cover

Hardev Singh:

Embryology of Gymnosperms

1978. XII, 302 pages, 121 figures, 1 table, 17x24cm, 1000 g
Language: English

(Encyclopedia of Plant Anatomy, Band X / 2)

ISBN 978-3-443-14011-3, bound, price: 71.00 €

out of print

BibTeX file

Contents

Author's preface top ↑

The last time (SCHNARF 1933; CHAMBERLAIN 1935) when the literature on the embryology of gymnosperms was compiled, the facts could hardly be woven into generalities. In fact the information was gathered mainly under the subheadings of the different orders or families of the group. In the intervening period, as literature built up, several botanists started looking at it conceptually and thus many unifying principles have emerged. Also a need for enhanced world resources of timber and wood pulp, has led to the development of tree breeding as a discipline. This discipline uses and also advances our understanding of the embryology of gymnosperms. Thus literature compilation in the area which is part of basic science (and therefore justifying its pursuit) and also of applied value (and thereby constituting relevant research) seems doubly fruitful. Bringing the recent information under one cover, so that it may be useful to the advanced level botany students had also been in my mind while writing the book. And above all the charm of the subject itself has a spell on me. The occurrence of pollination drop, alveoli in female gametophyte, the tiered embryo in conifers, the long lasting life cycle, the enigmatic Gnetum and Welwitschia, the far flung and restricted distribution of several taxa, all seem unique. And some of these phenomena have passed to the present times, unchanged through their long geological history. The pollination drop mechanism was present even in the Palaeozoic times! Is it not likely that even the karyotypes of many of them may not have altered over millions of years?

Of interest to every botanist, food technologists, pharmacologists, specialists in forestry, paleobotanists, relevant research institutes, institutes for applied botany, institutes for wood research, agricultural colleges, science libraries.

Contents top ↑

1 Introduction 1
1.1 Classification and Delimitation of the Group 1 1
1.2 The Two Scopes of Embryology 3
1.3 Some Important Names and Dates 4
2 Microsporangium 6
2.1 Development and Internal Differentiation 6
2.2 Exothecium and Endothecium 10
2.3 Tapetum 12
2.4 Microsporogenesis 20
2.5 Spore Wall 26
2.6 Dehiscence 31
3 Pre-Pollination Ovule 33
3.1 Components of the Ovule 33
3.2 Orientation and Symmetry of the Ovule 34
3.3 Initiation of the Ovular Parts 34
3.4 Development of Nucellus 40
3.5 Mature (Primary) Nucellus 44
3.6 Pollen Chamber 47
3.7 Megasporogenesis 51
3.8 Integument and other Covering Structures 56
4 Pollination Mechanism 61
4.1 General Mechanism 61
4.2 Pollination Drop 62
4.3 Winged Pollen 66
4.4 Special Mechanisms 66
4.41 Picea orientalis Type 66
4.42 Pinus-Picea Type 66
4.43 Pseudotsuga-Larix Type 68
4.44 Abies-Cedrus Type 69

