Luciana Gabriella Angelini

Ramie (Boehmeria nivea (L.) Gaud.) and Spanish Broom (Spartium junceum L.) fibres for composite materials: agronomical aspects, morphology and mechanical properties.

The agronomic characteristics of Ramie and Spanish Broom were investigated for seven years in the pedoclimatic conditions of Central Italy. The chemical, physical and mechanical properties of these fibres were also examined in order to evaluate the feasibility to use them in composite materials. Results demonstrate that Ramie grown in the temperate environment can be harvested three times a year. The yield of green Ramie plants per annum was almost 10 000 g m−2. The fresh Ramie plant is composed, by weight, of 30% green leaves and 70% green stems. The yield dry fibre is almost 3% of the green stems, giving a total yield of 200 g m−2. Spanish Broom can reach a fresh biomass yield of 4000 g m−2 per annum, represented by 53% of long slender terete green branches which constitutes the economic products. The dry yield per annum was about 1800 g m−2 with a dry branchlets yield of 900 g m−2. Ramie and Spanish Broom cortical fibres are multiple elementary fibres (ultimates) arranged in bundles. In Ramie, the elementary fibres are bound by gums and pectins, while in Spanish Broom they are bound together by lignin. Both species showed a thick secondary cell wall indicating a high cellulose content. Ramie ultimate fibres are flattened and irregular in shape, while those of Spanish Broom are more regular in shape. The diameter of the ultimates varies from 10 to 25 μm in Ramie, while the Spanish Broom ultimates ranges from 5 to 10 μm; the diameter of the whole bundle is about 50 μm for both species. Ramie fibre showed a content of lignin, pentosans and extractives lower than Spanish Broom. Both fibres had a high content of cellulose which, on the base of X-ray analysis, was evaluated to be in excess of 70%. Ramie and Spanish Broom fibres had tensile strength of 950 MPa and 700 MPa, respectively. The elastic moduli were ≈65 and ≈20 GPa, respectively, which well compare with the modulus of E-glass fibres (70–90 GPa). The strength of the fibre-matrix interface was measured using the single filament fragmentation technique and an epoxy resin as the polymer matrix. Values for carbon and glass fibres in the same resin were also measured for comparison. The interface strength for the vegetable fibres was higher than that of carbon and glass, likely due to a mechanical lock mechanism. These values confirm both fibres as potential replacement for man made fibres in composite materials.

Variation in agronomic characteristics and seed oil composition of new oilseed crops in central Italy

The following new potential oilseed crops for industrial uses have been considered for agronomic traits and seed oil composition during a 3 year trial in Central Italy: Calendula officinalis (calendic acid); Camelina sativa and Lepidium sativum (linolenic acid); Coriandrum sativum (petroselinic acid); Euphorbia lagascae and Vernonia galamensis (epoxy fatty acids); Madia sativa (linoleic acid); Lesquerella fendleri (hydroxy fatty acids). Agronomic characteristics were examined in replicated field trials and phenological and morphological assessments were made. Seed oil content was determined by the Soxhlet method. Fatty acids were determined by gas liquid chromatography after transesterification to the methyl esters. A range of variation within most species was established for genetic differences in such traits as date of flowering, plant height, seed yield and oil percentage. Mean oil content in Camelina sativa, Lepidium sativum, Madia sativa and Coriandrum sativum was also influenced by the climatic conditions occurring in the different years, decreasing in the driest seasons. Some species (Coriandrum sativum, Madia sativa, Vernonia galamensis, Euphorbia lagascae and Lesquerella fendleri) produced high levels (more than 50%) of a single fatty acid in their seeds. This finding is favourable for industrial uses by minimising dowstream processing costs. On the other hand, other species (Lepidium sativum, Camelina sativa, Calendula officinalis) contained a mixture of fatty acids in their seeds. Some of these species showed good agronomic traits, including tolerance to drought and to high temperature, making them potentially suitable for cultivation in the Mediterranean area. For most of them, further breeding work should be directed towards increasing seed oil content and eliminating certain wild characteristics such as fruit dehiscence.

Rubia tinctorum a source of natural dyes: agronomic evaluation, quantitative analysis of alizarin and industrial assays

Common madder (Rubia tinctorum L.) produces anthraquinone pigments in its roots, one of them being alizarin (1,2 dihydroxy anthraquinone) which has been used for dyeing textiles since 2000 B.C. Four madder genotypes were evaluated for their agronomic characteristics as well as for their industrial value in order to test this species domestication potential for the Mediterranean area and to assess its value as a new industrial dye crop. Pigments were separated from methanolic and ethereal extracts and quantified by HPLC. Good agronomic performance was observed in the different accessions of R. tinctorum which were tested. Root yield increased from young (5 months old) to mature plants (30 months old) reaching a mean value of 120 g plant−1, which corresponds to a yield of 8 t ha−1. Variation in yield capacity was observed among the different accessions. Young roots showed a higher alizarin content than 15 and 30 month old plants. However, the total amount of alizarin present in a plant increased from 181.8 mg plant−1 to 917.8 mg plant−1 in 5 to 30 month old plants. A range of variation in alizarin content was established for genetic differences within madder. Industrial assays demonstrated good performance when using a weight of dry powder which is 30% of the weight of material to be dyed for dyeing cotton, wool and silk yarns. Resistance to fading appears to be fairly good for dyed wool.

