Drought tolerance in tough lovegrass (Eragrostis plana): understanding mechanisms and competitive ability.
2024
BASTIANI, M. O. | GUIDORIZI, K. A. | BENEDETTI, L. | ROCKENBACH, D. | CARATTI, F. C. | ZABALA-PARDO, D. M. | AVILA, L. A. | SOUZA, G. M. | LAMEGO, F. P. | MARLON OURIQUES BASTIANI, UNIVERSIDADE FEDERAL DE PELOTAS; KEZIA APARECIDA GUIDORIZI, UNIVERSIDADE FEDERAL DE PELOTAS; LARIZA BENEDETTI, UNIVERSIDADE FEDERAL DE PELOTAS; DALVANE ROCKENBACH, UNIVERSIDADE FEDERAL DE PELOTAS; FERNANDA CASSIANE CARATTI, UNIVERSIDADE FEDERAL DE PELOTAS; DIANA MILENA ZABALA-PARDO, UNIVERSIDADE FEDERAL DE PELOTAS; LUIS ANTONIO AVILA, UNIVERSIDADE FEDERAL DE PELOTAS; GUSTAVO MAIA SOUZA, UNIVERSIDADE FEDERAL DE PELOTAS; FABIANE PINTO LAMEGO, CPACT.
Abstract: Eragrostis plana Nees is a perennial grass weed, native to South Africa and an invasive species of dry rangelands across Asia, Australia, and South America. We hypothesise that E. plana has evolved mechanisms of acclimation to drought conditions to a greater extent than bahiagrass (Paspalum notatum), an important native grass forage species of livestock rangelands of Brazil, leading to a competitive advantage. We measured morphological, physiological, and biochemical response traits in E. plana and P. notatum to water deficit and competition. Levels of drought tolerance in the two species were greatest at the tillering growth stage, driven by low levels of leaf relative water content in E. plana and early stomatal regulation to avoid water loss in P. notatum. The mechanisms used to dissipate energy excess under drought are associated with an efficient antioxidant system and the biosynthesis of compatible osmolytes (proline). Despite reductions in fitness, both species survived a series of drought cycles, where E. plana showed a competitive advantage over P. notatum. These results help to explain the invasion success of E. plana in rangelands and demonstrate its potential threat to native biodiversity, particularly under drought conditions.
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