Plant Stress - Global Science Books

Plant Stress
Abbreviation: Plant Stress
Print: ISSN 1749-0359
Frequency and Peer status: Biannual, Peer reviewed
Scope and target readership: Plant Stress deals with the network of biotic and abiotic aspects inducing stress in plants.
Plant Stress will consider manuscripts that explore the following topics:
1) Environmental stress;
2) Modelling stress and stress-reduction;
3) Physiological, biochemical, molecular, ecological, genetic and economic aspects of plant stress at the cellular, tissue, organ or whole
plant level. Preference will be given to multi-level studies;
4) Programmed Cell Death directly related to a stress factor;
5) Reactive oxygen species and destructive cellular mechanisms;
6) Stress caused by diseases (temperate and tropical) induced by fungi, bacteria, insects, viruses, phytoplasmas and nematodes.
Editor-in-Chief
Jaime A. Teixeira da Silva, Kagawa University, Japan
Technical Editor
Kasumi Shima, Japan
Statistics Advisor
Marcin Kozak, Warsaw University of Life Sciences, Poland
Editorial Board and Advisory Panels (Listed alphabetically)
Anne J. Anderson, Utah State University, USA
Christian P. Andersen, US Environmental Protection Agency,
USA
Niranjan Baisakh, Louisiana State University, USA
Saikat Kumar Basu, University of Lethbridge, Canada
Pankaj Kumar Bhowmik, Lethbridge Research Centre,
Agriculture and Agri-Food Canada, Canada
Dimitris L. Bouranis, Agricultural University of Athens, Greece
Juan Francisco Jiménez Bremont, Institute for Scientific and
Technological Research of San Luis Potosi, Mexico
Suriyan Cha-um, National Center for Genetic Engineering and
Biotechnology, Thailand
Styliani N. Chorianopoulou, Agricultural University of Athens,
Greece
Prem S. Chourey, USDA-ARS, USA
Pio Colepicolo, Universidade de São Paulo, Brazil
Tracey Cuin, University of Tasmania, Australia
James F. Dat, Université de Franche-Comté – INRA, France
Luis A. del Río, Estación Experimental del Zaidín, CSIC, Spain
Alberto Dias, Universidade do Minho, Portugal
Esmaeil Fallahi, University of Idaho, USA
Jeroni Galmés, Universitat de les Iles Balears, Spain
Faouzi Haouala, Institut Supérieur Agronomique de Chott
Mariem, Tunisia
Xinhua He, University of California, Davis, USA
Luke Hendrickson, Australian National University, Australia
Abdelbagi M. Ismail, International Rice Research Institute,
Philippines
PR Jeyaramraja, Hamelmalo College of Agriculture, The State of
Eritrea
Vladimir V. Kuznetsov, Russian Academy of Sciences, Russia
Carlos A. Labate, Escola Superior de Agricultura Luiz de Queiroz,
Brazil
Christophe Laloi, ETH Zurich, Switzerland
Albino Maggio, University of Naples Federico II, Italy
Ramamurthy Mahalingam, Oklahoma State University, USA
Ezaz A. Mamun, University of Sydney, Australia
Sanjib Nandy, Lethbridge Research Centre, Agriculture and
Agri-Food Canada, Canada
Mary M. Peet, North Carolina State University, USA
S. Reza Pezeshki, University of Memphis, USA
Geert Potters, University of Antwerp, Belgium
Sergey Shabala, University of Tasmania, Australia
Harminder Pal Singh, Panjab University, India
Christine Stone, NSW Department of Primary Industries,
Australia
Karen Tanino, University of Saskatchewan, Canada
Lining Tian, Southern Crop Protection and Food Research Centre,
Agriculture and Agri-Food Canada, Canada
Ilias S. Travlos, Benaki Phytopathological Institute, Greece
Vincent Vadez, International Crops Research Institute for the
Semi-Arid Tropics, India
Boris B. Vartapetian, Timiryazev Institute of Plant Physiology,
Russian Academy of Sciences, Russia
Selvakumar Veluchamy, North Carolina State University, USA

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Guest Editor
Dr. Naser A. Anjum
Department of Botany, Aligarh Muslim University (AMU), Aligarh, India
Agricultural Biotechnology Research Center (ABRC), Academia Sinica, Taiwan
Centre for Environmental and Marine Studies (CESAM) & Department of Chemistry, University of Aveiro,
Portugal
Cover graphs/photos: Left scheme: Schematic representation of plant responses to Fe-overload (Sperotto et al., pp 57-69).
