Affiliation:
1. Crop Protection Department Universidade Federal de Pelotas Pelotas Brazil
2. Botany Department Federal University of Pelotas Pelotas Brazil
3. Embrapa Pecuária Sul Bagé Brazil
Abstract
AbstractEragrostis 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.
Funder
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Empresa Brasileira de Pesquisa Agropecuária
Universidade Federal de Pelotas
Subject
Plant Science,Agronomy and Crop Science,Ecology, Evolution, Behavior and Systematics