Differential Plasticity of Leaf and Root Acquisitive Traits among Six Prunus Taxa under Short-Term Versus Prolonged Drought or Salinity Stress

Studies on the relationships between above- and below-ground plant traits under stresses are limited. Besides, the variation of these relationships across species and time scales is largely unknown. We tested the leaf and root trait response relationships under drought or salinity stress among congeneric taxa and between short-term versus prolonged time scales. A glasshouse experiment was established involving six Prunus taxa whose leaf and root traits were measured after imposing 30 and 60 days (short and prolonged time scales) of watering treatments (reverse osmosis water to the point of run-off daily as control, 33% of evapotranspiration of control plants as water stress, and 3.3 dS m^-1 mixed chloride solution to the point of run-off daily as salinity stress). We found no parallel drought- or salinity-induced responses between analogous above- and below-ground acquisitive traits, namely specific leaf area (SLA) and specific root surface area (SRA). Meanwhile, the degree of stress plasticity of SLA and SRA tended to be dependent on taxa and time scale. The results highlight that the stress responses of leaf and fine-root traits can differ across species and time scales and suggest the existence of a wide range of combinations of leaf and fine-root trait stress-responses – reflecting interspecific differences in stress adaptation.