Silicon and Nano-silicon in Environmental Stress Management and Crop Quality Improvement: Progress and Prospects

By Masayuki Fujita and Mohammad Pessarakli

Silicon and Nano-silicon in Environmental Stress Management and Crop Quality Improvement: Progress and Prospects provides a comprehensive overview of the latest understanding of the physiological, biochemical and molecular basis of silicon- and nano-silicon-mediated environmental stress tolerance and crop quality improvements in plants. The book not only covers silicon-induced biotic and abiotic stress tolerance in crops but is also the first to include nano-silicon-mediated approaches to environmental stress tolerance in crops. As nanotechnology has emerged as a prominent tool for enhancing agricultural productivity, and with the production and applications of nanoparticles (NPs) greatly increasing in many industries, this book is a welcomed resource.

• Enables the development of strategies to enhance crop productivity and better utilize natural resources to ensure future food security
• Focuses on silicon- and nano-silicon-mediated environmental stress tolerance
• Addresses the challenges of both biotic and abiotic stresses

• Language: English
• Publisher: Academic Press
• Release date: Apr 6, 2022
• ISBN: 9780323998222

Book preview

Front Cover for Silicon and Nano-silicon in Environmental Stress Management and Crop Quality Improvement - Progress and Prospects - 1st edition - by Hassan Etesami, Abdullah H. Al Saeedi, Hassan El-Ramady, Masayuki Fujita, Mohammad Pessarakli, Mohammad Anwar Hossain

Silicon and Nano-silicon in Environmental Stress Management and Crop Quality Improvement

Progress and Prospects

Edited by

Hassan Etesami

Soil Science Department, College of Agriculture and Natural Resources, University of Tehran, Tehran, Iran

Abdullah H. Al Saeedi

Department of Environment and Natural Resources, Faculty of Agriculture and Food Science, King Faisal University, Al-Hofuf, Saudi Arabia

Hassan El-Ramady

Soil and Water Department, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh, Egypt

Masayuki Fujita

Faculty of Agriculture, Kagawa University, Kagawa, Japan

Mohammad Pessarakli

University of Arizona, Tucson, AZ, United States

Mohammad Anwar Hossain

Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh, Bangladesh

Table of Contents

Cover image

Title page

Copyright

List of contributors

About the editors

Preface

Chapter 1. Sources of silicon and nano-silicon in soils and plants

Abstract

1.1 Introduction

1.2 Sources of silicon and nano-silicon in soils

1.3 Nano-silicon role in soils

1.4 Silicon and nano-silicon in plants

1.5 Conclusion

Acknowledgment

References

Chapter 2. Silicon and nano-silicon: New frontiers of biostimulants for plant growth and stress amelioration

Abstract

2.1 Introduction

2.2 Prospect of silicon and nano-silicon as biostimulants

2.3 Silicon: an underestimated element for plant growth

2.4 Emerging role of nano-silicon

2.5 Crosstalk with phytohormones for the elicitation of enhanced tolerance

2.6 Molecular mechanism of the alleviation of stress by silicon and nano-silicon

2.7 Conclusions, current status, and future perspectives

Conflict of interest

Acknowledgments

References

Chapter 3. Silicon uptake, acquisition, and accumulation in plants

Abstract

3.1 Introduction

3.2 Silicon uptake, acquisition, and accumulation in higher plants

3.3 Si accumulation and deposition in different parts of plant

3.4 Conclusion and future perspective

References

Chapter 4. Biological function of silicon in a grassland ecosystem

Abstract

4.1 Introduction

4.2 Silicon distribution in meadow plants

4.3 Silicon in relation to plant community structure in alpine meadow

4.4 Silicon in relation to plant carbon, nitrogen and phosphorus concentration

4.5 Silicon in relation to plant physiological aspects in presence of N-fertilization

4.6 Conclusions and perspective

Acknowledgements

References

Chapter 5. Use of silicon and nano-silicon in agro-biotechnologies

Abstract

5.1 Introduction

5.2 Silicon for plant health

5.3 Nano-silicon

5.4 Conclusions and perspectives

Acknowledgments

References

Chapter 6. The genetics of silicon accumulation in plants

Abstract

6.1 Introduction

6.2 Genetic and molecular basis of Si uptake and movement of Si within plant cells

6.3 Distribution of Lsi channels and Silp1 proteins in plants

6.4 Conclusion

References

Chapter 7. Silicon-mediated modulations of genes and secondary metabolites in plants

Abstract

7.1 Introduction

7.2 Overview and assortment of plant secondary metabolites

7.3 Stress and protection reactions in relation to the secondary metabolites production

7.4 Silicon modulation of secondary metabolism within stress condition

7.5 Silicon-mediated expression of transcription factors and some associated secondary metabolite responsive genes

7.6 Conclusion and perspective

References

Chapter 8. Silicon improves salinity tolerance in crop plants: Insights into photosynthesis, defense system, and production of phytohormones

Abstract

8.1 Introduction

8.2 Salinity-induced injuries in plants

8.3 Regulatory role of Si to mitigate salt stress

8.4 Conclusion and future prospects

References

Chapter 9. Nanosilicon-mediated salt stress tolerance in plants

Abstract

9.1 Introduction

9.2 Effect of salt stress on plants

9.3 Silicon: a beneficial nutrient in saline agriculture

9.4 Nanosilica: types, sources, synthesis, and uptake mechanism

9.5 Chemistry of nano-Si in salt-contaminated soil

9.6 Nano-Si-mediated tolerance in plants under salinity stress

9.7 Conclusion

9.8 Future direction

References

Chapter 10. Silicon- and nanosilicon-mediated drought and waterlogging stress tolerance in plants

Abstract

10.1 Introduction

10.2 Drought and waterlogging stress definition and forms

10.3 Ecological grouping of plant according to drought and waterlogging stress tolerance

10.4 Response of plant physiology, biochemistry, and molecular biology of drought and waterlogging stress tolerance in plants

10.5 Effect of drought and waterlogging stress on plant and yield components

10.6 Mechanisms of drought and waterlogging stress in plants

10.7 Role of silicon and nanosilicon in alleviating the deleterious effect of drought and waterlogging stress

10.8 Mechanisms of silicon- and nanosilicon-mediated drought and waterlogging stress tolerance in plants

10.9 Conclusion and future perspectives

Acknowledgment

References

Chapter 11. Silicon and nanosilicon mediated heat stress tolerance in plants

Abstract

11.1 Silicon and plants

11.2 Silicon dynamics and distribution in plants

11.3 Nanosilicon and plants

11.4 Use of nanosilicon to promote plant growth and heat stress tolerance

11.5 Role of silicon and nanosilicon particles in improving heat stress endurance

11.6 Regulation of antioxidant activities by silicon in crop plants under heat stress

11.7 Mechanisms of silicon-mediated amelioration of heat stress in plants

11.8 Silicon and nanosilicon against several plant diseases

Reference

Chapter 12. Silicon-mediated cold stress tolerance in plants

Abstract

12.1 Introduction

12.2 Mitigation of low-temperature stress by Si

12.3 Concluding remarks

Acknowledgment

References

Chapter 13. Silicon and nano-silicon mediated heavy metal stress tolerance in plants

