University of Hohenheim

About: University of Hohenheim is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Population & Soil water. The organization has 8585 authors who have published 16406 publications receiving 567377 citations.

Jatropha Diterpenes: a Review

Abstract: Terpenes are the largest group of phytochemicals that exhibit diverse functions in mediating antagonistic and beneficial interactions in, and among, organisms. For many years the abundance and distribution of terpenoid compounds in plants have benefitted both nature and human civilization. Jatropha species, belonging to the family Euphorbiaceae, are a rich source of terpenoid compounds. Among the terpenes, diterpenoid compounds have dominated the research area in Jatropha species with respect to their novel chemical structures and medicinal values. The present review describes the chemistry and biological activities of an array of Jatropha diterpenes. The diterpenes isolated from Jatropha species belongs to rhamnofolane, daphnane, lathyrane, tigliane, dinorditerpene, deoxy preussomerin and pimarane skeletal structures. Among the 68 diterpenes collated in this review, the biological activity of compounds varied distinctly—the majority of the diterpenes exhibited cytotoxic, antitumor and antimicrobial activities in vitro. To name a few, jatrophone, spruceanol and jatrophatrione exhibited antitumor properties against P338 lymphocytic leukemia and japodagrol against KB carcinoma cells. Whereas, curcusone B exhibited anti-invasive effects against cholangiocarcinoma cells. The phorbol esters (Jatropha factor C1–C6) and Jatropherol exhibited insect deterrent/cytotoxic properties. Many diterpenes (jatrophalactam, faveline derivatives, multifolone, curcusone, jatrophone derivatives etc.) showed in-vitro cytotoxic activity, while japodagrin, jatrogrossidione derivatives and jatropholone derivatives exhibited antimicrobial activities. Jatropha diterpenoids having a wide spectrum of bioactivity could form lead compounds or could be used as templates for the synthesis of new compounds with better biological activity for utilization in the pharmaceutical industries.

Wind‐blown nutrient transport and soil productivity changes in southwest Niger

Abstract: This study was conducted to quantify nutrient losses by saltation and suspension transport. During two convective storms, mass fluxes of wind-blown particles were measured in a pearl millet (Pennisetum glaucum) field in southwest Niger, on a sandy, siliceous, isohyperthermic Psammentic Paleustalf. The trapped material at three heights (0·05, 0·26 and 0·50 m) and a sample of vertically deposited dust were analyzed for total element contents of K, C, N and P. The nutrient content of the material at 0·05 m was similar to the nutrient content of the topsoil. At 0·50 m, the material was three times richer in nutrients than the topsoil, whereas the deposited dust, trapped at 2·00 m, was 17 times richer. For all four elements, a total element (TE) mass flux profile was fitted throughout the observations. From the TE profiles, the following nutrient losses from the experimental plot were estimated: 57·1 kg ha−1 K, 79·6 kg ha−1 C, 18·3 kg ha−1 N, and 6·1 kg ha−1 P. The TE profiles showed a maximum value in the saltation layer. The suspended TE mass fluxes above the saltation layer were an order of magnitude lower than the saltation fluxes, but extended to greater heights. Therefore, saltation and suspension are both able to transport significant quantities of nutrients. While saltation results in only a local redistribution of nutrients, suspension may transport dust over thousands of kilometers, resulting in a regional loss of nutrients.

Beyond organic farming - harnessing biodiversity-friendly landscapes.

Abstract: We challenge the widespread appraisal that organic farming is the fundamental alternative to conventional farming for harnessing biodiversity in agricultural landscapes. Certification of organic production is largely restricted to banning synthetic agrochemicals, resulting in limited benefits for biodiversity but high yield losses despite ongoing intensification and specialisation. In contrast, successful agricultural measures to enhance biodiversity include diversifying cropland and reducing field size, which can multiply biodiversity while sustaining high yields in both conventional and organic systems. Achieving a landscape-level mosaic of natural habitat patches and fine-grained cropland diversification in both conventional and organic agriculture is key for promoting large-scale biodiversity. This needs to be urgently acknowledged by policy makers for an agricultural paradigm shift.

