The Relation of the Characteristics and Yield of Wax to Plant Age.

Plants have been used as a source of wax for cenituries, and the search for plant species that produce more wax of a better quality has been in progress for as many years. It has been recognized only for the past few decades. however, that various factors other than plant species, such as environment, genetic make-up of the plant, and maturity of the plant, may affect the quality and quantity of wax exudate. McNAIR (11) has shown that there is a definite relation between the properties of plant waxes and climate; and CONRAD and NEELY (2) in a study of cotton showed that an hereditary factor controls the quantity of lint wax. Only fragmentary evidence, however, has been preseinted to show that plant maturity may affect the deposition of wax on the plant surfaces. HOWES (5) observed that the yield of wax from the carnauba palm, candelilla, and fruits of bay-berry varied in soiime way with age of the plant organs. DAHLGREN (3) studied the yield of carnauba wax from unexpanded and expanded leaves and concluded that under some conditions expanded or old leaves yield more wax per leaf than unexpanded or young leaves. Studies by SAHAi and CHIBNALL (13) on the wax of Brussels sprout, and JORDAN and CHIBNALL (8) on the wax of the runner bean, have shown that wax is synthesized continually throughout the life of the plant, with the formation of wax occurring not just at the growing tips but in all the plant organs except the roots. It is apparent, therefore, that the synthesis and yield of wax are related to plant age, and that the relationship might vary greatly in some cases. It has been the purpose of the present study to observe the relation of the yield and the physical and chemical characteristics of wax to plant maturity.