Abstract

13.1 Introduction

13.2 Heavy metals: Functions, effects, and classification based on necessity

13.3 Silicon/nano-silicon plays a vital role in the alleviation of heavy metals toxicity in plants

13.4 Conclusion

References

Chapter 14. Silicon- and nanosilicon-mediated disease resistance in crop plants

Abstract

14.1 Introduction

14.2 Role of Si and nano-Si in mitigating plant stresses

14.3 Disease resistance modulation by Si

14.4 Conclusion and future perspective

References

Chapter 15. Silicon and nanosilicon mitigate nutrient deficiency under stress for sustainable crop improvement

Abstract

15.1 Introduction

15.2 Silicon and nanosilicon application in soil and plants

15.3 Silicon/nano-Si and micronutrients

15.4 Si/nSi-mediated alleviation of heavy metal stress in plants

15.5 Conclusion and future prospective

Acknowledgments

Conflict of Interest

References

Chapter 16. Silicon as a natural plant guard against insect pests

Abstract

16.1 Introduction

16.2 Effect of Si on host plant selection for oviposition and feeding

16.3 Si physical defense against herbivores

16.4 Effect of Si on palatability and digestibility

16.5 Effect of Si on biology, feeding behavior, and performance of insects

16.6 Effect of Si on natural enemies and tritrophic interaction

16.7 Commercial sources of Si and their induced resistance against herbivory

16.8 Combined effect of Si with other amendments and plant growth regulators

16.9 Conclusions and future prospects

References

Chapter 17. Recent developments in silica-nanoparticles mediated insect pest management in agricultural crops

Abstract

17.1 Introduction

17.2 Synthesis of SiNPs

17.3 Uptake and deposition of SiNPs

17.4 SiNPs versus conventional insecticides in insect pest management

17.5 SiNPs in tri-trophic interactions

17.6 SiNPs and genetic engineering

17.7 Toxicity of SiNPs to crop plants

17.8 SiNPs: Advantages and disadvantages

17.9 Conclusions and future line of work

References

Chapter 18. The combined use of silicon/nanosilicon and arbuscular mycorrhiza for effective management of stressed agriculture: Action mechanisms and future prospects

Abstract

18.1 Introduction

18.2 Silicon-mediated plant stress alleviation

18.3 Nanosilica-mediated plant stress alleviation

18.4 Arbuscular mycorrhizal fungi-mediated plant stress alleviation

18.5 Plant stress alleviation mediated by the combined use of silicon and arbuscular mycorrhizal fungi

18.6 Conclusions and future perspectives

Acknowledgments

References

Chapter 19. Biodissolution of silica by rhizospheric silicate-solubilizing bacteria

Abstract

19.1 Introduction

19.2 Plant growth-promoting rhizosphere bacteria

19.3 Silicate-solubilizing bacteria

19.4 Plant growth-promoting effects of silicate-solubilizing bacteria

19.5 Conclusion and future perspectives

Acknowledgments

References

Chapter 20. Silicon and nano-silicon in plant nutrition and crop quality

Abstract

20.1 Introduction

20.2 Silicon as micronutrient

20.3 Direct impact of Si and Si-NPs on plants

20.4 Si-NPs as a delivering agent for fertilizers

20.5 Effects of Si and Si-NPs on plant nutrient uptake

20.6 Effects of Si and Si-NPs fertilizer on protein and amino acids contents

20.7 The role of Si and Si-NPs in crop quality

20.8 Conclusions and future perspectives

References

Chapter 21. Effect of silicon and nanosilicon application on rice yield and quality

Abstract

21.1 Introduction

21.2 Impacts of Si and nano-Si on rice yield and quality

21.3 Conclusion and future perspective

References

Chapter 22. Biological impacts on silicon availability and cycling in agricultural plant-soil systems

Abstract

22.1 Introduction

22.2 Plants and phytogenic silica

22.3 Further organisms and corresponding BSi pools

22.4 Implications for ecosystem functioning and services of agricultural plant-soil systems

22.5 Concluding remarks

22.6 Future directions

Acknowledgments

References

Chapter 23. Nanosilica-mediated plant growth and environmental stress tolerance in plants: mechanisms of action

Abstract

23.1 Introduction

23.2 Nanosilica stability in solution and efficiency in providing Si to crops

23.3 Effects of nanosilica on plants grown under environmental stress

23.4 Limitations and future perspective

References

Further reading

Chapter 24. Manipulation of silicon metabolism in plants for stress tolerance

Abstract

24.1 Background

24.2 Impact of stresses on plant growth

24.3 Metabolic changes under stress

24.4 Agronomic approaches for abiotic stress management

24.5 Nutrition role in stress tolerance

24.6 Impact of silicon nutrition under stresses

24.7 Role of silicon in plant metabolism

24.8 Conclusions and remarks

References

Chapter 25. Directions for future research to use silicon and silicon nanoparticles to increase crops tolerance to stresses and improve their quality

Abstract

25.1 Introduction

25.2 Future directions of silicon/nanosilicon application in agriculture

25.3 Concluding remarks

Acknowledgments

References

Index

Copyright

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List of contributors

Asim Abbasi,     Department of Zoology, University of Central Punjab, Punjab Group of College, Bahawalpur, Pakistan

Seyed Abdollah Hosseini,     Plant Nutrition Department, Abiotic Stress Group, Agro Innovation International, Timac Agro, France

Sobia Afzal,     Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan

Adeel Ahmad,     Institue of Soil and Environmental Science, University of Agriculture Faisalabad, Faisalabad, Pakistan

Iftikhar Ahmad,     Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan

Zahoor Ahmad,     Department of Botany, University of Central Punjab, Punjab Group of College, Bahawalpur, Pakistan

Muhammad Ali,     Department of Environmental Science, Faculty of Agriculture & Environment, The Islamia University of Bahawalpur, Bahawalpur, Pakistan

Abdullah Alsaeedi,     Department of Environment and Natural Resources, Faculty of Agriculture and Food Science, King Faisal University, Al Hofuf, Saudi Arabia

Tarek Alshaal

Department of Soil and Water, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh, Egypt

Department of Applied Plant Biology, University of Debrecen, Debrecen, Hungary

Megahed Amer,     Soils Improvement Department, Soils, Water and Environment Research Institute, Sakha Station, Agricultural Research Center, Kafr El-Sheikh, Egypt

Muhammad Arslan Arshraf,     Department of Botany, Government College University, Faisalabad, Pakistan

Arkadiusz Artyszak,     Department of Agronomy, Warsaw University of Life Sciences—SGGW, Warsaw, Poland

Muhammad Ashar Ayub,     Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan

Celaleddin Barutçular,     Department of Filed Crops, Faculty of Agriculture, Cukurova University Adana, Adana, Turkey

Zaffar Bashir,     Centre of Research for Development and PG Microbiology, University of Kashmir, Srinagar, India

Aneesa Batool

Proteomics Laboratory, Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology Kashmir, Srinagar, India

