Environmental diagnosis through plants

Reading nature and soils

In the development process of a plant, there is a phenomenon called "dormancy", which appeared about 150 million years ago. Germination is blocked and no seed is capable of germinating directly.
To germinate, the seed must be in precise environmental conditions corresponding to its genetics and its own biology.
Some seeds will need to be in the soil with a little moisture (such as wheat, pink radishes or cultivated lettuces), others will require specific and more complex conditions to allow the "breaking of dormancy".
Thus, the seed of hawthorn or mistletoe must pass through the stomach of a bird to be able to germinate, whereas the olive tree will require the rumination of the goat.

Some species break their dormancy in the presence of the salts that make up chemical fertilisers or pesticides.
Plants then become, when one knows the germination conditions of botanical species, indicators of the state of the soils and offer a true environmental diagnosis.

If we know that Japanese knotweed germinates in the presence of heavy metals, we can deduce that wherever this plant grows the soils are polluted. Environmental pollutions become detectable by plants which become indicators of the state of the soils.

There are, moreover, two types of pollution: one by synthetic pesticides and heavy metals but also a contamination of soils which may seem more "natural" but which is the result of soil compaction, loss of porosity and poor quality of organic matter brought to agricultural land.
Plants allow us to discover our environment and to analyse its qualities or defects. Is it healthy or polluted? The question applies as well to our environment as to our food, bought in shops or produced in one’s garden or on one’s farm.

Thanks to plants, each of us can become a "private detective" and highlight all these pollutions or anomalies which unfortunately remain hidden from the general public.

This article was produced with the support of Gérard Ducerf, botanist and author of numerous works, notably the 3 volumes of "L’encyclopédie des Plantes Bio-Indicatrices"