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Influence of extraction solvent (buffer, methanol, acetone) and time on the quantification of indoIe‐3‐acetic acid in plants
Author(s) -
Sundberg Björn
Publication year - 1990
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1990.tb02094.x
Subject(s) - acetone , extraction (chemistry) , chromatography , chemistry , acetic acid , methanol , hydrolysis , solvent , indole 3 acetic acid , auxin , biochemistry , organic chemistry , gene
The effect of extraction solvent and time on the measured indole‐3‐acetic acid (IAA) level was investigated in plant materials having different contents of lAA‐conjugates, Tissues from pine ( Pinus sylvestris L.). tobacco ( Nicotiana tabacum L.), and maize ( Zea mays L.) were extracted for 1–9 h with Na‐phosphate buffer (pH 7.5). 80% methanol and 70% acetone. IAA was measured by combined gas chromatography‐selected ion minitoring‐mass spectromctry (GC‐SIM‐MS) with [ 13 C 6 ]‐IAA as an internal standard. Extraction of maize seedlings with buffer gave a higher estimate of free IAA than did extraction with methanol or acetone, which produced similar values. The increase in free IAA after buffer extraction was paralleled by a stoichiometric decrease in lAA‐ester conjugates, indicating that free IAA was formed during buffer extraction by hydrolysis of these conjugates, which are abundant in maize seedlings. The amount of hydrolysis during a 1‐h extraction period was estimated to be ca 3% of the total lAA‐ester pool. However, in the pine extraxylary tissues and tobacco in‐ternodes which lack a significant lAA‐ester pool, buffer extraction resulted in the same IAA estimate as extraction with the organic solvents, but produced a cleaner extract. For all the plant materials investigated, a 1‐h extraction period was sufficient for equilibrating the internal standard with the endogenous IAA pool.