Veit Martin Dörken:

The evolutionary relevance of vegetative long-shoot/short-shoot differentiation in gymnospermous tree species

2012. 93 pages, 41 figures, 12 tables, 23x31cm, 640 g
Language: English

(Bibliotheca Botanica, Heft 161)

ISBN 978-3-510-48032-6, paperback, price: 94.00 €

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deciduousness gymnosperm tree evolution


Synopsis top ↑

This well illustrated monograph treats the correlation of deciduousness (shedding leaves at a certain season) and long-shoot/short-shoot differentiation focused on gymnospermous tree species. The vast majority of gymnosperms are evergreen and within this group deciduousness has generally been regarded as a derived feature. Comparative studies of angiospermous tree species indicate that the vegetative long-shoot/short-shoot differentiation correlates well with deciduousness. The total leaf area of an entire short-shoot equals the leaf area of lamina of a single long-shoot leaf. So the lamina of a long-shoot leaf is replaced by the total leaf area of an entire short-shoot in the following vegetation period. This simple correlation is not observed in any of the studied gymnosperms except Ginkgo. Consequently, the evolutionary pathway to the long-shoot/short-shoot differentiation in gymnospermous tree species must be different from the evolutionary traits in angiospermous trees. It is shown that some evergreen gymnosperms can be regarded as derived from deciduous ancestors while others still represent the primitive deciduous condition.

This monograph consists of two parts: In the first part several gymnospermous and angiospermous tree species have been investigated morphologically, anatomically and physiologically. In the second part those data were mapped on paleobotanic and palaeogeographic data in order to test the initial hypothesis that deciduousness has in the past been more frequent among gymnospermous tree species than the recent diversity can reflect.

This book is of interest for all botanists and researchers on angiospermous and gymnospermous trees.

Book Review: Journal of the North Carolina Academy of Science top ↑

Plant biologists have long wondered about the nature of short-shoots in woody plants. Short-shoots are short lateral branches on woody plants that bear leaves and sometimes reproductive structures. Ginkgo biloba is a good example, with stubby, leaf-bearing short-shoots along the long shoots or main axis. Some workers have treated them as mere taxonomic characteristics, others have looked at them as keys to understanding plant growth and development. Few have looked at them in a phylogenetic light, as Dörken does. Short shoots occur on many gymnosperm and woody angiosperms, but relatively few studies have been done to investigate both their structure and phylogeny.  Dörken’s contribution studies in depth the relationships between the long- and short-shoots themselves and the leaves borne on them; he further investigates their evolutionary implications. Despite the title, this study thoroughly investigates both gymnosperms and angiosperms. The author investigates if possession of short-shoots is related to deciduousness in both gymnosperms and in angiosperms, and whether deciduousness is primitive or derived, as is commonly supposed, in the gymnosperms. The author clearly demonstrates a strong correlation between deciduousness and possession of short shoots, especially in angiosperms. Further, the author presents a strong case, based on his studies, coupled with biogeograpical and paleobotanical information, that deciduousness is primitive and the evergreen state is derived in some gymnosperm lineages. An important conclusion is that within gymnosperms and angiosperms the pathways leading to deciduousness were different.

Dörken’s study details a topic in which there is a small but growing literature on the nature of short-shoots, and synthesizes a number of concepts, such as deciduousness, chlorophyll, leaf area, morphology, and phylogeny in novel ways.  While this is certainly a translation from German, the work is well written, and the author supports his case with numerous tables and clear illustrations.   Given that this is essentially a comparative work between gymnosperms and angiosperms and contains a very strong angiosperm component, the title of the work probably should have reflected this element. This study is intended for botanical researchers, but any biologist interested in the structure, ontogeny and especially evolutionary development of gymnosperms and angiosperms would find this work of great interest.

James E. Mickle, North Carolina State University, Dep. of Plant Biology

Journal of the North Carolina Academy of Science, 129 (1), 2013, p. 36

Table of Contents top ↑

Abstract 3
1 Introduction 5
2 Materials and methods 9
2.1 Length-frequence diagrams 9
2.2 Measurement of leaf area 12
2.3 Measurement of the chlorophyll content 12
2.4 Measurement of shoot weight 12
2.5 Electronic microscopy, paraffi n technique and photography 12
2.6 Special terms used in this study 13
3 Results 15
3.1 Correlation between foliage and shoot system 15
3.2 Differences in length between long- and short-shoots 16
3.3 Comparisons of annual investment in shoot biomass between
long- and short shoots 16
3.4 Number of long- and short-shoots in different ages of an individual 24
3.5 Number of leaves and single-leaf area of long- and short-shoot leaves 25
3.6 Annual investment in shoot biomass per long-shoot leaf and leaf area 29
3.7 Annual investment in shoot biomass per short-shoot leaf and leaf area 29
3.8 Annual investment in shoot biomass per single-leaf and leaf area
in taxa without shoot differentiation 30
3.9 Comparison of annual investment in shoot biomass per 1 cm2
long-shoot leaf area and 1 cm2 short-shoot leaf area 31
3.10 Comparison of the total leaf area of an entire short-shoot
with single long-shoot leaf 31
3.11 Anatomical comparisons between long and short-shoot leaves 31
3.12 Chlorophyll content 31
3.13 Shoot abscission . 31
3.13.1 Shoot abscission in Cupressaceae (Gymnospermae) 38
3.13.2 Shoot abscission in Larix decidua (Pinaceae, Gymnospermae) 38
3.13.3 Shoot abscission in Quercus robur (Fagaceae, Angiospermae) 38
3.14 Anomaliess 50
3.14.1 Pinus with anomalous formed short-shoot 50
Pinus sylvestris 50
Pinus monophylla 50
3.14.2 Sciadopitys verticillata with anomalous formed cladodes 56
4 Discussion 61
4.1 Correlation between shoot differentiation and deciduousness 61
4.2 Correlation between long- and short-shoots 61
4.3 Correlation between long- and short-shoot leaves 63
4.4 Shoot abscission and its evolutionary meaning 65
4.4.1 Shoot abscission in Quercus robur, Fagaceae (Angiospermae) 65
4.4.2 Shoot abscission in Larix, Pinaceae (Gymnospermae) 66
4.4.3 Shoot abscission Cupressaceae (Gymnospermae) 66
4.5 Evolutionary implications for different groups 70
4.5.1 Angiospermous trees 70 Cercidiphyllum (Cercidiphyllaceae, Angiospermae) 70 Nothofagus (Nothofagaceae, Angiospermae) 70
4.5.2 Gymnospermous trees 72 Pinus (Pinaceae, Gymnospermae) 72 Cedrus (Pinaceae, Gymnospermae) 75 Larix (Pinaceae, Gymnospermae) 76 Pseudolarix (Pinaceae, Gymnospermae) 76 Metasequoia (Cupressaceae s.l., Gymnospermae) 76 Sciadopitys verticillata (Sciadopityaceae, Gymnospermae) 77 Ginkgo (Ginkgoaceae, Gymnospermae) 78
5 Conclusions 81
6 Acknowledgements 83
7 Bibliography 85
Index 91
List of genera and species 92