Germination Of Lepidium Sativum Research Articles

Lanthanum and cerium functionalised forestry waste biochar for phosphate removal: Mechanisms and real-world applications

Phosphorus as a diminishing finite resource, yet is an essential element for the growth of biota. However, elevated concentrations in water can imbalance ecosystems and cause eutrophication. To address both problems, two highly efficient biochars, namely La-OB and CeLa-OB were synthesised by lanthanum and cerium doping. The performance of La-OB and CeLa-OB were evaluated in both batch and dynamic regimes with synthetic phosphate (PO43--P) solutions and eutrophic lake water. PO43--P adsorption mechanisms were investigated in terms of pH, kinetics, isotherms, activation energy, thermodynamics and using in-depth characterisation (XPS, FTIR, XRD, BET, pHpzc and SEM-EDX). The feasibility of using such biochar in ‘real life’ situations was studied with column filtration of lake water with low and high PO43--P concentrations. Reusability/desorption and toxicity in the water environment was also considered. The mechanistic study showed that both biochars predominantly had inner-sphere complexes with La and Ce ligands (as a monolayer), while outer-sphere complexation was less common. The exothermic adsorption process followed the Elovich kinetic and Langmuir isotherm models, with a maximum adsorption capacity of 112 mg/g for La-OB and 40 mg/g for CeLa-OB. In column filtration trials the adsorption capacity reached 78 mg/g, while low metal leaching (0.08 mg/L) and low toxicity to Lepidium sativum germination were detected. The results indicated that these biochars, especially La-OB, could be used in circular economy-based water treatment.

Sulfonic Cryogels as Innovative Materials for Biotechnological Applications: Synthesis, Modification, and Biological Activity.

Polymeric hydrogels based on sulfo-containing comonomers are promising materials for biotechnological application, namely, for use as a system for delivering water and minerals during seed germination in conditions of an unstable moisture zone. In this work, cryogels based on 3-sulfopropyl methacrylate and 2-hydroxyethyl methacrylate copolymers were obtained by the cryotropic gelation method. The morphology, specific surface area, and swelling behaviors of cryogels are found to depend on the total concentration of monomers in the reaction system and the content of the gel fraction in cryogels. Cryogels formed in the presence of nanodiamonds are shown to exhibit high biological activity during the germination of Lepidium sativum L. variety Ajur seeds, which manifests itself by stimulating seed germination and a significant increase in the raw weight of sprouts. These results indicate that sulfonic cryogels have a high potential to improve seed germination and plant growth, proving that such cryogels can be used as environmentally friendly materials for agricultural applications.

Allelopathic potential of Helleborus dumetorum and its prospects for conservation with gardening

To tackle global biodiversity loss, we will need to sustain biodiversity beyond protected areas. Here we present a case study of a rare and threatened native species Helleborus dumetorum. First, we assessed by laboratory experiments if H. dumetorum has a competitive advantage over weeds because of its allelopathic potential; secondly, we reviewed the literature to discuss if this threatened species could be conserved as an ornamental species for gardening while at the same time its cultivation would benefit local biodiversity. Using bioassays, we tested the allelopathic potential of aqueous extracts of H. dumetorum leaves and of soil samples, collected at or away from H. dumetorum plants, on garden cress Lepidium sativum germination and seedling development. The results confirmed the presence of H. dumetorum aqueous allelochemicals in leaves as well as allelopathic effects of the soil where H. dumetorum was growing, supporting the competitive advantage of H. dumetorum. Literature review combined with our observations in the field indicated more characteristics of H. dumetorum suitability for ornamental purposes and species’ conservational opportunities: easy and successful transplanting, survival in various habitats, no invasive potential, flowering in early spring, long-lived leaves. Our study shows, that considering threatened native plants for ornamentals could have a multitude of benefits for local biodiversity.

