TY - JOUR A1 - Rudolph-Mohr, Nicole A1 - Vontobel, Peter A1 - Oswald, Sascha Eric T1 - A multi-imaging approach to study the root-soil interface JF - Annals of botany N2 - Background and Aims Dynamic processes occurring at the soil-root interface crucially influence soil physical, chemical and biological properties at a local scale around the roots, and are technically challenging to capture in situ. This study presents a novel multi-imaging approach combining fluorescence and neutron radiography that is able to simultaneously monitor root growth, water content distribution, root respiration and root exudation. Methods Germinated seeds of white lupins (Lupinus albus) were planted in boron-free glass rhizotrons. After 11 d, the rhizotrons were wetted from the bottom and time series of fluorescence and neutron images were taken during the subsequent day and night cycles for 13 d. The following day (i.e. 25 d after planting) the rhizotrons were again wetted from the bottom and the measurements were repeated. Fluorescence sensor foils were attached to the inner sides of the glass and measurements of oxygen and pH were made on the basis of fluorescence intensity. The experimental set-up allowed for simultaneous fluorescence imaging and neutron radiography. Key Results The interrelated patterns of root growth and distribution in the soil, root respiration, exudation and water uptake could all be studied non-destructively and at high temporal and spatial resolution. The older parts of the root system with greater root-length density were associated with fast decreases of water content and rapid changes in oxygen concentration. pH values around the roots located in areas with low soil water content were significantly lower than the rest of the root system. Conclusions The results suggest that the combined imaging set-up developed here, incorporating fluorescence intensity measurements, is able to map important biogeochemical parameters in the soil around living plants with a spatial resolution that is sufficiently high enough to relate the patterns observed to the root system. KW - Roots KW - soil-root interaction KW - root distribution KW - Lupinus albus KW - lupin KW - pH dynamics KW - oxygen dynamics KW - soil water distribution KW - rhizosphere KW - fluorescence imaging KW - neutron radiography Y1 - 2014 U6 - https://doi.org/10.1093/aob/mcu200 SN - 0305-7364 SN - 1095-8290 VL - 114 IS - 8 SP - 1779 EP - 1787 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Induli, Martha A1 - Cheloti, Michael A1 - Wasuna, Antonina A1 - Wekesa, Ingrid A1 - Wanjohi, John M. A1 - Byamukama, Robert A1 - Heydenrich, Matthias A1 - Makayoto, Moses A1 - Yenesew, Abiy T1 - Naphthoquinones from the roots of Aloe secundiflora JF - Phytochemistry letters N2 - Two new naphthoquinones, 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione and 5,8-dihydroxy-3-methoxy-2-methylnaphthalene-1,4-dione, were isolated from the roots of Aloe secundiflora together with the known compounds chrysophanol, helminthosporin, isoxanthorin, ancistroquinone C, aloesaponarins I and II, aloesaponols I and II, laccaic acid D methyl ester and asphodelin. The structures were elucidated based on spectroscopic evidence. This appears to be the first report on the occurrence of naphthoquinones in the genus Aloe. Aloesaponarin I and 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione showed anti-bacterial activity against Mycobacterium tuberculosis with MIC values of 21-23 mu g/mL in the Microplate Alamar Blue Assay (MABA) and Low Oxygen Recovery Assay (LORA); 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione also showed cytotoxicity against the Vero cell line (IC50 = 10.2 mu g/mL). KW - Aloe secundiflora KW - Asphodelaceae KW - Roots KW - Naphthoquinone KW - 5-Hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione 5,8-Dihydroxy-3-methoxy-2-methylnaphthalene-1,4-dione KW - Anthraquinone KW - Aloesaponarin I KW - Mycobacterium tuberculosis Y1 - 2012 U6 - https://doi.org/10.1016/j.phytol.2012.04.014 SN - 1874-3900 VL - 5 IS - 3 SP - 506 EP - 509 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Abdissa, Negera A1 - Induli, Martha A1 - Akala, Hoseah M. A1 - Heydenreich, Matthias A1 - Midiwo, Jacob O. A1 - Ndakala, Albert A1 - Yenesew, Abiy T1 - Knipholone cyclooxanthrone and an anthraquinone dimer with antiplasmodial activities from the roots of Kniphofia foliosa JF - Phytochemistry letters N2 - A new phenylanthrone, named knipholone cyclooxanthrone and a dimeric anthraquinone, 10-methoxy-10,7'-(chrysophanol anthrone)-chrysophanol were isolated from the roots of Kniphofia foliosa together with the rare naphthalene glycoside, dianellin. The structures were determined by NMR and mass spectroscopic techniques. The compounds showed antiplasmodial activities against the chloroquine-resistant (W2) and chloroquine-sensitive (D6) strains of Plasmodium falciparum with 10-methoxy-10,7'-(chrysophanol anthrone)-chrysophanol being the most active with IC50 values of 1.17 +/- 0.12 and 4.07 +/- 1.54 mu g/ml, respectively. KW - Kniphofia foliosa KW - Asphodelaceae KW - Roots KW - Anthraquinone KW - Knipholone cyclooxanthrone KW - 10-Methoxy-10,7 '-(chrysophanol anthrone)-chrysophanol KW - Dianellin KW - Malaria Y1 - 2013 U6 - https://doi.org/10.1016/j.phytol.2013.02.005 SN - 1874-3900 VL - 6 IS - 2 SP - 241 EP - 245 PB - Elsevier CY - Amsterdam ER -