [14C]GA19 to [14C]GA20 and of [14C]GA20 to [14C]GA1, and appeared 
to promote the deactivation pathway [14C]GA20 to [14C]GA29 to 
[14C]GA29-catabolite. Application of auxin counteracted these effects, but did 
not restore the conversion of [14C]GA20 to [14C]GA1 to the level found in intact 
plants. The results indicate that auxin is necessary for normal GA biosynthesis 
in stems of tobacco.

DOI: 10.1007/s004250100663
PMID: 11762165 [Indexed for MEDLINE]


3. Plant Cell Physiol. 2001 Jul;42(7):763-7. doi: 10.1093/pcp/pce099.

Azospirillum spp. metabolize [17,17-2H2]gibberellin A20 to 
[17,17-2H2]gibberellin A1 in vivo in dy rice mutant seedlings.

Cassán FD(1), Lucangeli CD, Bottini R, Piccoli PN.

Author information:
(1)Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, 
Universidad Nacional de Río Cuarto, Campus Universitario, 5800 Río Cuarto, 
Argentina.

Azospirillum spp. are endophytic bacteria with beneficial effects on 
cereals--effects partially attributed to gibberellin production by the 
microorganisms. Azospirillum lipoferum and Azospirillum brasilense inoculated to 
rice dy mutant reversed dwarfism in seedlings incubated with [17,17-2H2]GA20 
with formation of [17,17-2H2]GA1, showing the in vivo capacity to perform the 
3beta-hydroxylation. When prohexadione-Ca, an inhibitor of late steps in 
gibberellin biosynthesis, was added to the culture medium, no complementation 
was observed and no [17,17-2H2]GA1 was produced. The latter suggests that the 
bacterial operating enzyme may be a 2-oxoglutarate-dependent dioxygenase, 
similar to those of plants.

DOI: 10.1093/pcp/pce099
PMID: 11479384 [Indexed for MEDLINE]


4. Plant J. 2000 Mar;21(6):547-52. doi: 10.1046/j.1365-313x.2000.00702.x.

Evidence that auxin promotes gibberellin A1 biosynthesis in pea.

Ross JJ(1), O'Neill DP, Smith JJ, Kerckhoffs LH, Elliott RC.

Author information:
(1)School of Plant Science, University of Tasmania, GPO Box 252-55, Hobart, 
Tasmania 7001, Australia. John.Ross@utas.edu.au

In shoots of the garden pea, the bioactive gibberellin (GA1) is synthesised from 
GA20, and the enzyme which catalyses this step (a GA 3-oxidase -- PsGA3ox1) is 
encoded by Mendel's LE gene. It has been reported previously that decapitation 
of the shoot (excision of the apical bud) dramatically reduces the conversion of 
[3H]GA20 to [3H]GA1 in stems, and here we show that endogenous GA1 and PsGA3ox1 
transcript levels are similarly reduced. We show also that these effects of 
decapitation are completely reversed by application of the auxin indole-3-acetic 
acid (IAA) to the 'stump' of decapitated plants. Gibberellin A20 is also 
converted to an inactive product, GA29, and this step is catalysed by a GA 
2-oxidase, PsGA2ox1. In contrast to PsGA3ox1, PsGA2ox1 transcript levels were 
increased by decapitation and reduced by IAA application. Decapitation and IAA 
treatment did not markedly affect the level of GA1 precursors. It is suggested 
that in intact pea plants, auxin from the apical bud moves into the elongating 
internodes where it (directly or indirectly) maintains PsGA3ox1 transcript 
levels and, consequently, GA1 biosynthesis.

DOI: 10.1046/j.1365-313x.2000.00702.x
PMID: 10758505 [Indexed for MEDLINE]


5. Plant Physiol. 1996 Feb;110(2):413-418. doi: 10.1104/pp.110.2.413.

Gibberellin Metabolism in Maize (The Stepwise Conversion of Gibberellin 
A12-Aldehyde to Gibberellin A20.

Kobayashi M(1), Spray CR, Phinney BO, Gaskin P, MacMillan J.

Author information:
(1)Department of Biology, University of California, Los Angeles, California 
90095-1606 (M.K., C.R.S., B.O.P.).

The stepwise metabolism of gibberellin A12-aldehyde (GA12-aldehyde) to GA20 is 
demonstrated from seedling shoots of maize (Zea mays L.). The labeled substrates 
[13C,3H]GA12-aldehyde, [13C,3H]GA12, [14C4]GA53, [14C4/2H2]GA44, and 
[14C4/2H2]GA19 were fed individually to dwarf-5 vegetative shoots. Both 
[13C,3H]GA12-aldehyde and [13C,3H]GA12 were also added individually to normal 
shoots. The labeled metabolites were identified by full-scan gas 
chromatography-mass spectrometry and Kovats retention indices. GA12-aldehyde was 
metabolized to GA53-aldehyde, GA12, GA53, GA44, and GA19; GA12 was metabolized 
to 2[beta]-hydroxy-GA12, GA53, 2[beta]-hydroxyGA53, GA44, 2[beta]-hydroxyGA44, 
and GA19; GA53 was metabolized to GA44, GA19, GA20, and GA1; GA44 was 
metabolized to GA19; and GA19 was metabolized to GA20. These results, together 
with previously published data from this laboratory, document the most 
completely defined gibberellin pathway for the vegetative tissues of higher 
plants.

DOI: 10.1104/pp.110.2.413
PMCID: PMC157734
PMID: 12226193