The photosynthetic process of ‘dormant’ plants has been inhibited
Following the experiments carried out with Erasmus students (the Plantish course), Professor Hazem M. Kalaji, Institute of Biology, SGGW, and his team demonstrated for the first time in the world that the process of photosynthesis was inhibited during the plants’ anesthesia
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Anaesthesia was first used in the 19th century. However, the physiological mode of action of anesthetic drugs still seems unclear. One of the questions is whether anesthetics have the same or similar effects on plants as on animals and humans.
In recent years, the studies conducted by Prof. F. Balušek of the University of Bonn (Germany) have proven that plants are sensitive to several anesthetics that have no structural similarities. Likewise in animals and humans, such anesthetics used in appropriate concentrations may block action potentials.
A preliminary study by Prof. Kalaji showed that after 2 hours of application, the diethyl ether significantly reduced the photosynthetic performance of the tested plant species. The quantum yield of photosystem II (ΦPSII) was significantly reduced in the belly pitcher plant (Nepenthes x ventrata), irrespective of whether the pitcher or the petioles were measured. The value of this parameter was lower in the ether-treated plant compared to the untreated plant by 51% (pitcher) and 23% (petiole,) respectively. There was an even bigger difference observed in the flytrap (Dionaea muscipula), amounting to 57% (Figure 1).
The negative effect of diethyl ether on the functioning of the photosynthetic apparatus is also evidenced by changes in the value of the maximum quantum yield of photosystem II (Fv/Fm). When exposed to the ether for 2 hours, the value of this parameter was lower in pitcher plants treated with the chemical compared to untreated plants by 34 and 27%, respectively. In flytrap plants, these differences amounted to 65% (Figure 2).
Figure 1. The quantum yields of photosystem II (ΦPSII) of plants treated with the anesthetic diethyl ether. The green column refers to untreated (control) plants and the red column to ether-treated ones.
Figure 2. The maximum quantum yield of photosystem II (Fv/Fm) of plants treated with the anesthetic diethyl ether. The green column refers to untreated (control) plants and the red column to ether-treated ones.
The preliminary studies carried out by Professor Kalaji and his team have confirmed that plants treated with anesthetics to induce loss of consciousness could be ideal models for studying general anesthesia issues, and could also act as a proper testing system for humans.
The reduction in the efficiency of plant photosynthesis appears to have resulted from the inhibition of chlorophyll accumulation (as suggested by Professor F. Baluška’s earlier research). Professor Kalaji and his team intend to continue their research in order to clarify the mechanism of action of anesthetics on photosynthesis and other related physiological processes.
