Temporal variations in carbohydrate allocation in plants: Impact of water stress on mutualistic interactions

• Grant number: 24/20233-4
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: March 31, 2025
• End date: September 29, 2025
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Anselmo Nogueira
• Grantee: Lucas José Reis Bartsch
• Supervisor: Pedro Rey Zamora
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Institution abroad: Universidad de Jaén, Spain
• Associated to the scholarship: 23/11202-5 - Effect of rhizobium and water regime in plants with extrafloral nectaries: attractiveness of ants, anti-herbivory defense potential and fitness., BP.MS

Abstract

Plants obtain energy through photosynthesis, distributing non-structural carbohydrates (NSC) to various organs throughout the day, with some resources allocated to maintaining mutualistic relationships with other species. However, the influence of carbohydrate availability in these tissues on the balance of such interactions remains underexplored. The restriction of soil water availability can significantly affect plant structure and metabolism, reducing photosynthetic rates and altering mutualistic interactions. This project aims to investigate how carbohydrate allocation to plant organs varies throughout the day and between juvenile and mature plants, as well as how these patterns shift in response to different levels of soil water availability. We will use as a model plant Chamaecrista nictitans, an annual legume with symbiotic nitrogen-fixing root nodules and sugar-rich extrafloral nectaries for ant anti-herbivore protection. We will work with 130 plants subjected to two levels of water availability: plants in soil at field capacity and plants under mild drought conditions. Destructive sampling will occur every four hours in 60 juvenile plants across the two water availability levels. Similarly, 60 mature plants will undergo the same destructive sampling three months later. The remaining ten plants will be monitored throughout the experiment to evaluate water potential overtime under the different soil water availability conditions. In both juvenile and mature sampling periods, we will measure NSC concentrations in organs (leaves, shoots, and roots), sugars in extrafloral nectar, and sugars in root nodules, along with gas exchange data and plant growth descriptors. We hypothesize that plants at different life stages and under water stress will show distinct patterns of carbohydrate allocation across organs and functional traits. Additionally, we expect water availability to influence carbohydrate allocation to extrafloral nectar and root nodules, affecting the balance between these mutualisms under water stress and potentially limiting their benefits. Given the expertise of Dr. Pedro J. Rey's Spanish research group in ecological interactions, manipulative plant experiments, and complex data analysis, master's student Lucas's internship will greatly support his training, providing practical research experience with an internationally recognized research group in our field.