## Results and Discussion
### Leaf Aroma Volatile Profile  
It is well established that volatile profiles in Lamiaceae may change in relation to several interacting preharvest factors, including genotype, chemotype, cultural environment, agronomic practice, geographic location, as well as chemical elicitation agents such as jasmonic acid and chitosan [45; 51; 52; 53]. This was the case in the current experiment, since the two perilla genotypes differed widely in the abundance of the two major aroma volatile components identified, perillaldehyde and perilla ketone (Table 4). Perillaldehyde (PA) constituted 41.6% of the total volatile profile in red perilla while it was not detected in the green one; on the other hand, perilla ketone (PK) was the most abundant (51.5%) volatile component detected in green perilla, whereas it was non-detectable in red-pigmented perilla (Table 4). In addition to PA and PK, benzaldehyde (26.7%) and cis-jasmone (21.2%) were the second most abundant compounds in red- and green-pigmented perilla, respectively (Table 4). The remaining major compounds such as benzaldehyde and \(\beta\)-linalo detected in both cultivars were 12.7- and 1.5-fold higher in red compared to green perilla, respectively whereas an opposite trend was recorded for cryophyllene (Table 4). Durenol and thymoquinone were only detected in red perilla leaves, whereas perillene and 4-trifluoroacetylimidazole were exclusively recorded in green cultivar (Table 4). The chemotype profiling revealed that _Perilla frutescens_ var. _frutescens_ produced exclusively perilla ketone (PK) and was classified as PK-chemotype, whereas _Perilla frutescens_ var. _crispa_ contained perillaldehyde (PA) instead of PK and was classified as PA-chemotype. These findings are in agreement with those of [PERSON] et al. [25] who reported that open-field Japanese red and green _Perilla frutescens_ var. _crispa_ cultivars ('AoShiso', 'Aka Shiso', 'Qing Su' and 'Purple Zi Su') produced exclusively PA, whereas Korean green perilla (_Perilla frutescens_ var. _frutescens_) contained PK. The high abundance of PA in red perilla adds nutritional value to the crop since this is the key volatile component responsible for the premium aroma and taste of perilla [15]. On the other hand, PK a terpenoid component present in green perilla leaves has been demonstrated to be toxic to animals (cattle and horses) causing pulmonary edema [9], but the effect as well as the toxic dose to humans is still equivocal [25]. Interestingly, several studies [54; 55] demonstrated that PA and PK trigger the Transient Receptor Potential (TRPA1) cation channels which are actively implicated in several biological mechanisms such as the chemesthetic and trigeminal sensations, indicating perilla as a potent functional vegetable. Upon salinization, the relative abundance of major aroma volatiles remained similar (no significant difference) to that of non-stressed plants, in both red- and green-pigmented perilla, with the exception of 1-octen-3-ol, perilla ketone, cis-jasmone and 4-trifluoroacetylimidazole (Table 4). Irrespective of perilla genotypes, treatment with 20 mM NaCl resulted in an increase in the levels of perilla ketone and 4-trifluoroacetylimidazole (Table 4). Moreover, a significant increase in the contents of 1-octen-3-ol (with 20 and 30 mM NaCl) and cis-jasmone (in all salt-stress treatments) was observed compared to untreated plants (Table 4). Triggering the biosynthesis and accumulation of cis-jasmone could be of high interest to the cosmetic industry since this volatile component is considered an important aroma agent for perfume, fragrance as well as in aromotherapy. The increase in essential oils content and their composition under salt stress conditions has been reported previously on several species belonging to the Lamiaceae family such as Satureja hortensis, Salvia officinalis, Thymus vulgaris, Ocimum basilicum and Salvia mirzayanii [56; 57; 58; 59; 60].