Phytoremediation Potential of Perennial Grasses

By D.P. Singh and Vimal Chandra Pandey

Phytoremediation Potential of Perennial Grasses provides readers with the knowledge to select specific perennial grass species according to site-specific needs. In addition, it demonstrates the potential opportunities for grass-based phytoremediation to yield phytoproducts, especially biomass-based bioenergy and aromatic essential oils as a green economy while in the process of remediating contaminated sites. The book brings together recent and established knowledge on different aspects of grass-based phytoremediation, providing this information in a single source that offers a cutting-edge synthesis of scientific and experiential knowledge on polluted site restoration that is useful for both practitioners and scientists in environmental science and ecology.

• Provides a holistic approach to grass-based phytoremediation, covering the ecological, economic and social issues related to its management
• Addresses the key role that grass-based phytoremediation plays in maintaining ecosystem services in polluted sites
• Includes strategies to mitigate costs related to the phytoremediation of polluted sites

• Language: English
• Publisher: Elsevier Science
• Release date: Mar 27, 2020
• ISBN: 9780128177334

D.P. Singh

Dr. Singh is Professor of Environmental Science and past director of the USIC at Babasaheb Bhimrao Ambedkar (Central) University, Lucknow, Uttar Pradesh, India. He completed his Post-doctoral Research from University College of Swansea, U.K. His research area is bioremediation and phytoremediation of contaminated sites. His research highlighting the transformation of waste into useful product by using biological resources deserves special attention as it is considered future technology for sustainable environmental development. Dr. Singh has published his research findings in international peer-reviewed journals. He has had 101+ research publication in reputed journals, 28 book chapters, and five books.

Book preview

Phytoremediation Potential of Perennial Grasses

Vimal Chandra Pandey

Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow, India

D.P. Singh

Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow, India

Contents

Cover

Title page

Copyright

Contributors

About the authors

Foreword

Preface

Acknowledgments

1: Perennial grasses in phytoremediation—challenges and opportunities

Abstract

1. Introduction to phytoremediation

2. Perennial grass genetic resources: what can they contribute toward phytoremediation?

3. Importance of perennial grasses

4. Why perennial grasses in phytoremediation?

5. Coupling phytoremediation with perennial native grasses

6. Perennial growth—an essential aspect for sustainable biomass source

7. Improvement of perennial grasses for enhanced phytoremediation

8. Perennial grass-based phytoremediation practices

9. Policy framework

10. Conclusions and future prospects

Acknowledgments

2: Vetiveria zizanioides (L.) Nash – more than a promising crop in phytoremediation

Abstract

1. Introduction

2. Morphology, reproduction, and propagation

3. Ecology and physiology

4. Geographical distribution and expansion

5. Multipurpose usage of vetiver grass

6. Limitations

7. Potential features of vetiver grass: the reason of vetiver’s success

8. Conclusions

Acknowledgment

3: The potential of Sewan grass (Lasiurus sindicus Henrard) in phytoremediation—an endangered grass species of desert

Abstract

1. Introduction to Sewan grass

2. Origin and geographical distribution

3. Ecology

4. Morphological description

5. Propagation

6. Important features of Sewan grass

7. Multiple uses

8. Phytoremediation

9. Biomass productivity of Sewan grass

10. Genetic diversity and conservation

11. Rhizospheric microbiology of Sewan grass

12. Conclusion and future prospects

Acknowledgment

4: Miscanthus–a perennial energy grass in phytoremediation

Abstract

1. Introduction

2. Miscanthus biology and taxonomy

3. Propagation

4. Easy harvesting

5. Miscanthus grass as a biofuel crop

6. Phytoremediation

7. Environmental consideration

8. Multiple uses

9. Merits and demerits of Miscanthus with SWOT analysis

10. Conclusion

Acknowledgment

5: Phragmites species—promising perennial grasses for phytoremediation and biofuel production

Abstract

1. Introduction

2. General aspects of Phragmites species

3. Important features of Phragmites species

4. Multiple uses and management consideration

5. Conclusion

6. Future perspectives

Acknowledgments

6: Feasibility of Festuca rubra L. native grass in phytoremediation

Abstract

1. Introduction

2. General aspects of F. rubra L.

3. Ecorestoration techniques

4. The role of F. rubra L. in phytoremediation of contaminated sites

5. Physiological and morphological response of F. rubra L.

6. Conclusion and future outlook

Acknowledgments

7: Reed canary grass (Phalaris arundinacea L.): coupling phytoremediation with biofuel production

Abstract

1. Introduction

2. Origin and geographical distribution

3. Ecology

4. Botanical description

5. Propagation

6. Main features of reed canary grass in relation to phytoremediation

7. Multiple uses of reed canary grass

8. Conclusions and future prospects

Acknowledgments

8: Switchgrass—an asset for phytoremediation and bioenergy production

Abstract

1. Introduction

2. General aspect of switchgrass

3. Multiple uses

4. Limiting factors

5. Phytoremediation

6. Bioenergy production

7. Carbon sequestration

8. Physiological adaptation

9. Conclusion and future perspectives

Acknowledgment

9: Cymbopogon flexuosus—an essential oil-bearing aromatic grass for phytoremediation

