Analysis of the effects of soil toxicity at the cell, organ, organism and ecosystem level with a view to phytoremediation of contaminated soils with woody plants (trees):

Stabilisation, decontamination, sustainable utilisation of heavy metal contaminated soil which exceeds critical levels, and risk assessment, especially concerning the interaction between organisms

The interdisciplinary project `From Cell To Tree’ presently comprises of 33 research projects ranging from the molecular level in cells, organs and organisms to complete ecosystems. The numbers in the illustration represent the initial 14 projects.

The model ecosystems are contained within 16 open-top chambers (OTCs), OTC area measures 6 m², height 2 m, 1.5 m deep. Soil compartments are lysimeters, roofs close automatically with the onset of rain. The treatments per chamber (4 repetitions each) are:

1. control (irrigation pH 5.5)
2. acid rain i.e. acid irrigation (pH 3.5)
3. heavy metals applied as dust to the top soil (pH 6.4)
4. the combination of acid rain and heavy metals.

Each chamber has two separate soil compartments (= model ecosystems), which are filled either with acidic (pH 4.5) or calcareous (pH 7.5) subsoil each of which is again divided into two sectors with and without a pathogen saprophyte system. Planting per 1/4-chamber: 3 spruce, 4 deciduous trees (2 poplar, birch, and willow), tree seedlings and herbaceous understorey plants with different growth strategies.

Control treatment	Heavy metal contaminated soil which led to leaf browning and leaf edge necrosis in poplar
Field plots June 2000	Field plots August 2002

In order to study reactions under field conditions and examine the spontaneous and controlled infestation of feeding and sucking insects, N¹⁵ uptake of the root tubers of alder, litter decomposition etc, experiments were repeated in nearby field plots (model ecosystems supplemented by beech, alder und maple).

	Number of plants in the chambers	Number of plants in the field plots
spruce	216	60
deciduous trees	288	220
understorey plants	567	240
seedlings	604	460
total	1684	980

Associated organisms: experimentally controlled inclusion of a saprophyte / pathogen system within the bulk soil, spontaneously appearing fungi in the soil, pathogenic leaf fungi, bacteria, earthworms and other soil organisms, controlled and spontaneous insect infestation, spider mites, weeds, mosses, lichens, snails, birds- and wasp nests…

A) Design Open-Top-Chambers Click to enlarge	B) Plantation Open-Top-Chambers Click to enlarge
C) Design Field Experiment Click to enlarge	D) Plantation in the Field Experiment Click to enlarge