Anatomical patterns, ultrastructure and phloem loading in peripheral vascular bundles in leaves of Aizoaceae (Caryophyllales)

• Grant number: 23/17492-5
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: March 31, 2024
• End date: June 29, 2024
• Field of knowledge: Biological Sciences - Botany
• Principal Investigator: Gladys Flávia de Albuquerque Melo de Pinna
• Grantee: Guilherme Tamassia Garcia
• Supervisor: Christina Kuhn
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Humboldt University, Germany
• Associated to the scholarship: 22/12130-5 - Ultrastructural relationships between chlorenchyma and phloem cells in peripheral vascular bundles in leaves of Aizoaceae (Caryophyllales), BP.IC

Abstract

The family Aizoaceae (Caryophyllales) is represented by a large number of succulent species, which can water-storage in all photosynthesizing cells, or present a distinction between water-storage parenchyma and chlorenchyma, being called all cell and storage cell succulents, respectively. In many species of Aizoaceae peripheral vascular bundles occur around the central rib, which may have phloem turned to the center of the leaf (exoscopic) or to the epidermis (endoscopic), the latter being the predominant in the family. In the present project the species Sesuvium portulacastrum (L.) L. (Sesuvioideae), a storage cell with exoscopic bundles and Delosperma napiforme Schwantes (Ruschioideae), also storage cell but with endoscopic bundles, are being used as anatomical models for the first ultrastructural study of peripheral phloem cells and their relationships with the chlorenchyma. In addition, the species Mesembryanthemum crystallinum L. (Mesembryanthemoideae), an all cell succulent without peripheral bundles, is being taken as a model reference for physiological investigation of Aizoaceae phloem, being our new objectives after studying the cell's ultrastructure: 1) to verify the occurrence and distribution patterns of H+-ATPases in the phloem; 2) to verify the displacement route of photosynthates to phloem loading. The material will be submitted to immunostaining essays and analyzed through confocal and transmission electron microscopy. Thereby, it is expected to obtain relevant information on the functional impact of such different anatomies encountered in leaves with similar terete morphologies of Aizoaceae.