• Korean Journal of Plant Resources
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• v.9 no.1
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• pp.11-21
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• 1996

This study has observed the development, structure and distribution of oil canals in mitsuba, seri, ashitaba and hamabohu, that are condiment herbs belonging to the Umbelliferae family, using a light microscope. Oil canals were found in the petioles, leaf blades, stems, roots, hypocotyls and cotyledons. Oil classified into distribution due to ring vascular bundles, as in mitsuba and seri, and distribution due to diffuse vascular bundles, as in ashitaba and hamabohu. Oil canal development in the cortex due to petiole thickening was followed by the development of collenchyma and vascular bundles. However, no vascular bundles were formed in some cases. Many oil canals were found in the periphery of the petioles. Oil canals in leaf blades were found on the adaxial and abaxial sides on the veins. Those around the main veins were larger. Steam oil canals were found in the cortex and pith in mitsuba and seri, and in the cortex and fundamental tissues around the xylem, in ashitaba and hamabohu, while those in the roots were found in the pericycle in mitsuba and seri, and in the collenchyma-like tissues and phloem in ashitaba and hamabohu. The transverse sections of oil canals were round or elliptical. The secretory cells in the cortex and pith were smaller than the neighboring parenchyma cells, while they were larger than the neighboring parenchyma cells in the phloem.