Elucidating the leaf anatomical and micromorphological characteristics of an air-purifying plant: heptapleurum arboricola (Araliaceae)

Heptapleurum arboricola (Araliaceae) is recognized for its potential as an air-purifying plant. This study aimed to elucidate the general leaf anatomical structure of H. arboricola and discuss the relevance of these structures in relation to its air-purifying capabilities. Additionally, the study aimed to provide valuable data for plant identification, aiding in the accurate classification and recognition of this species. Leaf samples were collected and sectioned, followed by observations using a light microscope to examine anatomical features. For micromorphological characteristics, samples were prepared and gold coated prior to observation under Scanning Electron Microscope (SEM). Results of the present study revealed that the leaf blade is bifacial, with a mesophyll layer consisting of a compact adaxial palisade and a spongy abaxial layer. The hypodermis beneath the adaxial epidermis consists of two to three layers of colorless cells, which protect the mesophyll from excess solar radiation. The epidermis is covered by a cuticle that, along with a dense arrangement of stomata on the abaxial surface, enhances the plant's capacity to remove indoor air pollutants like benzene. Notably, the mesophyll palisade cells are irregular in shape and smaller than typical columnar forms, which is attributed to the plant’s adaptation to low light conditions. Furthermore, the presence of waxes, mucilage cells, and secretion canals indicates the potential presence of chemical compounds that may contribute to the plant's medicinal properties. In conclusion, the study highlights the anatomical adaptations of H. arboricola that contribute to its effectiveness as an air-purifying plant. These findings provide essential insights into the structure-function relationship in this species, with implications for its use in improving indoor air quality and in medicinal applications.