Biological Activities of Humic Substances

Nardi, Serenella; Carletti, Paolo; Pizzeghello, Diego; Muscolo, Adele

doi:10.1002/9780470494950.ch8

Cited by 115 publications

(77 citation statements)

References 130 publications

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“…This was a typical short-time effect that has been previously observed in treated plants with HSs or other biostimulants (Nardi et al, 2009; Azcona et al, 2011; Ertani et al, 2012). In a long period, when the plant reached maturity, the main effects were quantified in terms of considerable increases in the total fresh fruit weight as well as the total number of fruits with respect to the control.…”

Section: Discussionsupporting

confidence: 64%

“…The most frequent effects induced by biostimulants are an improved activity of soil microbiota (Corte et al, 2014), an increased production of growth regulators-like activity in both soil (Frankenberger and Arshad, 1995) and plants (Jindo et al, 2012; Pizzeghello et al, 2013), and an increased root development, which favors the adsorption of nutrients (Canellas et al, 2002; Nardi et al, 2002; Khan et al, 2009). In plants, biostimulants stimulated numerous metabolic pathways (Nardi et al, 2007, 2009; Schiavon et al, 2008; Ertani et al, 2012). Specifically, a cellulosolytic apple hydrolysate and a blueberry extract have been shown to increase maize growth via the induction of nitrogen and phenylpropanoid pathways, which increased photosynthetic efficiency (Ertani et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…The majority of studies on the effects of biostimulants in plants involve short-term experiments with seed germination and young plantlet growth, and little information is available on the maturity phase (Nardi et al, 2002, 2009; Rose et al, 2014). Recently, Pascual et al (2008) found that the application of sewage sludge positively affected the growth and fruit yield of pepper plants.…”

Section: Introductionmentioning

confidence: 99%

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Capsicum chinensis L. growth and nutraceutical properties are enhanced by biostimulants in a long-term period: chemical and metabolomic approaches

et al. 2014

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Two biostimulants, one derived from alfalfa plants (AH) and the other obtained from red grape (RG), were chemically characterized using enzyme linked immuno-sorbent assays, Fourier transform infrared (FT-IR) and Raman spectroscopies. Two doses (50 and 100 mL L−1 for RG, and 25 and 50 mL L−1 for AH) of biostimulants were applied to Capsicum chinensis L. plants cultivated in pots inside a tunnel. The experimental design consisted of the factorial combination of treatment (no biostimulant, plus AH, plus RG) at three doses (zero, low, and high) and two time-course applications (at the second and fourth week after transplantation) and the effects were recorded at flowering and maturity. Both biostimulants contained different amounts of indoleacetic acid and isopentenyladenosine; the AH spectra exhibited amino acid functional groups in the peptidic structure, while the RG spectra showed the presence of polyphenols, such as resveratrol. These results revealed that at flowering, RG and AH increased the weights of fresh leaves and fruits and the number of green fruits, whereas at maturity, the biostimulants most affected the fresh weight and number of red fruits. At flowering, the leaves of the treated plants contained high amounts of epicatechin, ascorbic acid, quercetin, and dihydrocapsaicin. At maturity, the leaves of the treated plants exhibited elevated amounts of fructose, glucose, chlorogenic, and ferulic acids. Moreover, green fruits exhibited a high content of chlorogenic acid, p-hydroxybenzoic acid, p-coumaric acid and antioxidant activity, while both AH- and RG-treated red fruits were highly endowed in capsaicin. The 1H high-resolution magic-angle spinning (HRMAS)-nuclear magnetic resonance (NMR) spectra of red fruits revealed that both products induced a high amount of NADP+, whereas RG also increased glucose, fumarate, ascorbate, thymidine and high molecular weight species. Our results suggested that AH and RG promoted plant growth and the production of secondary metabolites, such as phenols.