In vitro study of the antimitotic power and in vivo acute toxicity of aqueous and organic extracts of the aerial part of Haloxylon scoparium Pomel. and evaluation of the correlation between the chemical profile and their biological activities

The present study was conducted on the extracts from the aerial part of Haloxylon scoparium Pomel. The current research has focused on the evaluation of the antimitotic activity with the Lepidium sativum phytotest on aqueous (decocted, infused, macerated) and organic extracts (methanolic extract, methanolic macerated, ethyl acetate extract, chloroform extract and petroleum ether extract) extracts of the aerial portion of Haloxylon scoparium. In order to visualise the correlation between the content of chemical compounds in the aqueous and organic extracts with the results of the Lepidium sativum phytotest, we have used the principal component analysis (PCA). Then, we were interested in studying the acute in vivo toxicity of the methanolic extract and the decocted of Haloxylon scoparium. Antimitotic activity has shown that the methanolic extract exhibited high inhibition of Lepidium sativum germination (IC50=128.16±3.89 µg/mL) than colchicine (IC50=474.66±1.86 µg/mL). The decocted also showed high inhibition compared to the other aqueous extracts (IC50=1359.00±106.69 µg/mL). The correlation study showed that there is a strong correlation between Lepidium sativum phytotest and total polyphenol (r=0.9453) and flavonoid (r=0.9884) composition. In addition, the MLD50 of the methanolic extract and the decocted was estimated at 2000 mg/kg. The present study shows that Haloxylon scoparium could be a potential antimitotic of low toxicity.

Physicochemical Characteristics of Biochar from Waste Cricket Chitin (Acheta domesticus).

The properties of biochar (BC) from crustacean chitin are relatively well understood, while there are few studies on BC from insect chitin. This study presents the characterization and phytotoxic assessment of BC produced from crickets and cricket chitin. Cricket powder (BCCR) and cricket chitin (BCCH) were pyrolyzed at 500 °C and 700 °C. Physicochemical characteristics, N ad-/desorption, FTIR, were examined. SEM images were also performed. Regardless of the pyrolysis temperature, biochars were characterized by a densely "packed" solid surface/monolithic type with a non-porous structure (0.05-0.22 m2/g) and high content of N (9.4-11.8%). BCCHs showed a higher pH (12.2-12.4) compared to BCCR (8.7-10.8). Based on the XRD analysis, BCs were characterized by an amorphous carbon turbostratic structure and a randomly oriented graphitic-like micro-crystallite structure. FTIR spectra of BCs confirmed the presence of various O2 and N-functional groups on the BC surface. BCCHs added to soil at rates from 0.5 to 1.5% significantly reduced the germination of Lepidium sativum. Stimulation of root elongation was also observed in the case of BCCR500 1.0% and BCCR700 1.5%. Thermal degradation of cricket powder and cricket chitin promotes the formation of organic N-containing heterocyclic rings, which lead to the production of N-doped carbons with potential uses in energy storage and the contaminations sorption.

Coagulation and biofiltration by Corbicula fluminea for COD and toxicity reduction of swine wastewater

The increase on pork meat demand is consequently leading to higher production of swine wastewater. These wastewaters are problematic due to their high organic matter load and nutrients content that can promote soil and aquatic sources contamination. The conventional effluents treatment technologies seem to be inefficient for total organic matter and contaminants removal while demanding high retention times. One of the steps considered for the swine wastewater treatment is solid-liquid separation. In this work, coagulation using polyDADMAC was evaluated and the effect of the coagulant concentration for this purpose was tested. This methodology was compared with an innovative approach involving biofiltration through the invasive bivalve Corbicula fluminea. The effects of the liquid to clam’s ratio was assessed as well as the mechanism of organic matter removal and the clams reuse capacity. The best chemical oxygen demand (COD) removal obtained was 51 % using 1 L of effluent per 150 clams. Moreover, it was possible to reuse the clams during 4 cycles without losing significant efficiency on the COD removal. Moreover, the toxicity of the treated wastewater was evaluated regarding Aliivibrio fischeri and Lepidium sativum. Aeration without clams reduced the toxicity levels. However, for Lepidium sativum germination index the best result was obtained for the wastewater treated by clams. Thus, C. fluminea presents potential for swine wastewater treatment.

