Himalayan soap pod (Gymnocladus assamicus) : an ecologically and economically important tree on the brink of extinction

190 Pages·2019·7.427 MB·English

by  Choudhury, Baharul Islam, Khan, M. L.

Himalayan Soap Pod Tree (Gymnocladus
assamicus): An Ecologically and Economically
Important Tree on the Brink of Extinction

Himalayan Soap Pod Tree
(Gymnocladus assamicus):
An Ecologically and Economically
Important Tree on the Brink of
Extinction
Dr Baharul Islam Choudhury
Department of Ecology and Evolutionary Biology
University of Toronto
25 Willcocks Street, Toronto ON, M5S 3B2 (Canada)
Email: [email protected]; [email protected]
Dr Mohammed Latif Khan
Department of Botany
Dr Harisingh Gour Central University
Sagar, Madhya Pradesh (India)
Email: [email protected]
CABI is a trading name of CAB International
CABI CABI
Nosworthy Way 745 Atlantic Avenue
Wallingford 8th Floor
Oxfordshire OX10 8DE Boston, MA 02111
UK USA
Tel: [phone] Tel: [phone]
Fax: [phone] E-mail: [email protected]
E-mail: [email protected]
Website: www.cabi.org
© Baharul I. Choudhury and M.L. Khan 2020. All rights reserved. No part of this
publication may be reproduced in any form or by any means, electronically, mechanically,
by photocopying, recording or otherwise, without the prior permission of the copyright
owners.
A catalogue record for this book is available from the British Library, London, UK.
ISBN-13: 978 1 78639 198 8 (hardback)
978 1 78639 199 5 (ePDF)
978 1 78639 200 8 (ePub)
Commissioning Editor: Ward Cooper
Editorial Assistant: Emma McCann
Production Editor: James Bishop
Typeset by Spi, Pondicherry, India
Printed and bound in the UK by Severn, Gloucester
Contents
Acknowledgements ix
General Introduction xi
1 Biology, Distribution and Population Status of
Gymnocladus assamicus 1
1.1 Introduction 1
1.2 Taxonomy of G. assamicus 2
1.2.1 Taxonomic description 2
1.2.2 Floral sexuality 2
1.2.3 Hermaphrodite flower 4
1.2.4 Male flower 5
1.2.5 Fruit 5
1.3 Ethnobotanical Uses of Fruits 6
1.4 Distribution 10
1.5 Population Status of Soap Pod tree and its Associated Vegetation 15
1.6 Microclimatic Conditions 28
1.7 References 30
2 Phylogeny and Phylogeography of the Genus
Gymnocladus and its Close Relatives 37
2.1 Introduction 37
2.2 Legume Diversity in the Eastern Himalayan Region 39
2.3 Gymnocladus and its Affinity 40
2.4 Geographic Distribution of Gymnocladus and Gleditsia Species 43
2.5 Phylogenetic Relationship 45
2.5.1. The unique Umtiza clade 45
2.6 Placement of Gymnocladus and Gleditsia in the Phylogenetic Tree 49
2.7 Complex Evolutionary History of Gymnocladus and Gleditsia 51
2.8 References 52
3 Reproductive Ecology of Gymnocladus assamicus 57
3.1 Introduction 57
3.2 Breeding Systems in Plants 58
v
vi Contents
3.3 Breeding Systems in Gymnocladus assamicus 60
3.4 Materials and Methods 61
3.4.1 Study trees 61
3.4.2 Reproductive phenology and floral biology 61
3.4.3 Flower visitors 62
3.4.4 Pollen viability and stigma receptivity test 63
3.4.5 Pollen morphology 65
3.4.6 Breeding systems 65
3.5 Results 65
3.5.1 Phenology 65
3.5.2 Floral sexuality 66
3.5.3 Pollen fertility 68
3.5.4 Nectar production 68
3.5.5 Scanning election microscopy of pollen 68
3.5.6. Breeding system 68
3.5.7. Pollinator spectra 70
3.5.8 Equilibrium male frequency in the population 74
3.6 Discussion 74
3.7 Evolution of G. assamicus Breeding System 76
3.8 References 77
4 Seed Biology and Modes of Regeneration 82
4.1 Introduction 82
4.2 Materials and Methods 84
4.2.1 Pod collection and measurement of pod traits 84
4.2.2 Seed dimensions and weight 85
4.2.3 Seed morphology and anatomy 85
4.2.4 Seed viability, germination and moisture content 85
4.2.5 Seed dormancy and different treatments to
break dormancy 86
4.2.6 Seed germination at different soil depths 86
4.2.7 Seed dispersal and predation in the field 86
4.2.8 Vegetative mode of regeneration 87
4.3 Results and Discussion 87
4.3.1 Pod and seed characteristics 87
4.3.2 Seed morphometry and related properties 90
4.3.3 Seed viability, germination and moisture content 94
4.3.4 Different treatments to break dormancy 94
4.3.5 Seed germination at different soil depths 97
4.3.6 Dispersal 98
4.3.7 Seed loss, predation and damage 98
4.3.8 Vegetative mode of regeneration 101
4.4 References 101
Contents vii
5 Seedling Dynamics and Ecology of Gymnocladus assamicus 108
5.1 Introduction 108
5.2 Materials and Methods 112
5.2.1 In situ experiments 112
5.2.2 Ex situ experiments in the nursery 112
5.2.3 Performance of reintroduced seedlings in natural habitats 114
5.3 Results and Discussion 116
5.3.1 Seedling functional morphology 116
5.3.2 Survival and growth of seedlings under in situ conditions 117
5.3.3 Growth and survival of seedlings under ex situ conditions 118
5.3.4 Survival and growth of transplanted seedlings 124
5.4 Implications for Silvicultural and Conservation Practices 127
5.5 References 128
6 Conservation and Management of Plant Biodiversity
in the Eastern Himalayan Region with Emphasis on
Soap Pod Tree (Gymnocladus assamicus) 135
6.1 Introduction 135
6.2 Biodiversity in India 136
6.3 Biodiversity in Northeast India 137
6.4 State-wise Biodiversity Status in Northeast India 141
6.4.1 Arunachal Pradesh 141
6.4.2 Assam 143
6.4.3 Manipur 145
6.4.4 Meghalaya 147
6.4.5 Mizoram 152
6.4.6 Nagaland 154
6.4.7 Sikkim 155
6.4.8 Tripura 156
6.5 Future Conservation Initiatives in Northeast India 156
6.6 Effective Conservation Strategies for G. assamicus 157
6.6.1 Conservation through cultivation 158
6.6.2 Silvicultural approaches and protected area management 159
6.6.3 Community-based conservation initiatives 159
6.6.4 In vitro method of conservation 161
6.7 Future Studies 162
6.8 References 163
Index 169

