The Application of Leaf Ultrasonic Resonance toVitis viniferaL. Suggests the Existence of a Diurnal Osmotic Adjustment Subjected to Photosynthesis.
The main objective of this study was to apply the air-coupled broad-band ultrasonic spectroscopy in attached transpiring leaves ofVitis viniferaL. to monitor changes in leaf water potential (Ψ) through the measurements of the standardized value of the resonant frequency associated with the maximum transmitance (f/fo). With this purpose, the response of grapevine to a drought stress period was investigated in terms of leaf water status, ultrasounds, gas exchange and sugar accumulation. Two strong correlations were obtained betweenf/foand Ψ measured at predawn (pd) and at midday (md) with different slopes. This fact implied the existence of two values of Ψ for a given value off/fo, which was taken as a sign that the ultrasonic technique was not directly related to the overall Ψ, but only to one of its components: the turgor pressure (P). The difference in Ψ at constantf/fo(δ) was found to be dependent on net CO2assimilation (A) and might be used as a rough estimator of photosynthetic activity. It was then, the other main component of Ψ, osmotic potential (π), the one that may have lowered the values of md Ψ with respect to pd Ψ by the accumulation of sugars associated to net CO2assimilation. This phenomenon suggests the existence of a diurnal osmotic adjustment in this species associated to sugars production in well-watered plants.
Unidad de Recursos Forestales, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Gobierno de AragónZaragoza, Spain; Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón, Universidad de ZaragozaZaragoza, Spain.
Domingo
D
Sancho-Knapik
Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears Palma de Mallorca, Spain.
Hipólito
H
Medrano
Unidad de Recursos Forestales, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Gobierno de AragónZaragoza, Spain; Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón, Universidad de ZaragozaZaragoza, Spain.
José J
JJ
Peguero-Pina
ICREA at CREAF Barcelona, Spain.
Maurizio
M
Mencuccini
Sensors and Ultrasonic Technologies Department, Information and Physics Technologies Institute, Spanish National Research Council Madrid, Spain.
Maria D
MD
Fariñas
Sensors and Ultrasonic Technologies Department, Information and Physics Technologies Institute, Spanish National Research Council Madrid, Spain.
Tomás G
TG
Álvarez-Arenas
Unidad de Recursos Forestales, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Gobierno de AragónZaragoza, Spain; Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón, Universidad de ZaragozaZaragoza, Spain.
Eustaquio
E
Gil-Pelegrín
Vitis vinifera; diurnal osmotic adjustment; drought; gas exchange; leaf ultrasonic frequency; water potential