Vulnerability to embolism, gaseous dynamics and anatomical traits in Citrus plants

• Grant number: 21/13329-7
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: April 01, 2022
• End date: August 31, 2022
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Rafael Vasconcelos Ribeiro
• Grantee: Marcela Trevenzoli Miranda
• Supervisor: Steven Jansen
• Host Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil
• Institution abroad: Ulm University, Germany
• Associated to the scholarship: 18/09834-5 - Vulnerability to embolism in citrus species: hydraulic characteristics, seasonal variation and relationships between canopy and rootstock, BP.DR

Abstract

Embolism has been proposed as one of the main causes of drought-induced tree mortality, resulting in reduced xylem conductivity and, ultimately, hydraulic failure. Embolism resistance varies among species and is typically evaluated by vulnerability curves (VCs) constructed by the relationship between xylem water potential and corresponding degrees of xylem embolism. Different methods have been developed for assessing VCs, and they may be estimated either by directly measuring the loss of conductivity due to embolism formation or by quantifying the number or volume of embolised vessels. Embolism can also be quantified through imaging methods such as the Optical method and Magnetic resonance, or gas extraction using the Pneumatic method. The pit membrane thickness - an anatomical characteristic of the xylem vessels - is associated with embolism formation and therefore, is a major role in embolism resistance. We have already performed several VCs using the Pneumatic method in Citrus plants and we obtained controversial data. We believe that such controversy is related to stem cutting and gas extraction in Citrus species, leading to r-shaped VCs. Alternatively, we hypothesized that the r-shaped curves found are due to some particularity in the pit anatomy of Citrus plants. To test the above assumptions, we will perform VCs using the Pneumatic method associated with imagery methods, such as Optical method and Magnetic resonance. We will also analyze the pit membrane thickness of Citrus plants in order to understand the Citrus anatomy and compare the influences of rootstock on the scion species. (AU)