COMPARATIVE ANATOMICAL STUDIES ON LEAVES AND STEM OF CERTAIN TAXA OF CONIFERS AND THEIR SYSTEMATIC SIGNIFICANCE | ||
| Journal of Plant Production | ||
| Article 10, Volume 29, Issue 7, July 2004, Pages 3949-3962 PDF (3.89 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jpp.2004.238684 | ||
| Author | ||
| R. A. Fouda, | ||
| Agric. Botany Dept., Fac. of Agric., Mansoura Univ., Mansoura, Egypt. | ||
| Abstract | ||
| Eight conifer taxa belonging to four families, i.e., Pinaceae, Taxodiaceae, Araucariaceae and Cupressaceae were collected during spring and summer of 2003 season to compare the anatomical structure of both leaves and stems and evaluate their systematic significance. The obtained results could be summarized as follows: Regarding the leaf structure, stomata type and their position, presence or absence of the hypodermis and endodermis; number of resin ducts, differentiation of mesophyll tissue and forms of transfusion tissue were varied within the studied taxa. Taxodium distichum leaves are characterized with differentiation of mesophyll tissue and spongy parenchyma, while, in the other studied taxa there is no such distinction. Needles of Pinus species are characterized with largest number of resin ducts, presence of the endodermis and infloding parenchyma cells in the mesophyll tissue compared with the other studied taxa . . Concerning the stem structure, the number and arrangement of resin ducts, number and thickness of eipthelial cell layers varied among the studied taxa. There are two types of resin ducts in Pinus species, .i.e., primary and secondary which are found in cortex and xylem tissue, respectively, while in other examined taxa were found only primary resin ducts. The largest number of resin ducts with scattered arrangement was found in Araucaria. The largest diameter of resin ducts with more number of epithelial cell layers was found Juniperus communis, while, the smallest diameter of resin ducts was found in Thuja. These characters may be used as a guide for classification of conifer families. The obtained results indicate also similarity of Taxodium with the Cupressaceae family in certain anatomical leaf and stem characters, i.e., absence of hypodermis and endodermis, number of resin ducts. Its pattern and structure in the leaf, as well as number and arrangement of resin ducts and its position in the stem. | ||
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