Abstract:
Salinity is an environmental condition that induces stress on plants especially under high soil salts levels.
It limits crop metabolic activities, hampers plant growth and synthesis of secondary metabolites. It also affects
osmotic potential in the plant root zone. A complete randomized block design was used to evaluate the effect of
salinity applied at 1.6, 2.4, 3.2 and 4.0 mS cm-1 on external and internal morphology of rose geranium (Pelargonium
graveolens L.) leaf and treatments were replicated three times. Scanning electron microscopy (SEM) and
transmission electron microscopy (TEM) were used to evaluate the morphology of the leaf. Salinity levels induced
the development of capitate trichome. Abaxial leaf position had the highest number of trichomes than the adaxial
leaf position. A strong polynomial (r2=0.97) relationship was found between capitate trichome and salinity. High
densities of capitate trichomes were found at a high salinity level. Although the development of asciiform trichome
was induced, it was in an insignificant level, trichomes densities are therefore not affected by salinity. It was
therefore concluded that rose geranium might have some degree of tolerance to salinity.
