by Anna Fregonara
In addition to eliminating various pollutants thanks to their microbiota, plants in the home have a positive effect on physical and psychological well-being, reducing stress
The “right” plants at home can improve the health of our body and mind. Their microbiota is also an accomplice. That’s right, those millions of microorganisms that work for us in our intestines (and not only) and which are increasingly discussed in the scientific literature, also live in plants. In fact, it is mainly bacteria and fungi that keep them healthy and luxuriant, which affects our well-being in different ways. The ability of plants to clean the air of pollutants is known and although there is not yet a robust body of research on the health benefits of indoor plants, their “strength” in helping, for example, to reduce stress, symptoms of depression, anxiety, improve mood, memory, concentration and lower blood pressure.
«The microbiota of plants is everywhere: on the leaves, on the roots, in the tissues. It is similar to man’s to the extent that it supports and enhances the health of the host organism, the goal is therefore the same. However, it is different in composition and functions because men and plants have different metabolisms», explains Paola Quatrini, associate professor of Microbiology at the University of Palermo, specializing in environmental microbiology. “The plant microbiota guarantees plant health by reducing the need for pesticides in agriculture and therefore contributes to obtaining healthier and healthier vegetables for humans”. However, the “force of nature” goes beyond the table. As demonstrated by a research conducted by the American Space Agency.
Against pollutants
It was 1989 when NASA researchers published a study on the ability of common house plants to remove pollutants (benzene, trichlorethylene and formaldehyde) in space stations. Many plant species tested, such as spathiphyllum, gerbera or dracaena, proved to be effective in their cleaning action from volatile organic compounds (VOCs). But the uniformity in the ability of very different species to improve air quality suggested that this was not a property of particular plants. Years later, Australian scholars hypothesized that the “detox” action of potted plants depended on earth bacteria. In other experiments, the plants were removed, leaving only the soil to act, the “eco-performance” of which, however, recorded a gradual decline over the course of a few weeks. Plants and earth are in fact an inseparable microcosm. In a more recent survey that appeared in Water, Air, & Soil Pollution, researchers measured the effectiveness of the plant-pot microcosm on total VOC levels in 60 offices for a few weeks. Three plants in an average-sized room have found large reductions, from 50 to 75 percent, in pollutants.
Photosynthesis
«Plants have a strong point: photosynthesis, the ability to produce energy, to transform light energy into chemical energy, releasing oxygen. At the same time they absorb carbon dioxide (CO2) and transform it into sugars which the plants feed on; this is how the so-called food chain starts, to which man also belongs», continues Quatrini. «In addition to cleaning the air from CO2, they eliminate other pollutants, for example VOCs, produced both by man and by the plants themselves: they too pollute, to keep insects away, however, producing vegetable VOCs called biogenic. Regardless of the origin, the polluting molecules are mechanically absorbed and fixed (adsorbed) on the leaf surface, on which, in addition to the pollutant-eating microbiota, there is a natural wax that dissolves these molecules».
At night
Some plants clean up the environment even at night because they keep the stomata, small holes in the leaves, always open and thus purify the air while we sleep. In the future, researchers hope to be able to select the most efficient microorganisms and spray them on plants to strengthen their depolluting microbiota.
Body and mind
A review of 42 studies that appeared last year in the International Journal of Environmental Research and Public Health also shows that just the presence of houseplants can affect mental health
Creativity
“The same results on the psyche emerged from researchers at Texas and A&M University who demonstrated how the presence of plants in working environments is also able to stimulate creativity”, says Alessandro Miani, president of the Italian Society of Environmental Medicine (Sima), doctor and university professor of environmental prevention. «It also seems to help reduce symptoms of depression, anxiety and mood disorders by lowering levels of the stress hormone, cortisol, and consequently positively influencing blood pressure and heart rate. Direct effects of plants on the central nervous system have also been highlighted, leading, for example, to a reduced activation of the amygdala and cortical areas involved in the response to stress and related to negative feelings, as well as a greater activation of the gratification, notoriously compromised in depressive states”.
Horticulture
“A study published in 2016 in the American Society for Horticultural Science showed that caring for plants is an activity that can work wonders for people suffering from depression, anxiety or dementia. It allows them to feel useful and committed to a specific purpose, that of taking care of something », she says. It has also been demonstrated in the journal Nutrients how horticultural therapy can help decrease stress levels in patients with anorexia nervosa.
Forest effect
«Plants make us feel good just by looking at them», continues the expert, «probably thanks to Edward Wilson’s biophilic hypothesis according to which man has an innate affinity with the natural environment that reminds him of his evolutionary origins”. Environmental psychologists suggest grouping plants: this would create a “forest effect” appreciated by the brain that perceives that habitat as a good place to stay. And that can only do us good.
June 25, 2023 (change June 25, 2023 | 08:33)
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