The Plant Family Brassicaceae ENVIRONMENTAL POLLUTION VOLUME 21 Editors Brain J. Alloway, Department of Soil Science, The University of Reading, U.K. Jack T. Trevors, School of Environmental Sciences, University of Guelph, Ontario, Canada Editorial Board I. Colbeck, Interdisciplinary Centre for Environment and Society, Department of Biological Sciences, University of Essex, Colchester, U.K. R.L. Crawford, Food Research Center (FRC) 204, University of Idaho, Moscow, Idaho, U.S.A. W. Salomons, GKSS Research Center, Geesthacht, Germany For further volumes: http://www.springer.com/series/5929 Naser A. Anjum l Iqbal Ahmad M. Eduarda Pereira l Armando C. Duarte Shahid Umar l Nafees A. Khan Editors The Plant Family Brassicaceae Contribution Towards Phytoremediation Editors Naser A. Anjum Iqbal Ahmad Centre for Environmental and Centre for Environmental and Marine Marine Studies (CESAM) & Studies (CESAM) & Department Department of Chemistry of Chemistry and Biology University of Aveiro University of Aveiro 3810-193 Aveiro 3810-193 Aveiro Portugal Portugal M. Eduarda Pereira Armando C. Duarte Centre for Environmental and Centre for Environmental and Marine Studies (CESAM) & Marine Studies (CESAM) & Department of Chemistry Department of Chemistry University of Aveiro University of Aveiro 3810-193 Aveiro 3810-193 Aveiro Portugal Portugal Shahid Umar Nafees A. Khan Department of Botany Department of Botany Faculty of Science Faculty of Life Sciences Hamdard University Aligarh Muslim University New Delhi, 110062 Aligarh 202002 India Uttar Pradesh, India ISSN 1566-0745 ISBN 978-94-007-3912-3 ISBN 978-94-007-3913-0 (eBook) DOI 10.1007/978-94-007-3913-0 Springer Dordrecht Heidelberg New York London Library of Congress Control Number: 2012936075 # Springer Science+Business Media B.V. 2012 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Foreword Plant Biology is reaching an extraordinary degree of conceptual complexity, especially since the crucial technological advances during the last two decades, halfway between the twentieth and twenty-first centuries. Integration from the molecular to the whole plant level of the mechanisms governing growth and developmental processes provides now a better and an increasingly diverse vision of the functioning of plants in different habitats and under changing environmental conditions. This is featuring a solid body of scientific knowledge which covers the various levels of plant research: cellular, biochemical, genetic, molecular, physiological, ecological and evolutionary. This plethora of knowledge and meth- odological consolidation now allows to more precisely understand the physio- logical and molecular mechanisms, to see the richness of phenotypic responses of plants to the diverse environmental situations, to deepen consistently in the evolutionary lines, to discern the molecular basis of variation for including all within the system’s biology, and to consider the diversity and specificities of plant functionalism. Spectacular progress is being made in the fundamental knowledge of reception of external signals and internal signaling pathways, the vital mechanisms of regulation of homeostasis, the integration of metabolic functions, and the differen- tiation and development of plants exposed to biotic or abiotic stress factors. As expected, this advanced insight into basic processes governing plants under adverse environmental conditions has substantially improved our expertise in practical applications, not only in the field of agronomy, but also in that of environmental restoration. Phytoremediation as a clean, sustainable technology is becoming an attractive way to recover degraded land. No wonder that research and publications on this topic have increased exponentially during the last years and that we face a rapidly expanding area where basic knowledge is being turned into effective environmental technology. It is not accidental that this new book entitled ‘The Plant Family Brassicaceae: Contribution Towards Phytoremediation’ focuses the issue of phytoremediation on the Brassicaceae. This large botanical family with 360 genus and 3,700 species not v vi Foreword only includes important food and industrial plants, but also Arabidopsis thaliana the plant model species par excellence. Small genome size, self-compatibility, short life cycle, small biomass, and large production of seeds make this Arabidopsis thaliana an ideal research object for studies into functional genomics. Identification of genes involved in metal uptake, transport and compartmentation and knowl- edge of key enzymes in metabolic pathways able to transform and detoxify organic pollutants provide the fundamental tools for the development of phytoremediation technologies. This extensive basic research in Arabidopsis thaliana allowed fast advances in the knowledge of the functioning of Brassicaceae species of high interest in phytoremediation processes, such as the close relative Arabidopsis halleri and Thlaspi caerulescens (Noccaea caerulescens), both species with ability to hyper- accumulate cadmium and zinc. Also the nickel hyperaccumulators of the genus Alyssum are within the Brassicaceae. Furthermore, the non-hyperaccumulating species of the genus Brassica, especially Brassica juncea and Brassica napus,the seed-oil canola which combines both industrial applications and phytoremediation potential, are being explored for phytoremediation technologies. These Brassica species have considerably lower shoot metal concentrations than metal hyperaccu- mulators. This is compensated, however, by the much higher biomass in Brassica sp. Thus, the focus on Brassicaceae in this new book is fully awarded by this predominant presence of representatives of this family in current research in phytoremediation. This leads to the question about the characteristics that makes Brassicaceae species so outstandingly attractive for recovering contaminated land. To our opinion, two features common to Brassicaceae may contribute to this: special pathways of secondary sulphur metabolism for glucosinolate synthesis and, probably in part related to this, the fact that most Brassicaceae, are non mycorrhizal. A high tissue level of antioxidants is a further characteristic of importance for performance under stressful conditions. Brassicaceae have a high sulphur requirement. Sulphur availability in mine spoils uses to range from normal to extremely high and most contaminated soils can fully satisfy the higher sulphur demand of the Brassicaceae. Moreover, in Brassicaceae the levels of sulphur containing metabolites that are important for basic metal tolerance, such as glutathion and phytochelatins seem to be affected only under extreme sulphur deficiency. Many Brassicaceae species are pioneers on waste areas and seem well- adapted to recently formed, badly structured substrates. No need for mycorrhization under these conditions implies high nutrient efficiency, especially for phosphorous. In Brassica crops differences in phosphorus acquisition are closely related to both root architecture traits and internal phosphorus use efficiency. Metal hyperaccumu- lators like Thlaspi caerulescens seem well adapted to the low phosphorus availabil- ity of mine waste areas and surplus phosphorus supply may not enhance their biomass production and/or metal extraction potential. Many species that perform well on mine spoils are mycorrhizal. Considerable amounts of heavy metals can be retained in the cell walls, especially of ecto- and ericoid mycorrhizal fungi, thus limiting metal uptake by the plants. Metallophytes that are non- mycorrhizal, such as most Brassicaceae and Caryophyllaceae species Foreword vii (e.g. Silene vulgaris), have their own mechanisms to exclude metals from either or both roots and shoots. Nonetheless, on polluted