Abstract

1. Introduction

2. Ecology

3. Origin and distribution

4. Botanical description

5. Propagation

6. Important aspects in relation to phytoremediation

7. Multiple uses of lemongrass

8. Medicinal use

9. Other commercial uses

10. Socio-economic development

11. Implementation strategies

12. Conclusion and future prospects

10: Saccharum spp.—potential role in ecorestoration and biomass production

Abstract

1. Introduction

2. Ecology

3. Morphological description

4. Geographic distribution

5. Propagation

6. Multiple uses

7. Role of Saccharum spp. in ecological restoration of waste land

8. Role of Saccharum spp. in ecological restoration of fly ash dumps

9. Biomass and bioenergy production

10. Conclusion

Acknowledgments

11: Bermuda grass –its role in ecological restoration and biomass production

Abstract

1. Introduction

2. Origin, geographical distribution, and occurrence

3. Ecology

4. Morphology and propagation

5. Abiotic stress tolerance of Bermuda grass

6. Multiple uses

7. Conclusion

Acknowledgments

12: Moso bamboo (Phyllostachys edulis (Carrière) J.Houz.)–one of the most valuable bamboo species for phytoremediation

Abstract

1. Introduction

2. Bamboo-provisioned ecosystem services

3. Major role of bamboo toward nature sustainability

4. Future research prospects

5. Conclusions

13: The application of Calamagrostis epigejos (L.) Roth. in phytoremediation technologies

Abstract

1. Introduction

2. Morphology, propagation, and reproduction

3. Ecology

4. Distribution and expansion

5. Suppression and control

6. Phytoremediation

7. Other uses

14: Potential of Napier grass (Pennisetum purpureum Schumach.) for phytoremediation and biofuel production

Abstract

1. Introduction

2. Origin and geographical distribution

3. Ecology

4. Taxonomy and morphological description

5. Propagation

6. Important features of Napier grass

7. Multiple uses

8. Phytoremediation

9. Bioenergy production

10. Conclusion and future prospects

Acknowledgment

15: Role of microbes in grass-based phytoremediation

Abstract

1. Introduction

2. Perennial grasses: suitable agents for phytomanagement

3. Phytoremediation strategies

4. Importance of microbial role in grass–based phytoremediation

5. Phytoremediation of different types of pollutants through perennial grass species

6. Pros and cons of phytoremediation with perennial grasses

7. Conclusions

16: Case studies of perennial grasses—phytoremediation (holistic approach)

Abstract

1. Introduction

2. Potential case studies of perennial grasses in phytoremediation

3. Conclusion and future prospects

Acknowledgment

Index

Copyright

Elsevier

Radarweg 29, PO Box 211, 1000 AE Amsterdam, Netherlands

The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom

50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States

Copyright © 2020 Elsevier Inc. All rights reserved.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions.

This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).

Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.

Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.

To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.

Library of Congress Cataloging-in-Publication Data

A catalog record for this book is available from the Library of Congress

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library

ISBN: 978-0-12-817732-7

For information on all Elsevier publications visit our website at https://www.elsevier.com/books-and-journals

Publisher: Joe Hayton

Acquisitions Editor: Marisa LaFleur

Editorial Project Manager: Lena Sparks

Production Project Manager: Omer Mukthar

Cover Designer: Matthew Limbert

Typeset by Thomson Digital

Contributors

Jitendra Ahirwal,     Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, India

Gordana Gajić,     Department of Ecology, National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia

Ksenija Jakovljević,     University of Belgrade, Faculty of Biology, Institute of Botany and Botanical Garden, Belgrade, Serbia

Shivakshi Jasrotia,     Department of Clinical Research, Delhi Institute of Pharmaceutical Sciences and Research, Government of N.C.T. of Delhi, India

Slobodan Jovanović,     University of Belgrade, Faculty of Biology, Institute of Botany and Botanical Garden, Belgrade, Serbia

Anuradha Kumari,     School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India

Deblina Maiti,     Central Institute of Mining and Fuel Research, Dhanbad, Jharkhand, India

Ambuj Mishra,     School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India

Miroslava Mitrović,     Department of Ecology, National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia

Vimal Chandra Pandey,     Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India

Divya Patel,     Department of Biotechnology, Sant Gadge Baba Amravati University, Amravati, Maharashtra, India

Pavle Pavlović,     Department of Ecology, National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia

Ashish Praveen

Plant Ecology and Environmental Science Division, National Botanical Research Institute, Lucknow, Uttar Pradesh

Department of Botany, Markham college of Commerce, VBU, Hazaribag, India

Apurva Rai,     Plant Ecology and Environmental Science Division, National Botanical Research Institute, Lucknow, Uttar Pradesh, India

Dragana Ranđelović,     University of Belgrade, Faculty of Mining and Geology, Department for Mineralogy, Crystallography, Petrology and Geochemistry; Institute for Technology of Nuclear and other Mineral Raw Materials, Belgrade, Serbia Belgrade, Serbia

Madhumita Roy,     Department of Microbiology, Bose Institute, Kolkata, India

Purabi Saikia,     Department of Environmental Sciences, School of Natural Resource Management, Central University of Jharkhand, Ranchi, India

