Phenotypic variation between high and low elevation populations of Rumex nepalensis in the Himalayas is driven by genetic differentiation

Rumex nepalensis, one of several plant species distributed across wide elevation gradient in Himalayas, was studied for difference in seed traits, phenology and photosynthetic characteristics in four populations from 800 m (sub-tropical population: SP), 1300 m (sub-temperate population: STP), 2200 m (temperate population: TP) and 4000 m (alpine population: AP) elevations above mean sea level. Seeds of AP were larger in size and germinated faster at 15 °C than at 25 °C compared to those from lower elevations. Seed raised four populations of the species studied under ex situ conditions of greenhouse showed that AP emerged late but was able to complete its post flowering phenophases much earlier, such that its life cycle was reduced by 14 days compared to SP. Ex-situ and in situ studies in the native habitat for all populations showed AP and SP to differed significantly in most of the photosynthetic traits, thus indicating the two populations to be genetically different. Further studies are required to understand how different genotypes of R. nepalensis would respond to atmospheric warming.