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Section: Discussionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Capsicum chinensis L. growth and nutraceutical properties are enhanced by biostimulants in a long-term period: chemical and metabolomic approaches

et al. 2014

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“…Current knowledge about the mechanism involved in the plant shoot-promoting action of DOM (and humic substances present in DOM) is rather fragmentary and poorly integrated into a consistent explicative model (Nardi et al, 2009;Trevisan et al, 2011;Berbara and García, 2014;Canellas and Olivares, 2014;Mora et al, 2014b). Indeed, the fact that HAs with diverse origins and structural features affect plant growth and development through common signaling pathways remains unexplained.…”

Section: Discussionmentioning

confidence: 99%

ABA-regulation of root hydraulic conductivity and aquaporin gene- expression is crucial to the plant shoot rise caused by rhizosphere humic acids

et al. 2015

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The physiological and metabolic mechanisms behind the humic acid-mediated plant growth enhancement are discussed in detail. Experiments using cucumber (Cucumis sativus) plants show that the shoot growth enhancement caused by a structurally well-characterized humic acid with sedimentary origin is functionally associated with significant increases in abscisic acid (ABA) root concentration and root hydraulic conductivity. Complementary experiments involving a blocking agent of cell wall pores and water root transport (polyethylenglycol) show that increases in root hydraulic conductivity are essential in the shoot growth-promoting action of the model humic acid. Further experiments involving an inhibitor of ABA biosynthesis in root and shoot (fluridone) show that the humic acid-mediated enhancement of both root hydraulic conductivity and shoot growth depended on ABA signaling pathways. These experiments also show that a significant increase in the gene expression of the main root plasma membrane aquaporins is associated with the increase of root hydraulic conductivity caused by the model humic acid. Finally, experimental data suggest that all of these actions of model humic acid on root functionality, which are linked to its beneficial action on plant shoot growth, are likely related to the conformational structure of humic acid in solution and its interaction with the cell wall at the root surface.

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“…These compounds are defined as bio-stimulants and include humic substances (HS) among others. HS can increase plant growth or even make a crop less susceptible to stressful conditions by several modes of action: activation of numerous plant metabolism pathways, increased activity of several soil enzymes, stimulation of microbial activity and an enhanced production of hormones in the soil or growth regulators in plants [189,190]. Using similar processes to those for extracting HS from the soil, peat, leonardite or lignite, organic fractions which are defined as humic-like substances (HLS) can be extracted from composted organic wastes.…”

Section: Fertilizer Production From Cull Tomato and Tomato Processingmentioning

confidence: 99%

Processing, Valorization and Application of Bio-Waste Derived Compounds from Potato, Tomato, Olive and Cereals: A Review

Fritsch

Stäbler

Happel³

et al. 2017

Sustainability

151

102

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Abstract:The vast and ever-growing amount of agricultural and food wastes has become a major concern throughout the whole world. Therefore, strategies for their processing and value-added reuse are needed to enable a sustainable utilization of feedstocks and reduce the environmental burden. By-products of potato, tomato, cereals and olive arise in significant amounts in European countries and are consequently of high relevance. Due to their composition with various beneficial ingredients, the waste products can be valorized by different techniques leading to economic and environmental advantages. This paper focuses on the waste generation during industrial processing of potato, tomato, cereals and olives within the European Union and reviews state-of-the-art technologies for their valorization. Furthermore, current applications, future perspectives and challenges are discussed.

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Biological Activities of Humic Substances

Cited by 115 publications

References 130 publications

Capsicum chinensis L. growth and nutraceutical properties are enhanced by biostimulants in a long-term period: chemical and metabolomic approaches

Capsicum chinensis L. growth and nutraceutical properties are enhanced by biostimulants in a long-term period: chemical and metabolomic approaches

ABA-regulation of root hydraulic conductivity and aquaporin gene- expression is crucial to the plant shoot rise caused by rhizosphere humic acids

Processing, Valorization and Application of Bio-Waste Derived Compounds from Potato, Tomato, Olive and Cereals: A Review

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