Mobility of boron-polyol complexes in the hemiparasitic association between Rhinanthus minor and Hordeum vulgare: the effects of nitrogen nutrition.

Boron (B) is an essential nutrient required for plant growth and physiological processes. Long-distance B transport is facilitated by the formation of B-polyol complexes. We investigated B uptake and distribution in response to differing levels of exogenous nitrogen supply in the hemiparasitic association between Rhinanthus minor and Hordeum vulgare (barley) and in unparasitised barley and single Rhinanthus plants.

Does legume nitrogen fixation underpin host quality for the hemiparasitic plant Rhinanthus minor?

The high quality of leguminous hosts for the parasitic plant Rhinanthus minor (in terms of growth and fecundity), compared with forbs (non-leguminous dicots) has long been assumed to be a function of the legume's ability to fix atmospheric nitrogen (N) from the air and the potential for direct transfer of compatible amino compounds to the parasite. Using associations between Rhinanthus minor and Vicia faba (Fabaceae) that receive N either exclusively via symbiotic associations with rhizobia supplying organic N fixed from N(2) or exclusively through the supply of inorganic nitrate to the substrate, the underlying reasons for the quality of legumes as hosts for this parasite are unravelled. It is shown that sole dependence of the host, V.

Growth and development of the facultative root hemiparasite Rhinanthus minor after removal of its host.

Facultative plant hemiparasites exhibit optimal growth only when attached to a suitable host. After attachment, stomata of the parasite remain continuously open, thus, optimising the extraction of host xylem sap. When the host shoot was removed from the hemiparasitic Rhinanthus/barley association ~14 days after attachment, the resulting host-free attached Rhinanthus continued to grow and develop similarly well as the attached parasites.

Cytokinin flows from Hordeum vulgare to the hemiparasite Rhinanthus minor and the influence of infection on host and parasite cytokinins relations.

Using the facultative root hemiparasite Rhinanthus minor L. and Hordeum vulgare L. as a host, the flows, depositions and metabolism of zeatin-type cytokinins [zeatin (Z), zeatin riboside (ZR), zeatin nucleotide (ZN)] within the host, the parasite and between host and parasite have been studied during the period 41-54 d after planting (i.

Abscisic acid (ABA) flows from Hordeum vulgare to the hemiparasite Rhinanthus minor and the influence of infection on host and parasite abscisic acid relations.

Using the facultative root hemiparasite Rhinanthus minor and Hordeum vulgare as a host, the flows, depositions, and metabolism of abscisic acid (ABA) within the host, within the parasite, and between host and parasite have been studied. When the plants were supplied with 5 mM NO(3)(-), there were weak or no effects of parasitism on ABA flows, biosynthesis, and ABA degradation in barley. However, ABA deposition was significantly affected in the leaf laminae (3-fold) and in the leaf sheath (2.