Figure 5.

Segregation of PAL activity level in a cross between a PAL over-expressing line and a C4H antisense line. A, PAL activity in leaves from 76 F₁ progeny containing the bean PAL2 gene but no C4H antisense gene. B, PAL activity in leaves from 78 F₁ progeny harboring both the bean PAL2 gene and the alfalfa C4H antisense transgene. The plants designated by black bars and numbered in A and B were analyzed in a preliminary experiment, and the seeds of all the other plants were sown together at a later time. The three sets of error bars indicate the relative PAL activities, plus sd, in populations of independent progeny of the 10-6 PAL over-expressor line (n = 25), from vegetatively propagated 13B parent plants (n = 12), and from independent wild-type (Wt) plants (n = 9). Relative activities are given because of the need to analyze the individual plants in separate batches, each of which included a set of replicated samples to aid normalization (see “Materials and Methods”). The absolute values of PAL enzymatic activity in the two parent lines 10-6 and 13B in the second seed batch analyzed were 5.1 and 26.9 nmol h⁻¹ mg⁻¹ protein, respectively. C, Northern-blot analysis of alfalfa C4H and total PAL transcripts in parental lines (marked 10 and 13) and lines containing both PAL and C4H transgenes. Total RNA (15 μg/lane) was isolated from the parental lines and selected progeny from the 10-6/13B cross. Asterisks (*) indicate plant lines with high PAL activity. avg, Average.