OOS 63-6 - Great listeners are great strategists: the three dimensions regulating seed behavior yield lessons for restoration

When to germinate is the most critical decision that most plants face, this early establishment phase is most limiting to the population growth of most plants, and selection may be stronger here than at any other life-history stage. Empirical studies confirm decades-old theory on adaptive plasticity in seed behavior (i.e., germination, quiescence and dormancy), including the ‘integrated strategy’ of using physical cues suggestive of future conditions to modify bet-hedging schedules (i.e., predictive germination). However, this myopic, two-dimensional regulatory view of seed behavior – one accounting for the physical environment, the other for post-emergence stochasticity – neglects a third dimension fundamental to most plants, the biotic realm. Indeed, for a focal plant, neighborhood interaction strengths range from highly competitive to facilitative, but idiosyncrasies across a physical stress gradient occur because neighbor density, biomass, and identity matter. That is, the effects of physical factors on establishment intimately depend on biotic factors. Importantly, the ‘ghost of plant interactions future’ is a potentially critical, detectable element. The biochemical recognition hypothesis posits that seeds use phytochemical cues from potential competitors (or facilitators) to evaluate how conducive their environment is to establishment (Renne et al., 2014). Biochemical recognition acuity (BRA), a fundamental concept, is the ability of seeds capable of physiological dormancy to detect and adaptively respond to phytochemical cues of particular neighbors via different behaviors. Our talk develops the three dimensions regulating behavior of physiologically dormant seeds, the most common form of seed plant dormancy. Synthesis suggests the joint action of BRA and physical cue use modulates bet-hedging schedules to form a complete ‘integrated strategy.’ Fundamental to BRA theory is its coevolution with vegetative functional traits such that seeds ‘know’ their resource acquisition and growth potential, including their plastic capacity, and match their functional strategy to the ecological conditions they deem conducive to success. We end by placing biochemical recognition theory in a geographic mosaic, including land management and restoration contexts.