Background/Question/Methods: Plants exhibit a plethora of plastic behaviors that belong to different categories, organizational levels and scales, to cope with the ever changing environmental challenges they are presented with. However, the sheer complexity and high operational costs of plastic systems suggest the involvement of higher-order control and coordination. Since each low-level behavior is in itself a manifestation of phenotypic plasticity, a higher-level plastic control of such behaviors may be defined as meta-plasticity. To use a well known example, while shade avoidance in response to low red/far-red ratios is a manifestation of a first-order phenotypic plasticity, the circumstances, timing, and magnitude of this spectral responsiveness may be controlled by higher-order metaplasticities. More specifically, to be affective and efficient, the context, timing and extent of low-level plastic behaviors are expected to depend on and controlled by contingent factors related to the specific state of the plant and the multiple challenges it is expected to tackle.

Results/Conclusions: Accordingly, meta-plastic control may rely on the operation of a variety of dedicated switches as well as internal morphogenetical contingencies that reflect the plant's evolutionary background, maternal and concurrent physiological state, ontogenetic stage, size, phenology, and various external cues that are correlated with concurrent and anticipated stresses, disturbances, biotic interactions and the time left for adaptive plastic modifications of variable magnitudes. Further study of the ecological implications and mechanistic controls of higher-level plasticities is expected to help us understand how plants manage the operational tradeoffs and avoid some of the potential costs involved in the manifestation of multiple plastic traits.