title: Close relationships between polar auxin transport and graviresponse in plants.
abstract: Gravitational force on Earth is one of the major environmental factors affecting plant growth and development. Spacecraft and the International Space Station (ISS), and a three-dimensional (3-D) clinostat have been available to clarify the effects of gravistimulation on plant growth and development in space and on ground conditions, respectively. Under a stimulus-free environment such as space conditions, plants show a growth and developmental habit designated as 'automorphosis' or 'automorphogenesis'. Recent studies in hormonal physiology, together with space and molecular biology, have demonstrated the close relationships between automorphosis and polar auxin transport. Reduced polar auxin transport in space conditions, or induced by the application of polar auxin transport inhibitors, substantially induced automorphosis or automorphosis-like growth and development, indicating that polar auxin transport is responsible for graviresponse in plants. This concise review covers graviresponse in plants and automorphosis observed in space conditions, and polar auxin transport related to graviresponse in etiolated Alaska and ageotropum pea seedlings. Molecular aspects of polar auxin transport clarified in recent studies are also described.
authors.affiliation: Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Ueda
authors.forename: K
authors.initials: K
authors.lastname: Miyamoto
authors.forename: E
authors.initials: E
authors.lastname: Uheda
authors.forename: M
authors.initials: M
authors.lastname: Oka
authors.forename: S
authors.initials: S
authors.lastname: Yano
authors.forename: A
authors.initials: A
authors.lastname: Higashibata
authors.forename: N
authors.initials: N
authors.lastname: Ishioka
mesh_terms: D001692:Biological Transport; D005118:Extraterrestrial Environment; D018522:Gravitropism / Q000502:physiology*; D007210:Indoleacetic Acids / Q000378:metabolism*; D063245:Plant Development; D010944:Plants / Q000378:metabolism*
chemical_list: D007210:Indoleacetic Acids
keywords: Automorphosis; PsAUX1; PsPINs; graviresponse; indole-3-acetic acid; polar auxin transport; space