Rhizoid formation

One particularly interesting application of these ideas is to the problem of double rhizoid formation in Fucus (19). Indeed do these arise directly from a l = 2 bifurcation from the spherically symmetric state or after the egg passes through the normal 1 - l pattern In this context it is useful to combine the TDGL method and the Keener theory ( o) to produce a formalism capable of describing the dynamics of the problem as we discussed in the section on dynamical self-organization. 

Table 3. Rhizoid formation with lAA in the mutant 72 of Funaria hygrometric(f...

Otto, K.-R. and Halbsguth, W., Stimulation of primary rhizoid formation on gemmae of March-antia polymorpha as caused by light and lAA, Z. Pflanzenphysiol, 80, 197, 1976. 

Fig.2A-C. Cell differentiation in auxin-free, MMG buffered at pH 5. Cells were cultured at an inoculum density of 0.05 mg ml in liquid medium. A Caulonema filaments 8 days after inoculation B conversion of 2 chloronemal apical cells into caulonemal apical cells in some of the filaments 3 days after inoculation C formation of rhizoids 12 days after the transfer of cells. Horizontal bars are lOO jam...

The above experiment indicates that a limitation of nutrients (e.g. partial starvation) enhances caulonema differentiation in protonema growing on the agar surface. Similar enhancement is also obtained in auxin-free, nitrate-limited liquid medium. Under the latter conditions, in the presence of 0.5 to 2.5 mM nitrate, both caulonema and rhizoids were produced. Their formation is independent of inoculum size between 0.05 and 2.5 mg ml" The cells cultured at a high cell density (0.5 mg ml ) in the low nitrate medium (LNM, nitrate 1.5 mM) responded to 1 juM lAA (Fig. 5), while cells in the medium with adequate nitrate (MMG, nitrate 8.4 mM) responded very slightly to 3 fiM lAA. Upon buffering these media at pH 5, cells responded to lower auxin concentrations and caulonema differentiated at 10-30 nM lAA. The cells grown in LNM or MMG respond to more or less the same... 

The differentiation of merocytes results in the formation of the apical cell of a branch primordium below every leaf. In many acrocarps the apical cell does not differentiate as an obvious branch primordium, or may be represented by a tuft of rhizoids or a small flat or concave area of... 

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