Phytotoxic potential of Vitex pseudo-negundo leaf and flower extracts and analysis of phenolic compounds

In the present study, aqueous extracts were obtained from the leaves and flowers of Vitex pseudo-negundo. The effects of these extracts were examined on the germination percentage and several developmental factors of three plant species, namely, Lepidium sativum, Amaranthus retroflexus and Taraxacum officinale. The major phenolic compounds of the leaf extract were Trans-ferulic acid (913.71 mg/L), Chloregenic acid (235 mg/L) and Hesperedin (115.68 mg/L), while those of the flower were Chloregenic acid (333 mg/L), p-Coumaric acid (256.04 mg/L) and Hesperedin (185.72 mg/L), as recognized by HPLC. The stock extract had a concentration of 10% (w/v) and was made from dried powders of the Vitex flower and leaf. The extract at 2.5% had a stimulatory effect on the seed germination of Lepidium sativum. A substantial increase (P ≤ 0.05) was observed in the germination percentage (98.3 and 96.6%, when using flower and leaf extract, respectively). The 7.5% extract (either leaf or flower) reduced root length to zero in A. retroflexus and T. officinale. However, in Lepidium sativum, there was a significant difference between leaf and flower extracts. At the same concentration (2.5%), leaf extract reduced fresh weight (0.43 g) more than the flower extract did (0.68 g). Taraxacum officinale and Amaranthus retroflexus showed a significant increase in the fresh weight of seedlings (0.2 g and 0.06 g, respectively) in response to the leaf extract (2.5%), compared to the control treatment, which indicates a stimulatory effect. In contrast, the highest concentration (7.5%) caused a significant inhibition (P ≤ 0.05%).

The Influence of New and Artificial Aged Microplastic and Leachates on the Germination of Lepidium sativum L.

With the increase in environmental monitoring and assessing, we are gaining insight into the extent of microplastic pollution in our environment. The threat posed by microplastics to biota could come, e.g., from leached substances. As some plastic materials have been decaying in nature for extended periods already, the toxic effects of leaching compounds need to be investigated. It is furthermore essential to understand the adverse effects of new plastic and how these effects differ from the effects elicited by old plastic material. Therefore, in the present study, the effects of exposure to leachates from new and artificial aged polycarbonate as well as new and aged polycarbonate granules on various germination parameters of Lepidium sativum were studied. Germination, root, and shoot length, as well as the calculated germination rate index as a measure for germination speed, was negatively influenced in substrate-free and substrate containing exposures. From an ecological and agricultural point of view, this implies possible yield losses with less germinating seeds, slower plant germination speed, and smaller seedlings in general.

Auxin like en humus líquido

Objetivo: Evaluar el efecto de muestras de humus líquido (HL) en el porcentaje, índice y velocidad de germinación de Lepidium sativum, Medicago sativa y Raphanus sativus.
 Diseño/metodología/aproximación: Se evaluó el efecto de muestras de humus líquido (HL), que se obtuvo a partir del extracto acuoso de una vermicomposta comercial. Se realizó un diseño completamente al azar empleando diferentes gradientes de concentración HL:agua (1 a 10-4 mg mL-1) y se comparó con el efecto de un gradiente de concentración de 10-10 a 10-2 mol L-1 de ácido indolacético (AIA). Se realizó un análisis de espectroscopia de infrarrojo a las muestras de HL y AIA, para la identificación de compuestoy/o estructuras moleculares similares entre ambas muestras.
 Resultados: Las semillas menos sensibles a los compuestos bioactivos presentes en la muestra de HL son M. sativa al presentar menor inhibición en todos los tratamientos, siendo más sensibles las semillas de L. sativum y R. sativus. Los tratamientos TC, TD y TE correspondientes a los extractos de HL mostraron tener ctividad biológica similar a los tratamientos T06, T07 y T08 del AIA, siendo el índice de germinación el principal bioensayo en donde se observa esta respuesta. El análisis de FT-IR del extracto de HL mostró semejanza al ser comparado con el espectro de AIA, encontrándose similitudes en las bandas correspondientes al grupo indol, que es el grupo funcional base del AIA.
 Limitaciones del estudio/implicaciones: Se recomienda realizar en una segunda etapa de investigación que incluya la extracción de compuestos indólicos a muestras de HL y su posterior purificación eidentificación, mediante técnicas espectroscópicas
 Hallazgos/conclusiones: Los efectos estimulantes e inhibitorios de la germinación se deben a la presencia de compuestos bioactivos con actividad biológica similar a los reguladores del crecimiento vegetal, por ello se analizaron las muestras de HL, empleando un equipo de espectroscopia de infrarrojo, encontrándose señales de compuestos con grupos funcionales similares al AIA. Esto nos permite dejar abierta la posibilidad a la presencia de AIA y buscar la caracterización del extracto de HL empleando técnicas de purificación e identificación como la espectrometría de masas.

