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Experimental Analysis on Temperature Gradient and environmental parameters in a Greenhouse: a case study on tomato soilless cultivation
No full textWe analyze the environmental parameters, with particular focus on the temperature spatial distribution, inside a greenhouse with a tomato soilless cultivation. The findings from our initial research indicate a significant thermal gradient in both the horizontal and vertical dimensions of the plants. Although the average measured temperature surpasses the recommended limits for optimal tomato production, its impact on the final yield is negligible compared to similar cultivations in literature. Notably, the temperature near the area where the tomatoes are collected remains within an appropriate range. This can possibly motivate the negligible productivity loss. However, we highlighted the relevance of selecting an appropriate position for temperature measurement. This aspect can have a large impact in developing proper optimization strategies, including active climate control and specific energy requirement minimization, as detailed throughout the paper
How do Arbuscular Mycorrhizal Fungi influence plant response to sub-optimal or stressful growing conditions in semi-artificial cropping systems?
No full textLettuce (Lactuca sativa L.) is an annual autogamous diploid plant belonging to Asteraceae and amongst the top ten most profitable crop worldwide due to its nutritional value. Increased cultivation of lettuce has led to major problematics, especially in fertilizer abuse both in soil and extra soil system, which damages the ecosystem and has an increasing cost for the farmers.
Arbuscular mycorrhizal fungi (AMF) are important beneficial microorganisms establishing mutualistic associations with most food crops and are important sustainable tools for nutrient uptake in many plants. In this context, AMF could help reduce the impact of fertilizers, improving plant nutrition, particularly phosphate (P) acquisition, and contributing to growing healthier plants for human consumption.
The first target of my PhD thesis was to evaluate the effect of AM fungus (AMF) Funneliformis mosseae in lettuce plants (Lactuca sativa L. var Salinas) cultivated in soilless culture in greenhouse and growth chamber with low concentrations of phosphorus. Different doses of P concentrations were tested to determinate the best practice: using the lowest possible quantity of P and at the same time avoiding the yield loss of lettuce. Some important bioactive compounds such as leaf content of chlorophylls, carotenoids and phenols were higher in mycorrhizal lettuce plants compared with non-mycorrhizal plants.
The antioxidant capacity in AMF plants showed higher values compared with control plants grown at optimal P nutrition level. Moreover, leaf gas exchanges were higher in inoculated plants than in non-inoculated ones. Nitrogen, phosphorus, and magnesium leaf content was significantly higher in mycorrhizal plants compared with non-mycorrhizal plants grown with the same P level.
These findings suggest that the biostimulant potential of F. mosseae can increase plants’ growth improving the nutritional quality of lettuce leaves, even when grown with sub-optimal P concentration.
In a second part, we compared lettuce plants (cv. Salinas) grown in soilless culture with optimal P concentration (+P/-AM), with sub optimal P concentration (-P/-AM) and with plants grown with lower P concentration (-50%) and inoculated with the AM fungus F. mosseae before transplanting (-P/+AM). The gene expression profile was analysed in both roots and leaves, and transcriptomic values were associated with physiological and biochemical parameters.
Overall, in comparison with -P/-AM plants, 3,057 genes were differentially regulated by mycorrhizal symbiosis (-P/+AM) and 2,606 genes were induced by optimal phosphate nutrition (+P/-AM). The pattern of differentially expressed genes for both effects showed major differences suggesting a context dependent regulation of genes related to photosynthesis, solute transport, metabolism of phytohormones, redox homeostasis, and transcriptional regulation.
Concerning metabolic pathways, mycorrhizal plants highlight the activation of genes involved in phenylpropanoids, carotenoids, and vitamins production. These data are coherent with the results of physiological and biochemical analyses. Transcriptomic, physiological, and biochemical data strongly support the potential of AM symbionts to act as biofertilizers for lettuce soilless cultivation with beneficial effects on both plant growth and leaf content of health promoting phytochemicals through genetic pathways largely different from those activated in plants grown with optimal P supply.
