Contrasting biomass allocation responses across ontogeny and stress gradients reveal plant adaptations to drought and cold

How plants allocate their biomass to different organs is essential to understand plant adaptation and distribution. Overall, biomass allocation may follow fixed rules across taxa. They are also likely to exhibit substantial departure from these rules during ontogeny and in response to particular limiting factors to optimize their growth and maximize their survival. However, how plants adjust their allocation priorities depending on size and age across stress gradients remain largely unkown in wild populations.
We examined ontogenetic variation in biomass allocation in Himalayan forb Potentilla pamirica across its 5250-5900 m elevation range, between populations from dry steppe, wet alpine and cold subnival zone. We tested whether biomass allocation followed optimal partitioning or fixed allometric rules using organ mass in 1019 individuals spanning 1-73 years.
We found shifting biomass fractions with plant size and age, supporting the optimal partitioning theory. Young plants (<10 ye...