45 research outputs found
Equivariant Q-sliceness of strongly invertible knots
No full textWe introduce and study the notion of equivariant Q-sliceness for strongly invertible knots. On the constructive side, we prove that every Klein amphichiral knot, which is a strongly invertible knot admitting a compatible negative amphichiral involution, is equivariant Q-slice in a single Q-homology
4-ball, by refining Kawauchi’s construction and generalizing Levine’s uniqueness result. On the obstructive side, we show that the equivariant version of the classical Fox–Milnor condition, proved recently by the first author [J. Topol. 17 (2024), 44 pp.], also obstructs equivariant Q-sliceness. We then introduce the equivariant Q-concordance group and study the natural maps between concor-
dance groups as an application. We also list some open problems for future study
Evaluation of two green composts for peat substitution in geranium ( Pelargonium zonale L.) cultivation: Effect on plant growth, quality, nutrition, and photosynthesis
No full textPeat is the most representative component in the preparation of growing media used in horticulture. However, environmental issues and increased production costs, related to peat extraction and commercialization, are stimulating the use of new materials and technologies as alternatives to peat-based growing media. Among other locally-produced materials, green compost is one of the most promising alternatives for peat substitution although its variability in terms of physico-chemical characteristics represents the main constraint. In the present work, two composts, differing in terms of the initial composting raw materials, were evaluated for peat substitution and their influence on plant growth and quality, nutrient and water uptake, and gaseous exchange activity. A bedding plant (geranium), cultivated in an intensive growing system, was chosen as the test plant and 100% peat as the control. During the greenhouse experiment, plants were grown in five different growing media, i.e. only peat, 30% and 50% peat volume replaced by the two composts. Growing medium characteristics, plant growth and biometric parameters, water and nutrient uptake, and gaseous exchange activity were evaluated as crop performance indicators. The green compost derived from mixed raw material negatively influenced plant nutrition and photosynthesis, thus significantly reducing plant biomass accumulation and quality. The green compost derived from selected material was found to be a valuable growing medium for peat substitution. This thus supports the widespread opinion that high-quality compost can be produced through the selection of
composting material
La pigmentazione nel fiore di Lilium
No full textIl Lilium costituisce una delle colture più importanti sia nel mercato floricolo italiano che in quello internazionale. La sua elevata popolarità è dovuta principalmente alle sue caratteristiche ornamentali quali il colore dei fiori e delle foglie, l’altezza degli steli, la forma delle infiorescenze e l’architettura della pianta, che rendono il Lilium una delle colture più apprezzate e conosciute in tutto il mondo.
Spesso accade che la qualità della pianta sia influenzata dalla stagione di coltivazione, derivando una peggiore qualità per le coltivazioni autunnali e invernali rispetto a quelle estive, riconoscibile dal precoce appassimento e abscissione dei tepali, dall’ingiallimento fogliare causato in molti casi dalle condizioni di oscurità e di basse temperature, dall’aborto o incompleta apertura dei fiori apicali, e dalla diminuzione di brillantezza e attenuazione dell’intensità del colore dei tepali, dovuta ad una minore radiazione solare. Questo fenomeno è più evidente nei fiori di Lilium con tonalità rosse, rosa e arancio ed è prevalentemente dovuto ad una ridotta sintesi di antociani.
La biosintesi di antociani è indotta da diversi fattori, quali ad esempio l’elevata escursione termica giornaliera o la stessa radiazione solare. Per riuscire ad aumentare la biosintesi di antociani nei prodotti vegetali si possono usare diverse strategie, generalmente impiegate per migliorare l’aspetto di prodotti orto-frutticoli; buoni risultati sono stati ottenuti su melanzana, melone, pomodoro e mele con la somministrazione di solfato potassico per via fogliare, quando le basse escursioni termiche determinano una scarsa colorazione dei frutti. Le concimazioni a base di azoto e potassio hanno portato un effetto positivo su diverse cultivars di piante da fiore, tra cui il gladiolo (Accati et al., 1994; DeVecchi e Barni, 1997). Tra i vari trattamenti possibili per il miglioramento dell’apertura dei fiori e il prolungamento della durata in vaso di molte specie è noto l’utilizzo degli zuccheri (in particolare del saccarosio) nell’acqua di conservazione; in alcuni casi un ulteriore effetto positivo osservato è stato l’aumento della concentrazione delle antocianine nei petali, e quindi la comparsa di colorazioni a tinte più forti. Recentemente sono apparsi dei risultati interessanti sull’ aumento della concentrazione delle antocianine in uva (cv Merlot) trattata con un nuovo prodotto acibenzolar-s-methyl (Bion) (Iriti et al., 2004),
Alla luce di tutte queste conoscenze presso l’Istituto Sperimentale per la Floricoltura (ISF) di Pescia sono state condotte prove sperimentali sul Lilium cresciuto in stagione sfavorevole (autunno/invernale) per migliorare la colorazione dei fiori, valutare la longevità di steli Lilium, valutare la percentuale di aborti.
