Lipid Fatty Acid Profile of <i>Asplenium scolopendrium</i> Gametophytes Modulated by Light Spectral Composition

We investigated the total lipid fatty acid (FA) composition of the fern Asplenium scolopendrium gametophyte, representing 25 individual FA species, for the first time. Conjugated octadecadienoates-18:2(10,12), rarely found in plant tissues-were identified. The possibility of modulating the lipid FAs composition under the action of light of different wavelengths on in vitro cultured gametophytes was demonstrated. Thus, exposure to blue (450 nm) and red (660 nm) light resulted in only insignificant changes in the minor FAs. This stability can be attributed to the fact that these wavelengths of light are necessary for photosynthesis and therefore optimal for the fern gametophyte. Green (GL, 525 nm) and far-red (FRL, 730 nm) light caused dramatic changes in the FA profile-the triene FAs decreased and the very-long-chain (VLC) FAs increased, mainly at the expense of saturated even-VLCFAs. This resulted in a dramatic decrease in the unsaturation index, indicating a decrease in membrane fluidity under GL and FRL illumination conditions. These changes indicate a significant rearrangement of the lipid metabolism of the A. scolopendrium gametophyte at light wavelengths not directly involved in photosynthetic processes (GL and FRL), in particular by triggering β-oxidation and blocking the plastidial pathway of FA synthesis.