Root microflora

Stevens C, Khan VA, Okoronkwo T, Tang AY, Wilson MA, Lu J, Brown JE (1990a) Soil solarization and Dacthal influence on weed, growth and root microflora of collards. HortScience 25 1260-1262... 

Damage to epicuticular waxes Altered photosynthesis Increased water loss Accumulation of acidic anions Leaching of ions, sugars, etc. Mineral imbalances Altered metabolism Increased susceptibility to winter freezing injury Death of fine roots Destabilization of trees Reduced water/mineral uptake Reduced water uptake Cations leached below roots Accumulation of acidic anions Altered structure/texture Altered microflora Reduced litter decomposition Altered N transformations Solubilization of metal ions... 

R. Kuchenbuch and A. Jungk, A method for determining concentration profiles at the soil-root interface by thin slicing rhizospheric soil. Plant Soil 68 391 (1982). R. Schonwitz and H. Ziegler, Quantitative and qualitative aspects of a developing rhizosphere microflora of hydroponically grown maize seedlings. Z Pflanzenernahr. Bodenk. 749 623 (1986). 

A further application of the manipulation of microbial activity in the rhizo-sphere is their potential to remediate contaminated land. Bioremediation involves the u.se of microorganisms that break down contaminants. Radwan et al. (255) found that the soil associated with the roots of plants grown in soil heavily contaminated with oil in Kuwait was free of oil residues, presumably as a result of the ability of the resident rhizosphere microflora to degrade hydrocarbons. The use of plants as a means to accumulate pollutants such as heavy metals (256,257) to degrade hydrocarbons and pesticides (255) is already widely implemented and has proven to be successful. In some cases, there is no doubt that it is the plant itself that is responsible for the removal of the contaminants. However, in most... 

A. A. Meharg and K. Killham, A novel method of determining root exudates in the presence of soil microflora. Plant and Soil I33 11 (1991). 

K. Old and T. Nicol.son, Electron microscopical. studies of the microflora of roots of sand dune grasses. New Phytol. 74 51-58 (1975). 

Beighton D and Lynch E (1995) Comparison of selected microflora of plaque and underlying carious dentine associated with primary root caries lesions. Caries Res 29, 154-158. 

Variation of Root and Microflora Rhizosphere Exudates in Genotypes of Barley... 

The aim of the present study was to find whether differences could be detected in the compositions of mixture of volatile compounds sampled from the root zone of two different cultivars of barley. To have a reasonable base for a relevant genetic variation in the plant material, two cultivars with different adaptation to acid soils were selected. The sampling was done from young plants, as the establishment of the rhizosphere microflora is of importance in early stages of plant development. 

A second source might be the products of the soil microflora, which then directly indicate a variation in the composition of the microflora in the root zone for the two cultivars. A third possible source for the observed variation is degradation of the components in the whole soil system. In this case different levels or kinds of microbiological activity are recorded. Probably we have a combination of the three suggested sources. 

In conclusion, we have found that even young unstressed plants of different cultivars show a variation in the chemical composition of their undisturbed root zones. We suggest that this variation shows a genetic potential of the plant in its control of the root zone environment and especially of its rhizosphere microflora. We suspect that this genetic potential will be of importance in selection and adaptation of agricultural crop plants in the future. 

Enteric bacteria have been found to differ with respect to the ability to become integrated into the endophytic microflora of alfalfa roots (Dong et al., 2001). A strain isolated from maize, Klebsiella pneumoniae 342, colonizes the interior of several host plants in higher numbers compared to... 

Research by Soler-Serratosa et al. (1996) using combinations of thymol and benzaldehyde for root-knot and cyst nematode control on soybeans showed that both compounds exhibited wide spectrum nematicidal activity with Meloidogyne spp. and Dorylaimid nematodes being more sensitive than cyst nematode and nonparasitic nematodes (Soler-Serratosa et al., 1996). In addition to the direct toxicity of these compounds to nematodes, it was hyopothesized that stimulation of beneficial microflora by the compounds or their products, altered host response, and a deleterious physicochemical environment may all contribute to reduced gall formation (Soler-Seratosa et al., 1996). 

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