Top, right: Lettuce anchored on polystyrofoam plank in an aeroponics system (Jie He, pp 14-30). Bottom right: Scanning
electron microscopy image of Cu-sufficient pollen grain of green gram plant (Nalini Pandey, pp 1-13).
Disclaimers: All comments, conclusions, opinions, and recommendations are those of the author(s), and do not necessarily
reflect the views of the publisher, or the Editor(s). GSB does not specifically endorse any product mentioned in any
manuscript, and accepts product descriptions and details to be an integral part of the scientific content.
Printed in Japan on acid-free paper.
Published: December, 2010.

The Guest Editor
Dr. Naser A. Anjum
ANJUM, Naser Aziz: Post-doctoral scientist at Centre for Environmental and Marine Studies (CESAM) and
Department of Chemistry, University of Aveiro, Santiago Campus, Aveiro, Portugal.
Dr. Anjum’s main area of research includes (a) the physiological, biochemical and molecular characterization of
economically important plants suffering from abiotic stress factors, (b) involvement of mineral nutrients and other
biotechnological approaches in the amelioration of abiotic stress effects in plants, (c) use of a combination of genetic,
biochemical, genomic and proteomic approaches to analyze the responses of various components of ascorbate-glutathione
pathway to environmental stress factors, (d) to understand stress signaling and stress tolerance, and (e) biomonitoring of salt
marshes along the Atlantic coast of Europe.
Born on February 4 th 1977 at Purnea, Bihar, India Dr. Anjum was awarded PhD (Botany) by Jamia Hamdard (Hamdard
University), New Delhi, India in 2007. Dr. Anjum graduated and masters in Botany from Tilka Manjhi Bhagalpur University,
Bhagalpur, Bihar, India. Earlier, Dr. Anjum served Aligarh Muslim University (AMU), Aligarh, India and Agricultural
Biotechnology Research Center (ABRC), Academia Sinica, Taiwan in different capacities.
A regular reviewer of International journals including Journal of Plant Physiology, Plant Growth Regulation, Plant
Biology, Australian Journal of Crop Science, Journal of Plant Breeding and Crop Science and Plant Omics Journal Dr.
Anjum has been Associate Editor/Member of Editorial Boards of International journals including American-Eurasian Journal
of Sustainable Agriculture, Asian and Australasian Journal of Plant Science and Biotechnology, Plant Stress, Dynamic
Soil, Dynamic Plant, Functional Plant Science and Biotechnology, Eurasian Journal of Agricultural and Environmental
Medicine.
A life member of Indian Society for Plant Physiology Dr. Anjum is also member of other important societies including
Society for Conservation of Nature and Indian Nitrogen Group.
Dr. Anjum has edited a book entitled ‘Ascorbate-Glutathione Pathway and Stress Tolerance in Plants’, published in
2010 by Springer (Science + Business Media B.V.) Dordrecht, The Netherlands. His two other important In Press edited
books are: 1. ‘Oxidative Stress in Plants: Causes, Consequences and Tolerance’, and 2. ‘Nitrate in Leafy Vegetables:
Toxicity and Safety Measures’ to be published by the IK International Publishing House Pvt. Ltd., New Delhi, India. Dr.
Anjum’s other publications include book chapters and dozens of research articles on various aspects in International journals
of repute including Plant Growth Regulation, Russian Journal of Plant Physiology, American Journal of Plant Physiology,
Photosynthetica, Scientia Horticulturae, Plant Science and Journal of Plant Nutrition. Dr. Anjum has presented papers and
delivered lectures in National and International Conferences and Symposia including International Botanical Congress
(IBC) 2005, held in Vienna, Austria.
Dr. Anjum has been selected as UGC-Dr. DS Kothari-Fellow of the year 2009 by University Grants Commissions-
Ministry of Human Resource Department (UGC-MHRD), Govt. India and been Internationally Recognized as one of The
World’s Foremost Achievers in his Field and been included in the 2009 Edition of Marquis Who’s Who in the World.

