Best poster for facultative parasites

7 July 2015

Stella Kabiri was awarded the prestigious Best Poster Award at the biennial meeting of the European Weed Research Society (EWRS). In her poster she showed that, contrary to obligate parasitic plants, seed germination of a facultative parasitic weed is not stimulated through root exudates from a host plant. The outcomes of the study will be used as a basis for developing and improving strategies for managing a relatively new parasitic weed species.

On the picture you can see Stella, in front of her poster, being congratulated by the chair of the International Jury, Dr Garifalia Economou.

In her poster, Stella presents outcomes of a combination of pot and Petri-dish experiments and a simulation study, on the life-history strategy of the facultative parasitic weed Rhamphicarpa fistulosa. Being a facultative parasite means that even in the absence of a host the weed is able to complete its life cycle. Yet, connected to the root system of a host the weed grows much more profound, by withdrawing water, assimilates and mineral nutrients from its host. R. fistulosa is a very widespread species in seasonally flooded wetlands in tropical and sub-tropical Africa. Since rice is increasingly being cultivated in this ecosystem, the parasitic weed is rapidly developing into a serious pest of rice in Africa. Up to sixty per cent of the harvest may be lost because of this parasite.

The novelty of the research is that the potential enhancement of seed germination by host root exudates was investigated. In pot experiments, Stella found a five times higher seed production rate of the parasitic weed when it was attached to a rice host plant. In Petri-dish experiments she then demonstrated that, despite this fecundity advantage, seeds of the facultative parasite where not at all stimulated by root exudates of the rice host plant. Finally, a simulation study was conducted to explore the logic behind the experimental outcomes. This study revealed that the opportunistic strategy of this facultative parasite is superior over a strategy where the parasite is dependent on a host plant for germination.

From 23 to 26 June, 182 posters were presented during the symposium on ‘Weed Management in Changing Environments’ in SupAgro, Montpellier, France. The title of Stella’s award winning poster was: ‘Exploring the life-history strategy of the facultative root parasitic weed Rhamphicarpa fistulosa’. Her poster was co-authored by Aad van Ast, Jonne Rodenburg and Lammert Bastiaans and developed within the PARASITE Integrated Programme of NWO WOTRO Science for global development.

Source: NWO