Fig. 3.

Growth of isolated leaf discs, cut from growing leaves of Nicotiana tabacum. (A) Relative growth rate (RGR) of a leaf disc floating on nutrient solution in continuous light (LL), 24 h after cutting the disc from a plant that was adapted to 12 h/12 h light/dark (entrained night phase shown in panel). (B) Visualization of leaf disc growth within 4 d. Discs in left Petri dish were cut immediately prior to taking the picture, while disc in the right Petri dish was cut with the same cork borer 4 d earlier. (C) Growth of leaf discs (n = 6, mean value and standard error) in area, fresh and dry weight 5 d after incubation (12 h/12 h light/dark). The leaf discs were all cut with the same borer (17.5-mm diameter) and were incubated either on nutrient solution or double-distilled water. (D) Growth of a leaf disc and of the leaf from which the disc was cut initially. Four days after cutting, the leaf disc, which had floated on nutrient solution, was put back in the hole of the leaf. The leaf was attached to the intact plant for the entire time. The small leaf disc to the right is cut from another leaf and depicts the size of the incubated leaf disc at the time of cutting. Due to the convex shape of the incubated leaf disc, disc and hole do not match perfectly.