Foreword
Naser A. Anjum
Centre for Environmental and Marine Studies (CESAM) & Department of Chemistry, University of Aveiro, Santiago
Campus, Aveiro, Portugal
E-mail: naziz4u@yahoo.co.in, dnaanjum@gmail.com
Over the last few decades, achieving sustainability in agriculture has emerged as a major goal to fulfill the requirements
of enough food to feed a rapidly increasing world population in changing environmental conditions. Various biotic and
abiotic stress factors continue to negatively affect various aspects of plant growth, development and productivity (Anjum et
al. 2010). In fact, the relative decrease in potential maximum yields caused by biotic and abiotic stress factors varies
between 54 and 82% (Bray et al. 2000; Cakmak 2005). Although concerted efforts so far have led to the development of a
number of improved cultivars, yield has been virtually static owing to susceptibility of these cultivars to biotic and abiotic
stresses, and a limited genetic variability in the cultivar germplasm. Nutrient management may be an important aspect for
better plant growth and development and can help to achieve optimum yield of major crop plants growing in varied
environmental conditions (Cakmak 2005). Besides, increasing evidence suggests that the maintenance of the mineralnutrients
status of plants plays a critical role in increasing both crop productivity and resistance to environmental stress
(Cakmak 2005; Umar 2006; Anjum et al. 2008a, 2008b; Umar et al. 2008; Anjum et al. 2010). The use of plant-mineral
nutrients and/or plant hormones and growth regulators are, in fact, potential options which can be used to alleviate a number
of abiotic stress-induced effects in plants and to achieve enhanced crop productivity as well in a sustainable way (Marschner
1995; Cakmak 2005; Umar 2006; Anjum et al. 2008a, 2008b; Umar et al. 2008; Anjum et al. 2010; Syeed et al. 2010). In
addition, information in the area of the role of plant nutrition in plant tolerance to various stress factors, tolerance
mechanisms, variability to tolerance, breeding and biotechnology and manipulation of plant-mineral nutrients protocols for
improvement crop plants against various stress factors are disorganized in the available literature.
These three special issues of Plant Stress represent a tremendous attempt, through invited reviews, mini reviews and
articles from leading scientists and researchers working worldwide on the link between plant nutrition and abiotic stresses.
The main objective of these volumes is to provide state-of-the-art and up-to-date knowledge of recent developments in the
understanding of plant responses to major abiotic stresses and the role of plant nutrition in the amelioration of abiotic stress
factor-induced effects in crop plants in a single literature source. These special issues critically evaluate the available
literature and discuss major problems through an understanding of the physiology, biochemistry and molecular biology of
plant stress responses and mechanisms of mineral nutrition-induced stress tolerance in plants in detail. However, to increase
our understanding of the interaction between plant nutrition and abiotic stress tolerance, much more work is needed to
uncover the complexities of individual major functions in plants.
I honestly hope that these special issues of Plant Stress shall be a great help to students, researchers and professionals in
botany, plant environmental science studies, agriculture, plant physiology and molecular biology, in both academic and
industrial sectors.
I am thankful to contributors for their significant manuscripts and in particular to the reviewers who assisted a lot in the
reviewing process and all the referees who provided their valuable comments thus making this special issue-cum-book
possible.
I would like to offer my grateful thanks to the Foundation for Science & Technology (FCT), Portugal
(SFRH/BPD/64690/2009), Council of Scientific & Industrial Research (CSIR), New Delhi, India [(9/112(0401)2K8-EMR-I
(312208/2K7/1)] and to the Agricultural Biotechnology Research Center (ABRC), Academia Sinica, Taiwan for financial

supports to my research.
Last but not least, I must be grateful to Dr. Jaime, the Editor-in-Chief of Plant Stress and Global Science Books Pvt. Ltd,
United Kingdom, who made these efforts successful in bringing out the present treatise on Plant Nutrition and Abiotic Stress
Tolerance.
Naser A. Anjum, PhD
Guest Editor
Post-Doctoral Scientist at Centre for Environmental and Marine Studies (CESAM) & Department of Chemistry, University
of Aveiro, Santiago Campus, Aveiro, Portugal.
