Dramatic changes in anatomical traits of a C₄ grass Chrysopogon serrulatus Trin. (Poaceae) over a 1000 m elevational gradient

Chrysopogon serrulatus (false beard-grass) is a dominant component of vegetation in the foothills of the Himalayas. To study whole plant morphology, individuals of C. serrulatus were collected from three plots at each of six locations spanning from 400 to 1, 400 m. The population colonizing the highest elevation showed noticeable morphological modifications in different plant organs. Roots showed increased xeromorphy, specifically increased metaxylem number and area. In the stem, especially outside of the vascular tissue, there was intensive sclerification indicative of increased xeromorphy as a survival strategy. At the highest elevation, leaves were wider; aerenchyma formation and increased sclerification were noted in the leaf sheath; and a greater proportion of storage parenchyma was observed in the leaf blade, all indicators of succulence. In contrast, leaves at lower elevations had xeric morphological features such as increased epidermal thickness, sclerification and more developed metaxylem area. In conclusion, shifting of morphological features in below- and above-ground plant parts of C. serrulatus were linked to shifts in environmental factors along this elevation gradient, thus enabling the successful distribution of this species along this elevation gradient.