Plants were grown in the Duke University Phytotron. Growth temperature was 23o C, light level was 350 µmol photons m-2 s-1 PAR with a 14 h photoperiod, and soil-less potting mix, without addition of fertilizer, was used. At 21 days after seed sowing, leaves from the third or fourth pair were collected between 11:30 a.m. and noon. RNA was extracted (RNeasy Plant Mini kit; QIAGEN, Inc.) and pooled from nine individuals. Subsequent cDNA synthesis and labeled cRNA synthesis were conducted according to procedures described in the Affymetrix on-line literature with Affymetrix components. Arrays and cRNA were submitted to the Duke Microarray Core Facility for hybridization, signal intensity data collection, and analysis of GeneChipTM internal control genes using Affymetrix protocols and MicroArray Suite version 5.0. Keywords = rosette leaves Keywords = moderate light Lot batch = 4000153