Formerly at:
Department of Botany, Aligarh Muslim University, Aligarh 202 002, India; and
Academia Sinica Biotechnology Center in Southern Taiwan, Tainan County, 74146 Taiwan
REFERENCES
Anjum NA, Umar S, Singh S, Nazar R, Khan NA (2008a) Sulfur assimilation and cadmium tolerance in plants. In: Khan
NA, Singh S, Umar S (Eds) Sulfur Assimilation and Abiotic Stress in Plants, Springer-Verlag, pp 271-302
Anjum NA, Umar S, Ahmad A, Iqbal M, Khan NA (2008b) Sulphur protects mustard (Brassica campestris L.) from
cadmium toxicity by improving leaf ascorbate and glutathione. Plant Growth Regulation 54, 271-279
Anjum NA, Umar S, Chan M-T (2010) (Eds) Ascorbate-Glutathione Pathway and Stress Tolerance in Plants, Springer
(Science + Business Media B.V.) Dordrecht, The Netherlands
Bray EA, Bailey-Serres J, Weretilnyk E (2000) Responses to abiotic stresses. In: Buchanan B, Gruissem W, Jones R (Eds)
Biochemistry and Molecular Biology of Plants, American Society of Plant Physiologists, pp 1158-1203
Cakmak I (2005) The role of potassium in alleviating detrimental effects of abiotic stresses in plants. Journal of Plant
Nutrition and Soil Science 168, 521-530
Marschner H (1995) Mineral Nutrition of Higher Plants, Academic Press, New York
Syeed S, Anjum NA, Nazar R, Iqbal N, Masood A, Khan NA (2010) Salicylic acid-mediated changes in photosynthesis,
nutrients content and antioxidant metabolism in two mustard (Brassica juncea L.) cultivars differing in salt tolerance.
Acta Physiologiae Plantarum, in press
Umar S (2006) Alleviating adverse effects of water stress on yield of sorghum, mustard and groughd by potassium
application. Pakistan Journal of Botany 38, 1373-1380
Umar S, Diva I, Anjum NA, Iqbal M (2008) Potassium nutrition reduces cadmium accumulation and oxidative burst in
mustard (Brassica campestris L.). Electronic International Fertilizer Correspondent 16 (June), 6-10
December, 2010

SPECIAL ISSUE: CONTENTS
Nalini Pandey (India) Role of Micronutrients in Reproductive Physiology of Plants
Jie He (Singapore) Mineral Nutrition of Aeroponically Grown Subtropical and Temperate Crops in the Tropics with
Manipulation of Root-Zone Temperature at Different Growth Irradiances
Amrit L. Singh, Ram S. Jat, Vidya Chaudhari, Himanshu Bariya, Seema J. Sharma (India) Toxicities and Tolerance of
Mineral Elements Boron, Cobalt, Molybdenum and Nickel in Crop Plants
Raul Antonio Sperotto, Felipe Klein Ricachenevsky, Ricardo José Stein, Vinicius de Abreu Waldow, Janette Palma Fett
(Brazil) Iron Stress in Plants: Dealing with Deprivation and Overload
Kanwar L. Sahrawat (India) Reducing Iron Toxicity in Lowland Rice with Tolerant Genotypes and Plant Nutrition
Bhupinder Singh, Seva Nayak Dheeravathu, Kalidindi Usha (India) Micronutrient Deficiency: A Global Challenge and
Physiological Approach to Improve Grain Productivity under Low Zinc Availability
Girdhar K. Pandey, Akhilesh K. Yadav, Poonam Kanwar, Narendra Tuteja (India) Role of Calcium in Regulating
Potassium-Sodium Homeostasis and Potassium as Nutrient Signal during Abiotic Stress Conditions
Ashraf M, Muhammad Afzal, Rashid Ahmad, Muhammad Aamer Maqsood, Sher Muhammad Shahzad, Ahsan Aziz,
Naeem Akhtar (Pakistan) Silicon Management for Mitigating Abiotic Stress Effects in Plants
María Begoña Herrera-Rodríguez, Agustín González-Fontes, Jesús Rexach, Juan J. Camacho-Cristóbal, José M.
Maldonado, María Teresa Navarro-Gochicoa (Spain) Role of Boron in Vascular Plants and Response Mechanisms to Boron
Stresses
1
14
31
57
70
76
94
104
115

Nalini Pandey (India) Role of Micronutrients in Reproductive Physiology of Plants (pp 1-13)
ABSTRACT
Invited Review: Plant reproductive biology is a key developmental process and has a great impact on plant productivity.