Stevia rebaudiana Bertoni as a source of bioactive compounds: the effect of harvest time, experimental site and crop age on steviol glycoside content and antioxidant properties.

BACKGROUND This study was aimed at identifying the effect of harvest time, experimental site and crop age on the no-calorie sweetener steviol glycosides (SG) and on the antioxidant properties of stevia leaf extracts. The experiment was conducted over two growing seasons at two sites in the northeastern plain of Italy. RESULTS The results showed that all analysed factors played an important role in defining the SG profile and the antioxidant properties of stevia extracts. A high level of phenols (78.24 mg GAE g⁻¹ DW by Folin-Ciocalteu method) and high antioxidant activity (812.6 µmol Fe²⁺ g⁻¹ DW by FRAP assay) were observed. The inhibition of DPPH free radicals was evaluated and an IC₅₀ mean value of 250 µg mL⁻¹ was obtained. Significant relationships among the total antioxidant capacity and the analysed compounds were found. CONCLUSION The results showed the possibility of obtaining, in the tested environments, very high SG yields thanks to the long-day conditions during the spring/summer season. The harvest time played a key role in determining the stevia quality, influencing the rebaudioside A/stevioside ratio. The strong antioxidant properties make very interesting the possibility of using stevia extracts to improve functional food properties.

Agronomic potential of Reseda luteola L. as new crop for natural dyes in textiles production

Abstract Six weld genotypes ( Reseda luteola L.) were evaluated for their agronomic characteristics in a 4-year field study carried out under rainfed condition in Central Italy in order to point out productive potential and the best harvest time to maximise yield of dye. Good agronomic performances were observed with an overall dry yield of about 40 g per plant and an estimated dry yield per hectare of 2.8 tons. Differences were found among the six accessions and some of them withstanded well to drought conditions experienced in drier growing seasons. The harvest of plants during flowering or during beginning of fruit ripening did not affect overall dry yield (40 and 45 g per plant at flowering and fruit maturity, respectively). The luteolin amount (expressed in mg g −1 dry weight) was affected by climatic conditions as experienced in two different growing seasons (1993 and 1994) and by the plant phenological stages at harvest being luteolin most abundant in the dryest year and in plants harvested during flowering. Genetic variability existed for the luteolin content in leaves plus reproductive structures (inflorescences and fruits) that varied from 13.6 to 28.7 mg g −1 dry weight in the six accessions tested in 1994. The dry powder from leaves and reproductive structures was used in the dyeing of cotton, wool and silk yarns. Good and bright yellow colours were observed using a ratio 30:100 (weight/weight) of weld on the textile materials. Separated weld organs showed different dyeing capacities being the leaves, inflorescences and fruits the most effective ones. Weld showed a progressive decrease in resistance to fading going from cotton, to the other kind of yarns. Finally, all dyed specimens exhibited good resistance to light and wash fastness making the use of weld a viable alternative to synthetic yellow dyes.

Unmanned Aerial Vehicle to Estimate Nitrogen Status of Turfgrasses

Spectral reflectance data originating from Unmanned Aerial Vehicle (UAV) imagery is a valuable tool to monitor plant nutrition, reduce nitrogen (N) application to real needs, thus producing both economic and environmental benefits. The objectives of the trial were i) to compare the spectral reflectance of 3 turfgrasses acquired via UAV and by a ground-based instrument; ii) to test the sensitivity of the 2 data acquisition sources in detecting induced variation in N levels. N application gradients from 0 to 250 kg ha-1 were created on 3 different turfgrass species: Cynodon dactylon x transvaalensis (Cdxt) ‘Patriot’, Zoysia matrella (Zm) ‘Zeon’ and Paspalum vaginatum (Pv) ‘Salam’. Proximity and remote-sensed reflectance measurements were acquired using a GreenSeeker handheld crop sensor and a UAV with onboard a multispectral sensor, to determine Normalized Difference Vegetation Index (NDVI). Proximity-sensed NDVI is highly correlated with data acquired from UAV with r values ranging from 0.83 (Zm) to 0.97 (Cdxt). Relating NDVI-UAV with clippings N, the highest r is for Cdxt (0.95). The most reactive species to N fertilization is Cdxt with a clippings N% ranging from 1.2% to 4.1%. UAV imagery can adequately assess the N status of turfgrasses and its spatial variability within a species, so for large areas, such as golf courses, sod farms or race courses, UAV acquired data can optimize turf management. For relatively small green areas, a hand-held crop sensor can be a less expensive and more practical option.