Effect of zinc deficiency in wheat on the release of zinc and iron mobilizing root exudates

Abstract: The effect of Zn deficiency in wheat (Triticum aestivum L. cv. Ares) on the release of Zn mobilizing root exudates was studied in nutrient solution. Compared to Zn sufficient plants, Zn deficient plants had higher root and lower shoot dry weights. After visual Zn deficiency symptoms in leaves appeared (15–17 day old plants) there was a severalfold increase in the release of root exudates efficient at mobilizing Zn from either a selective cation exchanger (Zn-chelite) or a calcareous soil. The release of these root exudates by Zn deficient plants followed a distinct diurnal rhythm with a maximum between 2 and 8 h after the onset of light. Re-supply of Zn to deficient plants depressed the release of Zn mobilizing root exudates within 12 h to about 50%-, and after 72 h to the level of the control plants (Zn sufficient plants). The root exudates of Zn deficient wheat plants were equally effective at mobilizing Fe from freshly precipitated FeIII hydroxide as Zn from Zn-chelite. Furthermore, root exudates from Fe deficient wheat plants mobilized Zn from Zn-chelite, as well as Fe from FeIII hydroxide. Purification of the root exudates and identification by HPLC indicated that under Zn as well as under Fe deficiency, wheat roots of the cv. Ares released the phytosiderophore 2′-deoxymugineic acid. Additional experiments with barley (Hordeum vulgare L. cv. Europa) showed that in this species another phytosiderophore (epi-3-hydroxymugineic acid) was released under both Zn and Fe deficiencies. These results demonstrate that the enhanced release of phytosiderophores by roots of grasses is not a response mechanism specific for Fe deficiency, but also occurs under Zn deficiency. The ecological relevance of enhanced release of phytosiderophore also under Zn deficiency is discussed. Einflus von Zn-Mangel bei Weizen auf die Abgabe von Zn- und Fe-mobilisierenden Verbindungen aus Wurzeln In Nahrlosungsversuchen wurde bei Weizen (Triticum aestivum L. Sorte “Ares”) der Einflus von Zn-Mangel auf die Abgabe von Zn-mobilisierenden Verbindungen aus Wurzeln untersucht. Im Vergleich zu den gut mit Zn ernahrten Pflanzen (Kontrollen) hatten die Zn-Mangelpflanzen hohere Wurzel- aber geringere Sprostrockengewichte. Nach dem Auftreten visueller Zn-Mangelsymptome an den Blattern (15–17 Tage alte Pflanzen) kam es zu starkem Anstieg der Abgabe von Verbindungen, die Zn sowohl von einem selektiven Kationenaustauscher (Zn-Chelit) als auch aus einem Kalkboden mobilisierten. Die Abgabe dieser Verbindungen aus Wurzeln von Zn-Mangelpflanzen zeigte einen ausgepragten Tagesrhythmus mit Maximum zwischen 2 und 8 Stunden nach Belichtungsbeginn. Wiederangebot von Zn zu Zn-Mangelpflanzen verminderte die Abgabe der Zn-mobilisierenden Verbindungen nach 12 Stunden auf 50% und nach 72 Stunden auf das Niveau der Kontrollpflanzen. Die Wurzelabscheidungen von Zn-Mangelpflanzen hatten vergleichbare Fahigkeit, Fe von frisch gefalltem FeIII-Hydroxid wie Zn von Zn-Chelit zu mobilisieren. Umgekehrt mobilisierten Wurzelabscheidungen von Fe-Mangelpflanzen sowohl Zn von Zn-Chelit als auch Fe von FeIII-Hydroxid. Reinigung der Wurzelabscheidungen und Auftrennung durch HPLC zeigten, das sowohl unter Zn- als auch Fe-Mangel die Wurzeln der hier verwendeten Weizensorte verstarkt das Phytosiderophor 2′-Desoxymugineic acid abgaben. Erganzende Versuche mit Gerste (Hordeum vulgare L., Sorte “Europa” ) zeigten, das auch bei dieser Pflanzenart sowohl unter Zn- als auch Fe-Mangel die Abgabe des fur die Gerstensorte “Europa” typischen Phytosiderophors (epi-3-Hydroxymugineic acid) erhoht wird. Die erhohte Abgabe von Phytosiderophoren durch Wurzeln von Gramineen ist somit keine spezifische Reaktion auf Fe-Mangel, sondern tritt auch bei Zn-Mangel auf. Die okologische Relevanz der verstarkten Abgabe von Phytosiderophoren auch unter Zn-Mangel wird diskutiert.