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Attività biostimolante di idrolizzati proteici sulla crescita e sul metabolismo di ZEA MAYS L.
Full text linkThe Italian Law n. 217 April 29, 2007 ratifies that "It can be defined as a compound, with biostimulant properties or biostimulant, any compound able to contribute in a positive way to the improvement of plant nutrition and development, regardless of the presence of nutritional elements".
In this PhD thesis two proteic hydrolysates provided by ILSA S.p.A have been tested: a hydrolysate of alfaalfa (EM) and one of meat flour (FC), differing for chemical characteristics. Both the products have shown to be endowed with a giberellin-like activity. Maize seedlings have been treated for 48 h with 0,01 ml/l e 0,1 ml/l of EM or FC. Obtained results demonstrated that the tested products are able to promote the plant growth and to influence tissue concentration of both macro and micro elements.
The performed analyses also included the determination of the enzyme activities involved in the nitrogen assimilation (nitrate reductase, NR, nitrite reductase, NiR, glutamine synthetase, GS, glutamate synthase, GOGAT, aspartate aminotransferase, AspAT) and in the Krebs cycle (malate dehydrogenase, MDH; isocitrate dehydrogenase, IDH; citrate synthase, CS).
RT-PCR has been adopted in order to further confirm the results on enzyme activities and to investigate the possible transcriptional regulation of the nitrogen and carbon pathways due to the application of the two hydrolysates. The expression of the genes encoding for the enzymes NR = nitrate reductase, AS = asparagine synthetase, CS = citrate synthase, IDH = NADP+-isocitrate dehydrogenase, MDH = malate dehydrogenase,have been then analyzed.
The results show that the plants responded positively to the use of these products, also suggesting their possible role in the common agricultural practices.Il Decreto Legislativo del 29 aprile 2006 n. 217 sancisce che "è definito concime con proprietà di biostimolante o biostimolante, qualsiasi concime in grado di contribuire positivamente al miglioramento della nutrizione e allo sviluppo delle specie vegetali, indipendentemente dalla presenza di elementi nutritivi".
In questo elaborato sono stati saggiati due idrolizzati proteici forniti dalla ditta ILSA S.p.A.: un idrolizzato di erba medica (EM), ed un idrolizzato di farina di carne (FC), diversi per caratteristiche chimiche. Entrambi i prodotti hanno mostrato di possedere attività giberello-simile. Plantule di Zea mays L. sono state trattate per 48 h con 0,01 ml/l o 0,1 ml/l di EM o FC. Dai risultati ottenuti si può affermare che i prodotti saggiati sono in grado di promuovere la crescita delle plantule ed influenzare il livello dei macro e micro elementi. Le analisi condotte hanno previsto la determinazione in foglie e radici dell'attività di diversi enzimi implicati nell'assimilazione dell'azoto (nitrato reduttasi, nitrito reduttasi, glutammina sintetasi, glutammato sintetasi, aspartato ammino transferasi) e nel ciclo degli acidi tricarbossilici (citrato sintetasi, NADP+-isocitrato deidrogenasi, malato deidrogenasi). Al fine di confermare i dati ottenuti e di evidenziare un'eventuale regolazione trascrizionale dei componenti del metabolismo dell'azoto e del carbonio da parte dei due idrolizzati, l'espressione di geni codificanti per alcuni di questi enzimi (NR = nitrato reduttasi, AS = aspartato ammino transferasi, CS = citrato sintetasi, IDH = NADP+-isocitrato deidrogenasi, MDH = malato deidrogenasi) è stata successivamente analizzata via RT-PCR (Reverse Transcription Polymerase Chain Reaction). I risultati ottenuti mostrano una positiva risposta all'applicazione di questi prodotti suggerendo un loro utilizzo nella comune pratica agricola, affiancati ai fertilizzanti minerali
Effects of an Alfalfa Protein Hydrolysate on the Gene Expression and Activity of Enzymes of the Tricarboxylic Acid (TCA) Cycle and Nitrogen Metabolism in Zea mays L.
No full textThe effects through which an alfalfa protein hydrolysate (EM) possessing gibberellin- and auxin-like
activity may promote plant nitrogen (N) nutrition have been investigated in Zea mays L. Treatment
with 0.01 or 0.1 mg L-1 EM for 48 h resulted in enhanced plant growth and leaf sugar accumulation.
Concomitantly, the level of nitrates decreased, whereas total N percentage was unchanged. The
activity of a number of enzymes involved in carbon (C) metabolism (malate dehydrogenase, MDH;
isocitrate dehydrogenase, IDH; citrate synthase, CS) and N reduction and assimilation (nitrate
reductase, NR; nitrite reductase, NiR; glutamine synthetase, GS; glutamate synthase, GOGAT;
aspartate aminotransferase, AspAT) was significantly induced by EM supply to plants, and the
transcription pattern of MDH, IDH, CS, and NR strongly correlated with data of enzyme activity.
The transcript accumulation of asparagine synthetase (AS) was also induced by EM in the roots.
