Variations in Luminosity, Temperature and Osmotic Potential Affect the Eragrostis plana Germination

Abstract

One of the exotic invasive species of greatest impact on the Pampa biome is lovegrass (Eragrostis plana Nees). This species, native of southwest Africa, was accidentally introduced in Brazil in the 1950s and has since become a troublesome weed of natural pasture, due to its high spreading power. In order to assess lovegrass seeds behavior against different potentially stressful factors, we evaluated wide ranges of luminosity, temperature and osmotic potential on E. plana germination. After exposure to treatments, vigor and seed germination were analyzed through the following: germination speed index (GSI), first count and accumulated germination. All evaluated variables influenced E. plana germination, suggesting a relative susceptibility to environmental factors such as light, temperature, and water availability, with respect to in vitro germination. This information can be used as an aid to planning future strategies to control the spread of this invasive grass.

Factors affecting seed germination of Eragrostis plana populations

“…For example, Eragrostis tenuifolia had 77% of germination under 12-h light, and 33% under complete darkness (Bittencourt et al, 2017), Eragrostis tef reached >70% germination under continuous light and just 56.5% in absolute darkness (Tiryaki, Kaplan, 2019), and Eragrostis tenella germination was inhibited, for all, in darkness condition (Chauhan et al, 2017). In general, E. plana populations germinated well with light, corroborating the findings of Bittencourt et al (2017) and Maldaner et al (2019). But also, some E. plana populations (PAL, VC, CAÇ) had important germination (>70%) in the darkness condition.…”

“…The study of seed dispersal and local adaptations to variable climatic conditions in invasive plants are clue elements in understanding their success, propagation, and populational growth (Clements, Jones, 2021). To E. plana, high seed germination rates were reported at 35C (Bittencourt et al, 2017;Maldaner et al, 2019). However, the temperature effects, water availability, and light on seed germination among populational have not been reported to date.…”

Biology of the invasive species Eragrostis plana in Southern Brazil: What have we learned and how may this help us manage it?

“…After 24 h at 25°C, constant humidity, and a 12 h photoperiod, 73.3% of the seeds germinated (Guido et al, 2017). Although the ideal germination temperature is 35°C (Bittencourt et al, 2017; Maldaner et al, 2019), the species can germinate between 12.3 and 40°C (Bittencourt et al, 2017; Caratti, 2019). The secondary dormancy of E. plana seeds can be broken by cold (Medeiros et al, 2014).…”