Podophyllotoxin content, above- and belowground biomass in relation to altitude in Podophyllum hexandrum populations from Kumaun region of the Indian Central Himalaya

The morphological features of Podophyllum hexandrum Royle, a 'critically endangered' medicinal herb and a source of podophyllotoxin, were studied in populations growing in different parts of the Kumaun region of the Indian Central Himalaya. Plant growth performance in terms of biomass accumulation and podopyllotoxin levels in the rhizomes collected from eleven natural populations (P1 to P11, altitude ranging from 2740 to 3350 m) were analyzed. Morphological features, e.g., plant height, stem diameter and leaf area were, in general, negatively correlated with an increase in the altitude. Maximum aboveground (8.46 g/individual) and belowground (48.18 g/individual) biomass values were recorded from a population (P9) at the lowest altitude (2740 m) and, in general, the species was found to perform better at the lower altitudes. The podophyllotoxin content of rhizomes ranged between 0.36 - 1.08% (on dry wt. basis) in different populations, and a positive correlation was observed between podophyllotoxin content and an increase in the altitude.