Composts and Water Extracts of Lignocellulosic Composts in the Aspect of Fertilization, Humus-Forming, Sanitary, Phytosanitary and Phytotoxicity Value Assessment

PurposeLignocellulosic biomass waste is produced in large quantities and only a small part is used for utility purposes. The aim of the work was to assess the fertilization value of the solid fraction and water extract of lignocellulosic composts.MethodsCompost I contained 42.86% pine bark, 34.28% grass, 20.0% sawdust and 2.86% chicken feathers; compost II contained 25.54% pine bark, 10.63% wheat straw, 51.07% sawdust and 12.76% chicken feathers. Seldom described physical properties and phytosanitary and sanitary status of composts as well as macro- and micronutrients and heavy metals concentrations were determined in the solid fraction and water extracts of composts and their impact on the germination of Lepidium sativum L. using PC analysis.ResultsComposts were characterized by good physical properties and a light product, safe phytosanitary status, which was related to the prevalence of potentially antagonistic fungi, especially in compost II. The frequency of Aspergillus fumigatus, considered an opportunistic human pathogen, decreased during the composting. Heavy metal concentrations did not exceed permissible values for improvers and cultivation media in the solid and aqueous compost fractions. The tested composts were sanitary safe. Both composts were non-toxic to plants, because the germination index in compost I was 70–195% and 95–195% in compost II. PCA analysis demonstrated that the majority of micro- and macronutrients and heavy metals had a significantly negative effect on root elongation and germination of the test plant (cress) seeds, especially in compost I.ConclusionsLignocellulosic waste after composting is a valuable and safe organic fertilizer.

Habitat Preference Within Its Native Range and Allelopathy of Garlic Mustard Alliaria petiolata

Even though Alliaria petiolata is a globally important invasive plant, for Europe it is a native humble understory species. I studied the population characteristics of A. petiolata in its native range (NE Slovenia) by evaluating its demographic structure (e.g. population size, density, plant fruit production) and herbivory damage in different habitats (forest understorey, forest edge, ruderal site). Moreover I tested the allelopathic potential of fresh A. petiolata leaves and roots on garden cress Lepidium sativum germination and seedling development. I performed bioassays with aqueous extracts and took a first step toward testing the presence of volatile potentially allelopathic compounds. The results showed that A. petiolata populations can become established at disturbed sites, even such without a tree canopy, but dense stands can be found only at disturbed forest edges. The bioassays confirmed the presence of A. petiolata aqueous and volatile allelochemicals in leaves and roots. Germination was suppressed more by volatiles, showing that allelopathy can act via volatile compounds and further suggesting their antifungal effects. The results allow predicting that the success of A. petiolata invasion in a non-native range might rely on its variable habitat tolerance (not being a strict ruderal species) and allelopathy.

Effect of various biochar rates on winter rye yield and the concentration of available nutrients in the soil

From 2012 to 2014 a field experiment was conducted on a podzolic soil. The aim of the study was to evaluate the yield and weed infestation of winter rye canopy depending on three biochar rates (10, 20 and 30 t/ha). The biochar was pyrolyzed from wheat straw at 350–650°C. After 12, 24, and 36 months from biochar incorporation into the soil pH, total carbon (C) and some elements in soil were determined. Additionally phytotoxicity of soil solid phase was assessed by the commercial toxicity bioassay – Phytotoxkit. The addition of biochar had a positive influence on grain yield of winter rye, which was related to the nutrient application in the form of biochar. The highest grain yields were obtained when biochar was applied at the rate of 20 t/ha. The air-dry weight of weeds in the rye crop grown in the biochar-amended plots was lower compared to the control plots. Incorporation of biochar into the soil at the rates of 20 and 30 t/ha caused a significant increase in the soil content of total C as well as of available P, K, Mg, Fe and B, relative to the control treatment. Moreover, the biochar-amended soil had higher pH because of the relatively high concentration in the biochar (pHKCl 9.9). The assessment of substrate toxicity revealed that biochar applied at the rates of 10 and 20 t/ha had no negative effects on the germination of Lepidium sativum L.