Acknowledgements
This work has been accomplished with immense support and contributions from
people across different walks of life and we extend our heartfelt gratitude to all.
We sincerely thank the village headmen (Gaon Bura) and villagers of Dirang
(West Kameng) for showing interest in our research and towards conservation of
Menangmanba-shi or the soap pod tree (G. assamicus) and sharing their knowledge
during this exploration. Especially, we wish to thank Mr Sang Khandu (Barchi
village) and Mr Jam Tsering (Yewang Village) of Dirang who helped immensely
during the field work. Mr Chanda of SFRI Orchid Orchard, Dirang, assisted in
the greenhouse experiment at Dirang and we are thankful to him.
We are grateful to Dr M. Bhattacharya, (previous Director, NRC Yak, Dirang)
for providing laboratory facilities, Mr Pijush Kumar Dutta, WWF-Nature, India,
Dirang Field Office for providing field support, Dr Anwaruddin Choudhury for
input in identification of bird species, and Principal Chief Conservator of Forest,
Itanagar for logistic support during the period of work. We also acknowledge
the services received from the instrumentation division, IIT Guwahati during
SEM of pollen and seed samples. Help received from BSI Shillong and Itanagar
and SFRI Itanagar is also appreciated. It is a pleasure to acknowledge the help
received from Mr Bijit Basumatry and Mr Bironjay Basumtary during field and
laboratory work.
Special thanks to Dr Ashesh K. Das of Assam University Silchar for in-
valuable comments on earlier versions of the chapters. Guidance received
through research collaborations from Dr Shaily Menon and Dr A. Townsend
Peterson is gratefully acknowledged. We also extend our sincere gratitude to
Dr S. Dayanandan, Dr A. Arunachalam, Dr K. Arunachalam, Dr L.B. Singha,
Dr O.P. Tripathi, Dr Kh. Ashalata Devi, Dr P. Gajurel, Dr A.R. Barbhuiya and
Dr A. Paul for insightful suggestions and feedback during the entire research
journey. Thanks to Madeline Jarvis-Cross for valuable comments on English lan-
guage. We also thank the anonymous reviewers who read the book proposal and
recommended it for publication. Financial support received from the Department
of Science and Technology, Govt. of India (Sanction no. SR/SO/PS-16/2002)
is duly acknowledged.
ix