Sudhish Kumar Shukla,     Department of Chemistry, Manav Rachna University, Faridabad, Haryana, India

Ashutosh Kumar Singh,     CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunan, China

D.P. Singh,     Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India

About the authors

Vimal Chandra Pandey Dr. Vimal Chandra Pandey is currently a CSIR-Senior Research Associate (CSIR-Pool Scientist) in the Department of Environmental Science at Babasaheb Bhimrao Ambedkar University, Lucknow, India. Dr. Pandey is well recognized internationally in the field of phytomanagement of fly ash/polluted sites. His research includes phytoremediation and revegetation of fly ash dumpsites, heavy metal polluted sites, and restoration of degraded lands with special reference to raising rural livelihoods and maintaining ecosystem services. He is a recipient of a number of awards/honors/fellowships such as (CSTUP-Young Scientist award, DST SERB-Young scientist award, UGC-Dr. DS Kothari Postdoctoral Fellowship and CSIR-SRA (Pool Scientist) Award, and a member (MNASc) of National Academy of Sciences, India (NASI), Commission Member of IUCN-CEM Ecosystem Restoration, and a member of the BECT’s Editorial Board. He has published more than 50 peer-reviewed articles in reputed international journals and 11 book chapters. He is the author and editor of two books published by Elsevier with several more forthcoming. He is also serving as a potential reviewer for several journals from Elsevier, Springer, Wiley, Taylor & Francis, etc. and received Elsevier Reviewer Recognition Awards from the editors of many journals. ORCID iD: https://orcid.org/0000-0003-2250-6726, Google Scholar: https://scholar.google.co.in/citations?user=B-5sDCoAAAAJ&hl.

D.P. Singh Dr. D.P. Singh is a professor of Environmental Science at Babasaheb Bhimrao Ambedkar University, Lucknow, and obtained his PhD from Department of Botany, Banaras Hindu University, Varanasi, India. He has been the recipient of Commonwealth post-doctoral fellowship and worked in the University College of Swansea (UK). His research has majorly focused in the area of wastewater treatment, microbiology, stress physiology, bioremediation, and bioenergy options. He has received several honors and awards to his credit. Dr. Singh has published more than 135 research publications in high impact factor journals of national and international repute. He has supervised more than 24 PhD students and several MSc and MTech students for their research work. He has delivered invited lectures in different seminars and symposia and served as a principal investigator for several governments funded projects. Dr. Singh has published five books in the field of Environmental Microbiology and Biotechnology, Stress Physiology, and Sustainable Management of Soil and Water.

Foreword

Phytoremediation Potential of Perennial Grasses is an important collection of the precise literature in the form of chapters that reveal applied and feasible ways in remediating polluted lands through multipurpose perennial grasses from the ecologically to socio-economically. The tactics are also such that offer many co-benefits, including the stabilization of pollutants. Aid to the green economy is mainly notable. Phytoproducts, for instance, biofuels (biogas and bioethanol), essential oils of aromatic grasses, ornamental grasses, and pulp-paper grasses as well as different derived grass products, are significant additional benefits. Presently, there is an urgent need to develop phytomanagement of polluted lands through perennial grasses that benefit society directly and indirectly. A multipurpose perennial grass-based phytoremediation is a fantastic example of environmental sustainability that has a constructive future across the nations. Native perennial grasses are suitable candidates for use in sustainable phytoremediation of polluted sites due to being nurse species and having good adaptive strategies.

This book explores the phytoremediation potential of perennial grasses that will tackle to link the gap between phytoremediation and grass bioeconomy through phytomanagement, to address the challenge of remediation of the increasing number and area of polluted sites through valuable grasses with least inputs, low risk, and minimum maintenance toward maintaining ecosystem services and raising rural livelihoods. This book is therefore focused on recent findings and strategies of the most valuable perennial grasses toward phytoremediation of polluted sites with multiple benefits. Moreover, it offers the description of morphological; ecology, physiology, origin, geographical distribution, expansion, and propagation as well as important features of the grass regarding phytoremediation.

I appreciate the efforts of authors Dr. Vimal Chandra Pandey and Prof. D.P. Singh, in bringing out this valuable edition through the leading global publisher, Elsevier Publishing, with 16 chapters covering various aspects of the Phytoremediation Potential of Perennial Grasses. I hope the book will be a noteworthy asset for PhD scholars, environmental scientists, researchers, practitioners, policy makers, entrepreneurs, and other stakeholders alike.

Prof. D.P. Singh

Chairman

University Grants Commission

New Delhi

10th January, 2020

Preface

Ever-increasing numbers and areas of industrially polluted sites is a major concern across the nations and have resulted in environmental pollution. The major challenge is to develop new and cost-effective solutions to decontaminate polluted sites. In this regard, the plants-based remediation especially grasses is a promising and cost-effective approach for the environmental clean up on a large scale.

Over two decades of scientific development in phytoremediation, its reliability among stakeholders has not yet been achieved. They remain doubtful about its current applicability or future prospects. To overcome this challenge, the book will address grass-based phytoremediation with green economy. It is thus desirable to explore commercial and perennial grass-based phytoremediation. Grasses are well known for their work as nurse plants. Nurse plants are considered not only to play a key role in recovering the properties and functions of the primary ecosystem, but also to drive succession in poor environments on the early stage of restoration. Thus, perennial grass-based phytoremediation can play a key role in remediation of polluted sites as well as maintaining ecosystem services.

