Figure 4.
(a) The shapes obtained from the solution of our model described by equations (2.1)–(2.7) which are qualitatively similar to the shapes displayed in figure 1. (1) Negative gravitropism observed for computed shapes with 
and 
. (2) Axially varying gravitropic orientation with increase in shoot length for 
and 
. (3) Axially varying curvature change with curvature reversal, observed in our model for 
and 
. (4) Apparent positive gravitropism for 
and 
. (b) Morphospace for shoot shapes as a function of the sensitivity parameter 
, and the elasticity parameter 
. We note that for 
, there are no qualitative differences from what is shown—when 
, the shoot turns without any inflection points, while when 
, it can have one or more points of inflection. A comparison with figure 1 shows that we can capture a range of different forms in terms of these two parameters. The colour map indicates the L2 norm of the shoot curvature 
. (Online version in colour.)