Screening and isolation of cytokinin-like substances from Thizobacteria for the enhancement of the growth of corn (Zea mays L.).

Date

4-2013

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Villa, Neilyn O.

Co-adviser

Zarate, Jocelyn T.

Abstract

Fifteen unknown bacteria were screened for cytokinin production using the leaf disks bioassay. After five days incubation, bacterial strains A00, P4, LGD-SF5 and LGA- TA1, showed green leaf color indicating delayed senescence, with strain A00 giving the highest absorbance values of 0.649 and 0.387 at 475 nm and 660nm wavelength, respectively. This is equivalent to chlorophyll retained at 11.22 mg/ml. In vivo cytokinin activity was evaluated through a pot trial using corn as host plant and inoculation of bacterial strains as cell pellets or culture broth. Corn growth response in terms of plant height showed that all four strains have significant plant growth enhancing activity when applied independently in both cells and broth manner of application. It was noted that when a mixture of the bacterial strains was applied as a broth, the average plant height observed had no significant difference with the other individually applied bacterial treatments, whereas when applied as cells, no significant growth enhancing activity was observed. This exemplifies the complexity of microbial interactions among species when applied as living cells suggesting possible antagonistic interactions at the expense of the plant. Partial molecular characterization of the strains using 16S rDNA homology sequence analysis showed that closest match for strains A00 and LGA-TA1 was Pseudomonas, for strain LGD-SF5 was Agrobacterium and for strain P4 a probable Klebsiella species.

Language

English

Location

UPLB Main Library Special Collections Section

Call Number

LG 993.5 2013 B4 P36

Document Type

Thesis

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