The results suggest that EM might promote nitrogen assimilation in plants through a coordinate
regulation of C and N metabolic pathways and open the way for further research on protein
hydrolysates as a valid tool to improve N use efficiency and, as a consequence, to reduce the intensive
use of inorganic N fertilizers in agriculture
Review: Long-term research activity on the biostimulant properties of natural origin compounds
No full textFor ten years the Department of Agricultural Biotechnology, University of Padua, supported by the company ILSA SpA, Arzignano, (VI), Italy, has been studying, via different methodologies, the biostimulant properties of products derived from different organic raw materials. The research activity includes the development of specific bioassays designed for understanding the biological activity of the various compounds and the evaluation of their effects on maize metabolism, grown under controlled conditions. Plants treated with these products confirmed their biological activity in terms of capacity to increase plant growth and stimulate plant nitrogen and carbon metabolisms. In addition, the effects of phenol-containing organic substances derived from agro-industrial byproducts were assayed on phenylpropanoid metabolism. Phenol-containing products, in particular, increased plant antioxidants, key elements for human health. The products also increased plant biomass, exerted a positive role on nitrogen metabolism and stimulated the activity and gene expression of phenylalanine ammonia-lyase, the first enzyme of the phenylpropanoid pathway. Our results indicate that biostimulants can be used as bioactive products in agriculture to increase plant yield and resistance to stress conditions
Sostanze umiche in: Biostimolanti Per Un’agricoltura Sostenibile. Cosa sono, come agiscono e modalità di utilizzo
No full textMini review: fruit residues as plant biostimulants for bio-based product recovery
Full text linkThe request of natural products has augmented in the last years due to the increase in intolerance and allergy reactions showed by humans versus pesticides and certain chemical compounds used in agriculture. In response to this demand, innovative methods and new natural matrices have been exploited to obtain products able to increase plant nutrients use efficiency. In this context, agro-industrial residues contain bioactive molecules, including antioxidants and phenols, which may be used by farmers to improve crop productivity. Phenols are ubiquitous in plants and are essential components of the human diet by virtue of their antioxidant properties. They may also act as positive growth regulators by modifying the root architecture and, consequently, the uptake of macronutrients, potassium especially. In order to understand their effects on the plant metabolic pathways, agro-industrial residues were supplied to maize plants and the activity of specific enzymes was evaluated. In this review, developments and improved understanding on fruit residues on primary and secondary plants metabolism are discussed
VALUTAZIONE DEGLI EFFETTI BIOSTIMOLANTI DEI SOTTOPRODOTTI DELL'INDUSTRIA AGRO-ALIMENTARE SUL METABOLISMO DI Zea Mays L.
No full textInteractions between plant-root exudates and soils in extracting humic-like substances
No full textPlants have evolved with roots in close contact with the solid phase of the soil therefore organic acid root exudates, in plant–root–microbial interactions, have attracted much interest not so much in terms of carbon source but as ‘signals’ for recognition or as precursors of phytohormone production (Marschner, 1995). Recent studies have demonstrated that organic acids (fumaric and succinic acids) occurring in the root exudates can dissociate HS in low and high molecular weight structures. This interpretation may support the hypothesis that the conformational behavior of dissolved humus in the rhizosphere, and therefore also the interaction of humic components with plant-root cells, may be controlled by the presence of root-exuded or microbe-released organic acids in the soil solution (Piccolo et al., 2003). Therefore, root exudates may be a better medium for extracting low molecular size (LMS) organic fractions than currently used alkaline solutions. Our objective was to compare the chemical and biological activity of LMS extracts using maize (Zea mays L.), and two forest species (Picea abies and Pinus sylvestris) root exudates to humic substances extracted by KOH (Stevenson, 1994). The identification of some organic acids species present in extracts have been investigated by GC/MS technique and the biological activity of the LMS humic/organic substances extracted was evaluated by determining their hormone-like activity. Two forest species (Picea abies Karst. and Pinus sylvestris L.) and two commercial maize hybrids (Zea mays L.: cultivars Mytos and Samantha; Dekalb, Italy) were used for this study. The root exudates were collected from maize seedlings treated with sterile Hoagland’s solution (Hoagland and Arnon, 1950), and forest plants raised in sterile conditions as described in a previous work (Nardi et al., 1997). Root exudates were determined as reported in Nardi et al. 2002. The LMS humic/organic substances were obtained by treating 2 g of an Eutric cambisol (EC) and a Rendzic leptosol (RL) (A horizons) with 20 ml of water or 20 ml of root exudates and shaken them at room temperature for 16 h under a N2 atmosphere. The suspensions were centrifuged at 10 °C and 5000 g for 30 min and the supernatants (extracts) were analyzed for total carbon. We ascertained that agrarian and forest seedlings release different types of exudates in the rhizosphere, and they have higher extracting abilities towards carbon then water when in contact with poorer substrates. Maize exudates are endowed with fumaric and succinic acids, while the forest ones exhibited only large amounts of succinic acid. GC/MS spectra revealed that the LMS fractions had a greater variety of fatty acids than the HS. The behaviour of these species could be related to their different environmental conditions (Ingestad, 1960). All soil extracts by exudates exhibited a hormonal activity that was not present in either water extracts or in the original exudates. The extracts from agrarian soil exhibited a higher hormone-like activity with respect to the extracts from forest soil. Concerning phenol content in the humus extract obtained by using the exudates, benzoic acid and in minor extent phtalic acid resulted to be the more present. Analysis of the phenolic pool demonstrated specificity on the extracted molecules not directly correlated with phenols present in pure exudates. Studies have shown that phenolic compounds have been found to be highly effective in plant defence against pathogens, nematodes, phytophagous insects (Rich et al., 1977; Russel et al., 1978; Dakora, 1995; Dakora and Phillips, 1996). In particular, benzoic acid is one of the most active phenolic compound inhibitors of fungi (Ravin et al., 1989; Weidenborner et al., 1989 & 1990). This paper reconfirms the important role of exudates in breaking out humic associations and in releasing hormone-like activities and pest inhibitors, suggesting the appropriate combination of factors for the best use of the humic fraction as plant growth regulators as well as plant pest control
Conoscere e valutare l'attività biostimolante
No full textI biostimolanti agiscono sul metabolismo vegetale ma, a differenza dei concimi, non basano la loro azione sull’apporto di elementi nutritivi ed è anche per questo che conoscere i meccanismi di azione delle sostanze umiche può aiutare gli utilizzatori a decidere le giuste dosi di applicazion
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