Reproduction in plant involves the interaction between the male and female gametophyte which depend on the sporophyte for
their nutrient requirement. Till recently, it was thought that adequate supply of micronutrients (Fe, Mn, Cu, Zn, Mo and B) was
required during the period of active vegetative growth. It has lately been shown that good vegetative growth of plants does not
necessarily go hand in hand with a high seed yield. In a large number of crops even under conditions of moderate micronutrient
deficiencies when biomass production is marginally reduced, the reproductive yield is severely decreased. This suggests a
requirement of micronutrients for floral induction and reproductive development independent of the requirement for production
of necessary assimilates. Sufficient evidence has emerged to show that the micronutrients, in particular Cu, Zn and B, are
critically required for reproductive development and that their requirement is possibly higher than what can be met by
retranslocation from the vegetative parts of the mother plants. Application of these micronutrients during an early stage of
reproductive phase make substantial improvement in pollen fertility, pollen-stigma interaction, seed setting and seed quality.
While there are numerous reports of response to micronutrient fertilization benefiting harvest yield of plants, information on
involvement of the micronutrients in plant reproductive development is limited. In recent years the identification of a number of
genes for the floral organs and specific transcription factors like the zinc-fingers has given new impetus to the role of
micronutrients in transcriptional regulation of reproductive development. In this review the current status on the systematic
studies on the role of micronutrients in reproductive biology of plants is discussed.
Jie He (Singapore) Mineral Nutrition of Aeroponically Grown Subtropical and Temperate Crops in the Tropics with Manipulation
of Root-Zone Temperature at Different Growth Irradiances (pp 14-30)
ABSTRACT
Invited Review: Plant growth and productivity are often limited by high root-zone temperatures (RZT) which restricts the growth
of subtropical and temperate crops in the tropics. High RZT temperature coupled with low growth irradiances during cloudy days
which mainly lead to poor root development and thus causes negative impact on the mineral uptake and assimilation. However,
certain subtropical and temperate crops have successfully been grown aeroponically in the tropics by simply cooling their roots
while their aerial portions are subjected to hot fluctuating ambient temperatures. This review first discusses the effects of RZT
and growth irradiance on root morphology and its biomass, the effect of RZT on uptake and transport of several macro nutrients
such as N [nitrogen, mainly nitrate, (NO − 3 )], P (H 2PO − 4 , phosphate), K (potassium) and Ca (calcium), and micro nutrient Fe
(iron) under different growth irradiances. The impact of RZT and growth irradiance on the assimilation of NO - 3 (the form of N
nutrient given to the aeroponically grown plants) and the site of NO - 3 assimilation are also addressed.
Amrit L. Singh, Ram S. Jat, Vidya Chaudhari, Himanshu Bariya, Seema J. Sharma (India) Toxicities and Tolerance of
Mineral Elements Boron, Cobalt, Molybdenum and Nickel in Crop Plants (pp 31-56)
ABSTRACT
Invited Review: The minerals boron (B), cobalt (Co), molybdenum (Mo) and Nickel (Ni) are beneficial to plant in trace amounts,
but excess levels of these cause toxicity limiting crop production. An attempt was made to review the phytotoxicity symptoms,
effects on growth and physiology and tolerance and amelioration of these toxicities in crop plants. Though, chlorosis and
necrosis of leaves are the common expression of toxicities of these minerals and except B the critical toxic concentration of Co,
Mo and Ni in soil has been worked out only for a few crops, the toxicity responses of these minerals in soil and plant tissues
vary considerably across the soils and crop genotypes. These toxicities reduce chlorophyll, affect cell metabolites and enzymes
specially antioxidant and lipid peroxidation, alter nutrient transport and have negative effects on cellular functioning, these all
result in reduced growth and yield. Existence of genetic variation among the crop genotypes highlight the differences in
tolerance and scoring for toxicity symptoms and biomass at early growth stages can be considered as reliable criteria for
screening for tolerance to toxicity. The Bo1 gene provides a major source of B toxicity tolerance. The restriction of uptake and
transport and internal tolerance mechanisms are the two important criteria which plants employ to combat high external
concentrations and hence tolerance could be attributed to the lower B, Co, Mo and Ni content of seed and lower uptake or
accumulation of these in the root and shoot and high yield in toxic soils. Ameliorating high-mineral soils using soil amendments
is expensive and extremely difficult. Use of tolerant crop genotypes, phytoremediation by tolerant crops, and inoculations of
beneficial microorganisms are the solutions.

