Plants respond to varying environmental conditions by multiple
morphological and chemical adaptations (Schoonhoven et al.,
2007). Abiotic factors fundamentally influence the establishment
and growth of plants. Thereby, plants under high fertilisation are
able to synthesise higher concentrations of primary metabolites
and may thus change their allocation of resources in the production
of secondary metabolites used for defence compared to plants
growing under low fertilisation. Several hypotheses were developed
in the past addressing the question whether a trade-off exists
between investment into growth and defence, assuming that the
production of secondary metabolites can be costly (Stamp, 2003).
Among these hypotheses, the growth differentiation balance
hypothesis (GDBH) predicts that under low availability of resources
for differentiation, carbon is shifted to the production of