The leaf as a strategy for preventing hydraulic failures in Caatinga plants

• Grant number: 20/07982-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2020
• End date: October 31, 2022
• Field of knowledge: Biological Sciences - Ecology
• Principal Investigator: Tomas Ferreira Domingues
• Grantee: Vinicius Dorea de Oliveira
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

We don't know much about the potential effects of global climate change on a large number of plant species or at the community level, especially with regard to changing rainfall patterns and rising temperatures in regions where there is a tendency for worsening droughts in duration and severity. The Caatinga is characterized by being a seasonally dry tropical forest, rich in diversity and has a socioecological system of global importance. However, this biome has always suffered and has been suffering from the unsustainable use of its natural resources and will most likely be negatively affected by the ongoing climate changes. Thus, the present work aims to investigate leaf hydraulic attributes associated with the hydraulic vulnerability of Caatinga plants. As an organ specialized in capturing carbon and transferring water to the atmosphere, the leaves have about 30% of the hydraulic resistance of the entire plant, playing a fundamental role in preventing common hydraulic failure in water scarcity scenarios. Recent studies have shown that leaves are the main hydraulic bottleneck in plants (Sack & Holbrook, 2006) thus, detailed measurements of the geometry of the veins will assist in future studies that will seek to model hydraulic conductance patterns (Cochard et al., 2004). With this in mind, some hydraulic functional attributes will be measured in this study, such as venation density, stomatal density, dry mass content per leaf area, among others, to correlate with species vulnerability to drought events. The P50 has been used to predict mortality induced by hydraulic failure, making it very important for modeling species mortality in global climate change scenarios. These results will be important to predict how some of the most abundant plant species in the Caatinga will respond with the intensification of droughts. Such information may become arguments for strengthening policies for the preservation and conservation of this important Brazilian biome.