Inducing Graded Growth Strategies in Plants: Exploring the Limitations of Non-Autonomous Models

A simple way to induce plants to adopt graded growth strategies is by including in the model time dependent survival or aging functions. This possibility has been explored by Paltridge & Denholm (1974) and by Denholm (1975), whose models treat the case of plants aging non-autonomously. Their models still produce the 'bang-bang' growth strategy, but other aging functions may be specifically devised to produce mixed strategies (Amir, 1978). This possibility has been extended by King & Roughgarden (1982a) who have induced multiple switches between vegetative and reproductive phases of growth by the choice of an appropriate function. However, it seems that these results exemplify a weakness rather than advantage of the non-autonomous model which may give rise to any pattern of growth provided the appropriate time dependent survival function has been incorporated in it.