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Differential effects of salinity and drought on germination response of Parkinsonia praecox determine its geographical distribution
VALERIA PAULA VILLARREAL 
, Analía Llanes, Laura Sosa
Abstract
Context. Germination and seedling growth are critical stages in the establishment of a species under adverse environmental conditions. Parkinsonia praecox is a species that can establish in soils with high salt concentrations and water deficit conditions. Aims. This study focused on the germination and early growth responses of P. praecox seeds exposed to different salinity and water deficit solutions, to understand its distribution and its potential to persist in stressful environments. Method. P. praecox seeds were exposed to NaCl (salinity) and PEG (water deficit) solutions at a range of potentials -0.4, -0.8, -1.2, -1.5 and -1.9 MPa and germination and early growth responses were evaluated. Controls were exposed to distilled water treatments (0 MPa). Key Results. Highest germination was obtained in the distilled water treatment, while drought imposed by PEG, and salinity, caused a decrease in the percentage and speed of germination. Seed germination significantly decreased at 1.2 MPa in the saline treatments, but at -0.8 MPa in PEG solutions. However, at -1.2 MPa and higher, the germination rate was higher in PEG-treated seedlings compared to those exposed to NaCl. Considerable early seedling growth was observed in low potentials and high saline conditions. Conclusion. The effects of salinity and drought on germination and early growth response of P. praecox contributes to the species’ restricted distribution in arid and saline regions Implications. These findings advance our knowledge of P. praecox responses under stressful conditions, highlighting this woody species’ potential as candidate in the rehabilitation of degraded environments.
BT23025 Accepted 11 September 2024
© CSIRO 2024
