Morphological response of chrysanthemum morifolium varieties to a growth retardant as modified by light

More than fifty years ago scientist discovered that the growth and behavior of many plants could be changed and often controlled by applying small amounts of organic chemicals to leaves, stems, or roots. These chemicals have become known as "growth regulators" and some have proved to be extremely useful. Today growth regulating chemicals are being used as standard practices in the production of farm crops and ornamental plants. The responses obtained from these confounds have been adapted to many commercial uses. New chemicals with new uses continually increase the list. How plants respond when sprayed. dusted, or soaked with growth regulators is of interest and practical value to the homeowner and to the amateur gardener as well as to the people producing crops for various commercial purposes. When chrysanthemums are grown in partial shade they have a tendency to become spindly and subject to a greater amount of plant breakage than when grown in full sun. It has been a standard recommendation to plant in the full sun. It was felt that perhaps the use of a growth regulator might extend the range of the chrysanthemum from full sun to partial shade. Much work can be found on the use of growth regulators in greenhouse bench and pot culture of chrysanthemums but little work has been done on outdoor chrysanthemums. Although previous studies have been made of light intensity and growth retardant effects on chrysanthemums, the two have not been combined under field conditions so far as could be discovered. The objective of this investigation was to determine the morphological modifications resulting from use of the growth retardant N-dimethyl amino succinamic acid (Alar-50) on plants grown under different light intensity levels.