Morphological plasticity of Abutilon theophrasti (Malvaceae) reveals its variable growth strategies in dealing with complex biotic environmental factors

Abstract

Abstract Increased density and delayed emergence are two major biotic factors in nature that have profound and complex effects on plants. No studies have attempted to compare the responses of plants to the two factors via morphological plasticity, particularly in dynamic patterns. We subjected plants of Abutilon theophrasti to four emergence times and three planting densities and measured and analyzed a number of mass and morphological traits at different growth stages. Across both stages, plants emerged in late spring had the highest total mass, and spring and late-spring plants had higher stem mass allocation than later germinants, but plants with delayed emergence had higher leaf and reproductive mass allocation, more leaves and less lateral roots, but lower stem length, stem and root diameter than early-emerged plants. Plants at high density had lower in total mass and most other traits, but higher stem allocation and length, with shorter petioles and lateral roots, than at lower densities. Results suggested plants in a dense population will prefer stem elongation to leaf/root growth, and even at the cost of reproduction, to ensure the survival of the present generations, while those emerged late will prefer leaf and reproductive growth to stem/root growth, for the persistence of future generations. The contrasting strategies revealed that plants are able to analyze the risk levels of environmental signals in a integrative way and adjust their growth strategy dependently, for better adaptation in both the recent and distant future.