Vectors of auxin, wave

Fig. 7.4 A-C. A model of control of morphogenesis by vectors of auxin wave propagation in the final phase (autolysis) of axial tracheid maturation in secondary xylem of the stem. A Trajectories of vectors of auxin wave propagation (a) in the cambial region and in differentiating secondary tissues as seen in radial (b) and transverse (c) sections. The breakdown of the cytoplasm is initiated when some critical angle (a) between the vector of auxin wave propagation and the cell axis is attained. B and C Vector trajectories associated with a model of regulation of earlywood and latewood differentiation. Ph conducting phloem Ph dividing phloem Cj cambial initial dividing xylem ...

Fig. 7.6. Two-dimensional simplification of the three-dimensional field of the vectors of auxin wave propagation arrows) in the aerial part of a plant with a continuous cambial envelope heavy black line). Broken lines represent the theoretical tangents to isophasic surfaces adjusted for the effects of external stimuli and interactions of colliding auxin waves in regions of branching. (Adapted from ZAJy cZKOWSKi and Wodzicki 1978 b)...

If there were no interaction between the auxin waves in branches and in the main stem, the branches would grow generally parallel to that stem. We propose that adjustment of the organ axes to the configuration of the auxin wave vectors in the zone of major polar transport of auxin results in deviation of the branch axes from the direction of gravity. 

As an extension of the preceding discussion about the probable consequences of interactions between auxin waves in branched shoot systems, a control mechanism capable of coordinated growth of all plant parts (axes) can be proposed. Vector fields in the zones of major polar transport of auxin in axes of various orders can be envisioned as morphogenic fields specifying positional information... 

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