EPIDERMAL ANATOMY OF BAIERA FROM THE UPPER TRIASSIC OF CHINA

1. Epidermal anatomy of Baiera
from the Upper Triassic of China
Sui Wan1 , Patrick Blomenkemper2 , Benjamin Bomfleur2 , Zhuo Feng1
1 Institute of Palaeontology, Yunnan University, Kunming 650500, China
2 Palaeobotany Research Group, Institute of Geology and Palaeontology, University of
Münster, D-48143 Münster, Germany.
2021. 12. 01

2. Outline
1. Introduction
2. Material and Methods
3. Results
4. Comparisons
5. Conclusions

3. l Baiera Braun is a leaf genus of fossil ginkgophytes (Zhou and Zheng,
2003).
l The genus first appeared in the Permian and was particularly
diversified during the Late Triassic to the Early Cretaceous (Zhou,
2003; Taylor et al., 2009).
l Anatomical characteristics of the Late Triassic Baiera leaves are
largely unknown (Zhou, 2020).
1. Introduction

4. (Sadegh, 1977)
Baiera muensteriana
10 mm 10 mm
Order Ginkgoales
Genus Baiera Braun (1843) Florin 1939
Type species: Baiera muensteriana Braun 1843
1. Introduction

5. Well-preserved Baiera leaves were collected from the Upper Triassic Xujiahe Formation of Sichuan, China.
2. Material and Methods

6. Baiera elegans Ôishi 1932
Baiera multipartita Sze et Lee 1952
Our material includes two species
2. Material and Methods

7. Baiera multipartita Sze et Lee 1952 Baiera elegans Ôishi 1932
(Ôishi, 1932)
Ø Only impression specimens have been documented
Ø Epidermal anatomies are poorly understood
(Sze et al., 1952)
2. Material and Methods

8. 2. Material and Methods LM
SEM
TEM
1. Cuticles were macerated
using 42% HF for 1 week;
2. Treated using Schulze’s
reagent (HNO3 + KClO3);
3. Treated using 10% potassium
hydroxide solution.

9. (A-C, the upper cuticle of Baiera multipartita; D-F, the lower cuticle of Baiera multipartita)
Cuticle characteristic of Baiera multipartita
20 μm
A B C
D E
coastal field
intercoastal field
20 μm
F
20 μm 20 μm
20 μm 20 μm
polar subsidiary cell
3. Results

10. (A-C, the upper cuticle of Baiera elegans; D-F, the lower cuticle of Baiera elegans)
A
100 μm
D
100 μm
B
20 μm
E
20 μm
C
20 μm
F
20 μm
coastal field
intercoastal field
polar subsidiary cell
3. Results Cuticle characteristic of Baiera elegans

11. 20 μm 20 μm
Baiera multipartita Baiera elegans
3. Results SEM observation of stoma

12. Cuticle ultrastructure of Baiera multipartita
A1: Polylamellate layer; A2: Granular layer; B:Fibrilous or spongy layer
A1
B
A2
B
TEM observation
3. Results

13. A2: Granular layer; B:Fibrilous or spongy layer
3. Results
B
A2
A2
B
Cuticle ultrastructure of Baiera elegans
TEM observation

14. Species
Upper stomata
density
Lower stomata
density
Subsidiary
cells
Locality & Age References
Baiera multipartite 18—26 50—65 3—6 Sichuan, China; Late Trassic this study
B. elegans 14—18 51—57 2—5 Sichuan, China; Late Trassic this study
B. ninglangensis
Chen et al. 2000
0 53 4—6 Yunnan, China; Late Trassic Chen et al., 2000
B. minuta Nathorst
1886
17 40 4—7 Hunan, China; Late Trassic Zhou, 1989
B. muensteriana
Saporta 1884
16—20 24—32 Franconia, Germany; Late Trassic Kirchner, 1992
B. furcata Braun
1843
10—15 35—45 5—7
Yorkshire, England; Middle
Jurassic
Harris et al., 1974
B. hallei Sze 1933 5—7 Henan, China; Middle Jurassic
Zhou and Zhang,
1992
B. baishanensis
Zhao et al. 2016
10—15 25—35 6—8 Jilin, China; Early Cretaceous Zhao et al., 2016
B. minima Yabe
and Ôishi 1933
25—30 4—6 Liaoning, China; Early Cretaceous
Yabe and Ôishi,
1933
4. Comparisons

15. Epidermal cells Subsidiary cells Guard cells References
TH
（μm）
A1
（%）
A2
（%）
B
（%）
TH
（μm）
A1
（%）
A2
（%）
B
（%）
TH
（μm）
A1
（%）
A2
（%）
B
（%）
Baiera multipartite 3.2 26 48 26 2.7 52 21 27 3.3 22 45 33 this study
Baiera elegans 5.3 60 40 3.4 60 40 1.95 100 this study
Baiera furcata 1.53 43.8 56.2 2.86 81.5 18.5 0.34 64.7 35.3
Guignard et
al., 2019
Ginkgo yimaensis 1.6 17 64 19 1.6 11 61 28 1.8 4 32 64
Guignard
and Zhou,
2005
Ginkgo biloba (male) 1.3 5 69 26 1.6 7 16 77 2.3 5 9 86
Guignard
and Zhou,
2005
Ginkgo biloba (female) 1.8 6 67 27 2.1 11 33 56 2.2 8 5 87
Guignard
and Zhou,
2005
4. Comparisons

16. l Both Baiera multipartita and Baiera elegans are amphistomatic; the lower surfaces generally have a
higher stomatal density.
l Each stoma possesses two slightly sunken kidney-shaped guard cells and 2–6 subsidiary cells. Polar
subsidiary cells are occasionally present. The apertures are mostly orientated longitudinally .
l On upper cuticles, epidermal cells are rectangular or polygonal, with strongly undulate anticlinal
walls; epidermal cells are slightly elongate above vein courses.
l On lower cuticles, epidermal cells are divided into well-defined coastal and intercoastal fields. In
intercoastal fields, epidermal cells are polygonal to rectangular or spindle-like in shape, whereas in
coastal fields, epidermal cells are elongate rectangular. Anticlinal walls of the epidermal cells are
straight or slightly curved.
l Ultrastructurally, Baiera multipartita has three layers and Baiera elegans has two layers. The layer
thickness of them also varies greatly.
5. Conclusion

17. Thanks!