Lucia Ceccarini

Soil Microbial Characteristics and Mineral Nitrogen Availability as Affected by Olive Oil Waste Water Applied to Cultivated Soil

Abstract Waste disposal is an urgent problem in those Italian areas devoted to olive oil production where a large amount of olive oil waste is produced in a short period of time. Given the high organic matter and macronutrient content of olive oil waste water, its use in agriculture could help to solve the disposal problem and, at the same time, to improve the physiochemical characteristics of intensely cultivated soils. However, olive oil waste water contains noteworthy quantities of phenols, which are toxic and have bacteriostatic activity. The effects of repeated spreading of olive oil waste water on alfalfa, on soil microbial properties, and on the availability of mineral nitrogen were determined. Doses of 0, 80, and 160 m3 ha−1 of olive oil waste water (OW) were spread over experimental plots sown with 3rd year alfalfa. Soil samples were collected at various intervals after OW application. The biomass, respiratory activity, metabolic quotient, mineralization index, and the potential nitrification activity (PNA) of the soil were measured. Polyphenol, organic carbon, and mineral nitrogen contents were measured on the same soil samples. In general, the spreading of OW caused slightly positive modifications to the soil microbial biomass and metabolic quotient. These modifications were temporary and disappeared as early as a few months after the treatment. The PNA, as well as the nitrate and nitrite contents, were lower in the treated plots during the vegetative cycle of alfalfa and after the last harvest, and appeared to be negatively correlated with polyphenols. The results of this experiment confirmed that the spreading of olive oil waste water on cultivated soil could be an eco‐compatible practice. Despite their origin, the OW had no toxic effects on the soil microflora, and in fact, stimulated growth and reproduction of cells. Only the PNA proved to be slightly reduced, but the yield was not negatively affected.

Determination of six steviol glycosides of Stevia rebaudiana (Bertoni) from different geographical origin by LC–ESI–MS/MS

Liquid chromatography electro-spray tandem mass spectrometry (LC-ESI/MS/MS) was applied to the determination of sweet glycosides (steviol glycosides), and toxic aglycon steviol in 24 samples of Stevia rebaudiana (Bertoni) aerial parts, which had been experimentally cultivated in Italy, although derived from seeds of different geographical origin. On the basis of the specific fragmentation of these compounds, an LC-MS/MS method was developed with the aim of quantifying analytes in plant material. Although toxic steviol was not detectable in all the samples, the samples with the highest levels of steviol glycosides were identified. Analysis of the different samples revealed that they were good quality samples, quality being directly linked to the presence of sweet glycosides in the plants cultivated in Italy, although there were differences in the content of these compounds according to the origin of the seeds, and in particular, a major concentration of compounds with major sweetness activity and minor toxicity was found in the population coming from Brazil (for example: sample 10, stevioside content 15.74±2.0% p/p and rebaudioside A content 3.09±0.39% p/p of dried plant). Finally, based on this metabolomic targeted approach, the results obtained for the samples were treated by Principal Component Analysis, identifying specific genotypic differences based on the geographic origin of the seeds.

Essential oil composition of Helianthus annuus L. leaves and heads of two cultivated hybrids “Carlos” and “Florom 350”

Abstract The composition of essential oils from leaves and flowers of two hybrids (Carlos and Florom 350) of Helianthus annuus cultivated in Tuscany (Italy) was investigated. The compounds were identified using gas chromatography (GC)/mass spectrometry (MS) analyses. Sixty-nine compounds were identified in the essential oils of leaves and flowers of sunflower plants harvested in July. Significant percentage variations were recorded between the leaves and flowers oil content. The monoterpenes were the major compounds present in both essential oils examined. α-pinene content was higher in flowers (72.6%) than in leaves (28.6%). The content of sabinene was ∼2 times higher in leaves than in flowers. There were no significant differences between the essential oil composition of the oils obtained from the same organs of the two hybrids.

Qualitative and quantitative analysis of essential oils of five lines Stevia rebaudiana Bert. genotypes cultivated in Pisa (Italy)

Abstract Stevia rebaudiana Bertoni, a plant originating in Paraguay, produces a variety of high-potency, low calorie sweeteners in its leaf tissue. The essential oil composition of the aerial parts of five different Stevia rebaudiana genotypes cultivated in Tuscany coast (Italy) were examined by GC and GC/MS. Forty different components were identified and the main constituents in all studying samples were spathulenol (13.4–40.9%), caryophyllene oxide (1.3–18.7%), β-caryophyllene (2.1–16.0%) and β-pinene (5.5–21.5%).

Abelmoschus esculentus (L.) Moench. and Abelmoschus moschatus Medik: Seeds production and analysis of the volatile compounds

Nine accessions of Abelmoschus esculentus (L.) Moench. and three of Abelmoschus moschatus Medik were both grown in Central Italy for the evaluation of the production of seeds. Furthermore, the volatiles emitted by the mature seeds were sampled by mean of SPME. Seventy compounds were detected in the headspace of the seeds of A. esculentus. The principal constituents common to all the nine accessions were isopentyl 2-methyl butanoate (24.5-59.1%) and heptanoic acid 2-methylbutyl ester (6.6-13.5%). In the headspace around the seeds of A. moschatus 93 components were detected. Among the main volatiles shared by the three accessions, n-tridecane (1.5-26.9%), isopentyl 2-methyl butanoate (0.2-14.3%) and decanal (1.6-5.7%) should be mentioned. Many differences were present in the volatiles emitted by the various accessions and between the two Abelmoschus species.