Essential Oil Compositions and Natural Herbicide Activity of Four Denaei Thyme (Thymus daenensis Celak.) Ecotypes

Denaei Thyme (Thymus daenensis Celak.) is a perennial plant from Lamiaceae family. The plant's leaves possess biological attributes that provide it with the potential to be used for medicinal purposes and newly for suppressing the growth of herbaceous plants. In this study essential oil (EO) compositions and phytotoxic effects of four T. deanensis ecotypes (ECTPs) of T. deanensis were evaluated on Amaranthus retroflexus, Avena fatua, Datura stramonium and Lepidium sativum germination and related growth traits.For this purpose, thyme plants were collected from different ecological locations of Fars Province, Iran to identify EOs content and compositions and also their phytotoxic activity. Gas chromatography (GC) and GC-Mass spectrometry (GC-MS) analysis of the EOs showed that thymol (20 - 60.5 %) and carvacrol (20.1 - 63.4 %) were the two major oil components found in the studied ECTPs. For evaluating phytotoxic activity, the concentrations, 0, 200, 400, 600, 800 and 1000 µl l-1 of the EOs were tested in vitro against seeds and their effect on germination percentage and rate, root and shoot length, fresh and dry weight of seedlings were determined. In general, higher EO concentration resulted in lower germination percentage and/or rate in all studied species. The overall results of germination test represent a reduction in germination percentage of most species at concentration of 200 µl l-1. The results reported herein suggest that herbicidal properties of the four ECTPs could be due to their EO concentrations and have potential as natural herbicides.

Cross-species approaches to seed dormancy and germination: conservation and biodiversity of ABA-regulated mechanisms and the Brassicaceae DOG1 genes

Seed dormancy is genetically determined with substantial environmental influence mediated, at least in part, by the plant hormone abscisic acid (ABA). The ABA-related transcription factor ABI3/VP1 (ABA INSENSITIVE3/VIVIPAROUS1) is widespread among green plants. Alternative splicing of its transcripts appears to be involved in regulating seed dormancy, but the role of ABI3/VP1 goes beyond seeds and dormancy. In contrast, DOG1 (DELAY OF GERMINATION 1), a major quantitative trait gene more specifically involved in seed dormancy, was so far only known from Arabidopsis thaliana (AtDOG1) and whether it also has roles during the germination of non-dormant seeds was not known. Seed germination of Lepidium sativum ('garden cress') is controlled by ABA and its antagonists gibberellins and ethylene and involves the production of apoplastic hydroxyl radicals. We found orthologs of AtDOG1 in the Brassicaceae relatives L. sativum (LesaDOG1) and Brassica rapa (BrDOG1) and compared their gene structure and the sequences of their transcripts expressed in seeds. Tissue-specific analysis of LesaDOG1 transcript levels in L. sativum seeds showed that they are degraded upon imbibition in the radicle and the micropylar endosperm. ABA inhibits germination in that it delays radicle protrusion and endosperm weakening and it increased LesaDOG1 transcript levels during early germination due to enhanced transcription and/or inhibited degradation. A reduced decrease in LesaDOG1 transcript levels upon ABA treatment is evident in the late germination phase in both tissues. This temporal and ABA-related transcript expression pattern suggests a role for LesaDOG1 in the control of germination timing of non-dormant L. sativum seeds. The possible involvement of the ABA-related transcription factors ABI3 and ABI5 in the regulation of DOG1 transcript expression is discussed. Other species of the monophyletic genus Lepidium showed coat or embryo dormancy and are therefore highly suited for comparative seed biology.