Raul Antonio Sperotto, Felipe Klein Ricachenevsky, Ricardo José Stein, Vinicius de Abreu Waldow, Janette Palma Fett
(Brazil) Iron Stress in Plants: Dealing with Deprivation and Overload (pp 57-69)
ABSTRACT
Invited Review: Iron (Fe) is an essential nutrient for plants and one of the most abundant elements in soils. However, it is
nearly inaccessible to plants because of its poor solubility in aerobic conditions at neutral or basic pH, resulting in much lower
concentrations than required for the optimal growth of plants. However, when Fe is taken up in excess of cellular needs, it
becomes highly toxic, since both Fe 2+ and Fe 3+ can act as catalysts in the formation of hydroxyl radicals, which are potent
oxidizing agents that may damage DNA, proteins and lipids. Plants must be able to sense and respond to Fe stress in terms of
both Fe-deprivation and Fe-overload. Depending on the level of severity, plants are unable to deal with such stress and undergo
dramatic changes in cellular metabolism with a sequential dismantling of cellular structures, resulting in growth inhibition and
ultimately plant death. Therefore, plants must tightly regulate Fe levels within the cell to ensure that Fe is present at adequate
levels. Here, we describe recent progress made in understanding how Fe is sensed by plants, and how plants are affected by
and try to deal with non-optimal Fe concentrations.
Kanwar L. Sahrawat (India) Reducing Iron Toxicity in Lowland Rice with Tolerant Genotypes and Plant Nutrition (pp 70-75)
ABSTRACT
Invited Mini-Review: Iron toxicity is a widespread nutrient disorder of lowland rice grown in tropical and sub-tropical regions of
the world on acid sulfate soils, Ultisols and sandy soils with a low cation exchange capacity, moderate to high in acidity, high in
easily reducible or active iron and low to moderately high in organic matter. The stress is caused by a high concentration of
ferrous iron in soil solution. It is estimated that iron toxicity reduces lowland rice yields by 12-100%, depending on the iron
tolerance of the genotype, intensity of the iron toxicity stress and soil fertility status. Iron toxicity can be reduced by using
iron-tolerant rice genotypes and through soil, water and nutrient management practices. The objective of this paper is to
critically assess the pertinent literature on the role of iron-tolerant rice genotypes and other plant nutrients in reducing iron
toxicity in lowland rice. It is emphasized that research should provide knowledge that would be used for increasing lowland rice
production and productivity on iron-toxic wetlands on a sustainable basis by integration of genetic tolerance to iron toxicity with
soil, water and nutrient management.
Bhupinder Singh, Seva Nayak Dheeravathu, Kalidindi Usha (India) Micronutrient Deficiency: A Global Challenge and
Physiological Approach to Improve Grain Productivity under Low Zinc Availability (pp 76-93)
ABSTRACT
Invited Review: Micronutrient deficiency in soils is a fast emerging phenomenon and a challenging abiotic stress in world
agriculture. Most important micronutrients that the developing and developed world is concerned from point of view of
sustaining grain productivity and malnutrition in human beings are iron and zinc. Biofortification of staple food crops with
micronutrients by either breeding for higher uptake efficiency or fertilization can be an effective strategy to address widespread
dietary deficiency in human populations. Cereal species greatly differ in their micronutrient efficiency (MiE), defined in this paper
as the ability of a plant to grow and yield well under micronutrient deficiency. MiE generally has been attributed to the efficiency
of acquisition of nutrients under conditions of their low soil availability rather than to its utilisation or (re)-translocation within a
plant. A higher zinc and iron acquisition efficiency of genotypes could be attributed to either or all of the following; an efficient
ionic metal uptake system, better root architecture i.e., long and fine roots with architecture favouring exploitation of
micronutrients from larger soil volume, higher synthesis and release of metal mobilising phytosiderophore by the roots and
uptake of Fe- and Zn-phytosiderophore complex. Seed Zn content has also been suggested to affect the respective MiE. Root
morphology and characteristics and interaction between micronutrients and other ionic radicals have been implicated as
determinants of MiE. This review attempts to examine critically the scanty and scattered reports available on status of
micronutrient deficiency with special reference to Zn, globally; morphological, biochemical and physiological basis of regulation
of MiE in cereals and approaches to improve MiE in terms of grain productivity and grain Fe and Zn vis-à-vis its bioavailability
under conditions of poor micronutrient availability.
