Morphological and anatomical characterization of Lobularia arabica (Boiss.) Muschl. (Brassicaceae) using light and scanning electron microscopy

Lobularia arabica (Boiss) Muschl is an herbaceous plant native to Egypt and Palestine. In Egypt it is reported in Mediterranean and Sinai phytogeographical regions. In this study, the root, stem, leaf, flower, fruit and seed macro and micromorphology of L. arabica were examined using light microscopy (LM). Moreover, scanning electron microscopy (SEM) was used for further investigation of surface sculpture of seed, pollen grain, fruit and leaf. Microscopically, the plant is generally characterized by anisocytic stomata as well as dense appressed non-glandular medifexed trichomes with nippled cuticle which are found in the leaf, stem, sepal, gynoecium and fruit; giving the plant a hairy texture. The seed shows a yellowish-brown testa enclosing an accumbent embryo. Seed coat pattern that was recorded with SEM showed reticulate surface with narrow anticlinal smooth walls and lobed striated smooth periclinal walls. SEM examination of fruit surface sculpture recorded by SEM revealed reticulate scalariform ornamentation and pollen grain showed reticulate ornamentation. Both of upper and lower epidermises of the leaf were almost the same, showing rectangular cells with slightly wavy anticlinal walls.