(A and B) Mean stem diameter (A) and plant height (B) measurements from hybrid aspen grown in soil are shown. Trees rooted in April were measured at 15 weeks (July), 26 weeks (August), and 33 weeks (October).

(C–F) Further analysis of 6-month-old plants: number of internodes (C), length of 50th internode (D), leaf area calculated from measurements of five leaves from around the 50th internode (E), and xylem cell number in a sector, with a central angle of 40°, of a stem transverse section taken from the 50th internode (F).

(G) Graph showing dry weight of 10-cm pieces of sapling stem. Samples were taken from the base, middle (50th internode), and top, except for 35S::PttCLE41, which had less than 50 internodes and a section taken midway between the top and bottom was used instead.