Effects of drought and N level on the interactions of the root hemiparasite Rhinanthus alectorolophus with a combination of three host species

Abstract

Increasing nitrogen deposition and more frequent drought events are likely to change plant interactions in natural grasslands. Both factors may also influence the interactions between hemiparasitic plants, regarded as keystone species in many grasslands, and their host species.• We grew a combination of three suitable hosts, a grass, a forb and a legume, with and without the hemiparasite Rhinanthus alectorolophus at three levels of nitrogen (N) and two levels of water availability in a factorial design.• Biomass of the hemiparasite and host community increased with N level and was reduced by drought to a similar degree. Larger plants in fertilised pots started to wilt earlier, and the presence of a hemiparasite further increased drought sensitivity. The hemiparasite strongly reduced biomass of the host community and overall productivity, and affected the competitive balance among host plants because it particularly reduced biomass of the dominant grass. These effects were the opposite of those of high N. The hemiparasite increased the root mass fraction of the hosts at all levels of N and water availability, indicating that the effect of the hemiparasite on the hosts was mainly due to loss of belowground resources.• Our results indicate that hemiparasites will not always respond more strongly to increased N availability and drought than autotrophic plants, and that hemiparasites can have similarly strong effects on grassland communities as soil fertility and drought. By preferentially attacking dominant species the hemiparasites might alleviate the negative effects of nutrient enrichment on grassland diversity.Plant Biology 22 (Suppl. 1) (2020) 84-92

The combined effects of water and nitrogen on the relationship between a native hemiparasite and its invasive host

“…Irrespective of water and nitrogen treatments, infection with the native parasitic vine strongly decreased total biomass of the invasive shrub by 70%. Similarly, Korell et al (2019) found that R. alectorolophus negatively affected growth of three perennial hosts, regardless of water 9 nitrogen treatments. We also observed that infection had a greater impact on shoot biomass and shoot : root ratio of hosts in high water than low water, irrespective of N supply.…”

“…Similarly, Korell et al . (2019) found that R. alectorolophus negatively affected growth of three perennial hosts, regardless of water × nitrogen treatments. We also observed that infection had a greater impact on shoot biomass and shoot : root ratio of hosts in high water than low water, irrespective of N supply.…”

“…Korell et al . (2019) found that water and nitrogen had no interactive effect on the association. By contrast, water and nitrogen did have an interactive influence on parasite effects on the annual grasses (Tĕšitel et al ., 2015).…”

Establishment of a hemiparasite Rhinanthus alectorolophus and its density‐dependent suppressing effect on a grass: A case study from golf roughs

“…The first hypothesis predicts better establishment of HP and larger suppressive effect of HP on a host in nutrient-rich soils as HP may benefit from a direct nutrient supply and better host quality (Irving & Cameron, 2009;Korell et al, 2020), while the second hypothesis suggests better performance of HP in nutrient-limiting soils due to decreased competition for light (Hejcman et al, 2011;Korell et al, 2020;Těšitel et al, 2015). There also is some evidence that HP may perform equally well regardless of soil fertility (Korell et al, 2020). In addition, we focused on density-dependent effects of the RA effect on tall fescue height and biomass ( Figure 1) and discuss some implications and recommendations for applied grassland management.…”

Plant functioning in a changing global atmosphere

“…Combinations of multiple air pollutants are the focus of Papazian & Blande (), who review plant physiological responses and ecological perspectives in natural and managed ecosystems, including potential uses of plants to mitigate air pollution, whereas Korell et al () investigated the effects of drought and nitrogen deposition on the interactions of a root hemiparasite ( Rhinanthus alectorolophus ) with three host species. De Micco et al () analysed whether dust deposition can change leaf anatomical functional traits and the efficiency of the photosynthetic apparatus in Centranthus ruber .…”