Flowering plant embryology: with emphasis in economic species/ Nels R. Nerster

Contents
Preface ix
1 Introduction 3
Background: General works on embryology 4
Background: Embryology and systematics 5
What is a flower? 6
The floral appendages 6
The sexual life cycle 7.
Literature cited 8
2 Stamen and Androecium 10
Stamen variation in representative families 10
Stamen anatomy 12
Growth ofthe stamen: The anther 14
Growth ofthe stamen: Filament elongation 15
Anther dehiscence 17
Evolution ofthe stamen 19
Literature cited 20
3 Pollen Development: Theme and Variations 22
Introduction to pollen 22
Summary ofpollen development 23
Pollen development in sorghum 23
Pollen development in sweet pepper 28
Pollen development in walnut 30
Pollen development in the mustardfamily 30
Pollen development in sunflower 32
Literature cited 35
4 Pollen Development: Details of Stages 36
Anther differentiation before meiosis 36
Pollen
sac before meiosis 36
Meiosis 37
Cytokinesis 40
Duration
ofmeiosis 43
VI
Tapetal behavior
Tapetal function
Post-meiosis: The pollen wall
Contents
Post-meiosis: Internal microspore/pollen events -55
Duration ofpollen development
Gene expression during pollen development <50
Numbers ofpollen produced
Literature cited
Carpel and Gynoecium
Carpel evolution and development
Carpel variations: General considerations
Carpel variations: Apocarpy
Carpel variations: Syncarpy
Carpel variations: Relations to otherflower parts
Carpel structure: Stigma
Carpel structure: Style and transmitting tissue
Literature cited
Ovule and Embryo Sac
Ovuleform and development
Ovule failure and ovule abortion
Megasporogenesis
Embryo sac (megagametophyte) development
Cells in the normal fPolygonum) type of embryo sac
Literature cited
Pollination and Pollen-Stigma Interaction
Pollen desiccation and rehydration (harmomegathy)
Life span ofpollen
Pollen food reserves
Factors in pollination success orfailure
Pollen-stigma interaction: Incongruity
Pollen-stigma interaction: Incompatibility
Pollen-stigma interaction: Self-incompatibility
The mentor pollen technique
Callose and incompatibility
Late-acting (ovarian) self-incompatibility
Molecular basisfor pollen-stigma interactions
Compatible interaction
Literature cited
Pollen Germination, Pollen Tube Growth, and Double Fertilization 119
Germination and early tube growth
Cells and nuclei
within the pollen tube
Dimorphic sperm cells and the male germ unit ^26
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96
lOI
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105
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107
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no
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Contents vii
Guiding and nurturing the pollen tube 129
Callose plugs 131
Swelling and branching ofpollen tubes 132
Pollen tube competition and carpel "filters " 134
Rate
and duration ofpollen tube growth 136
Pollen tube growth in ovary
and ovule 136
Pollen tube discharge and doublefertilization 138
Polyspermy 146
Literature cited 147
9 Endosperm 150
Generalizations and historical interpretations 150
Cytology
ofendosperm 151
Introduction to endosperm types 151
Multicellular endosperm 152
Coenocytic/multicellular endosperm 153
Helobial endosperm 160
Coenocytic endosperm 160
Endosperm
haustoria 161
Perisperm 161
Movement ofcarbohydrates into endosperm 163
Storage products in endosperm 165
Aleurone layer and mature endosperm 165
Functions ofendosperm 167
Speculations on endosperm variation 168
Literature cited 169
10 The Embryo 172
Introducing the cotyledon(s) 172
The zygote 172
Proembryo initiation 175
The suspensor - 775
The early proembryo proper 178
Embryogenesis in dicots 179
Embryogenesis in monocots 187
Nutrition oft he embryo 195
Induction of dormancy 201
Green (chlorophyllous) embryos 202
Polyembryony 203
Apomixis 203
Summary: Embryo and seed 204
Literature cited 204