Material and methods
Studied species
Abutilon theophrasti Medicus (Malvaceae) is a native species to China and India, now spreads worldwide. It is an annual weedy species, erect with stout stems, usually can grow to a height of 1-1.5 m. Through rapid growth, it can reach reproductive maturity within 90 d, and complete its life cycle in ~5 mo (McConnaughay et al. 1999), with substantial plasticity in allocation, morphology and architecture in response to varying environmental factors (McConnaughayet al. 1992). It colonizes relatively nutrient-rich habitats, being ubiquitous in open fields, on roadsides, and in gardens.