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A unit PIPE pneumatic model to simulate gas kinetics during measurements of embolism in excised shoots

Grant number: 19/24519-1
Support type:Research Grants - Visiting Researcher Grant - International
Duration: February 08, 2021 - February 20, 2021
Field of knowledge:Agronomical Sciences - Agronomy - Crop Science
Principal Investigator:Rafael Vasconcelos Ribeiro
Grantee:Rafael Vasconcelos Ribeiro
Visiting researcher: Melvin Thomas Tyree
Visiting researcher institution: Zhejiang Normal University (ZJNU), China
Home Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The pneumatic method developed by our group has improved our understanding about xylem vulnerability to embolism, mainly in species from tropical forests, where the existing methods are difficult to be used. Although the validation of the method had been done for more than 20 species comparing curves measured by the conventional techniques, further development is needed to prove that the air discharged by using the pneumatic approach is related to the xylem embolism. Several groups all over the world have been working on experiments to validate and use the method for different plant organs such as leaves and roots, a theoretical verification and approach are fundamental to explain the good correlations obtained until now. The Pneumatic method involves measuring the kinetics of gas movement down the axis of a stem while independently measuring stem water potential with a stem psychrometer or by measuring balance pressure of excised leaves with a pressure chamber. The aim of this proposal is to provide a theoretical background to the pneumatic measurements and show that the kinetics of pressure change through axial gaseous diffusion is closely related to the proportion of embolized vascular tissue either on a volume basis or on hydraulic conductance basis. For this, Prof. Tyree - the pioneer on studies of plant water relations and expert on modeling - will help us to develop a model to explain the most probable gas pathway that could account for the pneumatic results and their correlation with embolism formation. In addition to the model development, Prof. Tyree will join us in a graduate course dedicated to methods in plant water relations offered to students of the Graduate Program in Plant Biology (IB/UNICAMP) and the Graduate Program in Tropical and Subtropical Agriculture (IAC). (AU)