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Abstract

CE145-66 is an improved early-maturing grain sorghum genotype, increasingly grown by farmers in the Sahelian part of Senegal. This genotype is known to have negative effects on the following groundnut crop, because of the release of allelopathic phenolic compounds into the soil. We have assessed the synthesis of phenolics in sorghum vegetative parts and the variations in synthesis between years and sites. Total phenols and phenolic acids in the aerial parts and roots of flowering sorghum plants from 52 farmers' fields at two sites (Sagnanème and Médina) in Senegal in 1996 and 1997 were measured. Thirty-eight soil samples, collected after the sorghum harvest, from sorghum rows and interrows also were analyzed for their phenolic content. Total phenols reached 1.1-1.5% of root dry weight and 1.1-2.2% of aerial parts dry weight, with little variation between sites, and large variability between years, presumably due to climatic conditions. Eight phenolic acids and three associated aldehydes were identified by HPLC, with p-hydroxybenzoic, p-coumaric, and ferulic acids the most abundant. Their totals reached 2.9-3.2 mg/g in 1996 and 2.6-2.8 mg/g in 1997 for the aerial part; and 3.3-3.6 mg/g in 1996 and 2.8-3.3 mg/g in 1997 for roots. In soils under sorghum rows, the mean water-soluble total phenols increased from 4.6 in 1997 to 6.7 micrograms/g in 1998 in Sagnanème, and from 3.8 in 1997 to 5 micrograms/g in 1998 in Médina. The concentrations of total phenols and phenolic acids were higher in rows than in interrows. All the phenolic monomers identified in vegetative parts were recovered in associated soil samples, with vanillic and p-hydroxybenzoic acids the most abundant. Finally, variability in plant phenolic content seemed more due to climatic than to cropping or soil factors, as differences between years appear more important than differences between or within sites.

Hierarchy of Carbon Source Utilization in Soil Bacteria: Hegemonic Preference for Benzoate in Complex Aromatic Compound Mixtures Degraded by Cupriavidus pinatubonensis Strain JMP134

“…A key factor to be considered in the study of sequential aromatic catabolism is the component amounts in the mixtures of AC, since the utilization profile would be substrate concentration dependent. In this bacterium, the identified preferences were observed in a range of concentrations higher than those that can be found in most natural, nonpolluted environments (35)(36)(37)(38). However, it is still possible that preference also takes place at lower concentrations and that the utilized growth and degradation tests do not have enough resolution to detect it.…”

Use of Plant Secondary Metabolites to Reduce Crop Biotic and Abiotic Stresses: A Review

“…Sorghum [Sorghum bicolor (L.)] is an annual grass belonging to the family Poaceae and subfamily Panicoideae. It originated in Africa and migrated to other continents [49]. Accounting for more than 22% of the world's sorghum production, the United States leads in the production globally [50].…”

Prospects for Sorghum cultivation in Poland

“…It is also grown in parts of Europe, mainly in France and Italy. Sorghum ranks fifth in world cereal production, after wheat, rice, maize and barley [2,[6][7][8].…”

“…The allelopathic potential of sorghum is linked to the presence of both hydrophilic phenolic compounds, i.e., phenolic acids and their aldehyde derivatives leached from the aerial parts of the plants and exuded by the root system, and hydrophobic compounds, i.e., sorgoleone and its analogues, produced and exuded by specialized root hairs [4,7]. Sorgoleone inhibits or restricts the growth of mono-and dicotyledonous weeds [33,34], e.g., the dominant weed in maize cultivation -Echinochloa crus-galli [32,35].…”