Exploring the hydraulic functioning of Viscum album L. and its relationship with the host tree Pinus sylvestris L.
Researcher:
Ferrio Díaz, Juan Pedro
Congress:
XVI Simposio Internacional Hispano-Portugués de Relaciones Hídricas en Plantas
Participation type:
Póster
Other authors:
José Victor dos Santos Silva(speaker), Eustaquio Gil-Pelegrín, Rubén Martín-Sánchez, Juan Pedro Ferrio, José Javier Peguero-Pina and Domingo Sancho-Knapik
Year:
2024
Location:
Zaragoza
Publication:
José Victor dos Santos Silva(speaker), Eustaquio Gil-Pelegrín, Rubén Martín-Sánchez, Juan Pedro Ferrio, José Javier Peguero-Pina and Domingo Sancho-Knapik. XVI Simposio Internacional Hispano-Portugués de Relaciones Hídricas en Plantas. 14-16 Feb 2024.
Introduction:
Excessive mistletoe infection tends to weak the host pine, which become more vulnerable to other threats such as intense droughts, that can entail anything from a slight stippling to partial or total death of the pine (Fig.1).
We assessed the response to drought during summer 2023 of Pinus sylvestris branches with different levels of mistletoe infection in Orihuela del Tremedal (Teruel, Spain).
Objective:
To explore the hydraulic functioning of mistletoe in order to elucidate the possible hydraulic causes behind the host pine decline.
METHODS: We have measured gas exchange, pre-dawn water potential and the stem water potential gradient at midday in branches of mistletoe and scots pine in two conditions: saturated soil field capacity and soil water deficit. We have also assessed the hydraulic conductivity.
Results and discussion:
Infected branches of scots pine without soil water stress showed a 30% less in stomatal conductance and carbon assimilation than non-infected branches. At the end of summer (with a predawn soil water potential of -1.40 MPa) both types of pine branches, infected and non-infected, showed a reduction in stomatal conductance and carbon assimilation of ca. 80%, while mistletoe barely reduced stomatal conductance by 20%. The higher stomatal conductance of mistletoe together with its lower specific hydraulic conductivity (Ks, Fig. 3) can explain their more negative midday water potential values measured. When calculating the stomatal conductance of the whole branch (gs,branch, mmol H2O s-1), the infected branches showed a much higher gs,branch than the expected for a given xylem hydraulic conductivity measured in the pine prior the infection. This was specially noticed under soil water stress conditions. It seems that in infected branches there is an imbalance between the whole-branch stomatal conductance and the xylem hydraulic conductivity, with in turn seems to harm the pine tissues after the mistletoe infection.
Introduction:
Excessive mistletoe infection tends to weak the host pine, which become more vulnerable to other threats such as intense droughts, that can entail anything from a slight stippling to partial or total death of the pine (Fig.1).
We assessed the response to drought during summer 2023 of Pinus sylvestris branches with different levels of mistletoe infection in Orihuela del Tremedal (Teruel, Spain).
Objective:
To explore the hydraulic functioning of mistletoe in order to elucidate the possible hydraulic causes behind the host pine decline.
METHODS: We have measured gas exchange, pre-dawn water potential and the stem water potential gradient at midday in branches of mistletoe and scots pine in two conditions: saturated soil field capacity and soil water deficit. We have also assessed the hydraulic conductivity.
Results and discussion:
Infected branches of scots pine without soil water stress showed a 30% less in stomatal conductance and carbon assimilation than non-infected branches. At the end of summer (with a predawn soil water potential of -1.40 MPa) both types of pine branches, infected and non-infected, showed a reduction in stomatal conductance and carbon assimilation of ca. 80%, while mistletoe barely reduced stomatal conductance by 20%. The higher stomatal conductance of mistletoe together with its lower specific hydraulic conductivity (Ks, Fig. 3) can explain their more negative midday water potential values measured. When calculating the stomatal conductance of the whole branch (gs,branch, mmol H2O s-1), the infected branches showed a much higher gs,branch than the expected for a given xylem hydraulic conductivity measured in the pine prior the infection. This was specially noticed under soil water stress conditions. It seems that in infected branches there is an imbalance between the whole-branch stomatal conductance and the xylem hydraulic conductivity, with in turn seems to harm the pine tissues after the mistletoe infection.