Figure 3.

Northern-blot analysis of the Arabidopsis LRX transcript levels. Total RNA was extracted from roots (Rt), young developing leaves and cotyledons (yL), rosette mature leaves (rL), cauline leaves (cL), floral stems (St), flower buds and opened flowers (Fl), stamens (S), carpels (Ca), pollen (Po), and pollinated carpels (PCa). Roots and young developing leaves were harvested from 14-d-old Columbia seedlings grown vertically on solidified Murashige and Skoog medium. All the other material was harvested from 35- to 40-d-old Columbia plants. Carpels were harvested from unopened flowers with young stamens to reduce pollen contamination. For northern analysis, 5 μg (2 μg for pollen) of total RNA was hybridized with ³²P-labeled gene-specific probes amplified by PCR from genomic DNA. Ribosomal RNAs were used as loading control (lower). No signal was obtained with the LRX7 probe and the result is not shown. AtLRX2 data will be presented elsewhere (N. Baumberger, M. Steiner, U. Ryser, B. Keller, and C. Ringli, unpublished data).