Department of Chemistry, Govt. College for Women, Cluster University Srinagar, Srinagar, India

Department of Chemistry, Baghwant University of Ajmer, Ajmer, India

Kaisar Ahmad Bhat

School of Biosciences and Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, India

Proteomics Laboratory, Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology Kashmir, Srinagar, India

Cid Naudi Silva Campos,     Federal University of Mato Grosso do Sul, Chapadão do Sul, Brazil

Zhong-Liang Chen

Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs/Guangxi Key Laboratory of Sugarcane Genetic Improvement/Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences/Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Nanning, P.R. China

College of Agriculture, Guangxi University, Nanning, P.R. China

Muhammad Dawood,     Department of Environmental Sciences, Bahauddin Zakariya University, Multan, Pakistan

Renato de Mello Prado,     School of Agricultural and Veterinary Sciences, São Paulo State University, Jaboticabal, Brazil

Amanda Carolina Prado de Moraes

Laboratory of Microbiology and Biomolecules, Department of Morphology and Pathology, Federal University of São Carlos (UFSCar), São Carlos, Brazil

Biotechnology Graduate Program, Federal University of São Carlos (UFSCar), São Carlos, Brazil

Jonas Pereira de Souza Júnior,     School of Agricultural and Veterinary Sciences, São Paulo State University, Jaboticabal, Brazil

Heba Elbasiony,     Department of Environmental and Biological Sciences, Home Economy Faculty, Al-Azhar University, Tanta, Egypt

Fathy Elbehery,     Central Laboratory of Environmental Studies, Kafrelsheikh University, Kafr El-Sheikh, Egypt

Alaa El-Dein Omara,     Agriculture Microbiology Department, Soil, Water and Environment Research Institute (SWERI), Sakha Agricultural Research Station, Agriculture Research Center, Kafr El-Sheikh, Egypt

Mohamed M. Elgarawani,     Department of Care Scientific Research Care and Training, Research and training Station, King Faisal University, Al Hofuf, Saudi Arabia

Nevien Elhawat

Department of Applied Plant Biology, University of Debrecen, Debrecen, Hungary

Department of Biological and Environmental Sciences, Faculty of Home Economic, Al-Azhar University, Cairo, Egypt

Hassan El-Ramady,     Soil and Water Department, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh, Egypt

Tamer Elsakhawy,     Agriculture Microbiology Department, Soil, Water and Environment Research Institute (SWERI), Sakha Agricultural Research Station, Agriculture Research Center, Kafr El-Sheikh, Egypt

Hugo Fernando Escobar-Sepúlveda,     Institute of Biological Sciences, The University of Talca, Talca, Chile

Hassan Etesami,     Soil Science Department, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran

Saad Farouk,     Agricultural Botany Department, Faculty of Agriculture, Mansoura University, Mansoura, Egypt

Patrícia Messias Ferreira,     School of Agricultural and Veterinary Sciences, São Paulo State University, Jaboticabal, Brazil

Fernando Carlos Gómez-Merino,     Laboratory of Plant Biotechnology, College of Postgraduates in Agricultural Sciences, Veracruz, Mexico

Libia Fernanda Gómez-Trejo,     Department of Plant Protection, Chapingo Autonomous University, Texcoco, Mexico

Roghieh Hajiboland,     Department of Plant Sciences, University of Tabriz, Tabriz, Iran

Robert Henry,     Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD, Australia

Mohammad Anwar Hossain,     Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh, Bangladesh

Iqbal Hussain,     Department of Botany, Government College University, Faisalabad, Pakistan

Muhammad Ammir Iqbal,     Department of Agronomy, University of Poonch Rawalakot Azad Kashmir, Rawalakot, Pakistan

Muhammad Jafir,     Department of Entomology, University of Agriculture, Faisalabad, Pakistan

Mallikarjuna Jeer,     Entomology, ICAR-National Institute of Biotic Stress Management, Raipur, India

Byoung Ryong Jeong,     Department of Horticulture, Division of Applied Life Science (BK21 Four), Graduate School, Gyeongsang National University, Jinju, Republic of Korea

Danuta Kaczorek

Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany

Department of Soil Environment Sciences, Warsaw University of Life Sciences (SGGW), Warsaw, Poland

C.M. Kalleshwaraswamy,     Department of Agricultural Entomology, College of Agriculture, University of Agricultural and Horticultural Sciences, Shivamogga, India

Muhammad Kamran,     School of Agriculture, Food and Wine, The University of Adelaide, South Australia, Australia

M. Kannan,     Department of Nano Science and Technology, Tamil Nadu Agricultural University, Coimbatore, India

Norollah Kheyri,     Department of Agronomy, Gorgan Branch, Islamic Azad University, Gorgan, Iran

Paulo Teixeira Lacava,     Laboratory of Microbiology and Biomolecules, Department of Morphology and Pathology, Federal University of São Carlos (UFSCar), São Carlos, Brazil

Yang-Rui Li,     Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs/Guangxi Key Laboratory of Sugarcane Genetic Improvement/Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences/ Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Nanning, P.R. China

Zaffar Malik,     Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan

Madeeha Mansoor,     Proteomics Laboratory, Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology Kashmir, Srinagar, India

Madhiya Manzoor,     Proteomics Laboratory, Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology Kashmir, Srinagar, India

Piyush Mathur,     Microbiology Laboratory, Department of Botany, University of North Bengal, Darjeeling, India

Tatiana Minkina,     Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia

Seyed Majid Mousavi,     Agricultural Research, Education and Extension Organization (AREEO), Soil and Water Research Institute (SWRI), Department of Soil Fertility and Plant Nutrition, Karaj, Iran

Sahar Mumtaz,     Department of Botany, Division of Science and Technology, University of Education, Lahore, Pakistan

Momina Nazir,     Department of Chemistry, Govt. College for Women, Cluster University Srinagar, Srinagar, India

Fatemeh Noori,     Department of Biotechnology and Plant Breeding, Sari Agricultural Sciences and Natural Resources University, Sari, Iran

Sana Noreen,     Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan

Aasma Parveen,     Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan

Abida Parveen,     Department of Botany, Government College University, Faisalabad, Pakistan

Shagufta Perveen,     Department of Botany, Government College University, Faisalabad, Pakistan

N.B. Prakash,     Department of Soil Science and Agricultural Chemistry, College of Agriculture, University of Agricultural Sciences, GKVK, Bangalore, India

Daniel Puppe,     Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany

Vishnu D. Rajput,     Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia

Rizwan Rasheed,     Department of Botany, Government College University, Faisalabad, Pakistan

Samiya Rehman,     Department of Biochemistry, University of Okara, Okara, Pakistan

Muhammad Riaz,     College of Natural Resources and Environment, South China Agricultural University, Guangzhou, P.R. China

Saima Riaz,     Department of Botany, Government College University, Faisalabad, Pakistan

Swarnendu Roy,     Plant Biochemistry Laboratory, Department of Botany, University of North Bengal, Darjeeling, India

Freeha Sabir,     Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan

Muhammad Hamzah Saleem,     College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China

