Comparison of leaf anatomical characteristics of Eupatorium odoratum, E. adenophorum and two relative plants.
A comparative study has been undertaken to elucidate variations in anatomical characteristics amongst invasive exotic species Eupatorium odoratum, E. adenophorum and local Eupatorium plants Herba Lycopi and Herba Eupatorii. Microtome section method has been used to differentiate the anatomical features and to study their relationship with the ecological environment. The results showed similarities in some leaf anatomical features such as large epidermal cell with epidermal hair, undeveloped palisade tissue and developed spongy tissue, etc., in all the plants. However, E. odoratum and E. adenophorum were characterized by secretory structures in outer epidermis covered by thick cuticle, much vascular bundles and more developed vascular tissues owing to the presence of drought environment, which were not present in the two local plants. These features reflected that two exotic species could preferably adapt the drought environment and have the stronger competitive ability to tolerate drought.