Comparative Anatomy and Histology of Leaf and Stem in S. aegyptiaca, S. deserti and S. spinosa PDF

Keywords

Leaves, stems, anatomy

Abstract

Leaves and stems of Salvia aegypliaca L. , S . deserti Decne. and S. spinosa L. show similar frequencies of diacytic stomata and of eglandular and glandular trichomes but differ as to size and distribution of trichomes. Studies of transverse sections of the stems indicate that the cortex is made of collenchymatous tissue in the corners immediately below the epidermis interchanged with 3 or 4 layers of well-developed palisade, chlorenchymatous cells in S. aegypliaca and S. deserli, and with 2 to 4 layers of small rounded. chlorenchymatous cells in S. spinosa. The remainder of the cortex is a distinct single layer of large parenchymatous cells in S. aegYPliaca and S. deserli. while in S. spinosa it consists of 4 to 7 layers of parenchymatous tissue. Transverse section of the leaves show that the three species are characterized by the presence of collenchymatous tissue on the adaxial and abaxial sides of the midrib regions and the presence of only palisade tissue in the intercostal regions. This study indicates that while these three species of Salvia share several common anatomical characters, S. aegypliaca and S. deserti are closely related to each other and are quite distinct from S. spinosa. On the basis of reduction in leaf size, increased development of palisade tissues in the leaf and stem. and increased leaf pubescence, it is suggested that S. deserli is most adapted to aridity while S. spinosa is the least.