Misurazione dei parametri relativi al colore impiegando un particolare e nuovo apparecchio, quale lo spettrometro per immagini o scanner spettrale VIS-NIR
Una nuova metodologia è stata adottata per la misurazione dei parametri relativi al colore, che ha previsto l’impiego; di un particolare apparecchio, quale lo spettrometro per immagini o scanner spettrale VIS-NIR, normalmente impiegato in altri processi industriali.
L’utilizzo di questa tecnica consente di ridurre i tempi di misurazione del colore con risposte immediate e molto accurate.
I risultati ottenuti indicano che i trattamenti effettuati migliorano la qualità dei fiori esaminat
Bat guano and Nettle slurry (Urtica dioica L.) used as biostimulants on Delosperma cooperi and Sedum rubrotinctum plants
No full textThe aim of the experiment was to evaluate the use and influence of Bat guano and Nettle slurry on the growth, flowering and mineral absorption of Delosperma cooperi and Sedum rubrotinctum plants. The 3 experimental groups in cultivation were: (1) group without biostimulants (CTRL), irrigated with water and previously fertilized substrate; (2) group Bat guano (BG) and fertilized substrate; (3) group Nettle slurry (Urtica dioica L.) (UD) and fertilized substrate. Treatments with Nettle slurry and Bat guano resulted in a significant improvement in the growth and flowering characteristics of Delosperma cooperi and Sedum rubrotinctum. The test showed in fact a significant increase in the agronomic parameters analysed in plants treated with Bat guano and Nettle slurry. In fact, all the plants treated with (BG and UD) showed a significant increase in the number of leave, flowers and inflorescences, in the vegetative, radical and inflorescence weight, in the flowering time. The test also resulted in an increase in the NPK mineral absorption and chlorophyll content of plants treated with bat guano and nettle slurry.Interesting aspects that make Bat guano and Nettle slurry valid alternatives to be used as plant biostimulants, when the plants are subjected to biotic and abiotic stresses, in particular transplant, water and salt stress
Application of Biohumus at different substrate replacement rates in the germination and cultivation of Zea mays
No full textResearch objective: This research aims to evaluate the biostimulant potential of biohumus in different substrate replacement rates on the growth of Zea mays seedlings. This is to increase knowledge of the use of biohumus in plant cultivation, which could be used in the formulation of new growing media and organic fertilisers.
Materials and Methods: The experiments, which began in January 2023, were conducted in the CREA-OF greenhouses in Pescia (Pt), on seedlings of Zea mays. The experimental groups were: group control, irrigated with water and substrate previously fertilized; group with 10% biohumus, irrigated and fertilised substrate; group with 20% biohumus, irrigated and fertilized substrate; group with 30% biohumus, irrigated and fertilized substrate; group with 40% biohumus, irrigated and fertilized substrate; group with 50% biohumus, irrigated and fertilized substrate; group with 60% biohumus, irrigated and fertilized substrate; group with 70%, irrigated and fertilized substrate; group with 100% biohumus, irrigated and fertilized substrate. On May 18, 2023, plant height, vegetative weight, roots volume and length, the number of microorganisms and pH in the substrate were determined.
Results and Discussion: The experiment showed that the use of biohumus enriched with microorganisms can significantly improved the vegetative and root growth of sown Zea mays seedlings. In general, a significant increase in plant height, vegetative and root weight, and root length was observed from 20% substitution of biohumus in the substrate. The theses that show a particularly clear improvement for all agronomic parameters analysed are those with 50% and 60% biohumus, peat substitution. Plants that received biohumus grew better than those that did not, and cereal plants grew better than those that were grown in plain soil. The nutrient content of biohumus stimulates the growth of the following crops: tomatoes, peppers, garlic, sweet corn, aubergines, bananas. Among other things, it stimulates the growth of chrysanthemum, marigold, geranium, petunia, and poinsettia flowers, as well as acacia and eucalyptus. Due to its macro- and micronutrient content, biohumus has a positive effect on plants (leaf area, root volume, root branching), and improves the soil's biological functions. Plants that received biohumus grew better than those that did not, and cereal plants grew better than those that were grown in plain soil. The growth of barley and cereals improved on a maize farm after biohumus was applied. There was a significant improvement in soil porosity on a maize farmland. Among the benefits of using biohumus as a fertiliser are: it eliminates harmful insects, reduces the infestation of harmful insects, reduces pathogen infestation of plants, fertilizes the soil, and improves the soil structure as a soil conditioner.