4.45 Tsuga Type 69
4.46 Agathis-Araucaria Type 69

4.5 Entomophily 72
4.6 Evolution 73
5 Male Gametophyte 75
5.1 Terminology 75
Microspore 76; Central Cell 76; Prothallial Cell 76; Antheridial Initial 77;
Antheridial Cell 77; Tube Cell 77; Stalk Cell 77; Body Cell 77; Male Gametes 77
5.2 General Pattern of Development and Variations 79
5.3 Fossil Forms 84
5.4 Gnetum and Welwitschia 85
5.5 Homologies 88
5.6 In Vitro Pollen Culture 89
6 Post-Pollination/Pre-Fertilization Ovule 96
6.1 Closing of Micropyle 97
6.2 Closure of Pollen Chamber 98
6.3 Intermediary Chamber 99
6.4 Patterns of Ovule Enlargement 100
6.5 Nucellar Vasculature 104
6.6 Nutritive Tissue 106
7 Female Gametophyte 110
7.1 General Pattern of Development 110
7.2 Variations 115
7.3 Gnetum and Welwitschia 119
7.4 Tent Pole 121
7.5 Archegonial Chamber 123
7.6 Megaspore Membrane 123
7.7 In Vitro Culture Studies 127
8 Pollen Tube and Male Gamete 131
8.1 Pollen Germination 131
8.2 The Common Pollen Tube 135
8.3 Pollen Tube in Cycads and Ginkgo 138
8.4 Body Cell and Male Gametes 139
8.41 Ciliate Sperms 139
8.42 Male Cells 150
8.43 Male Nuclei 151
8.5 Multiple Male Gametes 152
9 Archegonium and Female Gamete 153
9.1 Single Archegonia and Archegonial Complexes 153
9.2 Neck Cells 157
9.3 Jacket Layer 159
9.4 Cytoplasm - Central Cell and Egg Cell 163
9.5 Egg Nucleus 171
9.6 Egg Nuclei of Gnetum 172
9.7 Prothallial Tubes of Welwitschia 172
9.8 Homologies 174
10 Fertilization 176
10.1 Release of Male Gametes 176
10.2 Male Gametes in Egg Cytoplasm 178
10.3 Fusion of Cytoplasms 179
10.4 Fusion of Nuclei 184
11 Embryo 188

11.1 Proembryogeny 188
11.11 Cycad and Ginkgo Type 191
11.12 Conifer Type 192
11.121 Terminology 193
Primary Proembryo 193; Primary Upper Tier (pU) 193; Primary Embryonal
Tier/Cells (pE) 193; Internal Division 193; Upper Tier (U) 194; Suspensor
Tier (S) 194; Embryonal Tier/Cells (E) 194
11.122 Variations 194
Pinaceae Variations 195; Pseudotszuga Variation 195; Athrotaxis Variation 196;
Callitris Variation 197
11.13 Ephedra and Sequoia Type 199
11.14 Gnetum and Welwitschia Type 200
11.2 Early Embryogeny 203
11.21 Suspensor System 203
Embryonal Suspensor (Es) 205; Suspensor Tube 205; Embryonal Tubes (et) 206
11.22 Polyembryony 206
11.221 Terminology 208
Simple Polyembryony 209; Cleavage Polyembryony 209; Unitary
Cleavage 209; Partial Cleavage 209; Total Cleavage 209; Inhibitory
Cleavage 209; Unitary Lobing 209; Determinate Cleavage Polyembryony 209;
Indeterminate Cleavage Polyembryony 209; Persistent Polyembryony 209;
Transitory Polyembryony 209
11.222 Phylogenetic Considerations 209
11.23 Embryogeny Formulae 210
11.24 Embryonal Mass 211
11.241 Cap Cells 218
11.25 'Rosette Embryos' and Suspensor Proliferation 220
11.3 Late Embryogeny 220
11.4 Mature Embryo 227
11.5 In Vitro Culture Studies 227
12 Postiertilization Ovule/Seed 230
12.1 Development of Seed Coat 230
12.2 Mature Seed Coat 231
12.21 Anatomy of the Three Layers 231
12.22 Vasculature 234
12.3 Other Coverings 237
12.4 Endosperm 237
13 Embryology in Relation to Time 242
13.1 Seasonal Development 242
13.2 Duration of the Reproductive Cycle 243
13.21 One-Year Type Reproductive Cycle 244
13.22 Two-Year Type Reproductive Cycle 246
13.23 Three-Year Type Reproductive Cycle 248
13.3 Ecological Considerations 251
14 Conclusions 252
14.1 Relevance of Embryology of Gymnosperms 252
14.11 Embryology and Forest Genetics 253
14.12 Embryology and Silviculture 255
14.13 Embryology and Taxonomy 256
14.131 Sciadopitys 256
14.132 Podocarpaceae and Phyllocladus 256
14.133 Sequoia 257
14.134 Cephalotaxus and Taxales 257
14.135 Thuja and Biota 259
14.136 Ephedra, Gnetum and Welwitschia 259
14.2 Prospects 260
Bibliography 262
Addendum 288
Author Index 291
Subject Index 297