Elucidating the Anatomical Features, Adaptive and Ecological Significance of Kopsia fruticosa Roxb. (Apocynaceae)

Abstract

Anatomical characteristics play a pivotal role in understanding the evolutionary relationship among various plant taxa and identifying species of pharmacological importance. Though the anatomical features of the family Apocynaceae have been widely recognized, there is limited research on the stem wood anatomy of Kopsia fruticosa, whereas nothing was previously known about its root wood anatomy. The present work describes and analyses its anatomy and correlates the anatomical features with the habitat and ecology of this plant. The oval shape of the young stem and the presence of unicellular trichomes, stone cells in the pith region, laticiferous canals, calcium oxalate crystals, and vascular bundles of two different sizes, viz., smaller in the broad, flattened region and more prominent on the two narrow sides, are remarkable features of the plant, which collectively may often be helpful in distinguishing K. fruticosa from other species of this genus. Apart from the previously known qualitative characteristics of the family Apocynaceae, the coalescence of pit aperture and storied pattern of vessels of K. fruticosa are newly observed features of the subfamily Rauvofiòideae. On the other hand, in the root wood, vessels are wider (33–64 μm), less frequent (about 53% more in the stem), and shorter, and the rays are larger (21–46 cells in height) and more frequent than those of stem wood; these are the valuable findings which strongly support the non-climbing nature of the studied plant. The vulnerability and mesomorphy indices for stem wood are 0.914 and 349, respectively, indicating plants’ adaptation toward a mesic habitat. The correlation of the anatomical traits of plants with the habitat and ecology represents their survivability in different situations. Consequently, anatomical features such as intraxylary phloem, vessel grouping, the storied pattern of vessels, the simple perforation plate, and intervascular vestured pits suggest that plants can tolerate drought. We firmly believe that the present study’s outcome can fulfil the research gaps of this hardy plant.