Conclusions: In order to maintain soil health and fertility, farmers need a sustainable alternative that is economically viable and productive. As part of ecological agriculture, the protection of food, agricultural and human ecosystems is emphasized, along with the improvement of soil fertility and the development of secondary income for farmers. The use of biohumus provides the best answer to ecological agriculture, which is synonymous with 'sustainable agriculture'. This article provides a basis for further researc
Biofertilizer based on liquid fermented with Inula viscosa, microorganisms and algae in the growth and biocontrol of Sphaerotheca pannosa var. rosae of seed rose plants
No full textResearch goal: Based on the information obtained from the literature on Inula viscosa, in particular on the insecticidal and antifungal capacities of this plant, the aim of this work was to carry out further experiments on a macerate based on Inula viscosa, microorganisms and algae in order to evaluate the bio stimulant and biocontrol capacities on rose plants obtained from seed.
Materials and Methods: The experiments, which started in January 2021, were conducted in the greenhouses of CREA-OF in Pescia (Pt). The experiment was divided into two parts. A seed germination test and a plant growth test, both conducted during the same experiment. The four experimental groups in cultivation were: i) group without biofertilizer, irrigated with water and previously fertilized substrate; ii) group with Inula biofertilizer, microorganisms and algae (INORT); iii) group with algae (Ascophyllum nodosum extract); iv) group with beneficial bacteria.
Results and Discussion: The test showed a significant increase in the agronomic parameters analysed in plants treated with the INORT biofertilizer on seed roses. The test also showed greater control of the pathogen Sphaerotheca pannosa var. rosae in seedlings sprayed with the biofertilizer. In fact, all plants treated with INORT showed a significant increase in the height and number of leaves per plant, in the vegetative and root weight of the plants, in the number and duration of flowers, a reduction in the attack of the pathogen Sphaerotheca pannosa var. rosae, an increase in seed germination and a reduction in the average germination time.
Conclusions: The experiment at CREA-OF in Pescia has therefore demonstrated how the application of a macerate based on Inula viscosa, microorganisms and algae can significantly improve the cultivation and quality of seed rose plants. As in other experiments, the application of this biostimulant also determined positive effects in the control of pathogenic fungi, in particular Sphaerotheca pannosa var. rosae. Other investigations are currently underway to study the biostimulant and desiccant capacities of the Inula plant, depending on the harvesting methods, the physiological state of the plants, the extraction method, the type of culture medium, the type and timing of maceration. The association with various microbial consortia and other plant-derived biostimulants will also be evaluated
Trichoderma spp. in innovative substrates for ornamental plants
No full textTrichoderma spp. are free-living fungi commonly widespread in soil and root ecosystems. Recent discoveries show them as opportunistic, avirulent plant symbionts as well as parasites of other fungi. Some strains establish robust and long-lasting colonization of roots by entering into the first epidermal layers. Root colonization frequently results in enhancing of growth and development, crop productivity or induction of resistance to abiotic and biotic factors.
Peat, mainly imported from the northern and eastern European regions, is the basic constituent of organic substrates commonly utilized in the cultivation of ornamental plants in pots or in benches. During the past few years, the supply of the peat is hampered by environmental and economical constraints. Recently, the European Commission decided to exclude all substrates containing peat from the release of the Community Eco-Label Mark. In this optic the need to reduce peat in ornamental substrates devised great attention and resulted in pressing and increasing research activity to set up new and innovative substrates for ornamental market.
The aim of the present PhD thesis is to select beneficial fungi belonging to Trichoderma genus, to be add as soil inoculants, in order to develop an innovative, economical and suitable substrate alternative to peat for cultivation of seed plants (Limonium sinuatum and Cupressus sempervirens) and of acidophilus species (Camellia japonica) of ornamental interest. The activity involved the selection of Trichoderma spp. isolates for their ability to grow in the roots, as endophytes, or in the rhizosphere, to protect plants against plant pathogens or to act as plant growth promoters. The preliminary screening for endophytism resulted in 10 interesting isolates (out of 162) for Limonium sinuatum, 9 (out of 162) for Cupressus sempervirens and 8 (out of 202) for Camellia japonica. From following rounds of screening, three Trichoderma isolates, among which T. asperellum 2046 in common for all the species, confirmed the best endophytic performance and improved growth.