This book will be useful for practitioners to select specific perennial grass species according to site-specificity of the contaminated site. As this book will show, there are clearly some potential opportunities in grass-based phytoremediation that also yield phytoproducts especially bioenergy (biomass) and aromatic essential oils as green economy while remediating contaminated sites. This book will provide new knowledge and insights of the phytoremediation potential of perennial grasses across the nations with economic returns. In this book, an attempt has been made to popularize grass-based phytoremediation among ecological engineers, environmental scientists, practitioners, policy makers, and stakeholders. It is first book on Phytoremediation Potential of Perennial Grasses and will be a valuable asset to the students, researchers, practitioners, policy makers, stakeholders alike.

Vimal Chandra Pandey, Author;

D.P. Singh, Author

Acknowledgments

We sincerely wish to thank Candice Janco and Marisa LaFleur (Acquisitions Editor), Lena Sparks (Editorial Project Manager), and Swapna Praveen (Copyrights Coordinator) from Elsevier for their excellent support, guidance, and coordination of this fascinating project. We would like to thank all the reviewers for their time and expertise in reviewing the chapters of this book. Vimal Chandra Pandey is grateful to the Council of Scientific and Industrial Research, Government of India, New Delhi for Senior Research Associateship under Scientist’s Pool Scheme (Pool No. 13 (8931-A)/2017). Finally, we must thank our respective families for their unending support, interest, and encouragement, and apologize for the many missed dinners!

1

Perennial grasses in phytoremediation—challenges and opportunities

Vimal Chandra Pandeya,*

Deblina Maitib

a    Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India

b    Central Institute of Mining and Fuel Research, Dhanbad, Jharkhand, India

*    Corresponding author

Abstract

Polluted sites, coal mine spoil, fly ash deposits, red mud dumpsites, and other dumpsites are a worldwide problem, contaminating nearby communities. These disposal sites are major source of environmental pollution. Phytoremediation has been popularized to remediate heavy metal-contaminated sites in the past few decades due to its cost-effectiveness and environmental sustainability. In this regard, the use of grasses is of utmost importance due to their rapid growth, large biomass, resistance to phytotoxicity, and genotoxicity by heavy metals as compared to herbs, shrubs, and trees. Phytostabilization by the compact root system of grasses retards the formation, mobility, and bioavailability of hazardous leachates by high uptake and accumulation of the complex mixtures of heavy metals within them. Such grasses prevent natural succession by weeds and other plants leading to safe grazing by animals. Among the members of Poaceae, aromatic grasses are economically important plants due to their essential oil production. They rank higher than edible grasses, which are susceptible to heavy metal contamination in their edible parts. This chapter describes the role of grasses in ecological and socio-economic sustainability of phytoremediation of polluted sites.

Keywords

ecological restoration

carbon sequestration

multiple uses

biomass production

genetic resources

1. Introduction to phytoremediation

Phytoremediation is a cost-effective green technology which exploits the ability of some plant species to uptake, metabolize, accumulate, and detoxify heavy metals or other harmful organic or inorganic pollutants from contaminated soil and waste materials (Besalatpour et al., 2008; Langella et al., 2014; Gołda and Korzeniowska, 2016; Pandey and Bajpai, 2019). This process is often a part of the integrated approach used during ecological restoration programs of degraded lands. The plants which are preferred for this process are chosen on the basis of their growth potential, massive biomass development, invasive nature, high pollutant accumulation potential in their roots or shoots, tolerance from the pollutants, and pollutant detoxification potential (De Koe, 1994; Pandey, 2012a, b; Pandey et al., 2014; Pandey et al., 2015a; Niknahad Gharmakher et al., 2018). Advantageously, the plants of the grass (Poaceae) family have demonstrated a huge potential in this aspect as various studies in literature using grasses have shown successful results in all of the earlier-mentioned criteria (Pandey et al., 2012b, 2015c; Pandey and Singh, 2015; Pastor et al., 2015; Verma et al., 2014). These grasses are often classified as accumulators and excluders on the basis of their tolerance potential to metals or pollutants. Accumulator plants have the potential to remain metabolically stable in conditions in which the concentrations of metals in their photosynthetic parts are relatively higher than the maximum allowable limits (Elekes and Busuioc, 2011; Houben and Sonnet, 2015; Gołda and Korzeniowska, 2016). This is because these plants efficiently counter the oxidative stress generated due to high metal accumulation (Sharma et al., 2018). On the other hand, excluder grass plants accumulate pollutants either in their roots or change them into complexes in the root zone, but restrict the pollutant movement up to the aerial parts. Roots of these plants are more tolerant to metals than shoots; the up taken metals are often accumulated inside the root cell vacuoles after detoxification (Fatima et al., 2018; Pastor et al., 2015). The processes concerning the rhizospheric metal bioavailability and their uptake by the adventitious roots of the grasses have been shown in Fig. 1.1. The bio-available metals are partitioned between the solid and solution phase around the soil particles by chemical reactions such as adsorption, complexation, precipitation, and redox reactions. The metals in solution phase are up taken by the roots through the root membranes. Metal uptake is also guided by active (symplastic movement of metals across cell membranes) or passive processes (movement of metal along cell walls) and various membrane protein metal transporters which transport the non-essential metals in addition to essential metals which are useful for biosynthetic processes. The transport process is then followed by metabolization, detoxification, and compartmentalization of the metals and varies from species to species (Adriano et al., 2004; Besalatpour et al., 2008; De Koe, 1994; Sharma et al., 2018).