Peroxidases identified in a subtractive cDNA library approach show tissue-specific transcript abundance and enzyme activity during seed germination of Lepidium sativum.

The micropylar endosperm is a major regulator of seed germination in endospermic species, to which the close Brassicaceae relatives Arabidopsis thaliana and Lepidium sativum (cress) belong. Cress seeds are about 20 times larger than the seeds of Arabidopsis. This advantage was used to construct a tissue-specific subtractive cDNA library of transcripts that are up-regulated late in the germination process specifically in the micropylar endosperm of cress seeds. The library showed that a number of transcripts known to be up-regulated late during germination are up-regulated in the micropylar endosperm cap. Detailed germination kinetics of SALK lines carrying insertions in genes present in our library showed that the identified transcripts do indeed play roles during germination. Three peroxidases were present in the library. These peroxidases were identified as orthologues of Arabidopsis AtAPX01, AtPrx16, and AtPrxIIE. The corresponding SALK lines displayed significant germination phenotypes. Their transcripts were quantified in specific cress seed tissues during germination in the presence and absence of ABA and they were found to be regulated in a tissue-specific manner. Peroxidase activity, and particularly its regulation by ABA, also differed between radicles and micropylar endosperm caps. Possible implications of this tissue-specificity are discussed.

Relevance of side reactions in anaerobic reductive dechlorination microcosms amended with different electron donors

In this study we examined the relative importance of side reactions, i.e. the formation of volatile fatty acids (VFA), and the reduction of alternative electron acceptors (nitrate, sulfate, Fe(III)), in enhanced dechlorination microcosms, amended with different electron donors, namely lactate, butyrate, and H 2+acetate mixture. Dechlorination reactions proceeded at low rates and consequently, nearly all of the reducing equivalents (over 99%) available from electron donor consumption were channeled to (side) reactions other than dechlorination. The relevance of these side reactions was more evident with lactate which was consumed at higher rate than other electron donors. Correspondingly, high levels of VFA and soluble Fe(II) accumulated in the supernatant of lactate-amended microcosms. Ecotoxicity experiments ( Lepidium sativum germination tests) also indicated that the supernatant was much more toxic/inhibitory than that of other microcosms. Among the electron donors tested, the H 2+acetate mixture, yielded the most promising results in terms of extent of dechlorination, negligible accumulation of by-products, and residual groundwater toxicity. Fluorescent In situ Hybridization analysis (FISH) confirmed that H 2+acetate-amended microcosms were dominated by Dehalococcoides spp., while a higher biodiversity was observed in the cultures fed with lactate or butyrate. Overall, the average amount of donor that was required for the removal of 1 μmol of chloride from the contaminant differed greatly among the donors, namely 2.13 meq/μmol Cl − for lactate, 1.01 meq/μmol Cl − for butyrate, and 0.39 meq/μmol Cl − for H 2+acetate mixture. Interestingly, dechlorinating activity was observed under sulfate-reducing conditions; this suggests that it may not be necessary to deplete the sulfate from the groundwater, for instance by supplying an excess electron donor, in order to achieve substantial dechlorination. Finally, in this study we found that the pathway of anaerobic lactate degradation shifted from the production of acetate and H 2 during active sulfate reduction to acetate and propionate upon sulfate depletion. Energetic considerations that support this finding were presented.

Endosperm-limited Brassicaceae Seed Germination: Abscisic Acid Inhibits Embryo-induced Endosperm Weakening of Lepidium sativum (cress) and Endosperm Rupture of Cress and Arabidopsis thaliana

The endosperm is a barrier for radicle protrusion of many angiosperm seeds. Rupture of the testa (seed coat) and rupture of the endosperm are two sequential events during the germination of Lepidium sativum L. and Arabidopsis thaliana (L.) Heyhn. Abscisic acid (ABA) specifically inhibits the endosperm rupture of these two closely related Brassicaceae species. Lepidium seeds are large enough to allow the direct measurement of endosperm weakening by the puncture force method. We found that the endosperm weakens prior to endosperm rupture and that ABA delays the onset and decreases the rate of this weakening process in a dose-dependent manner. An early embryo signal is required and sufficient to induce endosperm weakening, which afterwards appears to be an organ-autonomous process. Gibberellins can replace this embryo signal; de novo gibberellin biosynthesis occurs in the endosperm and weakening is regulated by the gibberellin/ABA ratio. Our results suggest that the control of radicle protrusion during the germination of Brassicaceae seeds is mediated, at least in part, by endosperm weakening. We propose that Lepidium is an emerging Brassicaceae model system for endosperm weakening and that the complementary advantages of Lepidium and Arabidopsis can be used in parallel experiments to investigate the molecular mechanisms of endosperm weakening.