A New HPLC‐ELSD Method To Quantify Indican in Polygonum tinctorium L. and To Evaluate β‐Glucosidase Hydrolysis of Indican for Indigo Production

A method to quantify the indigo precursor indican (indoxyl‐β‐d‐glucoside) in Polygonum tinctoriumL. has been developed. Plant material was extracted in deionized water, and indican was identified and quantified using high performance liquid chromatography (HPLC) coupled to an evaporative light scattering detector (ELSD). Results confirmed that with this method it is possible to measure indican content in a short time, obtaining reliable and reproducible data. Using this method, leaf indican content was quantified every 15 days during the growing season (from May to October) in P. tinctorium crops grown in a field experiment in Central Italy. Results showed that indican increased along the growing season until flowering and was positively affected by photosynthetic active radiation (PAR). Indican is naturally hydrolyzed by native β‐glucosidase to indoxyl and glucose, the indoxyl yielding indigo. The activity of two enzymes, sweet almond β‐glucosidase and Novarom G preparation, were compared with P. tinctorium native β‐glucosidase to evaluate indigo production. Results showed that the ability to promote indigo formation increased as follows: almond β‐glucosidase ≤ Novarom G.

Effect of Nitrogen Fertilization and Harvest Time on Steviol Glycosides, Flavonoid Composition, and Antioxidant Properties in Stevia rebaudiana Bertoni

This work investigated the effect of nitrogen fertilization and harvest time on the flavonoid composition and antioxidant properties of Stevia rebaudiana leaves. At the same time, changes in stevioside (Stev) and rebaudioside A (RebA) contents were recorded. A pot trial under open air conditions was set up, testing five N rates and three harvest times. The results showed that, by using an adequate N rate and choosing an appropriate harvest time, it was possible to significantly increase and optimize the bioactive compound levels. In particular, higher RebA, RebA/Stev ratio, total phenols and flavonoids, luteolin-7-O-glucoside, and apigenin-7-O-glucoside levels and antioxidant capacity were recorded by supplying 150 kg N ha(-1). Reduced or increased N availability in comparison with N150 had no consistent effect on Stevia phytochemicals content. Significant correlations were also found between stevioside and some of the flavonoids, indicating a possible role of flavonoids in the stevioside metabolic pathway, which deserves more investigations.

Light Quality Influences Indigo Precursors Production and Seed Germination in Isatis tinctoria L. and Isatis indigotica Fort.

Isatis tinctoria L. and Isatis indigotica Fort. are biennial herbaceous plants belonging to the family of Cruciferae that are used as a source of natural indigo and show several morphological and genetic differences. Production of indigo (indigotin) precursors, indican (indoxyl β‐D glucoside) and isatan B (indoxyl ketogluconate), together with seed germination ability were compared in Isatis tinctoria and Isatis indigotica grown under six different light conditions (darkness, white, red, far red, blue, yellow light) at 25°C. Light quality influenced both germination and production of indigo precursors in the two Isatis species. Different responsiveness to far red and blue light was observed. Indeed, a detrimental effect on germination by blue and far red light was found in I. tinctoria only. Different amounts of isatan B were produced under red and far red light in the two Isatis species. In I. tinctoria, the level of main indigo precursor isatan B was maximal under red light and minimal under far red light. Whereas in I. indigotica far red light promoted a large accumulation of isatan B. The photon fluence rate dependency for white and yellow light responses showed that the accumulation of indigo precursors was differently influenced in the two Isatis species. In particular, both white and yellow light enhanced above 40 μmol m−2s−1 the production of isatan B in I. indigotica while only white light showed a photon fluence dependency in I. tinctoria. These results suggest a different role played by the labile and stable phytochrome species (phyA and phyB) in the isatan B production in I. tinctoria and I. indigotica. I. indigotica, whose germination percentage was not influenced by light quality, demonstrated higher germination capability compared with I. tinctoria. In fact, I. tinctoria showed high frequency of germination in darkness and under light sources that establish high phytochrome photoequilibrium (red, white and yellow light). Germination in I. tinctoria was negatively affected by far red and blue light. I. indigotica seeds appear to be indifferent to canopy‐like light (far red). Our results provide further insights on the distinct behaviour of I. tinctoria and I. indigotica that belong to two different genetic clusters and different original environments.

Comparison of Soil Organic-Matter Characteristics under the Energy Crop Giant Reed, Cropping Sequence and Natural Grass

The objective of this study was to determine, on the same pedological, topographic, and climatic conditions, the effects of a continuous giant reed cropping (GR), a cropping sequence (CS), and untilled natural grass (NG) on some soil characteristics. Selected characteristics included total soil organic carbon (TOC), light fraction carbon (LFC), dissolved organic carbon (DOC), and microbial biomass carbon (MBC). The various humic fractions and their ratios, humification ratio (HR), humification degree (HD), and humification index (HI) were also evaluated. Results indicate that GR, characterized by low tillage intensity, showed greater values than tilled management system (CS) for all the previously mentioned properties, with the exception of the humification parameters, which were not statistically different between the two systems. Regarding the difference between GR and NG (the latter usually considered as a reference or baseline for evaluating attributes of soil quality), GR generally showed greater values for all organic parameters, with the exception of MBC and humus characteristics.