Differential in vitro response of microsomal subfractions to auxins

Conference · Tue May 01 00:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5725725

Wilkinson, E E; Brightman, A O; Zhu, X -Z; Morre, J ^[1]

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1. Purdue Univ., West Lafayette, IN (USA)

Soybean microsomes incubated with or without 1 {mu}M 2,4-D loose phosphatidylcholine, phosphatidylinositol and other phospholipids. Vesicles labeled in vivo with ({sup 14}C)choline prior to isolation and incubation exhibit rapid 2,4-D-induced hydrolysis of phosphatidylcholine to a plateau within 15 min. As much as 50% of the radioactivity of the membrane appeared in the soluble supernatant. However, when separated into plasma membrane (PM)-enriched and PM-depleted fractions, the PM-enriched fraction was unresponsive to auxin. Similarly, highly purified pM fractions from soybean microsomes exhibited no auxin-stimulated breakdown of phosphoinosotides, and no stimulations of phospholipase C or of phospholipase A{sub 2}. Instead, PM exhibited an auxin-stimulated NADH oxidase activity not shown by microsomes depleted of PM. The results suggest that in vitro auxin effects on phospholipid metabolism involve components of the microsomal fraction other than PM such as the endoplasmic reticulum or tonoplast, whereas PM responds by enhanced NADH oxidase activity.

• OSTI ID: 5725725
• Report Number(s): CONF-9007196--
• Journal Information: Plant Physiology, Supplement; (USA), Journal Name: Plant Physiology, Supplement; (USA) Vol. 93:1; ISSN PPYSA; ISSN 0079-2241
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
AMINES
AMMONIUM COMPOUNDS
AUXINS
BIOCHEMICAL REACTION KINETICS
CARBON 14 COMPOUNDS
CELL CONSTITUENTS
CHOLINE
DRUGS
ESTERS
GLYCINE HISPIDA
HYDROXY COMPOUNDS
IN VITRO
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LECITHINS
LEGUMINOSAE
LIPIDS
LIPOTROPIC FACTORS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MICROSOMES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
PHOSPHOLIPIDS
PLANT GROWTH REGULATORS
PLANTS
QUATERNARY COMPOUNDS
REACTION KINETICS
RIBOSOMES
TRACER TECHNIQUES