A Study of Developmental Changes in Composition of the Macadamia.

In recent years the macadamia [Macadanmia ternifolia F. von Mueller, var. integrifolia (Maiden and Betche) Maiden] has assumed increasing commercial importance in the Hawaiian Islands. The Hawaii Agricultural Experiment Station has placed emphasis on establishing varieties and developinig improved cultural practices, and toward the latter end it has becoine desirable to secure knowledge concerning the normal physiological development of this interesting fruit. The present paper sets forth results of a study on the changes in size, weight, anid chemical composition of the macadamia fruit from flowering to maturity. Preliminary work (7) has shown that this fruit requires from 215 to 230 days after flowering to reach maturity, and that the mature dry embryo contains about 75 per cent. oil. Very few studies have been reported on the physiological development of perennial oil-seed fruits since THOR and SMITH (11) reported on the pecan. Studies on oil-seeds have been largely confined to quick growing crops such as cotton (4), flax (2), rape, hemp, poppy, and sunflower (5). CHEEL and MORRISON (1) describe some characteristics of macadanmia oil, but, other than a preliminary paper by the writer (7), no physiological account of fruit development in miiaeadamia has thus far appeared. Materials and methods