Mahima Misti Sarkar,     Plant Biochemistry Laboratory, Department of Botany, University of North Bengal, Darjeeling, India

Jörg Schaller,     Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany

Ehsan Shokri,     Department of Nanotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Karaj, Iran

Munna Singh,     Department of Botany, University of Lucknow, Lucknow, India

Xiu-Peng Song,     Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs/Guangxi Key Laboratory of Sugarcane Genetic Improvement/Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences/ Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Nanning, P.R. China

Syeda Refat Sultana,     Department of Filed Crops, Faculty of Agriculture, Cukurova University Adana, Adana, Turkey

Gelza Carliane Marques Teixeira,     School of Agricultural and Veterinary Sciences, São Paulo State University, Jaboticabal, Brazil

Sumaira Thind,     Department of Botany, Government College University, Faisalabad, Pakistan

Dan-Dan Tian,     Institute of Biotechnology, Guangxi Academy of Agricultural Sciences, Nanning, P.R. China

Libia Iris Trejo-Téllez,     Laboratory of Plant Nutrition, College of Postgraduates in Agricultural Sciences, Texcoco, Mexico

Muhammad Zia ur Rehman,     Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan

Krishan K. Verma,     Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs/Guangxi Key Laboratory of Sugarcane Genetic Improvement/Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences/Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Nanning, P.R. China

Ejaz Ahmad Waraich,     Department of Agronomy, University of Agriculture Faisalabad, Faisalabad, Pakistan

Danghui Xu,     State Key Laboratory of Grassland Agro-ecosystems/School of Life Science, Lanzhou University, Lanzhou, P.R. China

Sajad Majeed Zargar,     Proteomics Laboratory, Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology Kashmir, Srinagar, India

Saman Zulfiqar,     Department of Botany, The Government Sadiq College Women University, Bahawalpur, Pakistan

About the editors

Dr. Hassan Etesami is a research scientist with 15 years of experience in the field of soil biology and biotechnology. He obtained his PhD degree from the Department of Soil Science, College of Agriculture & Natural Resources, University of Tehran, Iran, where he is currently a member of the faculty as an associate professor. He has also passed a research course as a visiting scholar under the supervision of Prof. Gwyn Beattie at Plant Pathology and Microbiology Department, Iowa State University, Iowa, United States, in 2013. Dr. Etesami has a special interest in developing biofertilizers and biocontrol agents that meet farmers’ demands. He has coauthored over 80 publications (research papers, review papers, and book chapters) in various areas including biofertilizers and biocontrol. He is also a reviewer of 115 journals. Dr. Etesami’s research areas include stressed agricultural management by silicon, microbial ecology, biofertilizers, soil pollution, integrated management of abiotic (salinity, drought, heavy metals, and nutritional imbalance) and biotic (fungal pathogens) stresses, plant–microbe interactions, environmental microbiology, and bioremediation.

Dr. Abdullah H. Al Saeedi is an associate professor in soil physics and water management, working at the Environment and Natural Resources Department, College of Agriculture and Food Science, King Faisal University, Saudi Arabia. He obtained his PhD from Liverpool John Moores University, UK (1992). Dr. Al-Saeedi has a research interest in soil water relationship, salinity, water management, and improving agriculture practice. He has many publications (research papers and book chapters) in soil physics, salinity, fertilizer requirement, GIS, and using nanosilica in improving agriculture productivity under different abiotic stresses. He reviewed many research paper manuscripts for different journals. He has been awarded Prince Mohammed Bin Fahad Prize for research. During his academic work, he has supervised many master’s degree students, worked in national research and academic project.

Dr. Hassan El-Ramady is a professor of plant nutrition and soil fertility, working at the Soil and Water Department, Faculty of Agriculture, Kafrelsheikh University, Egypt. He received his PhD from the Technical University of Braunschweig, Germany (2008). He started his postdoctoral scholarships with ParOwn funded by Egypt to Hungary in 2012, then 2013 and 2014 funded by HSB, Hungary to Debrecen University, again from 2018 to 2019 at Debrecen University. He visited also the United States (2012 and 2014), Austria (2013), Italy (2014), Brazil (2015), and Germany (2014, 2015, 2016, and 2017). His current research program focuses on the biological plant nutrition and its problems including new approaches like nanoparticles under stress. He has over 100 peer-reviewed publications, 30 book chapters, and has edited 5 Arabic books, and he was a lead editor for the book The Soils of Egypt. He is Editor-in-Chief and associate editor for some journals like Frontiers in Soil Science, Egyptian Journal of Soil Science and Environment, Biodiversity, and Soil Security. He is a reviewer for more than 150 journals (https://publons.com/researcher/1671675/hassan-el-ramady/28.08.2021).

Dr. Masayuki Fujita is a professor in the Department of Plant Sciences, Faculty of Agriculture, Kagawa University, Kagawa, Japan. He received his BSc in chemistry from Shizuoka University, Shizuoka, and his M.Agr. and PhD in plant biochemistry from Nagoya University, Nagoya, Japan. His research interests include physiological, biochemical, and molecular biological responses based on secondary metabolism in plants under biotic (pathogenic fungal infection) and abiotic (salinity, drought, extreme temperatures, and heavy metals) stresses, phytoprotectants and biostimulants, phytoalexin, cytochrome P-450, glutathione S-transferase, phytochelatin, and redox reaction and antioxidants. He has over 200 peer-reviewed publications and has edited 32 books and special issues of journals.

Dr. Mohammad Pessarakli is a professor in the School of Plant Sciences, College of Agriculture and Life Sciences at the University of Arizona, Tucson, Arizona, United States. His work at the University of Arizona includes research and extension services as well as teaching courses in Turfgrass Science, Management, and Stress Physiology, currently teaching the Plants and Our World course to large classes of over 200 students each semester. He has edited the Handbook of Plant and Crop Stress and the Handbook of Plant and Crop Physiology (both titles published by, formerly Marcel Dekker, Inc., currently Taylor and Francis Group, CRC Press), and the Handbook of Photosynthesis, Handbook of Turfgrass Management and Physiology, and the Handbook of Cucurbits. He has written 45 book chapters, he is Editor-in-Chief of the Advances in Plants & Agriculture Research journal, Editorial Board member of the Journal of Plant Nutrition and Communications in Soil Science and Plant Analysis, as well as the Journal of Agricultural Technology, and a member of the Book Review Committee of the Crop Science Society of America, and Reviewer of the Crop Science, Agronomy, Soil Science Society of America, and HortScience journals. He is the author or coauthor of over 200 journal articles in 20 different journals. Dr. Pessarakli is an active member of the Agronomy Society of America, Crop Science Society of America, and Soil Science Society of America, among others. He is an Executive Board member of the American Association of the University Professors, Arizona Chapter. Dr. Pessarakli is a well-known internationally recognized scientist and scholar and an esteemed member (invited) of several Who’s Who as well as numerous honor societies (i.e., Phi Kappa Phi, Gamma Sigma Delta, Pi Lambda Theta, Alpha Alpha Chapter). He is a Certified Professional Agronomist and Certified Professional Soil Scientist, designated by the American Registry of the Certified Professionals in Agronomy, Crop Science, and Soil Science. Dr. Pessarakli is a United Nations Consultant in Agriculture for underdeveloped countries. He received his BS degree (1977) in Environmental Resources in Agriculture and his MS degree (1978) in Soil Management and Crop Production from Arizona State University, Tempe, and his PhD degree (1981) in Soil and Water Science from the University of Arizona, Tucson. Dr. Pessarakli’s environmental stress research work and expertise on plants and crops is internationally recognized.

