Mario Macchia

Quantitative analysis of emergence of seedlings from buried weed seeds with increasing soil depth

Abstract Trials were carried out to investigate the effects of seed burial depth on seedling emergence rate of 20 weed species. Marked depth-mediated variation in emergence ability of the different species was observed, together with a general pattern of decreasing emergence with increasing soil depth. At 10 cm, only johnsongrass, velvetleaf, catchweed bedstraw, and cutleaf geranium emerged, albeit only in limited numbers. Species most severely inhibited by burial depth were buckhorn plantain, large crabgrass, common purslane, chickweed, and corn spurry, none of which emerged from beyond 6 cm. In all species, depth-mediated inhibition was found to be sigmoidal (polynomial regression). In addition, the number of seedlings and rate of seedling emergence decreased when depth of burial increased. The depth at which the number of emerged seedlings was halved varied by species and ranged from 3.6 cm for common purslane and chickweed to 7 cm for velvetleaf and catchweed bedstraw. Excessive burial depth generally induced dormancy (in roughly 85% of cases) rather than suicide germination. A close inverse relation (second-degree equation) between seed unit weight and depth-mediated inhibition was observed. The physiological involvement of depth inhibition in seed bank ecology is discussed. Nomenclature: Buckhorn plantain, Plantago lanceolata L. PLALA; catchweed bedstraw, Galium aparine L. GALAP; common chickweed, Stellaria media (L.) Vill. STEME; common purslane, Portulaca oleracea L. POROL; corn spurry, Spergula arvens L. SPRAR; cutleaf geranium, Geranium dissectum L. GERDI; johnsongrass, Sorgum halepense (L.) Pers. SORHA; large crabgrass, Digitaria sanguinalis (L.) Scop. DIGSA; velvetleaf, Abutilon theophrasti Medicus ABUTH.

Temperature and Water Potential as Parameters for Modeling Weed Emergence in Central-Northern Italy

Abstract Predicting weed emergence dynamics can help farmers to plan more effective weed control. The hydrothermal time concept has been used to model emergence as a function of temperature and water potential. Application of this concept is possible if the specific biological thresholds are known. This article provides a data set of base temperature and water potential of eight maize weeds (velvetleaf, redroot pigweed, common lambsquarters, large crabgrass, barnyardgrass, yellow foxtail, green foxtail, and johnsongrass). For five of these species, two ecotypes from two extreme regions of the predominant maize-growing area in Italy (Veneto and Tuscany), were collected and compared to check possible differences that may arise from using the same thresholds for different populations. Seedling emergence of velvetleaf and johnsongrass were modeled using three different approaches: (1) thermal time calculated assuming 5 C as base temperature for both species; (2) thermal time using the specific estimated base temperatures; and (3) hydrothermal time using the specific, estimated base temperatures and water potentials. All the species had base temperatures greater than 10 C, with the exception of velvetleaf (3.9 to 4.4 C) and common lambsquarters (2.0 to 2.6 C). All species showed a calculated base-water potential equal or up to −1.00 MPa. The thresholds of the two ecotypes were similar for all the studied species, with the exception of redroot pigweed, for which the Veneto ecotype showed a water potential lower than −0.41 MPa, whereas it was −0.62 MPa for the Tuscany ecotype. Similar thresholds have been found to be useful in hydrothermal time models covering two climatic regions where maize is grown in Italy. Furthermore, a comparison between the use of specific, estimated, and common thresholds for modeling weed emergence showed that, for a better determination of weed control timing, it is often necessary to estimate the specific thresholds. Nomenclature: Barnyardgrass, Echinochloa crus-galli (L.) Beauv. ECHCG; common lambsquarters, Chenopodium album L. CHEAL; green foxtail, Setaria viridis (L.) Beauv. SETVI; johnsongrass, Sorghum halepense (L.) Pers. SORHA; large crabgrass, Digitaria sanguinalis (L.) Scop. DIGSA; redroot pigweed, Amaranthus retroflexus L. AMARE; velvetleaf, Abutilon theophrasti Medik. ABUTH; yellow foxtail, Setaria pumila (Poir.) Roemer & J. A. Schultes SETLU.

Metabolite fingerprinting of Camptotheca acuminata and the HPLC-ESI-MS/MS analysis of camptothecin and related alkaloids.

The major phytochemical constituents, namely, alkaloids, flavonoids and ellagic acid derivatives, of leaves of Camptotheca acuminata were identified using high performance liquid chromatography (HPLC) coupled with electrospray mass spectrometry (ESI-MS) in extracts of plants cultivated in Italy and collected at different growth stages. Alkaloids related to camptothecin were identified and quantified by HPLC coupled with ESI-tandem mass spectrometry (MS/MS) employing, respectively, an ion trap and a triple quadrupole mass analyser. The fragmentation patterns of alkaloids related to camptothecin were analysed and a specific Multiple Reaction Monitoring HPLC-MS/MS method was developed for the quantitative determination of these constituents. The described method provides high sensitivity and specificity for the characterisation and quantitative determination of the alkaloids in C. acuminata.