The results obtained clearly highlight that lettuces in soilless culture during symbiosis can overcome phosphorus deficiency in nutrient solution proving that arbuscular fungi can act as an effective biofertilizer increasing biomass and leaves area of a host plant and promoting the biosynthesis of health-related compounds for a balanced human diet
Arbuscular Mycorrhizal Fungi Increase Nutritional Quality of Soilless Grown Lettuce while Overcoming Low Phosphorus Supply
Get PDFLettuce is widely used for its healthy properties, and it is of interest to increase them with minimal environmental impact. The purpose of this work was to evaluate the effect of the arbuscular mycorrhizal fungus (AMF) Funneliformis mosseae in lettuce plants (Lactuca sativa L. cv. Salinas) cultivated in a soilless system with sub-optimal phosphorus (P) compared with non-inoculated controls at two different P concentrations. Results show that lettuce inoculation with the selected AMF can improve the growth and the nutritional quality of lettuce even at sub-optimal P. Leaf content of chlorophylls, carotenoids, and phenols, known as important bioactive compounds for human health, was higher in mycorrhizal lettuce plants compared with non-mycorrhizal plants. The antioxidant capacity in AMF plants showed higher values compared with control plants grown at optimal P nutrition level. Moreover, leaf gas exchanges were higher in inoculated plants than in non-inoculated ones. Nitrogen, P, and magnesium leaf content was significantly higher in mycorrhizal plants compared with non-mycorrhizal plants grown with the same P level. These findings suggest that F. mosseae can stimulate plants growth, improving the nutritional quality of lettuce leaves even when grown with sub-optimal P concentration
EFFETTI DEL BORO E DEI FUNGHI MICORRIZICI SUL BASILICO (OCIMUM BASILICUM L.), CON PARTICOLARE RIFERIMENTO ALL’ACCUMULO DI METABOLITI SECONDARI ( ACIDO ROSMARINICO)
No full textRIASSUNTO
Aumenta sempre di più la sensibilità delle persone al connubio esistente tra alimentazione e salute umana. La ricerca di prodotti naturali capaci di soddisfare tali nuove esigenze è oramai costante. Il mio lavoro si è focalizzato sul basilico (Ocimum basilicum L.), pianta appartenente alla famiglia delle Lamiaceae, che comprende nel suo insieme numerose specie di interesse mondiale come piante officinali includendo anche lavanda, menta, rosmarino, salvia, timo, santoreggia, ecc.
Il basilico è un importante fonte di oli essenziali, di composti fenolici e di antiossidanti. Per questo motivo è ampiamente utilizzato come additivo alimentare per evitare la degradazione degli alimenti e svolge un importante ruolo nel prevenire le diverse malattie correlate allo stile di vita e all’invecchiamento.
Il mio lavoro si è basato sullo svolgimento di due esperimenti, in entrambi i casi impiegando due varietà di basilico, uno con foglie verdi (“Tigullio”, basilico del tipo “Genovese”) e uno con foglie rosso-viola (“Dark Opal”).
Il primo esperimento prevedeva l’utilizzo di due diverse concentrazioni di boro (0.25 e 20 mg/L) utilizzate nella soluzione nutritiva e l’influenza delle diverse concentrazioni sulla crescita, sul contenuto fogliare di B e di acido rosmarinico nelle piante di basilico coltivate in idroponica (floating system). Il boro è un elemento che risulta indispensabile per la vita delle piante perché interviene nelle varie fasi della crescita della pianta come la fioritura, la germinazione del polline e la fruttificazione.
L'obiettivo del secondo esperimento, invece, è stato quello di verificare se funghi e batteri micorrizzici possono migliorare la crescita del basilico e, allo stesso tempo, aumentare la produzione di acido rosmarinico.
Le micorrize sono delle associazioni simbiotiche permanenti che si instaurano tra le radici della pianta e alcuni tipi di funghi presenti nel terreno e possono indurre grandi vantaggi in termini di sviluppo radicale, maggiore resistenza a stress biotici e abiotici e una maggiore velocità di crescita.
Nella prima prova si è verificata una maggiore tolleranza di B nel cultivar rosso-viola rispetto alla cultivar verde dovuto probabilmente ad una maggiore capacità antiossidante delle foglie rosse.
Nella seconda prova, in linea generale, non si sono verificate differenze significative dal punto di vista statistico. Questi risultati sono dovuti probabilmente alle elevate concentrazioni di nutrienti somministrati nella soluzione nutritiva che potrebbero aver inibito l’effetto positivo delle micorrize
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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