Studies onArtemisia afra Jacq.: The phloem in stem and leaf |
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Authors: | C E J Botha Ray F Evert |
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Institution: | (1) Department of Botany, University of Fort Hare, Private Bag X1314, 5700 Alice, Republic of South Africa;(2) Departments of Botany and Plant Pathology, University of Wisconsin, Madison, Wisconsin, USA |
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Abstract: | Summary The structure of the phloem was studied in stem and leaf ofArtemisia afra Jacq., with particular attention being given to the sieve element walls. Both primary and secondary sieve elements of stem and midvein have nacreous walls, which persist in mature cells. Histochemical tests indicated that the sieve element wall layers contained some pectin. Sieve element wall layers lack lignin. Sieve elements of the minor veins (secondary and tertiary veins) lack nacreous thickening, although their walls may be relatively thick. These walls and those of contiguous transfer cells are rich in pectic substances. Transfer cell wall ingrowths are more highly developed in tertiary than in secondary veins. |
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Keywords: | Anatomy Artemisia Cell wall composition Compositae Phloem Sieve element |
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