Figure 1.1   Mechanisms of metal uptake by the grass roots from soil. Modified from Adriano et al., 2004.

Additionally, grasses possess an elaborate root structure, highly propagating underground rhizomatous stems which bind the soil to prevent erosion and leaching of contaminants. These structures also assist in rapidly covering vast acres of contaminated lands to form a thick green cover (Aprill and Sims, 1990; Langella et al., 2014; Subhashini and Swamy, 2013; Verma et al., 2014). In addition to having elaborate fibrous roots and rhizomes, some other general characteristics are simple, exstipulate, sessile leaves having parallel venation, tubular sheath at leaf base surrounding the internodes, sessile inflorescences having compound spikes with bracteates containing incomplete, zygomorphic, hypogynous flowers, 3–6 stamens having long filaments, and dithecous anthers in androecium, single carpel with a short style, bifid stigma, and a superior ovary having a single ovule with basal placentation in gynoecium, fruits having pericarp fused with seed coat and monocot seeds embedded in endosperm (Jeguirim et al., 2010). Thus, utilization of grasses as initial colonizers ultimately aids in developing an aesthetic landscape (Subhashini and Swamy, 2013). Specifically, aromatic grasses have proven to be much more efficient subjects for phytoremediation of a range of pollutants from waste lands and in turn benefits from ecological to socio-economic importance (Verma et al., 2014; Pandey and Singh, 2015; Pandey et al., 2019). Some widely cultivated aromatic grasses belong to Vetiveria sp. (Vetiver grass) and Cymbopogon sp. (Lemon grass) genera (Desai et al., 2014). One of the products yielded by aromatic grasses is essential oils which advantageously do not get contaminated by the pollutants even if the metal has been up taken in the plant body. The reason for such results is that oil extraction from the plant parts is done through steam distillation. Many studies have also proven that oil production by such plants is not affected significantly under various abiotic stresses (Gupta et al., 2015; Aftab et al., 2011; Verma et al., 2014; Pandey and Singh, 2015; Pandey et al., 2019).

Globally, millions of hectares of land is currently lying barren and has been extensively contaminated due to various industrial activities (Zurek et al., 2013). However, very meagre studies have been done in the aspect of possibilities of grass growth on such areas as phytoremediating agents. Till now, the hyperaccumulation property or phytoextraction of metals has mostly been identified in dicotyledonous herbs and shrubs, which are mainly annual in their life cycle (Adriano et al., 2004; Antoniadis et al., 2017). Biomass harvest of these species will thus be a single event with confined potential for further growth as it mainly occurs from the apical meristems which gets harvested during biomass cropping (Antoniadis et al., 2017). However, the regeneration potential of the grasses is confined to the base of the shoot origination above the root system, which doesn’t get diminished even after biomass harvest. The perennial life cycle of these plants are an advantage to the phytoremediation process as the shoot biomass can be harvested a number of times which adds to continuous phytoextraction of pollutants from the contaminated substrate (Awasthi et al., 2017; Gołda and Korzeniowska., 2016). Natural colonization in an ecosystem is often witnessed by the presence of grasses as initial successors; which are also termed as native to the particular area. They have the potential to regrow and adaptable to a variety of environmental stresses; such plants should constitute the pioneer species for plantation on contaminated lands which outweighs the concept of planting edible plants, as the inclusion of latter plants doesn’t declines the transmission of pollutants to the food chain through grazing livestock. Subsequently over years of grass plantation, the remediated land could be utilized to end uses like a productive agricultural land, esthetic tourist place, or left as such to continue to become a part of the landscape (Awasthi et al., 2016; De Koe., 1994; Subhashini and Swamy., 2013).

2. Perennial grass genetic resources: what can they contribute toward phytoremediation?

Continuous increase in the percentage of industrially degraded lands across the world requires an effective strategy of phytoremediation (Zurek et al., 2013). Sometimes, monoculture of grass species is less efficient in remediating a contaminated site compared to a mixed culture. Mixed crops of the perennial grasses can restore the soil quality, biodiversity, and energy flow of degraded ecosystems (Creutzig et al., 2015; Saha and Kukal., 2015). In this context, an appropriate genetic resource material is necessary for developing a perpetuating vegetation cover on such sites (Zorica et al., 2005). Though indigenous and site-specific grasses have often been used, yet specific exotic grasses can also perform better on many degraded sites (Sharma et al., 2018). Thus before a phytoremediation program supply of planting material should be organized for specific sites which may include a mixture of grass species. Efforts should be carried out to document the genetic resources of the grasses for their utilization in remediation programs (Sharma et al., 2018; Zorica et al., 2005). Some studies have denoted that perennial grasses are most important plants for phytoremediation due to their huge biomass production potential, low requirement of fertilizers, and ability to grow even on less fertilized soils (Zurek et al., 2013; Gołda and Korzeniowska, 2016). In addition they provide multiple benefits like improvement in soil structure and quality, reduction in erosion, and increase in biodiversity. Growing perennial grasses on degraded lands are much more sustainable than regular agricultural practices because the later may promote soil erosion and would not yield the adequate economic return. Additionally, on an ecosystem point of view, grasses are a group of ecologically dominant plant species, because they are found covering extensively on any barren or degraded land (Awasthi et al., 2017; Singh et al., 2018; Subhashini and Swamy, 2013).

