When Water Availability Is Low, Two Mediterranean <i>Salvia</i> Species Rely on Root Hydraulics
2021
Elisa Abate | Maria Azzarà | Patrizia Trifilò
Increase in severity and frequency of drought events is altering plant community composition, exposing biomes to a higher risk of biodiversity losses. This is exacerbated in the most fragile areas as Mediterranean biome. Thus, identifying plant traits for forecasting species with a high risk of drought-driven mortality is particularly urgent. In the present study, we investigated the drought resistance strategy of two Mediterranean native species: <i>Salvia ceratophylloides</i> Ard. (<i>Sc</i>) and <i>Salvia officinalis</i> L. (<i>So</i>) by considering the impact of drought-driven water content decline on plant hydraulics. Well-watered samples of <i>Sc</i> displayed higher leaf and stemsaturated water content and lower shoot biomass than <i>So</i> samples, but similar root biomass. In response to drought, <i>Sc</i> showed a conservative water use strategy, as the prompt stomatal closure and leaves shedding suggested. A drought-tolerant mechanism was confirmed in <i>So</i> samples. Nevertheless, <i>Sc</i> and <i>So</i> showed similar drought-driven plant hydraulic conductance (K<sub>plant</sub>) recover ability. Root hydraulic traits played a key role to reach this goal. Relative water content as well as loss of cell rehydration capability and membrane damages, especially of stem and root, were good proxies of drought-driven K<sub>plant</sub> decline.
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