The emergence of adaptive diversification from plant's light competition

Abstract

Light competition, the main force in shaping plant height, is ubiquitous in the plant kingdom. Plant height was commonly treated as a competitive strategy and investigated under the game-theoretic framework. However, how plant heights are shaped by light environment under natural selection has not yet been fully understood. Aiming at revealing the potential mechanism causing the height diversification and complex evolutionary dynamics, we here propose an eco-evolutionary model of the plant competing for light, in which the benefit and cost due to light competition as well as density-dependent selection are considered. We provide the criteria for producing different evolutionary consequences. The results show that the moderate levels of competitive costs boost the diversity of plant height, and that the eco-evolutionary feedback results in complex nature of the height evolution. In the power-type cost, the evolutionary consequence of plant height highly depends on the shape of benefit and cost functions, and the height evolution under convex benefit or concave cost displays a trend of evident diversification, which is most pronounced when the two factors are added together, whereas a homogenization tendency of the height evolution occurs in the opposite cases. Meantime, the classification of evolutionary states under different benefit-cost combinations exhibits distinct structure patterns. Generally, more complex evolutionary dynamics are caused if we consider the Hill-type cost: the multiple evolutionary equilibria and phase transitions between these evolutionary equilibria could occur. These results help us in part understand why plant heights in the plant kingdom are highly diverse.