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.

Metabolic profiling of Vitex agnus castus leaves, fruits and sprouts: Analysis by LC/ESI/(QqQ)MS and (HR) LC/ESI/(Orbitrap)/MSn

Food supplements based on Vitex agnus castus L. (Verbenaceae) fruits, also known as chasteberry, are routinely used by women against somatic and psychic premenstrual symptoms such as depression, sadness or irritability. With the aim of highlighting the differences in the chemical profiles of cultivated fruits and different parts of wild plants (fruits, leaves and sprouts) of V. agnus castus, a method concerning with the quali-quantitative study of the derived hydroalcoholic extracts was carried out by using high-performance liquid chromatography coupled to electrospray negative ionization Orbitrap multicollisional high resolution mass spectrometry (LC/ESI/(Orbitrap)MS(n)) and high-performance liquid chromatography coupled to electrospray negative ionization triple quadrupole tandem mass spectrometry (LC/ESI/(QqQ)MS) in multiple reaction monitoring (MRM) mode.

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%).

Genetic analysis of hullability in sunflower

Abstract Significant increase in sunflower meal protein content could be achieved by a decrease in seed crude fibre through seed dehulling before oil extraction. In order to evaluate the presence of genetic variability suitable for the establishment of a breeding programme to improve the character of hullability, crosses were made in 1989–1990 among eleven randomly chosen inbred sunflower lines, according to a diallelic schema. In the following growing season the 55 F1 hybrids obtained and the eleven parental lines were sown according to a randomized block design with three replications. The following characters were determined: achene yield, weight of 1000 achenes, % achene oil and hull (HC), mechanical hull extraction (FH) and hullability (H) obtained from the ratio FH/HC. Analysis of variability of the character demonstrated that both additive and non-additive variability were significant with moderate heritability in a narrow sense. Hullability is shown to have a strongly positive correlation with mechanical hull extraction and with % achene hull. The biological negative correlation existing between % achene hull and % achene oil leads to serious complications in selection for high hullability without decreasing oil yield. A very promising inbred line (L3) was identified, with positive GCA effects for hullability, oil content and seed yield, suggesting new breeding strategies to overcome the barriers in simultaneous improvement of the above characters. A genetic improvement programme must therefore take into account both intrinsic parental characteristics (GCA) and also those of the different hybrid combinations (SCA). Furthermore, a very useful contribution to hullability could come from a global study in which genetic effects are considered together with effects linked to the mechanical process, pedoclimatic conditions, crop management techniques and possible interaction between these factors.

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.

Description of 90 inbred lines of castor plant ( Ricinus communis L.)

The research describes the field comparison of 90 inbred lines of castor plant derived from both selected and wild germplasm. It was carried out in central-western Italy. An important aim of this work was to describe each inbred line based on 19 morphological traits concerning stem, leaves, racemes and capsules and then to suggest a list of descriptors to International Union for the Protection of New Varieties of Plants as to conduct the Distinctness, Uniformity and Stability test also on the castor plant. The plants in the field were grown at wide distances to avoid competition and enable observation of the growth habit, particularly the specific capacity of branching. An additional characterization of the inbred lines was obtained measuring 7 quantitative traits related to main stem and first raceme; the number of racemes per plant was used to quantify the plant branching. The results allowed distinguishing almost all the genotypes using only the morphological traits. Nectaries at the node, emergences on the stem and petioles, colour of nectaries on petiole resulted important plant descriptors. The two pairs of inbred lines (Tor87#9 vs. Tor87#83 and Pod87#255Hy2 vs. Rot95#55-23) were distinguished thanks to the quantitative traits. Based on the morphological traits, two UPGMA dendrograms, one for the dwarf and one for the normal genotypes, were characterized and the resulting clusters better explained the relationships among the various inbred lines. Six genotypes (Pod87#389, Tor87#81A, Tor87#220B, Tor87#287, Tor87#287Hy, and Liba21) resulted unable to flower in the field; in these inbred lines the induction to flower is particularly influenced by the environmental growth conditions. Regarding the branching ability, the strong apical dominance of two inbred lines (Pod94#31-2 and Pod93#211) obtained from previous breeding programs was confirmed and it was possible to detect other interesting genotypes (Pod87#287A, Pod87#287B, Tor86#67). The several inbred lines described herein showed a wide range of phenotypes that might be useful in various fields of research.