Anatomical and Morphological Properties of Trichomes in Four Iranian Native Salvia Species under Cultivated Conditions

The morphological specifications play a substantial role in classification and breeding programs of various plant taxa. In the current study, some macro- and micro-morphological features of Salvia nemorosa, Salvia syriaca, Salvia frigida and Salvia virgata (three accessions), were investigated using scanning electron microscopy and image analysis program. The completely randomized design (CRD) was used to compare the morphological properties (r=4). Macro-morphological and agronomical measurements showed that Salvia species have great potential for cultivation as medicinal and ornamental plants. The cluster analysis suggested that S. virgata and S. frigida located in the same group; on the other side, S. syriaca and S. nemorosa had more similarity. The micro-morphological results showed that glandular trichomes (GTs) and non-glandular trichomes (NGTs) were widely distributed over the leaf and flower surfaces. The peltate GTs with high-density covered sepal and petal and were observed with low density on the leaves. The comparison with different species showed that the highest size and density of GTs belonged to Salvia virgata. The GTs are large and cover a significant portion of the flower surface (3.85-18.45%). The multicellular GTs were observed in S. nemorosa and S. virgata A1 and A2. The uniseriate and multicellular NGTs covered the adaxial leaf surface in different species. Besides, relative variation in GTs was observed in the three studied S. virgata accessions (15.33- 30.58 trichomes per mm2), which indicates the role of environmental conditions in trichomes formation. A wide range of variation in most of the micro- and macro-morphological traits of Salvia genotypes observed in cultivated condition.