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Complete tylosis formation in a latest Permian conifer stem
Zhuo Feng1, Jun Wang, Ronny Rößler
1Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming, PR China.
Fossil conifer wood reveals extensive tylosis formation, indicating a strong reaction to environmental stress rather than injury or disease. This study offers new insights into ancient plant defense mechanisms.
Area of Science:
- Paleobotany
- Plant Anatomy
- Ecology
Background:
- Tylosis formation in extant plants is known, but its significance in fossil plants remains poorly understood.
- This study presents the first detailed description of tylosis formation in a fossil woody conifer.
Purpose of the Study:
- To describe complete tylosis formation in the fossil conifer Shenoxylon mirabile.
- To discuss the ecophysiological implications of tylosis formation in this ancient plant.
Main Methods:
- Studied permineralized stem of Shenoxylon mirabile from the Upper Permian of China.
- Utilized standard thin-sectioning techniques and transmitted light microscopy.
Main Results:
- Observed ray parenchyma cells protruding into tracheids, forming balloon-shaped tyloses that occluded lumen.
- Tyloses developed extensively from heartwood to sapwood within growth rings.
- Host tracheids showed concentric zonation related to tylosis development phases.
Conclusions:
- Extensive tylosis development suggests high vulnerability and strong response to environmental stress.
- Tyloses were likely an ecophysiological response to constant stimuli, not wound or pathogen defense.
- This finding enhances understanding of plant stress responses in deep time.
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