The overall genetic resources of the perennial grass family are categorized into (1) wild varieties of the domesticated grass species of same genus, (2) seminatural form of the domesticated grass species, and (3) domesticated populations of the plant adapted in a specific region, also known as ecotype and the cultivars undergoing constant breeding techniques (Sokolovic et al., 2017). It is the largest, monocotyledonous angiosperm family of Poales order, with a variable number of species as per the previous literature. The number of species varies from 7500 to 11000, grouped into 650–785 genera, 25–50 tribes, and 3–12 subfamilies (Boller and Greene, 2010; Gibson, 2009). As also stated earlier, the grass family is also categorized into aromatic and non-aromatic grasses. The later ones are also known as pasture grasses (Cynodon dactylon); some are also included in food crops (Triticum aestivum, Zea mays, Oryza sativa, Hordeum vulgare) and in groups of trees (Dendrocalamus sp., Bambusa sp.) (Boller and Greene, 2010; Delgado-Caballero et al., 2017; Sokolovic et al., 2017). Diverse list of perennial grasses which can be used as genetic resources for phytoremediation of waste lands are given in Table 1.1. Here, we are describing only 13 most important grasses for phytoremediation along with their multiple uses (Table 1.2). They are widely known by their common names which are: Vetiver, Sewan grass, Miscanthus, Common reed, Red fescue, Reed canary grass, Switch grass, Lemon grass, Wild cane, Bermuda grass, Eurasian grass, Moso bamboo, and Elephant grass. All these grass species have been reported as a potential candidate for phytoremediation in various studies. The marketable products from these grasses and multiple utilizations have been explored in the present chapter, while their sustainability toward phytoremediation of waste lands will be analyzed in details in the chapters.

Table 1.1

Table 1.2

2.1. As a phytoremediator

Grasses specifically perennial grasses have been reported to reduce metal toxicity and induce phytoremediation by various authors in literature (Cui et al., 2018; Ghosh et al., 2015; Gołda and Korzeniowska, 2016; Suchkova et al., 2010; Yasin et al., 2015; Ziarati et al., 2015). Perennial grasses are metal-tolerant plants and are generally terrestrial, herbaceous or but may be woody (Bamboo) or aquatic in nature. Reportedly they accumulate or phytostabilize metals in their roots and eventually reduces the concentration of metals from the soil. For example, Madejon et al. (2002) reported that Bermuda grass (Cynodon dactylon) can stabilize spill affected soils while Tall fescue showed Pb phytoextraction and grew effectively in Pb contaminated soil without reduction in biomass (Begonia et al., 2005). Thomas et al. (2014) reported that Bermuda grass roots release exudates which can form complexes with Pb. Apart from accumulating heavy metals, various grasses have been reported to degrade hydrocarbons. For example, Efe Sunday and Ephram (2014) showed that Axonopus grass species can phytoremediate hydrocarbons from soil and can be effectively grown throughout the globe. Such characteristics of tolerance to wide range of climatic conditions are an advantage of the grass community over herbs, shrubs, and trees for utilization in phytoremediation. Some more characteristics which make grasses suitable for phytoremediation are (1) presence of phytoliths in some grasses which are siliceous compounds present in epidermal cells; they impart resistance against many abiotic stresses like metal toxicity, (2) drought-resistant nature, and (3) feedstock for bio-energy and bio-products (Singh et al., 2018; Talik et al., 2018).

2.2. Ornamental grasses in park

Ornamental grasses have become increasingly popular for the past few years because they are adaptable to a wide range of climatic conditions including exceptionally wet or dry environment, and have wider utilization area. In addition, these grasses require minimum maintenance, have less pest problems compared to other herbs, and able to grow in problematic soils on which other ornamental plants are unable to grow (Davidson and Gobin, 1998). Their myriads of useful properties have attracted the community of Landscape architects, designers, and nurserymen for developing an aesthetic landscape (Gao et al., 2008). They can be used for developing ground covers, edging borders, container planting, and erosion control. Some of them have special foliage colors which can draw the attention of wildlife specially butterflies and birds (Liu et al., 2012). Studies have also shown that ornamental grasses can also be adopted for phytoremediation of contaminated soils. For example, Festuca arundinacea can efficiently reduce total petroleum hydrocarbons (TPH) from 10,000 mg kg−1 TPH contaminated soil. Italian ryegrass (Lolium multiflorum) could grow effectively in soil having increasing Cd concentration (Liu et al., 2013). Some other grasses which have been screened as per their adaptability, utilization in terms of growth, stress resistance, and ornamental value are Nassella tenuissima, Cortaderia selloana, Saccharum arundinaceum, Panicum virgatum, Carex albula, C. chungii, Dianthus gratianopolitanus, S. ravennae, C. muskingumensis, Miscanthus sinensis, Arundo donax, M. sinensis, Chasmanthium latifolium (Gao et al., 2008). Davidson and Gobin (1998) reported Andropogon gerardii, Calamagrostis epigejos, Carex sp., Erianthus ravennae, Festuca hervierri, Festuca lemanii, Molinia caerulea, Panicum virgatum, Saccharum ravennae, and Spartina pectinata to have very high horticultural value and visual appeal. They were evaluated under field conditions for a period of 4 years and assessed on the basis of their survival, growth, and development in colder regions.

