In: Phyton 61 (2021): S. 25-30; DOI: 10.12905/0380.phyton60-2021-0025; Published online on 2 December 2021

Constraints to shoot growth and biomass allocation in Astragalus peterfii growing in two different stressful habitats
Alexandra Suteu, Dan Gafta & Florin Crisan
with 2 figures and 1 table
Key words: Dominant shoot, shoot growth, biomass allocation, drought stress, exposed habitat, light deficiency, low genetic variability, narrow endemic, plastic adjustments, shade-avoidance syndrome, tall grasslands.

Summary
Suteu A., Gafta D. & Crisan F. 2021. Constraints to shoot growth and biomass allocation in Astragalus peterfii growing in two different stressful habitats. – Phyton (Horn, Austria) 61: 25–30, with 2 figures and 1 table.
We aimed at detecting possible trade-offs in shoot growth and differences in biomass allocation to woody tissues between two contiguous sub-populations of Astragalus peterfii growing in different conditions – partial shading in tall Stipa-dominated grasslands (TSG), and partly exposed but drought prone, gravel-rich soils in sparse, low Festuca-dominated vegetation (SFV). The dominant shoots of 100 randomly selected ramets from each sub-population were sampled for biometric measurements. When controlling for the effect of dry biomass, the mean shoot height and diameter were larger and, respectively, not significantly smaller in TSG than in SFV.The shoot diameter displayed a negative quadratic response to shoot dry biomass in TSG whereas no growth constraints were detected in SFV. The size-independent, dry biomass (i.e.,the wood density) of shoots was on average significantly lower inTSG than in SFV.In conclusion, an obvious signal of trade-off in the use of resources for shoot growth, attributable to phenotypic plasticity, was only detected under light-deficient conditions.