IN VITRO HARDENING OF CULTURED CAULIFLOWER AND CHRYSANTHEMUM PLANTLETS TO HUMIDITY
A study was made of the effect of agar and polyethyleneglycol (PEG) concentration on the in vitro hardening of cultured cauliflower and chrysanthemum plantlets. Increasing the agar concentration and the addition of PEG reduced plant growth but increased wax formation on cultured leaves. Procedures are described whereby the relative humidity (RH) in the atmosphere of the culture vessel is reduced. Optimum growth and in vitro hardening occurred when plantlets were cultured at 80% RH. Following this treatment plantlets could be directly transferred to soil, without humidity protection, and wilting did not occur. Growth by photolithotrophy was stimulated by culturing plantlets on sucrose-free medium.
Short, K.C., Warburton, J. and Roberts, A.V. (1987). IN VITRO HARDENING OF CULTURED CAULIFLOWER AND CHRYSANTHEMUM PLANTLETS TO HUMIDITY. Acta Hortic. 212, 329-334