3. Importance of perennial grasses

The perennial grasses which will be discussed in the present book have a myriad of utilization aspects which have been classified into ecological, societal, and economic aspects. In short, ecological aspects comprise the use of the grasses for restoration, phytoremediation, climate change mitigation, biodiversity conservation, wild life shelter, soil erosion control carbon sequestration, providing ecological corridors. Societal aspects include their utilization as raw material for crafts, huts and animal shades, fodder, cultural programs, rope manufacturing; while economic aspects include their role in bioenergy, medicine, essential oil, pulp and paper manufacturing industry compared to their cultivation costs (Fig. 1.2). These aspects have been discussed in detail as follows:

Figure 1.2   Ecosystem services provided by perennial grasses.

3.1. Ecological aspects

3.1.1. Restoration

Restoration of degraded environments often gets limited due to harsh environmental conditions. These effects can be minimized by using nurse plants which can improve the performance of nearby target species. The later procedure is known as facilitation, which is the benefit caused to some plants toward their establishment from the closely associated neighbors. Grasses have enormous potential to be included in nurse plants in restoration management procedures as per promising experimental results (Padilla and Pugnaire, 2006). To cite a few examples, in one study the grass Calamagrostis epigejos showed greater dominance and survival potential on bare ash deposits due to its multiple tolerances to the conditions and competitive ability (Mitrovic et al., 2008). Another grass Miscanthus can be used to cover the soil for a longer period as because the inputs of organic matter from the shedded leaves are expected to increase the soil organic matter and improve soil structure, compared to other arable crops. Studies have reported that the humus content, cation exchange capacity, and water retention capacity of the soil increased under a 4–8 year old Miscanthus plantation. A full-grown stand of Miscanthus accumulates after 2–3 years yields 8–20 tons of below-ground (0–40 cm) and above-ground dry matter per hectare respectively. The dense root mat can penetrate up to a depth of 2.5 m and prevent leaching of ions to the groundwater table (Jeguirim et al., 2010). In another study, Maiti and Maiti (2015) could successfully grow Cymbopogon citratus in a grass-legume mixture for ecorestoration of a steel industry waste dump. The grass species having potential for fly ash dumps’ restoration is identified on the basis of their ecological and socio-economic significance as well as dominance at ash dumpsites to support rural livelihoods. These are Saccharum spontaneum, Cynodon dactylon, Saccharum bengalense (syn. Saccharum munja), Dactyloctenium aegyptium, Cyperus esculentus, Fimbristylis bisumbellata, and Eragrostis nutans. S. spontaneum and S. munja have great ability to colonize on bare fly ash deposits. Therefore, they can be exploited as a valuable genetic grass resource for ecological restoration (Pandey, 2015; Pandey et al., 2015b, 2015c).

3.1.2. Phytoremediation

Various studies have also suggested the phytoremediation potential of the grass species. Randelovic et al. (2018) reported that Calamagrostis epigejos can uptake a significant amount of the available metals from soil in its roots, which shows phytostabilization. Phragmites grass species are one of the best plants which can remediate pollutants from contaminated soil or wastewater. Nayyef Alanbary et al. (2018) reported P. karka’s ability to phytoremediate sand contaminated with hydrocarbons of crude oil sludge. Aromatic grasses on the other hand are recently being promoted for phytoremediation due to their economic value, adaptability, remediation potential, and negligible contamination of the marketable products. China et al. (2014) reported that Cymbopogon citratus can phytostabilize Cu from its mine tailings in presence of amendments. Gautam and Agarwal (2017) reported that C. citratus grown on a mixture of soil-sludge-red mud could give better oil yields while the metals in the oil were within Food Safety and Standards Authority of India limits in spite of the higher metal levels in leaves. Similarly, Tall Fescue intercropped with alfalfa showed better removal of soil polyaromatic hydrocarbons than monoculture of alfalfa (Sun et al., 2011). The remediation and utilization of contaminated sites for sustainable development is possible through phytomanagement, desired globally. Market opportunities in phytoremediation are pressing need for environmental remediation with economic return. In this perspective, aromatic grasses have been considered more than promising crop for phytoremediation programs. As they are safe and their main product essential oil is free from the metal toxicity risk and is unpalatable to herbivores. Profitable and effective phytoremediation requires a collection of suitable aromatic grass species that are stress tolerant and produce high yield of essential oil under such stressed environments (Verma et al., 2014; Pandey and Singh, 2015; Pandey et al., 2019).

