Comparative Stem Anatomy of Some Dicotyledon Plants from 7 Families

Abstract

The objective of this research was to compare the anatomy of selected plant stems from different families. The specimens were 23 collected plant stems (3-4 species per each family) from 7 families (Amaranthaceae, Asteraceae, Cucurbitaceae, Euphorbiaceae, Leguminosae-Papilionoideae, Lamiaceae, and Piperaceae). The specimens were subjected to paraffin-based tissue preparation in preparation of permanent slides displaying cross-sections of stem tissue suitable for the study of arrangement of permanent tissues and vascular tissues in different plant stems using light microscopy. The results showed that sclerenchyma tissue arrangements were different in plants of different families, for example, in Asteraceae, the sclerenchyma forms clusters adjacent to the phloem structure. The sclerenchyma of Cucurbitaceae plants is circumferentially arranged in the cortex. In Piperaceae, the sclerenchyma is organized as a continuous band around the pit. The arrangement of the vascular tissues is also different in various families, for example, the vascular bundle spreads around the stem in the Asteraceae family. The vascular bundle penetrates into the pit of the Amaranthaceae and Piperaceae plants. While plants of the Cucurbitaceae family contain two groups of phloem (bicollateral bundle). Sclerenchyma and vascular organization, which are conserved in plants of the same family and distinctive from that of other families, can be exploited in identification and classification of the unknown plants. The unique tissue structures in the stem of plants from different family could also be fruitful for species identification, teaching and taxonomic studies.