Biostimulants for sustainable crop production - Biostimulants for sustainable crop production -

Plant biostimulants: a new paradigm for the sustainable intensification of crops Introduction The establishment of the term ‘biostimulant’Plant biostimulants as functional ingredients of fertilizing products Improving nutrient use efficiency Improving tolerance to abiotic stress Improving crop quality Improving the availability of confined nutrients in the soil or rhizosphere Identifying the bioactive constituents of plant biostimulants Humic and fulvic acids Seaweed extracts Protein hydrolysates Microbial biostimulants Conclusion Acknowledgments Where to look for further information References Bioactive compounds and evaluation of biostimulant activity Introduction Active components Data requirements Mode of action The omics approach Hormone-like activity and in vitro assays Conclusion and future trends References Non-microbial and microbial categories of biostimulants Humic substances (HS) as plant biostimulants in agriculture Introduction Production and characteristics of humic substances Humic substances and plant nutrition Effects of humic substances on soil Biological activities of humic substances Commercial humates in agriculture Conclusions References Seaweed extracts as plant biostimulants in agriculture Introduction Classification, legal requirements for biostimulant registration and the biostimulant market Effects and mode of action of seaweed extracts on plant primary and secondary metabolism Primary metabolites of seaweeds Plant growth stimulation Plant protecting agent Antibacterial properties of algal extracts Effect of seaweed extracts on plant physiology Seed germination Shoot growth Root growth Fruit set Product quality Effects and mode of action of seaweed extracts on abiotic stress tolerance of horticultural and agronomic crops Effect of seaweed extracts on modulation of the rhizosphere microbial population Conclusion References Biostimulant action of protein hydrolysates on crops Introduction Bioactive compounds Effects of protein hydrolysates on germination, growth, and yield of crops Soil nutrient availability and nutrient-use efficiency Crop tolerance to abiotic stress Product quality Conclusion and future trends Where to look for further information Acknowledgement References Silicon as a biostimulant in agriculture Introduction Silicon availability in fertilizers and growing media Plant accumulation, transport and deposition of silicon Si transport via passive and active transport systems Si location and deposition in plant tissue: beyond biosilicification Silicon and plant abiotic defense: drought and salinity Silicon and plant abiotic defense: tolerance to heavy metals Silicon and plant abiotic defense: tolerance to other environmental stresses Silicon and enhanced growth Si and hormonal influences Effects of Si on germination and enhanced growth Si and micropropagation Silicon and phytotoxicity Regulatory issues Summary and future trends Effect of Si on plant-growth promoting rhizobacteria and other beneficial microbes Seeing past silicic acid: availability and mobility of silica nanoparticles Enhancing Si accumulation in lower accumulators Si biofortification of foods Abbreviations Where to look for further information References Plant growth-promoting rhizobacteria (PGPR) as plant biostimulants in agriculture Introduction Plant growth promotion Plant growth-promoting rhizobacteria (PGPR) and abiotic stress Plant growth-promoting rhizobacteria (PGPR) against biotic stress Microbe-microbe interactions Production of antibiotics Competition for resources Microba-to-plant signalling Specialized antimicrobial compound production by plants Dangers of assuming the effectors or mechanisms are known Root exudates Interspecific and intraspecific microbial interactions in the rhizosphere Intermicrobial signalling affects on microbial metabolism Other forms of microbial interactions Conclusion and future trends Where to look for further information References Arbuscular mycorrhizal fungi as biostimulants for sustainable crop production Introduction Functions and benefits of arbuscular mycorrhizal (AM) fungi Bidirectional nutrient exchange Soil nutrient limitation Soil water limitation Soil quality Symptoms of arbuscular mycorrhizal (AM) associations in favourable environments Factors impairing mycorrhizal effectiveness Requirements for successful implementation of arbuscular mycorrhizal (AM) fungi in sustainable plant production Agronomical aspects Inoculum-related aspects The current market for mycorrhizal products Conclusion Where to look for further information References Innovation and practical applications Designing and formulating microbial and non-microbial biostimulants Introduction The biostimulant development process Generation of product ideas and preliminary assessments Process development Screening products for biostimulent activity and understanding their mode of action Quality control and safety Field trials Regulation and market positioning Industrialization and commercialization Industrial case study 1: mycorrhizal inoculants Industrial case study 2: vegetal-based protein hydrolysates Future trends References Plant biostimulants and their influence on nutrient use efficiency (NUE)Introduction Humic and fulvic substances Modes of action relevant to nutrient use efficiency Influence of humic substances on plant growth Plant nutrient uptake, nutrient solubility and utilization Conclusion Microbial biostimulants Arbuscular mycorrhizal fungi (AMF)Azotobacter and Azospirillum Modes of action relevant to nutrient use efficiency Arbuscular mycorrhizal fungi Azotobacter and Azospirillum Conclusion Seaweeds and algae Modes of action relevant to nutrient use efficiency Root growth Nutrient transport Nutrient assimilation and storage Conclusion Protein hydrolysates Modes of action relevant to nutrient use efficiency Direct effects of nutrient form in soils Root growth/morphology Nutrient transporter and assimilation Conclusion Conclusion and future trends References Combining plant biostimulants and precision agriculture Introduction Monitoring spatial variability in soil and plants Site-specific management based on uniform management zones Site-specific application of farming inputs Precision application techniques for biostimulants Case study: biostimulants in precision viticulture Conclusion and future trends Where to look for further information References