Chemistry of Growth as Represented by Carbon/Nitrogen Ratio Regeneration of Willow Cuttings

Abstract

Experiments on regeneration of cuttings of Salix viminalis have been carried out with normal cuttings and with cuttings injected with KNO3 and various sugars. Initiation of growth is due to stimulated respiration, giving energy for the withdrawal of N into the bast, and its consequent upward trans-location, particularly to the buds. The injected sugars hasten this considerably, especially easily respirable sugars such as glucose and lactose. In excess KNO3 prevents the commencement of growth. Loeb''s hormone hypothesis is explained as a gradation of the C/N ratio throughout the cutting. Shoots grow at the area of the lowest C/N ratio, roots at the higher. The effect of a leaf at the apex or base of the shoot is also interpreted on this basis.