Abstract
Background: Resource Availability Hypothesis (RAH) states that natural selection favors slow-growing plants with high levels of defense and lower rates of damage in less productive environments, and fast-growing plants with low levels of defense and high rates of damage in more productive environments.
Methods: A model of optimal energy allocation to the growth, reproduction, and production of stable defensive substances in plants under different environmental productivities.
Results: An exponential increase of environment productivity makes optimal a lower investment of energy to the production of defensive substances and thus, lower concentration of defensive substances, but differences in their concentrations among environments with different productivities are rather weak. Contrary to RAH, plants growing in more productive environments lost a lower lifetime proportion of vegetative tissue than plants from less productive environments. Higher environmental productivity led to a lower effect of defense on fitness for resistant strategies; however, the absolute value of the reproductive success was higher at higher environmental productivity.
Conclusions: The optimal energy allocation approach allows for an understanding of why some plants growing at environments with higher productivity lose proportionally less biomass than plants growing at environments with lower productivity, even when they produce higher concentrations of defensive substances.