Impacts of short-term germination delay on fitness of the annual weed Agrostemma githago (L.)

Abstract

Time of seedling emergence is an important step in the life cycle of annual plants because it may determine subsequent performance and success. Timing of emergence is especially critical to plant performance in habitats like arable fields which are subject to frequent disturbances. Within-season variation in timing of germination in the range of only a few days is typical for many arable weeds. However, since it is unclear whether such small deviations in germination date translate into fitness differences in the course of the life cycle, the aim of this paper was to quantify the effects of short germination delays on plant performance. We conducted two generalized randomized block experiments in an unheated greenhouse to study the impact of delayed germination (1, 2, 3 and 7 d) with and without competition, respectively, on the fitness of the arable weed species Agrostemma githago (L.). We expected that delayed germination significantly reduces fitness in terms of several life-history traits, and that the decrease of fitness is higher in the presence of competition. Under realistic conditions with competition through barley, Agrostemma plants with delayed germination of 7 d produced 54% fewer shoots, 57% less biomass, 52% fewer flowers, 36% lighter seeds and were 23% shorter as compared to control plants without delayed germination. Without additional stress through competition with barley this pattern was less pronounced. Thus, in the situation of interspecific competition, early emerging seedlings have biologically significant fitness advantages over later emerging seedlings of the same species.

The Anthelmintic Ingredient Moxidectin Negatively Affects Seed Germination of Three Temperate Grassland Species

“…We found that the commonly used anthelmintic Cydectin (0.1% moxidectin) can reduce seedling number by almost two thirds and lead to a 12-d delay of germination when applied in a 10 mg l -1 concentration. Already a 7-d delay of germination can lead to significantly reduced plant fitness in terms of biomass and flower production as has been shown for the arable weed species Agrostemma githago [37]. In contrast to our results, an authorisation study that tested the germination response of 12 herbaceous plant species to moxidectin did not find adverse effects [11].…”

Sheep trampling on surface‐lying seeds improves seedling recruitment in open sand ecosystems

“…The point of germination initiation as well as habitat characteristics is crucial for seedling fate. In highly competitive and stable environments, where struggle for light predominates, early emergence is beneficial for plant fitness (Orrock & Christopher 2010;Rühl et al 2016). By contrast, in ecosystems characterized by drought periods, accelerated emergence bears the risk of higher seedling mortality due to sudden water limitations (Orrock & Christopher 2010;Ludewig et al 2014).…”

Temperature moderates impact of formulated moxidectin on seed germination of three temperate grassland species

“…higher MGT, poses the risk that seedling development does not correspond to climate patterns species are adapted to [ 65 ]. Later germination in spring reduces biomass development above- and belowground compared to older seedlings [ 66 ]. These effects may be so strong that seedlings germinating later in spring can not develop sufficient root-soil contact to endure subsequent warmer and dryer summer periods and therefore may have a lower survival probability.…”