On the ontogeny of stomata and glandular hairs in some Indian mangroves

Mature stomata of four mangrove taxa of different families reveal three distinct types of stomatal complex on abaxial surfaces, such as diacytic (in Acanthus ilicifolius), anomocytic (in Aegialitis rotundifolia and Xylocarpus granatum), and paracytic (in Ceriops decandra). In transverse section, there is a beak-like cuticular outgrowth overarching the stomatal pore either at the outer side or at both the outer and inner side of the stomatal pore. The guard-cell mother-cell divides once longitudinally to form two guard cells and the development of subsidiary cells is not at all concerned with the former cell. Ontogenetically it is revealed that the development of a stomatal complex in these investigated taxa is aperiginous (X. granatum) and periginous (A. ilicifolius, A. rotungifolia and C. decandra). Glandular hairs (salt gland) are present only at the adaxial surface of leaves in A. ilicifolius and A. rotundifolia. In A. ilicifolius it is pear-shaped and protrudes from the normal epidermal layer while in A. rotundifolia it is present within a cup-shaped crypt in the epidermal layer. In both the cases, the ontogenic pathway is similar, at least up to the three-celled stage, but at maturity, the morphology is quite different. The salt gland consists of 4–8 radiating terminal cells, two stalk cells and one basal cell.