Plants
can be a basic component of environmental recovery. According
to this preamble our study is devoted to select the wild ones
exploitable in conditions characterized by:
a)
Strong summer water stress and/or poorness of nutrients in the
soil (for instance quarries and slopes of Mediterranean climate);
b) High content of toxic elements (for instance dumps
and leaching water in mining areas).
Plant
species selection according to a) is performed by laboratory
studies and field trials. In laboratory seed germination is
tested and enhanced by different chemical, physical and mechanical
treatments. In the field the plant species responses to real
conditions were tested by sowing in experimental plots or in
areas to be revegetated.
Plant
species selection according to b), firstly of the more common
ones, is performed by sampling in sites contaminated for a long
time, where the plants can evolve a tolerance. On the basis
of the contents of the toxic elements in the different plant
parts, escluder and accumulator species can be selected. Escluders
are useful to reduce the environmental spreading of the contaminants
by eolic and water erosion; while accumulators are useful to
clean-up the contaminated soil or water. The interesting species
are also studied for their tolerance thresholds, for relationships
between bioavailability and root uptake of the toxics, for biomass
production, reproduction forms more easely performed, etc.