The Apical Organization and Phyllotaxis of the Oil Palm

The oil palm apex is described, together with investigationsof its phyllotaxis as revealed by apical dissection and measurementson mature stems and axillary structures. The rate of growthof the apex is remarkably low, being correlated with both plastochroneand phyllotaxis height. This is discussed in relation to therates of dry-matter production determined for adult palms. Thephyllotaxis as determined in the apex is remarkably constant,irrespective of extremes of age and habitat, and the same patternis found almost unchanged in the leaf bases on mature stemsgrowing under plantation conditions. Modification of the characteristicphyllotaxis height occurs due to internal factors resultingin the basal swelling of the palm stem and the different phyllotaxisof branching systems, both vegetative and reproductive, andalso due to external factors which cause constrictions in thestem. These modifications result from different rates of longitudinaland radial growth during development, and cause considerablechange in phyllotaxis.