Anatomical structure and histochemical characteristics of Artemisia selengensis in wetland environments

The anatomy and histochemistry of Artemisia selengensis from a wetland environment were studied using an optical microscope and epifluorescence microscope. The results showed that: 1) The adventitious roots in A. selengensis have a tetrarch vascular cylinder, endodermis, cortex, schizogenous aerenchyma, air spaces, lignified hypodermis, and a suberized exodermis and epidermis. The stems of A. selengensis include a pith cavity, cortex and epidermis. 2) Apoplastic barriers are found in roots and stems. The barriers in adventitious roots consist of the endodermis and exodermis with its Casparian bands and suberin lamellae (and some lignification), and a suberized epidermis. Stems have cuticles, endodermis and exodermis with its Casparian bands and suberin lamellae, and a suberized and lignified periderm. 3) The air space consists of aerenchyma in roots, and pith cavities and aerenchyma in stems. The stem of A. selengensis develops a conspicuous cortical expansi-schizogenous aerenchyma and aerial stem pith cavities. These combinations of traits enable A. selengensis to be well adapted to wetland environments.