Leaf Micromorphology and Pollen Grain Characteristics of Nicotiana glauca. R.C. Graham and Nicotiana tabacum. L.(Solanaceae, Nicotianoideae)

Abstract

The micromorphological variation of the leaf and pollen grain characteristics in two species of Nicotiana was examined using a light microscope (LM) and scanning electron microscopy (SEM). These species are Nicotiana glauca R.C. Graham (wild species) and Nicotiana tabacum L. (cultivated species). The leaves are simple. The other leaf micromorphological features presented variation. The leaf architectural characteristics were also observed. Leaf venation is pinnate brochidodromous. The epidermal cell shape, on the abaxial leaf surface, is polygonal to irregular in Nicotiana glauca but it is so adaxially in all the two species the cells are irregular on both the epidermal layers. The anticlinal walls are either straight or sinuous. The leaves are amphistomatic. The stomata are commonly anomocytic to anisocytic. Foliar trichomes are glandular and non-glandular. Some of the foliar micromorphological characters as viewed under SEM were beneficial in species identification. The pollen shape is prolate with aperture tricolpate without opercula, the colpi shallow sunken with their ends acute. The exine sculpture is reticulate with granulate or granulate-microperforated to fine granulate and irregularly reticulate to perforate. Keywords: Leaf micromorphology- Pollen grains - Light microscope (LM); Scanning electron microscopy (SEM)- Nicotiana Solanaceae -Nicotianoideae.