The lower graph is just culture growth (CFU/ml). You can see that the two mutants (red and green lines) grew slightly slower than the control (blue line). The upper graph is the transformation frequencies. You can see that the two mutants behave identically, and that their transformation frequencies are 100-fold higher than wildtype in log-phase growth and 10-fold higher as growth slows. The dotted red circle indicates two samples that gave no transformants, so the values plotted are upper-limit estimates of the true transformation frequencies.
I also made the chromosomal DNA preps from these two mutants and from a parallel pair of mutants whose mutation has been identified (200 µl of each, at about 150 ng DNA/µl). I set 50 µl aside for the postdoc's sequencing.