Biodegradation study of crop residues as affected by exogenous inorganic nitrogen and fungal inoculants

The comparative decomposition of chickpea residue, and chopped and unchopped wheat straw was investigated in pits for 120 days. Microbial biomass, humus, C/N ratio, pH, Electrical conductivity (EC), dehydrogenase, alkaline phosphatase, cellulase, xylanase, total phenol and soluble protein were determined to assess their response to the addition of inorganic nitrogen and mixed fungal inoculum of Aspergillus nidulans, Phanerochaete chrysosporium and Trichoderma viride. The evaluation of physico-chemical parameters (organic matter, organic carbon, N, C/N, pH, EC, microbial biomass) revealed that by supplementing unchopped wheat straw with 1% urea and mixed fungal inoculum, a lowest C/N ratio of 10.7, lowest biomass of 9.54 and highest humus content of 13% can be achieved within 3 months. Germination of Lepidium sativum (cress seeds) showed a germination index >60%, in this treatment. The enzyme assay for dehydrogenase indicated highest microbial activity in uninoculated treatments compared to fungal inoculated counterparts, in the second month sampling (active phase of composting). However, cellulase and xylanase activity showed an upward trend during curing phase of composting. Chickpea residue compost, though resulted in a C/N ratio of 17.3, but its germination index was less than 60%. The rapid quality tests conducted for H2S, NH3, NO3 and starch confirmed the stability and maturity of finished compost prepared from wheat straw through microbial inoculants.

Influence of salts and phenolic compounds on olive mill wastewater detoxification using superabsorbent polymers

For a selection of nine commercially available superabsorbent polymers, the absorption capacity was evaluated for the principal absorption-inhibition constituent of OMW, mineral salts and for phytotoxic-components, the phenolic compounds. A double exponential model was established for electrical conductivities ranging 4.2–25,000 μS cm −1. For solutions of phenolic compounds ranging 0–0.5 g l −1, a distribution coefficient near unit was achieved, while for OMW, the phenolic compounds were concentrated inside the gel as the distribution coefficient was 1.4. Correction of OMW pH towards neutrality was found to increase the absorption capacity by up to 35%. The phytotoxicity was assessed by the germination of Lepidium sativum. Inhibition in plant growth occurred for all OMW dilutions without superabsorbent polymers application. For 5% of OMW (COD 5 g l −1 and 200 ppm of phenolic compounds) immobilised in PNa 2 (1 g l −1), plant growth was promoted being observed a 120% growth germination, thus indicating that olive mill wastewater detoxification occurred.

Humic substances to reduce salt effect on plant germination and growth

Soluble humic substances and saline solutions (NaCl solution or compost water extract) were tested in laboratory experiments of fertigation. The saline solutions were used at two levels of electrical conductivity (EC) (0.5 and 4 mS cm− 1); humic substances (HS) were solubilized in distilled water at two concentrations as humic carbon (HC) (30 and 60 mg L− 1). A mixture of NaCl solution with an EC of 4 mS cm− 1 and humic substances at 60 mg L− 1 as HC was also used to evaluate if HS can reduce the effect of NaCl on Lepidium sativum germination and Maize growth. Germination tests carried out without soil, showed that the best treatment was with HS. Growth tests, using an English soil seeded with Maize, presented the best result when the mixture of saline solution–humic substances was used; while the worst plant performance was obtained with NaCl solution alone. In addition, the treatments with NaCl solution alone caused, in the treated soil, a high release of C and N in soluble forms which could cause environmental pollution problems. Finally, a stimulation of soil metabolic potential occurred using HS at low concentration as HC.