Plasticity of xylem architecture can be a species specific strategy to reduce vulnerability to climate change. To study how the evergreen shrub Erica arborea regulates its xylem at different time scales as a response to climatic variability, we compared time series of annual xylem traits such as ring-width (growth), vessel size (hydraulic diameter and mean vessel area), vessel density, and potential conductivity (Kh) at two sites characterized by contrasting Mediterranean climates in Italy and Spain. Shrubs regulated their xylem in response to major differences in climate by modifying mostly their growth and vessel density. The different adjustment of xylem observed at the two sites was partly explained by the nonlinear nature of the relationship between the studied traits and temperature. Xylem development was mostly limited by low winter temperature at the cold and moist site, where plants produced more vessels per unit area of xylem and reduced growth in comparison with the warm and dry site. The responses of vessel size and density to climate were opposite. Vessel size and Kh were similar at the two sites and exhibited less sensitivity to climate than vessel density and growth. Humid conditions in spring increased growth and vessel size but decreased vessel density at the cold site, whereas the effect on xylem adjustment of high temperatures during the vegetation period was generally contrary to that of high moisture availability. These results likely express within species adaptations of the hydraulic function and the safety-efficiency trade-off in response to climate. A decline in growth in response to a recent decrease in precipitation at the dry site could be interpreted as a first sign of vulnerability to increasing drought severity. Similar to other species, climate change may have contrasting effects for E. arborea at its cold and dry distributional limits. © International Association of Wood Anatomists, 2013.
XYLEM ADJUSTMENT IN ERICA ARBOREA TO TEMPERATURE AND MOISTURE AVAILABILITY IN CONTRASTING CLIMATES
BATTIPAGLIA, Giovanna;
2013
Abstract
Plasticity of xylem architecture can be a species specific strategy to reduce vulnerability to climate change. To study how the evergreen shrub Erica arborea regulates its xylem at different time scales as a response to climatic variability, we compared time series of annual xylem traits such as ring-width (growth), vessel size (hydraulic diameter and mean vessel area), vessel density, and potential conductivity (Kh) at two sites characterized by contrasting Mediterranean climates in Italy and Spain. Shrubs regulated their xylem in response to major differences in climate by modifying mostly their growth and vessel density. The different adjustment of xylem observed at the two sites was partly explained by the nonlinear nature of the relationship between the studied traits and temperature. Xylem development was mostly limited by low winter temperature at the cold and moist site, where plants produced more vessels per unit area of xylem and reduced growth in comparison with the warm and dry site. The responses of vessel size and density to climate were opposite. Vessel size and Kh were similar at the two sites and exhibited less sensitivity to climate than vessel density and growth. Humid conditions in spring increased growth and vessel size but decreased vessel density at the cold site, whereas the effect on xylem adjustment of high temperatures during the vegetation period was generally contrary to that of high moisture availability. These results likely express within species adaptations of the hydraulic function and the safety-efficiency trade-off in response to climate. A decline in growth in response to a recent decrease in precipitation at the dry site could be interpreted as a first sign of vulnerability to increasing drought severity. Similar to other species, climate change may have contrasting effects for E. arborea at its cold and dry distributional limits. © International Association of Wood Anatomists, 2013.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
