Biomaterial Database

Effect of asymmetric auxin application on Helianthus hypocotyl curvature. 1989

F Migliaccio, and D L Rayle

Department of Biology, Yale University, New Haven, Connecticut 06511.

Indole-3-acetic acid was applied asymmetrically to the hypocotyls of sunflower (Helianthus annuus L.) seedlings. After 5 hours on a clinostat, auxin gradients as small as 1 to 1.3 produced substantial (more than 60 degrees) hypocotyl curvature. This result suggests the asymmetric growth underlying hypocotyl gravitropism can be explained by lateral auxin redistribution.

UI	MeSH Term	Description	Entries
D007210	Indoleacetic Acids	Acetic acid derivatives of the heterocyclic compound indole. (Merck Index, 11th ed)	Auxin,Auxins,Indolylacetic Acids,Acids, Indoleacetic,Acids, Indolylacetic
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006112	Gravitation	Acceleration produced by the mutual attraction of two masses, and of magnitude inversely proportional to the square of the distance between the two centers of mass. It is also the force imparted by the earth, moon, or a planet to an object near its surface. (From NASA Thesaurus, 1988)	G Force,Gravistimulation,Gravity,Force, G,G Forces,Gravities
D006368	Helianthus	A genus herbs of the Asteraceae family. The SEEDS yield oil and are used as food and animal feed; the roots of Helianthus tuberosum (Jerusalem artichoke) are edible.	Jerusalem Artichoke,Sunflower,Helianthus annuus,Helianthus tuberosus,Artichoke, Jerusalem,Sunflowers
D012399	Rotation	Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Clinorotation,Clinorotations,Rotations
D018520	Plant Shoots	New immature growth of a plant including stem, leaves, tips of branches, and SEEDLINGS.	Plant Shoot,Shoot, Plant,Shoots, Plant
D018522	Gravitropism	The directional growth of organisms in response to gravity. In plants, the main root is positively gravitropic (growing downwards) and a main stem is negatively gravitropic (growing upwards), irrespective of the positions in which they are placed. Plant gravitropism is thought to be controlled by auxin (AUXINS), a plant growth substance. (From Concise Dictionary of Biology, 1990)	Geotropism,Geotropisms,Gravitropisms
D018546	Hypocotyl	The region of the stem beneath the stalks of the seed leaves (cotyledons) and directly above the young root of the embryo plant. It grows rapidly in seedlings showing epigeal germination and lifts the cotyledons above the soil surface. In this region (the transition zone) the arrangement of vascular bundles in the root changes to that of the stem. (From Concise Dictionary of Biology, 1990)	Hypocotyls