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La marchitez vascular causada por Fusarium spp. es una enfermedad limitante de la producción de berenjena en el Caribe colombiano. Se evaluó el portainjerto silvestre Solanum mammosum L., injertado por el método de empalme terminal, con el cultivar comercial de berenjena Solanum melongena L. Corpoica CO15, con nueve repeticiones, comparándolo con el desarrollo de los testigos S. melongena Corpoica CO15 y S. mammosum sin injertar, bajo un diseño completamente aleatorizado, determinándose la resistencia de estos tratamientos a la marchitez. En un segundo experimento se evaluaron tres alternativas de nutrición foliar T1 = testigo (aspersión de agua), T2 = fuente rica en potasio (K: 344 g L-1); T3 = fuente rica en calcio (Ca: 96 g L-1 de CaO); T4 = fuente rica en fósforo (P: 300 g L-1 de P2O5), bajo un diseño completamente aleatorizado con cuatro repeticiones. En ambos experimentos se utilizaron nueve plántulas por unidad por tratamiento, sembradas en macetas con 3,5kg de suelo franco limoso e inoculadas con Fusarium spp. cepa FS02, en casa de malla. La inoculación se realizó en plántulas de 30 días de desarrollo (de 3-4 hojas verdaderas), mediante heridas en la base del tallo y en las raíces de cada planta, con 20mL de suspensión (5.000 conidias mL-1). El uso del portainjerto silvestre S. mammosum y los nutrientes minerales mediante aplicación foliar, redujeron significativamente la incidencia y severidad de la enfermedad. Vascular wilt caused by Fusarium spp. It is a limiting disease of eggplant production in the Colombian Caribbean. The wild rootstock Solanum mammosum L., grafted by the terminal splicing method, with the commercial eggplant cultivar Solanum melongena L. Corpoica CO15, was evaluated with nine repetitions, comparing it with the development of the controls S. melongena Corpoica CO15 and S. mamosum without grafting, under a completely randomized design, determining the resistance of these treatments to wilting. In a second experiment, three foliar nutrition alternatives were evaluated: T1 = control (water spray), T2 = source rich in potassium (K: 344 g L-1); T3 = rich source of calcium (Ca: 96 g L-1 of CaO); T4 = source rich in phosphorus (P: 300 g L-1 of P2O5), under a completely randomized design with four repetitions. In both experiments, nine seedlings were used per treatment, planted in pots with 3.5kg of silt loam soil and inoculated with Fusarium spp. FS02 strain, in a mesh house. Inoculation was carried out on seedlings of 30 days of development (3-4 true leaves), through wounds at the base of the stem and in the roots of each plant, with 20mL of suspension (5000 conidia mL-1). The use of wild S. mammosum rootstock and mineral nutrients through foliar application significantly reduced the incidence and severity of the disease

Background Heavy metal exposure affect plant productivity by interfering, directly and indirectly, with photosynthetic reactions. The toxic effect of heavy metals on photosynthetic reactions has been reported in wide-ranging studies, however there is paucity of data in the literature concerning thallium (Tl) toxicity. Thallium is ubiquitous natural trace element and is considered the most toxic of heavy metals; however, some plant species, such as white mustard ( Sinapis alba L.) are able to accumulate thallium at very high concentrations. In this study we identified the main sites of the photosynthetic process inhibited either directly or indirectly by thallium, and elucidated possible detoxification mechanisms in S. alba . Results We studied the toxicity of thallium in white mustard ( S. alba ) growing plants and demonstrated that tolerance of plants to thallium (the root test) decreased with the increasing Tl(I) ions concentration in culture media. The root growth of plants exposed to Tl at 100 μg L −1 for 4 weeks was similar to that in control plants, while in plants grown with Tl at 1,000 μg L −1 root growth was strongly inhibited. In leaves, toxic effect became gradually visible in response to increasing concentration of Tl (100 − 1,000 μg L −1 ) with discoloration spreading around main vascular bundles of the leaf blade; whereas leaf margins remained green. Subsequent structural analyses using chlorophyll fluorescence, microscopy, and pigment and protein analysis have revealed different effects of varying Tl concentrations on leaf tissue. At lower concentration partial rearrangement of the photosynthetic complexes was observed without significant changes in the chloroplast structure and the pigment and protein levels. At higher concentrations, the decrease of PSI and PSII quantum yields and massive oxidation of pigments was observed in discolored leaf areas, which contained high amount of Tl. Substantial decline of the photosystem core proteins and disorder of the photosynthetic complexes were responsible for disappearance of the chloroplast grana. Conclusions Based on the presented results we postulate two phases of thallium toxicity on photosynthesis: the non-destructive phase at early stages of toxicant accumulation and the destructive phase that is restricted to the discolored leaf areas containing high toxicant content. There was no distinct border between the two phases of thallium toxicity in leaves and the degree of toxicity was proportional to the migration rate of the toxicant outside the vascular bundles. The three-fold (nearly linear) increase of Tl(I) concentration was observed in damaged tissue and the damage appears to be associated with the presence of the oxidized form of thallium − Tl(III).

One hundred and sixteen Eggplant accessions were tested in the field for resistance to Verticillium dahliae Kleb. Disease assessment was based on external and internal symptoms. Plants were scored for both types of symptoms and the amount of disease (% of diseased plants and severity index) was calculated for each accession. Disease ratings based on external symptoms did not always coincide with those for vascular discoloration of resistant accessions. No accessions possessed high resistance. However, some accessions showed levels of resistance characterized by percentage of diseased plants and, particularly, by disease severity values for both external symptoms and vascular discoloration lower than those for the susceptible cv. Florida Market. Resistance found in the original Eggplant accessions (S₀) was transmitted in single-plant selected S₁ and S₂ progenies. A new term, slow wilting (SW), is proposed to indicate the type of resistance exhibited by some resistant accessions. Centosedici accessioni di Melanzana sono state saggiate in pieno campo per la resistenza verso Verticillium dahliae. Ogni accessione è stata valutata considerando la percentuale di piante malate e l'indice di gravità della malattia sia dei sintomi esterni che degli imbrunimenti vascolari. Nelle accessioni resistenti la gravità dei sintomi esterni di malattia non ha coinciso sempre con quella degli imbrunimenti vascolari. Nessuna accessione è risultata altamente resistente, tuttavia alcune hanno mostrato livelli di resistenza caratterizzati da percentuali di piante malate e, in particolare, da indici di gravità di malattia, sia per i sintomi esterni sia per gli imbrunimenti vascolari, significativamente più bassi di quelli della cv. suscettibile Florida Market. La resistenza individuata nelle accessioni originali di Melanzana (S₀) è stata trasferita alle progenie S₁ e S₂ ottenute per autoimpollinazione da piante selezionate. Si propone un nuovo termine, 'slow wilting' (SW), per indicare il tipo di resistenza manifestato da alcune accessioni resistenti.