For more information about Dr. Pessarakli, please visit:

https://cals.arizona.edu/spls/content/mohammad

https://cals.arizona.edu/spls/people/faculty

Dr. Mohammad Anwar Hossain is serving as a professor in the Department of Genetics and Plant Breeding, Bangladesh Agricultural University (BAU), Mymensingh, Bangladesh. He received his BSc in Agriculture and MS in Genetics and Plant Breeding from BAU, Bangladesh. He also received an MS in Agriculture from Kagawa University, Japan, in 2008 and a PhD in Abiotic Stress Physiology and Molecular Biology from Ehime University, Japan in 2011 through Monbukagakusho scholarship. As a JSPS postdoctoral researcher, he has worked on isolating low phosphorus stress-tolerant genes from rice at the University of Tokyo, Japan during the period of 2015–17. His current research program focuses on understanding physiological, biochemical, and molecular mechanisms underlying abiotic stresses in plants and the generation of stress-tolerant and nutrient-efficient plants through breeding and biotechnology. He has over 70 peer-reviewed publications and has edited 13 books, including this one, published by CRC Press, Springer, Elsevier, Wiley, and CABI.

Preface

Hassan Etesami¹, Abdullah H. Al Saeedi², Hassan El-Ramady³, Masayuki Fujita⁴, Mohammad Pessarakli⁵ and Mohammad Anwar Hossain⁶, ¹Soil Science Department, College of Agriculture and Natural Resources, University of Tehran, Tehran, Iran, ²Department of Environment and Natural Resources, Faculty of Agriculture and Food Science, King Faisal University, Al-Hofuf, Saudi Arabia, ³Soil and Water Department, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh, Egypt, ⁴Kagawa University, Kagawa, Japan, ⁵University of Arizona, Tucson, AZ, United States, ⁶Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh, Bangladesh

Crop plants growing under field conditions are constantly exposed to various abiotic and biotic stress factors leading to decreased yield and quality of produce. To achieve sustainable development in agriculture and to increase agricultural production for feeding an increasing global population, it is necessary to use ecologically compatible and environmentally friendly strategies to decrease the adverse effects of stresses on the plant. Silicon is recently recognized as a beneficial plant nutrient element and many growers already include it in their crop fertility programs. It has been widely reported that silicon can promote plant growth and alleviate various stresses as well as increase the quantity and improve the quality of the yield of many plant species. It is probably the only element that can enhance the resistance to multiple stresses. When present in excess, silicon is not noxious to plants and is also free from pollution and noncorrosive. In the last decade nanotechnology has emerged as a prominent tool for enhancing agricultural productivity. The production and applications of nanoparticles have greatly increased in many industries, such as energy production, healthcare, agriculture, and environmental protection. The application of nanoparticles has attracted interest for their potential to alleviate abiotic and biotic stresses in a more rapid, cost-effective, and more sustainable way than conventional treatment technologies. Recently, research related to silicon- and silicon-nanoparticles-mediated abiotic stresses and nutritional improvements in plants has received considerable interest from the scientific community. While significant progress has been made in silicon biochemistry in relation to stress tolerance, an in-depth understanding of the molecular mechanisms associated with the silicon- and nano-silicon-mediated stress tolerance and biofortification in plants is still lacking. Gaining a better knowledge of the regulatory and molecular mechanisms that control silicon uptake, assimilation, and tolerance in plants is, therefore, vital and necessary to develop modern crop varieties that are more resilient to environmental stress.

In this book, "Silicon and Nano-silicon in Environmental Stress Management and Crop Quality Improvement: Progress and Prospects," we present a collection of 25 chapters written by leading experts engaged with silicon- and nano-silicon-mediated environmental stress management and crop quality improvement. This book aims to provide a comprehensive overview of the latest understanding of the physiological, biochemical, and molecular basis of silicon- and nano-silicon-mediated environmental stress tolerance and crop quality improvements in plants. Numerous figures and tables are included in this book to facilitate comprehension of the presented information.

Finally, this book will serve as a unique key source of information and knowledge for graduate and postgraduate students, instructors/educators, and frontline plant scientists around the globe and would be a valuable resource for promoting future research in plant stress tolerance as well as crop quality improvement through biofortification. We believe that the information presented in this book will make a sound contribution to this fascinating area of research and to the agricultural scientific community.

Chapter 1

Sources of silicon and nano-silicon in soils and plants

Hassan El-Ramady¹, Krishan K. Verma², Vishnu D. Rajput³, Tatiana Minkina³, Fathy Elbehery⁴, Heba Elbasiony⁵, Tamer Elsakhawy⁶, Alaa El-Dein Omara⁶ and Megahed Amer⁷,    ¹Soil and Water Department, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh, Egypt,    ²Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs/Guangxi Key Laboratory of Sugarcane Genetic Improvement/Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences/Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Nanning, P.R. China,    ³Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia,    ⁴Central Laboratory of Environmental Studies, Kafrelsheikh University, Kafr El-Sheikh, Egypt,    ⁵Department of Environmental and Biological Sciences, Home Economy Faculty, Al-Azhar University, Tanta, Egypt,    ⁶Agriculture Microbiology Department, Soil, Water and Environment Research Institute (SWERI), Sakha Agricultural Research Station, Agriculture Research Center, Kafr El-Sheikh, Egypt,    ⁷Soils Improvement Department, Soils, Water and Environment Research Institute, Sakha Station, Agricultural Research Center, Kafr El-Sheikh, Egypt

Abstract

Silicon (Si) is an important nutrient, particularly under stressful enticements, although its essentiality for higher plants still needs more evidence. This element in bulk- and nano-form has fascinating features, which attracts the workers in agriculture, industry, pharmaceutical, and many other allied sectors. The sources of Si are crucial information for better understanding the nature of this element and cycling in soils and plants, especially for recent applications as nano-fertilizers, nano-pesticides, nano-sensors, and others. Based on these sources and forms, the bioavailability and uptake by plants of different Si forms depend on soil and rhizosphere catheterizations. These sources and forms of Si are also important for better understanding the fate and action of Si in soil and plants. Further, studies are needed about this element, in which many fascinating features about it will be discovered day by day.

