The Origin of a New Concept

Some of the general attributes of such systems operating in higher plants can be deduced theoretically on the basis of experimental data available in the literature. These attributes are summarized below  

A distinctive feature of higher plants is axial polarity of the whole body. This implies that the control systems also have an analogous polarity. Such systems can be described mathematically by application of the principles of vector and tensor calculus. 

Among known plant hormones, only auxin exhibits basipetally polar transport. Auxin transport has a striking polarity which mirrors the structural and functional axial polarity of the plant body. Thus, even though other phytohormones are known to cause morphogenic effects, a prominent (and probably dominant) role in the spatial and temporal control of plant morphogenesis must be ascribed to auxin and especially to the still obscure processes comprising the mechanisms of its basipetal transport. 

The actual control system allows propagation of morphogenic information over long distances with seemingly equal precision in all directions. Consequently, in spite of apparent coupling with the transport of auxin, the control system cannot depend directly upon the messages carried basipetally by the auxin molecules themselves. 

Wodzicki et al. 1982, Porandowski et al. 1982), and by variations of sterile culture techniques in isolated stem segments. The latter allowed fully controlled application of synthetic and natural substances (Brown and Wodzicki 1969, ZAJi czKOwsKi 1969, 1973, 1978, Zaj czkowski and Wodzicki 

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