3.1.3 Climate change mitigation

The most prominent factor, which is driving climate change and global warming are the increased atmospheric concentrations of greenhouse gases (GHGs). The main GHGs after water vapor is carbon dioxide (CO2). The present atmospheric concentration of CO2 is 38% higher than that existed during the preindustrial era, that is, 387 ppm. The average global surface temperature has been projected to increase by 1.5–5.8°C by the end of the 21st century (Stavi and Lal, 2013). In this context, the immediate benefit of biomass production by growing perennial grasses is the sequestration of atmospheric CO2 in the shoot and root. Additionally, the grasses, which are an important source of bio-energy feedstock, are an added advantage which can replace fossil fuels. Further, these perennial grass biomasses are also renewable or appropriately renewable source of energy (Creutzig et al., 2015). It has also been reported that perennial grass bio-fuel crops have more carbon storage potential and lower N2O emission potential than agricultural crops. Thus, the climate changes mitigation potential of perennial grasses showing bio-energy production is the most suitable option and can accomplish many solutions simultaneously, namely, abatement of CO2 emissions, mitigation of global warming, tropical deforestation, and fossil fuel depletion (Anderson-Teixeira et al., 2012).

3.1.4. Biodiversity conservation

Cultivation of perennial grasses and biomass production can also increase biodiversity of the area by developing the habitat heterogeneity (Berendse et al., 2015). Perennial bio-energy grass cultivation can gradually develop diversity of flora and fauna in the area, apart from other ecosystem services to the local people. Rendering of ecosystem services by these cultivation systems will indirectly reduce biodiversity loss from the nearby natural ecosystems by decreasing the anthropogenic pressure. Dominance of rhizomatous perennial grasses can mitigate nutrient imbalance, which is one of the major cause which affects biodiversity in degraded ecosystems (Bai et al., 2010).

3.1.5 Wild life shelter

According to reports, dense field of perennial grasses such as Saccharum spontaneum, Cynodon dactylon, Cyperus esculentus, and Fimbristylis umbellata also increase countryside faunal biodiversity and provides home to wild animals like Indian rhinoceros (Singh et al., 2018). Similar studies have been reported for Panicum virgatum (Trocsanyi et al., 2009). Tall stands of Miscanthus, which have attained a height of more than 4 m have a considerable visual impact and serves as a habitat for more number of larger birds and mammals than other herbaceous crops as the grass vegetation harbor more ecological niches (Lewandowski et al., 2000).

3.1.6 Soil erosion control

Perennial grasses provide ground cover throughout the year and have enormous potential in soil conservation and erosion control. This is in virtue of their massive root system, which binds soil particles which act as porous vegetative barrier on sloppy lands and are an alternative to cost-intensive soil physical structures. Functionally, the vegetative barriers perform similar to soil physical structures by reducing soil erosion (Chowdhury et al., 2009). Festuca rubra has been extensively used to prevent erosion and stabilize slopes, hillsides, irrigation channels, and banks (Strausbaugh and Core, 1977). Phalaris arundinacea is also a cool-season, perennial grass, which is also used for soil stabilization as well as forage production (Lavergne and Molofsky, 2004). Alternatively, Lasiurus sindicus is a warm season grass of the Indian deserts, which develops a good rangeland and stabilizes blowing sand dunes (Chowdhury et al., 2009).

3.1.7 Carbon sequestration

Higher biomass developing perennial grasses reduces carbon in the atmosphere by rendering a dual role of substituting fossil fuels as well as carbon sequestration in the soil through their deep root system. Higher biomass production of such grasses is desirable not only for bio-energy but also for carbon sequestration because more biomass leads to more carbon storage (Creutzig et al., 2015; Saha and Kukal, 2015). For example, Miscanthus x giganteus plantation which is a bio-energy yielding grass can give 13 ton shoot dry matter ha−1 year−1 and 21 ton root dry matter ha−1 year−1; while the total carbon mitigated by this crop is 7 ton ha−1 year−1 depending on the time of harvest (Clifton-Brown et al., 2007). Similarly, Phalaris arundinacea gives a biomass of 8 ton ha−1 (Zhou et al., 2011). Phyllostachys edulis yields an aboveground biomass of 138 ton ha−1 which is the highest range of above-ground biomass yielded among all the bamboo communities in the world. The net production of this bamboo species is also similar to the forest productivity under same climate conditions, which again proves the fact that perennial grasses can not only phytoremediate polluted sites but are also important for inducing carbon sequestration (Isagi et al., 1997). Vetiveria zizanoides is also an indispensable plant with respect to soil carbon sequestration as well as erosion control due to its deep root system. Comparatively, the amount of carbon sequestered by the grass in its biomass is 15 ton ha−1 year−1. Additionally, it also gives an economically important essential oil from its roots, which is used in perfumery industry. The deep root system of the grass contributes in nutrient sequestration from wetlands and also prevents their leaching. Lignocellulosic biomass of high yielding perennial grasses can also be pyrolyzed to obtain high carbon bio-char which can be used as a