Kim D, Wu LL, Kaufman PB.

ASGSB Bull. 1993 Oct; 7: 33.

Dept. of Biology, Univ. of Michigan, Ann Arbor 48109-1048.

Dose-dependent effects of exogenously supplied indole-3-acetic acid (IAA) on differential cell elongation in gravistimulated oat (Avena sativa) shoot pulvini was examined in this study. The bottom portions of graviresponding oat shoot pulvini show about 1,000 times higher sensitivity to IAA than do top portions, and vertically-held control pulvini. This difference in sensitivity to IAA was not affected by the presence of 10 micromoles alpha-naphthylphthalamic acid (NPA) even though NPA did cause a shift in the IAA dose-response curves for tissue elongation in graviresponding oat shoot pulvini. When oat pulvini were treated with 1 mM CaCl2, both top and bottom parts of graviresponding pulvini became more sensitive to exogenously supplied IAA compared to control pulvini without calcium treatment. Calcium treatment also increased the rate of upward bending during the early stages of the gravitropic response in oat pulvini. IAA binding assays reveal that bottom halves of gravistimulated Avena shoot pulvini contain an IAA-binding protein (ABP) with a higher affinity constant for IAA than that in top halves. The biological function of this ABP during the gravitropic response involves the activation of a plasma membrane localized proton pump. The biochemical properties of this ABP will be discussed in our poster.

Publication Types:

• Meeting Abstracts

Keywords:

• Avena sativa
• Calcium
• Calcium Channel Blockers
• Indoleacetic Acids
• Phthalimides
• Proton Pumps
• Pulvinus
• alpha-naphthylphthalamic acid
• indoleacetic acid
• NASA Discipline Number 40-50
• NASA Discipline Plant Biology
• NASA Program Space Biology
• Non-NASA Center

Other ID:

• 95607925

UI: 102212743

From Meeting Abstracts