Keywords

Silicon cycling; silicon extraction; nano-silica; Si-bioavailability; nano-fertilizers

1.1 Introduction

After oxygen, silicon (Si) is the second most abundant element in the earth’s crust (28%) and the most abundant element in soils (54%) [1,2]. Silicon is very common in soils and forms a lot of minerals like silicon dioxide (SiO2), quartz, and alumino silicates [3]. Many fractions of Si could be found in soils as liquid phases, which consist of the dissolved Si forms in soil solution, that is, the complexes of silicic acid-inorganic compounds, the monosilicic acid (H4SiO4) and polysilicic acid [4]. Based on many distinguished properties, several applications of Si could be mentioned such as mediating stress tolerance in plants like salinity [5–7], drought [8–10], high-pH stress [11], water deficit stress [12], and metal toxicity [13,14]; as a fertilizer [15,16]; and maintaining soil health [14]. Nano-silicon or SiO2 nanoparticles (Si-NPs) are considered a very important source of Si, which could be applied to promote plant resistance to many stressful conditions [17]. These Si-NPs have been used in many applications like phytoremediation [18], wastewater treatment [19], nano-pesticides [20,21], food processing units [22], nano-fertilizers [23], industrial applications [24], biomedical issues [25], and biosensors [17] as well as improving crop output during stress conditions [26].

Due to its fascinating roles under stress on plants, Si is well known as a beneficial or quasi-essential element, although it has been classified as a nonessential nutrient because it does not fulfill the criteria of essentiality and has no evidence to be involved in plant metabolism [27,28]. The most important Si form for plant uptake is monosilicic acid (H4SiO4) and its solubility in soil and uptake by plant roots depends on clay content, soil organic matter, and Si fractions in soils like Fe/Al oxides/hydroxides [4,29]. Many studies confirmed the role of silicon nano-fertilizers in increasing the biomass and productivity of various plants species [30,31] and others under stresses such as rice under salinity [32], maize under salinity [33], coriander under lead stress [34], rice under fluoride stress [35], and common bean subjected to metal toxicity and sodic soil [26]. These Si-NPs have been applied in agriculture for mitigating different environmental stresses through their utilization as nano-fertilizers, nano-herbicides, and nano-pesticides [17,26]. A great concern recently has been adopted about the production of nano-silica (NS) from different agro-wastes [21,36] as a new concept of nano-management [37].

Therefore this work attempts to update information about the sources of silicon and nano-silicon in soil and agricultural crops. Silicon cycling and its bioavailability in soils, factors affecting this bioavailability to plants, and its uptake by plants particularly under stress will also be handled.

1.2 Sources of silicon and nano-silicon in soils

1.2.1 Silicon in soils and its forms

Silicon is surrounded in the periodic table near as boron (B), carbon (C), nitrogen (N), oxygen (O), phosphorus (P), and sulfur (S) all of which considered as important nutritional elements, as well as aluminum (Al), gallium (Ga), germanium (Ge), and arsenic (As), all considered as nonessential and/or harmful elements. Silicon levels in rocks range from 23% to 47% (basalt to orthoquartzite) [38], depending on soil types. Desilification and fertilization processes are active in certain heavily weathered soils, that is, latosols or latosolic red soils in the tropical regions. Carbonaceous minerals, such as limestones and carbonites, contain trace quantities of Si [38,39]. Silcretes are a form of derived soil that contains a sufficient amount of Si (more than 46%). The percent of Si in the petrocalcic horizon is much smaller than silcretes (8%), and the quantity of Si in minerals present in certain strongly weathered Oxisols is even lower [17,38]. Most of the soils are high in Si, some soils are low, especially the plant-available type of Si [40]. These types of soils include the Oxisols and Ultisols, which are highly weathered, leached, acidic, and low in base saturation [41], and the Histosols, which have a lot of organic matter but very little mineral content [42]. Furthermore, soils with a high proportion of quartz sand and those that have been subjected to long-duration plant productivity have low availability of Si in plants [17,43].

The biogeochemical conditions are the main factors controlling the fractions and availability of Si in soils [44], where Si can increase the availability of phosphorus in Artic soils as nonagricultural or anthropogenic management practices [45]. In soils, Si is separated into three phases: liquid, adsorbed, and solid [39,46,47]. Sauer and Burghardt [47] listed silica as one of the crystalline types of Si in the solid phase fraction. The crystalline of primary and secondary silicates, which are common in mineral soils produced from rocks and sediments, were previously the only crystalline types [43,48,49]. Quartz and disordered silica make up the majority of the silica products (Fig. 1.1). The Si fractions in the solid phase also include amorphous, poorly crystalline, and microcrystalline shapes [39,43]. The soluble and adsorbed phases of Si are identical, except the soluble components are mixed in the soil solution, while the adsorbed phase components are retained on soil particles, Fe and Al oxides/hydroxides. The Si content and abundance in soil are highly dependent on soil-forming processes, and as a result, soil profile. Except for organic soils, mostly mineral soils are composed of sand particles (mostly SiO2), different types of primary crystalline such as olivine, augite, hornblende, quartz, feldspars-orthoclase, plagioclase, albite, and mica and secondary silicate are clay minerals such as illite, vermiculite, montmorillonite, chlorite, and kaolinite. In most cases, these silicates are very sparingly soluble and bio-geochemically inert. Polymerized silicic acid is only partly water soluble in soil, while monosilicic acid (H4SiO4) soluble in water. Inorganic, organic, and organic–inorganic complexes in soil, such as clays, organic matter, and organic–inorganic complex, can be adsorbed with water soluble [40,43,50,51].

Figure 1.1 A brief demonstration for transformation of nanoparticles in soil and plant systems. This transformation includes different pathways in soil and plant systems. This transformation in plant system may include the accumulation on root surfaces or different assimilation methods in plants cells, whereas the transformation in soil system may be happened through the physical or chemical methods.

1.2.1.1 Silicon in solid forms

The three major types of Si in the solid state are amorphous forms, poorly crystalline and microcrystalline forms, and crystalline forms. The crystalline types of Si, which are primarily used as silicates and silica materials (primary and secondary), account for the majority of Si in the solid phase. Sand and silt particles comprise the main mineral-bearing silicates inherited in soils, while the secondary silicates are found in clay particles formed by pedogenic processes involving phylo-silicates and Al-Fe oxides/hydroxides [4,43]. The Si exists in poorly crystalline and microcrystalline types, that is, short-range ordered silicates and chalcedony and secondary quartz [43]. Short-range ordered silicates in soil horizons are favored when pH H2O > 5.0 [52], and imogolite is formed by the precipitation of H4SiO4 with Al hydroxides [39,53,54]. Amorphous forms include biogenic and lithogenic forms and they are present in soils ranging from 1 to 30 mg g−1 on soil mass basis [55]. The biogenic types, which are made up of plant residues and microorganism remains, are referred to as biogenic opal. Plants accumulate Si as silica bodies or phytoliths in their leaves, culms, and stems, while microorganisms contribute as microbial and protozoic Si [43,56]. When soluble Si in the soil is supersaturated, opal A is formed [55]. The solubility of various types of Si in the solid phase has a broad impact on its content in the soil. The solubility of silica-bearing minerals is depending on the density of silica tetrahedral and wide-range crystals [55,57]. Amorphous silica is expected to contribute more than quartz due to its higher solubility (1.8–2 mM silicon). Similar to quartz, amorphous silica dissolution rates increased linearly with saturation but exponentially dependent on the electrolytes [58]. Since quartz is extremely stable and thermodynamically resistant to weathering, its solubility ranged from 0.10 to 0.25 mM silicon [38]. As a result, if quartz is abundant in both residual and transported parent products, it will have a marginal contribution to Si in soil solution. Biogenic-based silica had higher (17-folds) solubility than quartz [59]. Since the release rate from plants litter is unaffected by cellulose hydrolysis and the released silica does not form complexes with organic matter, phytolithic silica is referred to as a pure inorganic lake [60]. The solubility of both crystalline and amorphous silica is approximately constant between pH 2.0 and 8.5, but it rapidly increases at pH 9.0 due to the decrease in H4SiO4 concentration in the soil solution [61], allowing crystalline and amorphous silica to dissolve to replenish or buffer the decreased H4SiO4 level in soil solution [40]. The plant available forms of Si present in soil ranging from 10 to over 100 mg kg−1. Less than 20 mg kg−1 Si are considered as poor and are mostly advised to amendment of Si in soil [51,62].

