Rapid auxin-induced stimulation of cell wall synthesis in pea internodes

Journal Article · Fri May 01 00:00:00 EDT 1987 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.84.9.2747· OSTI ID:5997778

Kutschera, U; Briggs, W R

The effect of auxin (indole-3-acetic acid; IAA) on growth and incorporation of myo-(2-/sup 3/H(N)) inositol ((/sup 3/H)Ins) into noncellulosic polysacchharides in the cell walls of third internode sections from red light-grown pea seedlings (Pisum sativum L. cv. Alaska) was investigated. Intact section were incubated on (/sup 3/H)Ins for 4 hr to permit uptake of the tracer and then IAA was added. Growth started after a lag phase of 15 min under these conditions. The sections were removed from the tracer and separated into epidermis and cortical cylinder (cortex plus vascular tissue). In the epidermis, IAA-induced stimulation of (/sup 3/H)Ins incorporation started after a lag of 15 min. The amount of incorporation was 15% higher after 30 min and 24% higher after 2 hr than in the control. In the cortical cylinder, IAA-induced stimulation of (/sup 3/H)Ins incorporation started only approx. = 1 hr after adding IAA. The ionophore monensin (20 ..mu..M) inhibited the IAA-induced growth by 95%. Under these conditions, the IAA-induced stimulation of (/sup 3/H)Ins incorporation and the IAA-induced increase in in vivo extensibility of the sections was almost completely inhibited, although oxygen uptake was unaffected. The authors suggest that wall synthesis (as represented by (/sup 3/H)Ins incorporation) and wall loosening (increase in in vivo extensibility) are related processes. The results support the hypothesis that IAA induces growth by rapid simulation of cell wall synthesis in the growth-limiting epidermal cell layer.

• Research Organization: Carnegie Institution of Washington, Stanford, CA
• OSTI ID: 5997778
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:9
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AUXINS
BIOCHEMISTRY
CELL WALL
BIOSYNTHESIS
TRITIUM COMPOUNDS
INOSITOL
PISUM
POLYSACCHARIDES
BACTERIA
CARBOHYDRATES
CELL CONSTITUENTS
CHEMISTRY
INOSITOLS
LABELLED COMPOUNDS
LEGUMINOSAE
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
PLANT GROWTH REGULATORS
PLANTS
RHIZOBIUM
SACCHARIDES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques