Abstract

As an introductory survey for assessment of the risk for dispersal of plant diseases in a closed hydroponic outdoor cultivation system for nursery stock production the dynamics of the microflora inhabiting the roots of selected crops and inhabiting different localities within the irrigation system were studied using sole carbon source utilization. Chamaecyparis lawsoniana, Ribes sanguineum and Symphoricarpos were used as target crops. Analyses of irrigation water focused on three layers in the irrigation pond (surface, epilimnion; mid layer at 40 cm depth, metalimnion; bottom at 200 cm depth, hypolimnion). Root and water samples were collected with five replicates at three cardinal incidents during the vegetation period (autumn; spring; summer). Additional samples were taken from other water sources feeding into the irrigation pond, namely the three wells (spring and summer) and the retained irrigation effluent (summer). The present study indicated shifts in functional diversity during the vegetation period, regarding both the grown crops and location within the irrigation system. It also showed differences between the chosen habitats. Differences also occurred between the sampling incidents with respect to utilization of Pythium specific carbon sources. With respect to carbon sources specific for Pythium ssp., utilization was high for the microflora of all three crops and started after a short lag-phase. Further, also utilization of Pythium specific carbon sources by the microflora inhabiting the studied water habitats was substantial. Discriminant analysis (DA) of the functional diversity at the chosen sampling sites with respect to sampling incidents was dominated by carbon sources specific for Pythium. However, utilization of precursors for phenolic compound metabolism, malonic acid and phenylalanine, was low in most cases. An negative correlation between a.-D-glucose, D-trehalose and cis-aconitic acid to phenylalanine was found for the root samples during the second sampling. Some compounds (D-fructose, a.-D-lactose, D-raffinose, L-aspartic acid, glycyl-L-aspartic acid, urocanic acid, glycerol, glucose-1-phosphate, glucose-6-phosphate) were found as discriminating between the samplings occurred for several of the studied habitats

Keywords

Biolog GN-panel; Chamaecyparis lawsoniana; irrigation system inhabiting microflora; Ribes sanguineum; root microflora; sole carbon source utilization (SCSU); substrate microflora; Symphoricarpos

Published in

European Journal of Horticultural Science
2003, Volume: 68, number: 2, pages: 67-76

SLU Authors

• Jung, Victoria

  • Department of Crop Science, Swedish University of Agricultural Sciences
    

• Alsanius, Beatrix

  • Department of Crop Science, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Horticulture


Permanent link to this page (URI)

https://res.slu.se/id/publ/315