1.2.1.2 Availability of silicon in soil

Silicon is present in a number of forms in the soil solution, including monomeric (H4SiO4, the plant bioavailable form), oligomeric, and polysilicic acid [50]. Some dissolved silicic acid in the soil solution forms complexes with organic and inorganic compounds. Polysilicic acids with a maximum degree of polymerization are classified as polymeric or high-molecular-weight-silica, whereas oligomeric or low-molecular-weight-silica has H4SiO4 chains up to 10 Si atoms in length [43]. Different types of oligomeric and polysilicic acids can be found [48]. Plant absorption and nutrition are affected by monosilicic acid, while soil aggregation is affected by polysilicic acid. As per Norton [63], polysilicic acid creates silica bridges between soil particles, which improves soil aggregation and water-holding and buffering capacity, particularly in light-textured soils. After a month of incubation with silicon-rich materials, soils of various textures have increased their water-holding ability [46]. Uncharged H4SiO4 is present in typical soils (pH 8 or less) [40]. At pH values greater than 9, H4SiO4 dissociates into H+ + H3SiO4 and then 2H+ + H2SiO4 2 at pH values greater than 11. When the silicic acid content is high and the pH is greater than 9, the formation of stabilized, multiple chains of H4SiO4 occurs [64]. The various types of silicon dioxide, silicate minerals, and plant residuum are the main sources of H4SiO4 in the soil solution. The amount of H4SiO4 produced by various SiO2 types is determined by their physicochemical properties. The H4SiO4 content in the soil influences the amount of SiO2 in the soil. The minerals that are insoluble and weather resistant, such as feldspar and a variety of silicates complex including circone, garnet, and tourmaline, add a less quantity of silicon to the soil [50,65].

Many factors influence the amount of H4SiO4 in the soil solution, which may include soil pH, temperature, size-shape, content of water and organic matter and potential of redox. These factors may influence the solubility of silicon-containing minerals [39,51]. The pH of the soil influences silicon solubility and mobility. The level of H4SiO4 in the soil solution depends on adsorption–desorption processes, which are highly dependent on the soil pH [66]. The amount of adsorbed H4SiO4 increases in soils with a lot of allophanes, Fe-enriched minerals of crystals, and particularly the more reactive multivalent metal hydroxides. The generation of SiO2 deposits in the form of crusts is increased during evaporation, transpiration, and freezing processes [67]. Liming and high organic matter content reduce the concentration and mobility of H4SiO4 in the soil solution, while acid-producing fertilizer application raises H4SiO4 content in soil solution [39,43,68,69].

1.2.1.3 Adsorption of silicon on solid phases

Dissolved silicic acid fractions are absorbed on a variety of solid phases in soils, such as clay particles and Fe and Al hydroxides [70,71]. The adsorption of secondary clay minerals is responsible for a minor loss in the level of Si in the soil solution [43,72]. The Fe and Al hydroxides, on the other hand, have a high adsorption potential and can extract substantial quantities of dissolved silicon from the soil solution [50]. The adsorption of monosilicic acid by oxides influenced the soil pH, redox potential (Eh), and metallic form. From pH 4 to 9, the amount of monosilicic acids adsorbed by oxides increases, and when the oxides of metals in the soil are Al-based rather than Fe, the amount is significantly higher. Ponnamperuma [73] found that increasing the waterlogging period of soil resulted in a loss of Eh, as well as an enhancement in the solubility of Si in soil [74,75]. In general, silicic acid is adsorbed onto secondary Fe-based oxides; a large quantity of silicic acid is adsorbed onto short-range, ordered ferrihydrite than crystalline goethite [39,76]. The group of OH in Fe-oxide surface is replaced with H4SiO4, resulting in the formation of a bi-dendatesilicate inner-sphere complex [77–79]. Polysilicic acid is produced when the Fe-oxide surface interacts with the orthosilicic acid in a specific way [50]. Since Fe oxides are abundant in soil, even if their silicon adsorption ability is low efficient than that of Al oxides, the iron oxides can regulate the H4SiO4 content in the soluble phase to some extent [40,75,80,81].

1.2.2 Silicon cycle in soil and its bioavailability

In soil, the Si cycle is influenced by solid, liquid, and adsorption rate of silicon. In the soil, the soluble silicon is presented in H4SiO4, polymerized and complexed silicic acid, with the form of uncharged H4SiO4 being absorbed by the plants and microorganisms [4]. Inside plant tissues or microorganism cell structures, absorbed Si is deposited as polymerized silica. Litter and microorganism remain return these polymerized silica bodies to the top soil, where they eventually join the highly soluble biogenic silica reservoir, which contributes to soil silicon [59,61,82,83]. Silicon is also applied to soils through organic manure and compost applications, and the decomposition of silicon-rich manure will enhance the availability of Si in the soil [40,84]. The biochemistry of Si in the liquid phase is controlled by a number of processes, including (1) the dissolution of silicon containing the minerals of primary and secondary, (2) vegetation and microorganisms absorption of H4SiO4 in the soil, (3) Si adsorption on and desorption from different solid forms, and (4) the preservation of stable Si in the soil structure (silica polymer), that is, fertile soil. By atmospheric deposition, wind-blown dust and phytolith particles from savanna fires often add Si to the soil [85–87]. However, as compared to the other silicon inputs to the soil-plant system, the contribution of silicon from the atmosphere to the soil solution is very low [86].

