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Labella R, Bochicchio R, Addesso R, Labella D, Franco A, Falabella P, Amato M. Germination Behavior and Geographical Information System-Based Phenotyping of Root Hairs to Evaluate the Effects of Different Sources of Black Soldier Fly ( Hermetia illucens) Larval Frass on Herbaceous Crops. PLANTS (BASEL, SWITZERLAND) 2024; 13:230. [PMID: 38256783 PMCID: PMC10819484 DOI: 10.3390/plants13020230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024]
Abstract
Insect larval frass has been proposed as a fertilizer and amendment, but methods for testing its effects on plants are poorly developed and need standardization. We obtained different types of black soldier fly (Hermetia illucens) frass via the factorial combination of (a) two insect diets, as follows: G (Gainesville = 50% wheat bran, 30% alfalfa meal, 20% maize meal) and W (43% sheep whey + 57% seeds); (b) two frass thermal treatments: NT = untreated and T = treated at 70 °C for 1 h. We tested the effects on the germination of cress (Lepidium sativum L.) and wheat (Triticum durum Desf.) by applying 1:2 w:w water extracts at 0, 25, 50, 75 and 100% concentration. Standardizing frass water content before extraction affected chemical composition. Frass extracts showed high electrical conductivity (8.88 to 13.78 mS cm-1). The W diet was suppressive towards Escherichia coli and showed a lower content of nitrates (e.g., WNT 40% lower than GNT) and a concentration-dependent phytotoxic effect on germinating plants. At 25% concentration, germination indices of G were 4.5 to 40-fold those at 100%. Root and shoot length and root hair area were affected by diet and concentration of frass extracts (e.g., root and shoot length in cress at 25% were, respectively, 4.53 and 2 times higher than at 100%), whereas the effects of the thermal treatment were few or inconclusive. On barley (Hordeum vulgare L.) grown in micropots on a silty loam soil, root mass was reduced by 37% at high extract concentration. A quick procedure for root hair surface area was developed based on the geographic information system (GIS) and may provide a fast method for incorporating root hair phenotyping in frass evaluation. The results indicate that below-ground structures need to be addressed in research on frass effects. For this, phyotoxicity tests should encompass different extract dilutions, and frass water content should be standardized before extraction in the direction of canonical procedures to allow comparisons.
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Affiliation(s)
- Rosanna Labella
- School of Agriculture, Forestry, Food and Environmental Sciences, University of Basilicata, 85100 Potenza, Italy; (R.L.); (D.L.)
| | - Rocco Bochicchio
- School of Agriculture, Forestry, Food and Environmental Sciences, University of Basilicata, 85100 Potenza, Italy; (R.L.); (D.L.)
| | - Rosangela Addesso
- Department of European and Mediterranean Cultures, Environment, and Cultural Heritage, University of Basilicata, 85100 Potenza, Italy;
| | - Donato Labella
- School of Agriculture, Forestry, Food and Environmental Sciences, University of Basilicata, 85100 Potenza, Italy; (R.L.); (D.L.)
| | - Antonio Franco
- Department of Science, University of Basilicata, 85100 Potenza, Italy; (A.F.); (P.F.)
- Spinoff XFlies s.r.l., University of Basilicata, 85100 Potenza, Italy
| | - Patrizia Falabella
- Department of Science, University of Basilicata, 85100 Potenza, Italy; (A.F.); (P.F.)
- Spinoff XFlies s.r.l., University of Basilicata, 85100 Potenza, Italy
| | - Mariana Amato
- School of Agriculture, Forestry, Food and Environmental Sciences, University of Basilicata, 85100 Potenza, Italy; (R.L.); (D.L.)
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Pandey BK, Bennett MJ. Uncovering root compaction response mechanisms: new insights and opportunities. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:578-583. [PMID: 37950742 PMCID: PMC10773992 DOI: 10.1093/jxb/erad389] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 11/08/2023] [Indexed: 11/13/2023]
Abstract
Compaction disrupts soil structure, reducing root growth, nutrient and water uptake, gas exchange, and microbial growth. Root growth inhibition by soil compaction was originally thought to reflect the impact of mechanical impedance and reduced water availability. However, using a novel gas diffusion-based mechanism employing the hormone ethylene, recent research has revealed that plant roots sense soil compaction. Non-compacted soil features highly interconnected pore spaces that facilitate diffusion of gases such as ethylene which are released by root tips. In contrast, soil compaction stress disrupts the pore network, causing ethylene to accumulate around root tips and trigger growth arrest. Genetically disrupting ethylene signalling causes roots to become much less sensitive to compaction stress. Such new understanding about the molecular sensing mechanism and emerging root anatomical traits provides novel opportunities to develop crops resistant to soil compaction by targeting key genes and their signalling pathways. This expert view discusses these recent advances and the molecular mechanisms associated with root-soil compaction responses.
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Affiliation(s)
- Bipin K Pandey
- Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK
| | - Malcolm J Bennett
- Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK
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Mehra P, Fairburn R, Leftley N, Banda J, Bennett MJ. Turning up the volume: How root branching adaptive responses aid water foraging. CURRENT OPINION IN PLANT BIOLOGY 2023; 75:102405. [PMID: 37379661 DOI: 10.1016/j.pbi.2023.102405] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/06/2023] [Accepted: 05/20/2023] [Indexed: 06/30/2023]
Abstract
Access to water is critical for all forms of life. Plants primarily access water through their roots. Root traits such as branching are highly sensitive to water availability, enabling plants to adapt their root architecture to match soil moisture distribution. Lateral root adaptive responses hydropatterning and xerobranching ensure new branches only form when roots are in direct contact with moist soil. Root traits are also strongly influenced by atmospheric humidity, where a rapid drop leads to a promotion of root growth and branching. The plant hormones auxin and/or abscisic acid (ABA) play key roles in regulating these adaptive responses. We discuss how these signals are part of a novel "water-sensing" mechanism that couples hormone movement with hydrodynamics to orchestrate root branching responses.
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Affiliation(s)
- Poonam Mehra
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK.
| | - Rebecca Fairburn
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Nicola Leftley
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Jason Banda
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Malcolm J Bennett
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK.
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