Wilting Of Foliage Research Articles

The main difficulty encountered in the propagation of American elm (Ulmus Americana L.) by softwood stem cuttings was the premature wilting of foliage, keeping them from subsequent rooting. Decreasing the natural intensities of illumination in our greenhouse during rooting proved to be a satisfactory method of controlling premature wilting. Good results were generally obtained with an illumination of about 1200 lux. It is believed that the transpiration of cuttings is decreased by the reduction of illumination, which so favours rooting. The effect of illumination has seemed to be influenced by three main factors: 1) The time of raking cuttings during summer; at the end of the summer a somewhat higher degree of illumination was advantageous. 2) Meteorological conditions during the season of taking cuttings; good rooting was still obtained within cuttings taken during very rainy summers and containing a high percentage of moisture even under an illumination lower than 1200 lux. 3) The age of parent-trees; the cuttings coming from old trees seemed to be more influenced by the degree of illumination than those coming from young ones.