Girdhar K. Pandey, Akhilesh K. Yadav, Poonam Kanwar, Narendra Tuteja (India) Role of Calcium in Regulating
Potassium-Sodium Homeostasis and Potassium as Nutrient Signal during Abiotic Stress Conditions (pp 94-103)

ABSTRACT
Invited Review: Calcium is a ubiquitous cation, which serves as a second messenger for numerous signals and confers
specific cellular responses in eukaryotes. Recent studies have established a concept termed ‘Ca 2+ signature’ that specifies Ca 2+
changes triggered by each signal. However, it is very fascinating how this pervasive cation can translate an infinite number of
stimuli into unique stimulus-dependent responses. Ca 2+ is a fundamental component of nutrition signaling under stress
condition. It interacts with various calcium sensors, which are directly involved in various molecular, biochemical and cellular
changes occurring during the plant’s adaptation to nutritional stress. Recently, in calcium signaling in plants, the CBL-CIPK
protein network has been implicated in phytohormone (ABA), abiotic stress and potassium nutrition signaling. This review will
mainly focus on the functional relationship of calcium-mediated salt stress tolerance, potassium nutrition, and
potassium-sodium homeostasis by involvement of the CBL-CIPK complex.
Ashraf M, Muhammad Afzal, Rashid Ahmad, Muhammad Aamer Maqsood, Sher Muhammad Shahzad, Ahsan Aziz,
Naeem Akhtar (Pakistan) Silicon Management for Mitigating Abiotic Stress Effects in Plants (pp 104-114)
ABSTRACT
Invited Review: Abiotic stress factors including salinity, drought, heat, frost, lodging, shading and ion toxicities may adversely
affect the crop productivity and quality. Increasing evidences suggest that adequate regulation of silicon (Si) may enable the
plants to survive the stress environment in a wide variety of crops. Si, once absorbed by the xylem veins, is deposited in the cell
wall of roots, reducing the apoplastic bypass flow, provides binding sites for salts and, thereby, reduces the uptake and
translocation of salts from roots to shoots. Si deposition in the cell wall increases the rigidity of cell wall and reduces the loss of
water through transpiration with a resultant decrease in salt uptake. An increase in internal storage of water within plant tissue,
due to reduced transpiration, allows higher growth rate and consequently mitigating detrimental effects of abiotic stresses. Si
stimulates antioxidant defense system which helps the plants to maintain the desired level of reactive oxygen species in stress
environment. Plants grown in the presence of Si show an erect growth, minimizing the amount of shade and allowing better
distribution of light within the canopy. Si can lower electrolyte leakage, promoting photosynthetic activity in plants grown in
stress environment. Si can positively affect the activities of certain enzymes and decrease the injury caused by abiotic stress
factors. Si reduces the toxicity of elements such as iron, aluminum, manganese and cadmium through reduced uptake,
complexation or immobilization and compartmentation or homogenous distribution of metal ions within the plant. This review
deals with the current knowledge of beneficial effects of Si with focuses being on possible mechanisms of minimizing abiotic
stress effects on plant growth and development.
María Begoña Herrera-Rodríguez, Agustín González-Fontes, Jesús Rexach, Juan J. Camacho-Cristóbal, José M.
Maldonado, María Teresa Navarro-Gochicoa (Spain) Role of Boron in Vascular Plants and Response Mechanisms to Boron
Stresses (pp 115-122)
ABSTRACT
Invited Review: To date, the primordial function of boron is its structural role in the cell wall through stabilization of molecules
containing cis-diol groups (borate esters with apiose residues of rhamnogalacturonan II). Nonetheless, boron is a micronutrient
also involved in a great variety of physiological processes in vascular plants. However the mechanisms underlying the various
metabolic disorders caused by boron deficiency are indeed unknown. Recently it has been reported that boron deficiency and
toxicity induce stress-responsive genes. In this contribution we review the mechanisms involved in boron uptake and
distribution, the role of boron in vascular plants, the effects of boron deficiency and toxicity on them, as well as the interaction
boron toxicity and salt stress. In addition, we discuss the most recent hypotheses proposed to explain how boron could exert its
function in vascular plants from a mechanistic point of view. The importance of understanding the role of boron in plants as well
as the response mechanisms to its deficiency and toxicity will allow us to improve the tolerance of crops to boron stresses.