The antagonistic activity of these selected strains, against fungal plant pathogens as Sclerotinia sclerotiorum, S. minor, Colletotrichum gleospoiroides and Rhizoctonia solani, has been evaluated in order to analyse if these isolates could be considered good beneficial fungi. In addition. T2046 was evaluated in biocontrol experiments on Limonium, against S. sclerotiorum and S. minor with mycoparasistim investigated as principal mechanisms.
Encouraging results herewith obtained, suggest that T. asperellum 2046 could be taken into account as bioactive ingredient of new biopesticide and/or biofertilizer to be used as inoculant for innovative substrates for ornamental plants
Effect of Glomus mosseae inoculation on growth and flowering improvement of Chamaecereus sylvestrii and Mammillaria laui
No full textThe aim of the experiment was to study how Glomus mosseae influences the growth and flowering of cacti such as Mammillaria laui and Chamaecereus sylvestrii. The experimental theses have been: (1) soil inoculated with Glomus mosseae and fertilized; (2) soil without Glomus mosseae, irrigated with water and fertilizer (control). The test showed a significant increase in the agronomic parameters analysed in plants treated with Glomus mosseae. In fact, all cactus plants treated with endomycorriza showed a significant increase in the vegetative and radical part of the plants, in the number of flowers per plant and in the duration of flowering. This endomycorriza can therefore also have beneficial effects on plants that are slow to grow and prolong the life of their flowers, beautiful to see but that normally short-lived. Further studies will be done on the use of mycorrhiza on cacti and succulents and the influence on resistance to biotic and abiotic stress of different typologies
Possible use of Spirulina and Klamath algae as biostimulants in Portulaca grandiflora (Moss Rose)
No full textThe aim of the experiment was to evaluate the use and influence of Spirulina and Klamath algae on the growth, flowering, germination and mineral absorption of Portulaca grandiflora plants. The 3 experimental groups in cultivation were: (1) group without algae (CTRL), irrigated with water and previously fertilized substrate; (2) spirulina group (SPR) and fertilized substrate; (3) Klamath group (KLT) and fertilized substrate. The test showed a significant increase in the agronomic parameters analysed in plants treated with Spirulina and Klamath algae. In fact, all plants treated with (SPR and KLT) showed a significant increase in plant height and number of stems, number and diameter of flowers, vegetative and roots weight, number of leaves and flowering time. The test showed that the use of Spirulina and Klamath in the culture medium can significantly influence the germination of the Portulaca grandiflora and resulted in a significant increase in chlorophyll content and improved absorption of NPK. These results could be of interest to growers who want to improve the quality of their ornamental crops by using products that are easy to manage and not harmful to the environment
Possible use of Inula viscosa (Dittrichia viscosa L.) for biostimulation of Oscularia deltoides and Corpuscolaria lehmanii plants and protection against Aphis nerii
No full textIn this study the possibility of using liquid Inula viscosa (Dittrichia viscosa L.) to improve the growth and quality of Oscularia deltoides and Corpuscolaria lehmanii plants and protection against Aphis nerii was evaluated. The 3 experimental groups in cultivation were: i) group without the use of Inula viscosa liquid macerate (CTRL), irrigated with water and previously fertilised substrate; ii) group treated with 1% of Inula viscosa liquid obtained from flowers (leaf spraying and soil irrigation), previously fertilized substrate (INU1); iii) group treated with 1% of Inula viscosa liquid obtained from leaves and stems (leaf spraying and soil irrigation), previously fertilized substrate (INU2). The test showed a significant increase in the agronomic parameters analyzed in plants treated with liquid Inula viscosa. In fact, all plants treated with Inula showed a significant increase in plant height, leaves number, vegetative and roots weight, branches and flowers number and flowering time in both Corpuscolaria lehmanii and Oscularia deltoides. An evaluation was also made of the number of individuals of Aphis nerii present on the plants of Corpuscolaria lehmanii and Oscularia deltoides to assess whether the macerate of Inula can be used for the control of these insects. The GC-MS analysis of active fractions strongly suggested costic acid as the compound responsible for contact toxicity against Aphis nerii. Probably in the plant treated with Inula viscosa there is an induction of the defense mechanisms that lead to greater resistance to biotic and abiotic stresses. The application of Inula macerate also improves the plant's defences against attacks by fungal pathogens and insects. Very interesting aspects, especially in view of a possible reduction of fertilizers and synthetic plant protection products
