Both smoking classic tobacco products and e-cigarettes significantly reduces photosynthesis.

It was the first such experiment in the world; no one had previously studied the effect of cigarette smoke on the physiological processes of plants. The scientists focused on two species: beans and hemp.

It is well-known that the negative effect of cigarettes on the human body may vary and depends on many factors, including chemical composition, the method of delivering substances to the body, the amount of released toxic substances and the health condition of the person.

However, in general, it can be said that conventional cigarettes are the most harmful. During combustion, over 7,000 chemicals are released., including about 70 carcinogens, such as formaldehyde, benzene and arsenic. Tobacco smoke also contains carbon monoxide, tar and large amounts of nicotine, which has addictive properties. Tar accumulates in the lungs, which increases the risk of heart disease, lung cancer and respiratory diseases.

As for tobacco heating products (THPs), which have been popular in recent years, they heat a tobacco insert to a temperature at which aerosols are released, but tobacco does not burn. Thanks to this, the amounts of released toxic substances are slightly smaller than in conventional cigarettes. However, as numerous studies have shown, these products still contain nicotine and various harmful substances, which is why they can also lead to addiction and health problems.

An alternative to THPs are e-cigarettes, i.e. devices in which a liquid containing nicotine is heated, producing vapours that the user can inhale. Since they do not contain tobacco, they release fewer toxic substances than conventional cigarettes. However, some of their ingredients can decompose at high temperatures, creating harmful compounds such as formaldehyde and acetaldehyde. Additionally, the flavourings contained in e-cigarette liquids can have a negative impact on the health of the respiratory system. There is also a risk that people who use e-cigarettes may become addicted to nicotine.

The scientists conducted research on the analogies between the reactions of plants and humans to environmental factors and external stimuli. Part of the research was checking whether substances released by the three types of products mentioned above can affect the condition of plants, and especially the photosynthesis process.

It turned out that they can - regardless of the source of substances and the plant species, a negative effect on the photosynthetic efficiency of the tested specimens was observed after just two hours of exposure.

In beans, smoke from a classic cigarette and aerosols from a THP caused negative changes in the course of the so-called chlorophyll fluorescence induction curve (OJIP), which may indicate disruptions in electron transport between photosystems and inhibition of the reduction of the first acceptors of photosystem I. Vapour from a disposable e-cigarette acted similarly, but not identically - it caused changes in a different phase of the curve, which may indicate blocking of initial photochemical processes and damage to the reaction centres of photosystem II.

In hemp, negative changes were visible in all phases of the OJIP curve.

After 24-hour exposure, most parameters indicating the efficiency of the photosynthetic apparatus of bean plants underwent negative changes, with the classic cigarette and THP having a more negative effect on them than the e-cigarette.

In hemp, the negative effect on the values of individual parameters related to photosynthesis was comparable, but in this case, scientists did not find any differences between the individual types of tobacco products.

The researchers conclude that using tobacco products, including conventional cigarettes, e-cigarettes and THPs, has - just like in humans - a negative impact on the health of plants. It harms them by disrupting key physiological processes, such as photosynthesis. (PAP)

Katarzyna Czechowicz

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tr. RL