MICROORGANISMS – TOOLS FOR CLOSED HYDROPONIC SYSTEMS?

Analyses of the functional diversity were performed for a pure culture of Pythium ultimum (Pu) as well as for the spermosphere of 6-day-old and of the rhizosphere of 6-week-old tomato plants with and without exposure to Pu on the basis of sole carbon source utilization (SCSU) using Biolog GN- panel, whereas the pure culture was assessed on both GN- and GP-panel.
The profiles were evaluated by performance of single carbon sources, average well color development, expressing the sum of absorbance units of all of the 96 wells divided by the total number of wells number of responding wells >0.5 abs.units and discriminant analysis.
With respect to AWCD, the Pu pure culture developed slowly reaching the stationary phase after 152 h whereas AWCD for both the spermosphere and rhizosphere microflora of tomato plants exposed to Pu utilized the given carbon sources more rapidly compared to their untreated controls.
The same trend was found for the number of positive wells.
For the fungal pure culture, utilization rate of both arbutin and aspargine was substantial.
For the evaluated spermosphere and rhizosphere microflora, utilization of -D-glucose, cis-aconitic acid, D-saccharic acid, D-trehalose, D-glucoronic acid and L-asparagine increased significantly when exposed to Pu.
There are indications for aspargine as one of the signature compounds for attack of Pu on tomato roots.

International Symposium on Growing Media and Hydroponics

B.W. Alsanius, M. Hultberg, S. Khalil

functional diversity, hydroponics, sole carbon source utilization, Pythium ultimum, rhizosphere and spermosphere microflora, tomato

https://doi.org/10.17660/ActaHortic.2001.548.22