Premium
Fate of l‐Phenylalanine in Soil and Its Effect on Plant Growth
Author(s) -
Sarwar M.,
Frankenberger, W. T.
Publication year - 1995
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1995.03615995005900060017x
Subject(s) - deamination , phenylalanine , phenylpyruvic acid , phenylacetic acid , shoot , chemistry , incubation , soil water , soil ph , horticulture , botany , biochemistry , biology , amino acid , enzyme , ecology
Phenylacetic acid (PAA) is a deamination product of phenylalanine (PHE) applied to soil, which can have a positive physiological effect on plant growth and development. The objective of this study was to determine the factors limiting deamination of PHE when added to soils, determine the major pathway upon detection of metabolic intermediates, and assess the growth‐promoting effect on maize ( Zea mays L.) of an exogenous application of PHE to soil. The highest activity of PHE deamination in soils occurred at pH 8.5 and on incubation temperature of 40°C. The soil assay used to determine these parameters was based on the amount of NH 4 ‐N cleaved from l ‐PHE when incubated for 48 h in the presence of toluene. A sigmoidal relationship was observed between NH 4 ‐N and PHE concentration, indicating cooperative kinetics. Both phenylpyruvic acid and PAA were detected by high‐performance liquid chromatography (HPLC) following the addition of PHE to soil. A glasshouse experiment revealed that an exogenous application of PHE as a soil drench to established uniform seedlings of maize had a significant effect on vegetative growth parameters (shoot height, shoot fresh weight, internodal distance, uppermost leaf collar base distance, and leaf width). Since PAA is a well‐established plant growth regulator, it was concluded that this metabolic product derived from PHE in soil was responsible for the stimulatory growth effects in maize.