Contributions from the Shimoda Marine Biological Station, No. 300.
Article first published online: 6 FEB 2005
Copyright © 1976 Wiley-Liss, Inc.
Journal of Morphology
Volume 150, Issue 3, pages 607–621, November 1976
How to Cite
Fujimoto, H. and Watanabe, H. (1976), Studies on the asexual reproduction in the polystyelid ascidian, Polyzoa vesiculiphora Tokioka. J. Morphol., 150: 607–621. doi: 10.1002/jmor.1051500302
The cost of this research has been partly defrayed from the Scientific Research Expenditures of the Department of Education of Japan and the Asahi Press.
- Issue published online: 6 FEB 2005
- Article first published online: 6 FEB 2005
New blastozooids of Polyzoa vesiculiphora, the polysytelid ascidian are produced by pallial budding of three types depending on the method of “isolated bud” formation; stolonic, planktonic and intermediate types. Differences among each type of bud are attributed to behavior of test-vessels composing a part of the bud. Isolated buds produced by each type are essentially equal in terms of their internal structures and their subsequent fate, and develop independently of their parent zooids. New test-vessels originate directly from the epidermis of a “prefunctional zooid,” while the test-vessels derived from the parent zooid finally disintegrate. The new test-vessels extended with branching under the ventral side of a “functional zooid,” ascend to the lateral side of it and participate in bud formation. Budding regions exist in three dimensions on the lateral wall of the mantle of the functional zooid, especially the right posterior part. During the life cycle of one functional zooid, the stolonic type buds appear at early and/or aged stages. Appearances of the stolonic type buds in early stages tend to repress those of the planktonic types. The number of planktonic type buds formed on a functional zooid at the same time is many more than that of the stolonic type. Such budding features are discussed from the viewpoint of behavior of the test-vessel system.