Figure 4.

Semiquantitative PCR of Sus RNA prepared from different plant organs and over fiber development: young fully expanded leaf (L), petal (P), and stem (S) and fiber RNA from bolls at 8, 10, 13, 17, and 21 DAF. Primers specific to SusA, -B, -C, and -D were used (A–D, respectively) and to a member of the ubiquitin family as a quantitative control (E). F compares relative expression levels of Sus isoforms shown in A to E by normalizing the fluorescence intensity of each PCR product on the gel to the respective Ubiquitin control and presenting this as a percentage of the maximum expression level for the Sus isoform in that tissue sample and developmental stage.