Physiological, biochemical, and anatomical responses of Araucaria araucana seedlings to controlled water restriction

Author(s)

Papu, S. ^[1] ; Berli, F. ^[2] ; Piccoli, P. ^[2] ; Paton, D. ^[3] ; Rodriguez, D. R. Ortega ^[4] ; Roig, F. A. ^{[1, 4, 5]}

Affiliation

^[1] Univ Nacl Cuyo, IANIGLA, CONICET, Argentine Inst Nivol Glaciol & Environm Sci, RA-5500 Mendoza - Argentina

^[2] Univ Nacl Cuyo, CONICET, IBAM, Agr Biol Inst Mendoza, RA-5507 Mendoza - Argentina

^[3] Univ Extremadura, Fac Sci, Plant Biol Ecol & Earth Sci, Avda Elvas S-N, Badajoz 06071 - Spain

^[4] Univ Sao Paulo, Escola Super Agr Luiz de Queiroz, Dept Forest Resource, BR-13418900 Piracicaba - Brazil

^[5] Univ Mayor, Fac Ciencias, Hemera Ctr Observat Tierra, Jose Toribio Medina 29, Santiago 8340589 - Chile

• Document type: Journal article
• Source: Plant Physiology and Biochemistry; v. 165, p. 47-56, AUG 2021.
• Web of Science Citations: 0

Abstract

Water stress triggers acclimation responses and can damage plants, which varies by species and stress levels. Ongoing climate change is projected to result in longer and more intense water stress conditions leading to an alarming increase in drought-induced forest decline. The aim of this study was to evaluate the physiological responses of leaves and stem wood anatomy from Araucaria araucana pot-grown three-year old seedlings, a conifer tree from northwestern Patagonia. Plants were subjected to moderate and severe water restriction regimes and compared to well-watered controls. Severe water stress reduced relative leaf water content and triggered an accumulation of free proline in leaves, regardless of age. Epicuticular wax extrusions increased in apical leaf stomata while photosynthetic pigments decreased, resulting in differential oxidative damage. The concentration of phenolic compounds was not affected by water restrictions. Plants exposed to restricted water regimes showed diminished middle leaf biomass and expansion (similar to 60% of total leaves), increased stem wood density, and experienced 7% and 30% mortality rates under moderate and severe water stress, respectively. Our findings suggest that under moderate water stress, analogous to short-term droughts, A. araucana seedlings activate physiological mechanisms that allow them to withstand short periods of drought, while more severe water stress and longer droughts can be severely harmful. (AU)

• FAPESP's process: 18/22914-8 - Global climate change in the Amazon tropical forest assessed by dendrocronological multi-proxy
• Grantee: Daigard Ricardo Ortega Rodriguez
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/53951-7 - Set up of a Multi-User Laboratory specializing in the use of near-infrared spectroscopy and X-ray densitometry in agroforestry applications
• Grantee: Mario Tommasiello Filho
• Support type: Multi-user Equipment Program
• FAPESP's process: 17/50085-3 - PIRE: climate research education in the Americas using tree-ring speleothem examples (PIRE-CREATE)
• Grantee: Francisco William da Cruz Junior
• Support type: Research Projects - Thematic Grants