Figure 10.

The expression pattern of CAC1A and CAC1B genes as determined by in situ hybridization and histological staining of GUS activity expressed from promoter:GUS transgenes. A, The spatial and temporal patterns of CAC1A and CAC1B mRNAs are near identical during embryo development. The CAC1A and CAC1B mRNAs were detected by in situ hybridization procedure described in the “Materials and Methods,” using gene-specific DIG-labeled antisense RNAs as probes; control hybridizations were conducted with DIG-labeled sense RNAs. Bar = 50 μm. B, Histological staining of GUS activity expressed in different Arabidopsis organs by CAC1A- and CAC1B-GUS transgenes. These data reveal that CAC1B is only expressed in a subset of the organs and tissues, whereas CAC1A is expressed at a higher level. Organs that are shown are as follows, and these are taken from plants that are developmentally staged as defined by Boyes et al. (2001). B1: rosette of plants between principal growth stages 1.08 and 1.12 ; B2: roots of same plants as shown in B1; B3: florets of plants at principal growth stage 6.30, green horizontal arrows point to flowers at 1 DAF and red vertical arrows point to flowers at 2 DAF; B4: flowers at 2 DAF from plants at principal growth stage 6.30; B5: silique at 5 DAF; B6: silique at 8 and 9 DAF, for CAC1A:GUS and CAC1B:GUS, respectively; B7: silique at 12 DAF. Red bars = 1 mm; blue bars = 0.1 mm.