1.2.2.1 Soluble silicon in soils and its bioavailability

Monosilicic acid (H4SiO4) is available in soil solution [88]. The silicate solubility depends on H4SiO4, which varies thermodynamically from ca. 10² to 10⁴ M (amorphous to quartz), corresponding to the soil Si 10³ M [89]. Despite this, the observed content of monosilicic acid (H4SiO4) in soil was about 0.1–0.6 mM [40,54,56,88], which is much lower than in saturated monosilicic acid solution and is primarily regulated by pH-dependent processes of adsorption–desorption on sesquioxides [39]. The sufficient quantity of Si can be absorbed by plant roots during the growing season, which is referred to as usable Si in soils, and it is typically used as a measure of the soil’s Si-supplying ability. Monosilicic acid is the most common source of Si absorbed and transported by plants. H4SiO4 readily polymerizes into polymeric Si(OH)4 in a monosilicic acid-saturated soil solution, where it is in a complex equilibrium with the form of silicates of amorphous and crystalline, exchangeable silicates, and sesquioxides [43]. Usable Si in soils is made up of monosilicic acid in soil solution and fragments of silicate element that can be smoothly converted into monosilicic acids (polymerized silicic acid, exchangeable silicates, and colloidal silicates). Soil Si is mostly found as monosilicic acid (pH 2–9), particularly at physiological values of pH, and transformation of monosilicic to ionic silicates is only possible at pH >9. The main factors affecting soil Si availability or Si-supplying strength are the types of soil and raw material, historical land-use changes, pH of soil, soil profile, soil Eh, organic matter, ambient air temperature, and corresponding mineral ions [39,50,51,90–92]. The degradation of grassland ecosystem due to intense human disturbance and drying climate can also impact the Si-distribution and bioavailability in soil [93]. Many studies were carried out for better understanding of the bioavailability of silicon in soils (e.g., [94–96]).

1.2.2.2 Soil pH, soil organic matter, and its texture

Monosilicic acid concentration has highly influenced the pH of the soil. The lowest level of monosilicic acid is located at pH 8–9, low or high which the level of monosilicic acid greatly enhances. When the pH of the soil solution drops from 7 to 2, the Si content in the solution can rise dramatically [97]. Various demonstrations have been shown that the availability of Si in soil is strongly linked to soil pH [50,98–102]. The key explanations are that a portion of the carbonate-bound silicates collected by the solution of buffer acetate (pH 4.0) is inaccessible to plants, and acetate buffer approach measured the Si supply potential of these calcareous soil [40,103,104]. Numerous demonstrations have been found that the soil with high or sandy texture is generally low in the availability of Si and thus have minimum Si-uptake strength, while soils with a hard or appropriate Si are in clay texture [57,98,100,101,104]. Minerals of clay soil with the highest specific surface have more efficiency to adsorb, and soil-available silicon level is significantly associated with the clay soil texture [104–106]. According to various studies, soil-available Si concentration potentially associated with physical clay fraction (0.01 mm) but not with smaller clay fraction (0.002 mm) in soil [107,108]. The soil particle size depends on the availability of Si in soil that depends on the acidity of soil condition [98]. Clay content and soil pH were substantially significantly correlated with the available Si content in acid soils (pH below 6.5), while pH, silt, and sand fractions were adversely related to Si available in soils (pH more than 6.5) [65,87]. So far, there have been contradictory demonstrations on the impact of soil organic matter on Si availability. The majority of authors accepted that the available Si in soil is significantly linked with organic matter of soil [101,108], while others conclude that there is no or even a nonsignificant association between available Si in soil and organic matter [101,107,108].

1.2.2.3 Adsorption–desorption balance

The mechanism of Si adsorption on active soil and desorption of soluble Si in the soil solution was found to control the plant-available Si fractions in the soil texture [43,50]. As a result, it was discovered that the characteristics of the soil adsorption complex (the phenomenon of sorption and desorption) have a significant impact on the available Si fraction in plants [109,110]. Soil sorption–desorption properties are largely determined by soil forms and soluble or amorphous Si. It was discovered that the desorption of Si from calcareous silty-loam soil suspension differed between standard and Si applied plants [111]. According to the experimental findings [111,112], the solubility of Si in different soil textures in which equilibrium was approached from under and supersaturation, the SiO2 (in soil) level was 103.10 M, which was intermediate between quartz and amorphous silica. SiO2 can be heavily leached out of soil profiles and become depleted due to desilification and fertilization during the weathering and soil-forming phase in highly weathered tropical soil, that is, oxisols. As a result, sesquioxides, not clay minerals of silicate, dominate the residual secondary minerals. H4SiO4 solubility in soils is lower than quartz (10⁴ M). Soil sorption and desorption characteristics appear to be heavily influenced by soil types, pH, and clay type [43].

1.3 Nano-silicon role in soils

National NPs are common in soil and are highly mobile and chemically reactive. These natural NPs have also a central role in buffering soil systems. They also can serve in limiting the concentration of potential toxic metals and providing a supply of metals for biochemical reactions [113]. However, engineered NPs like NS in agroecosystems still remain largely unknown. NS has several roles in improving the efficiency of agrochemicals, soil health, and crop production [114]. The transformation of these NPs in soil is controlled by several chemical, physical, and biological reactions, which are highly dynamic processes and their fate, behavior, and biological impacts are controlling these NPs in soils [114]. Many drivers can also control the transformation of these NPs (and their processes) in soil such as soil organic matter (through the aggregation), ionic strength (by the aggregation), soil pH (by the aggregation and dissolution), redox potential (Eh; by reduction and oxidation), inorganic ligands (through sulfidation, chlorination, and phosphorylation), and microorganisms, which control all physical and chemical transformation [114]. There is a need for more investigations about the fate and behavior of NS in soils under environmental conditions. This behavior may depend on the properties of silicon NPs and soil characterizations (Table 1.1). The role of soil pH, soil salinity (EC), cation exchange capacity (CEC), soil texture, redox potential (Eh), and other soil properties may control the fate and behavior of nano-silicon in soil.

Table 1.1

RNS-SFe, Mercapto-propyltrimethoxy silane- and ferrous sulfate-modified nano-silica; CF, continuous flooding; AWD, alternate wetting and drying; CEC, cation exchange capacity; Eh, redox potential; SOM, soil organic matter; NA, not available.

1.4 Silicon and nano-silicon in plants

The role of silicon in plant nutrition has gained great concerns among several researchers, which confirmed the mitigative role of Si during unfavorable environmental conditions although there is no evidence about the essentiality of Si for higher plants [125]. Si has a distinguished role in mitigating plant nutritional stresses in mineral form or nano-form as reported in the following subsections. The main biological features of Si and nano-Si could also be listed in Table 1.2.

Table 1.2

1.4.1 Silicon role and its mechanism in plants

Silicon is a well-known and common mineral constituent of higher plants, but its essentiality still needs evidence. It has distinguished roles for stressful plants including abiotic and biotic stress as reported by several reviews, which confirmed this statement (e.g., [126–133]). Silicon (Si) is a macro-element and acts a vital function in plant cycles. Si is the eighth greatest common element in nature and the second greatest common element in the soil following O2; however, most of Si is not available to plants [9,29,126,134–137]. Plants can only absorb Si as monosilicic acid (H4SiO4), which is naturally present in the soil; however, the concentration varies depending on the soil properties (texture, pH, minerals, organic matter, and other factors). Above a certain concentration, the monosilicic acid accumulation in plant tissues causes SiO2 precipitation and eventual deposition in cell walls, phytoliths, trichomes, and silica bodies with the exception of strongly growing area of the cell [30,135]. It is reported that different Si transporter genes (e.g., LSi1, LSi2, and LSi6) were stated to help in the transportation of monosilicic in the plant [17]. While Si is not widely recognized as an essential nutrient, it is frequently regarded as a valuable element or structural element