cover

Abraham Fahn; David F. Cutler:

Xerophytes

1992. IX, 176 pages, 90 figures, 20 tables, 17x24cm, 620 g
Language: English

(Encyclopedia of Plant Anatomy, Band XIII Teil 3)

ISBN 978-3-443-14019-9, bound, price: 64.00 €

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Keywords

botanyplantanatomaXerophyte

Contents

English descritpion top ↑

This book surveys current knowledge on the morphological and anatomical adaptations and survival strategies enabling plants to grow and complete their life cycles in arid, semi-arid and saline regions.

These adaptations are numerous and diverse; when considered with associated physiological modifications it is clear that very few generalizations should be made about xerophytes. Here the authors have sought to organise information both from an extensive literature, and from their own research, so that it can be presented in a digestible form. To make the text concise, only selected examples of detailed anatomical descriptions are provided. There are many more in the literature; for example, in other volumes in this series (such as NAPP-ZINN, 1984, 1988), books dealing with systematic plant anatomy and a plethora of papers. The more significant of them are referred to in the text.

The subject matter is organised in this way: the concept of adaptation to environment is followed by a brief consideration of arid regions and their floras; terms are defined; an account of various survival strategies is given. Next there is an account of the underlying anatomical/histological characters commonly found in the plants concerned, first in photosynthetic organs (mainly leaves) then in the plant axis (roots and stems). Adaptations to salinity are described. A brief summary section brings out the more important topics.

Contents top ↑

Introduction 1
Adaptations 1
Arid regions 5
The flora of arid regions 10
Xerophytes 13
Types of Xerophytes 13
Drought escaping plants 15
Ephemerals 15
Seed-dispersal mechanisms 18
Hygrochasy 18
Myxospermy 19
Morphological adaptations of annual plants to the amount of rain
in the growing season 26
Desert summer annuals 26
Drought resisting plants 28
Morphological characteristics of plants growing in arid and
semi-arid regions 28
Below ground organs 28
Shallow and deep roots 28
Specialized below-ground structures 30
Thickend roots 34
Contractile roots 34
Xylopodia 36
Lignotubers 36
Cryptogeal germination 37
Dune plants 38
Above-ground part of the plant 41
Split axis 49
Anatomical characters 50
A general survey of anatomical xeromorphic characteristics 51
Photosynthesizing organs 51
The epidermis 51
Cell volume 52
Stomata 54
Trichomes 60
Papillae 66
Epidermis of Mesembryanthemaceae 69
Toothed and lobed leaf margins 70
Cuticular water absorption 71
Absorbing trichomes of epiphytes 71
Absorption of water by epidermal cells others than trichomes 73
Specialized cells 77
Leaf involution and recurvation 79
Leaf size and mesophyll characteristics 80
Achievement of similar structural adaptation by different tissues 82
Ratio of internal free surface to external surface 84
Chlorophyll 84
Vascular bundles 86
Grass leaves 86
Succulent plants 90
Tracheoid idioblasts 92
Cacti and some other succulents 95
Mucilage 99
CAM plants 100
C4 plants 102
Kranz type of leaf anatomy 103
Location of the bundle sheath chloroplasts 105
Cell wall composition 105
Desiccation-tolerance 105
Ultrastructural changes occuring in resurrection plants 108
The plant axis 109
The primary body 109
Velamentous roots 111
The secondary body 114

Cork tissue 114
Photosynthetic old stems 116
Fibres 116
Included phloem 117
Annual rhythm of cambial activity 120
Ecological trends in xylem structure 121
Adaptations to salinity 123
Xylem characteristics 124
Roots 124
Mangroves 126
Salt glands 130
Glands eliminating salts into the vacuole 130
Glands eliminating salts to the outside of the cells 130
Structure and function of salt glands 135
Nutritional factors 136
Proteoid roots 137
Mycorrhizae 138
Concluding remarks 140
The leaf xeromorphic xerophytes 140
Axis-xeromorphic xerophytes 141
Roots 141
Stem 142
Adaptation to salinity 143
References 144
Author index 164
Subject index 168
Index of plant names 171