Production and characterization of auxins from plant growth- promoting bacteria (PGPB)

Date

7-2004

Degree

Bachelor of Science in Agricultural Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Florinia E. Merca

Co-adviser

Erlinda S Paterno

Abstract

Auxin production by ten PGPB, B4C, TCeR 48, TCeRe 37W, B4B, BS 58, TCeRe 66, TOM I Y, BTCaRe 65, TS 24 and BS 206 was evaluated by addition of L-tryptophan in the production medium. Extraction of auxins was done by ethyl acetate partitioning. The ethyl acetate extract was dried and re-constituted in -[PLC-grade methanol. The extracts were then analyzed using TLC and HPLC. TLC analyses indicated the presence of IAA or ICA in TCeRe 37W, TS 24, TCeRe 66, BS 206, BS 58, TCeR 48, BTCaRe 65 and B4B. Possible presence of unutilized L- tryptophan, IPyA and IAAld was also observed. Several unidentified spots were also obtained in TLC. HPLC analysis confirmed the presence of IAA in all POPE. Quantification of IAA showed that B4B was a prolific producer of IAA with 331.07 ug/mL after 12 days and TOM I Y the least producer with 0.19 μg/mL after 6 days. Activity of PGPB extracts and eluates from cut portions of chromatogram from preparative TLC was investigated by the modified Wheat Coleoptile Assay using mungbean hypocotyls. Extract from TS 24 showed significantly higher growth with mean incremental growth of 4.2 mm. Conversely, TCeR 48 and B4B were found to be inhibitory with mean increment growth of 0.4 and 0.9 mm respectively. Purified extracts, TS 24-C, B4B-E, TCeRe 66-B, 8413-D, TS 24-D, TS 24-B and TCeR 48-0, showed significant difference with mean incremental growth range of 2.6-3.1 min. This study showed that the PGPB particularly B4B is a prolific IAA producer and concentration beyond 1.70 μg/mL was observed to exert growth inhibitory activity. The possible presence of inhibitors in the extracts cannot be discounted.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2004 A13 M45

Document Type

Thesis

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