RT Journal Article SR Electronic T1 Separating the Roles of Acropetal and Basipetal Auxin Transport on Gravitropism with Mutations in Two Arabidopsis Multidrug Resistance-Like ABC Transporter Genes JF The Plant Cell Online JO Plant Cell FD American Society of Plant Biologists DO 10.1105/tpc.107.051599 A1 Lewis, Daniel R. A1 Miller, Nathan D. A1 Splitt, Bessie L. A1 Wu, Guosheng A1 Spalding, Edgar P. YR 2007 UL http://www.plantcell.org/content/early/2007/06/08/tpc.107.051599.abstract AB