Abstract:

In order to effectively absorb nutrients from naturally heterogeneous soil, plant roots employ various plastic responses to the environment heterogeneity through evolution and adaptation. In addition, plant roots also face competition from both intra- and inter-specific competitors. Factors affecting the outputs of root competition include nutrient availability, scale and degree of soil heterogeneity and ability of root plasticity. Competition adds a new dimension to plants; plant roots may alter their normal plastic responses, e.g., root competition will affect the spatial distribution of root systems. Different plastic responses of roots will in turn influence root competition per se. Previous studies have revealed that plants with high root morphological plasticity and high physiological plasticity achieved competitive advantages. Plants differ in their root nutrient foraging plasticity, and therefore may not have fixed ways of responding to competition. The uniqueness and traits of species need to be considered in comprehending the mechanisms of their plastic responses of root foraging in competition and the consequences. The responses of roots to competitors may also be influenced by the competitors, and the competitive status of the plant may change. Closely related plants may be more likely to avoid the competition from each other. A few studies have focused on integration of root competition and root foraging plasticity, as well as the impact of root competition on the community structure. This review is intended to discuss this issue.

Key words: nutrient heterogeneity, root competition, root nutrient foraging plasticity