The excessive use of synthetic chemicals in agriculture demands sustainable alternatives to comba... more The excessive use of synthetic chemicals in agriculture demands sustainable alternatives to combat crop-affecting microorganisms. Plant-derived secondary metabolites have garnered attention as promising candidates with antimicrobial properties. This study investigates the antimicrobial potential of tobacco plants, specifically non-commercial accessions Nic 1015 (“TI 1341”) and BHmN, recognized for their rich bioactive compounds. Our objectives encompassed the extraction of leaf surface compounds and the assessment of their in vitro antimicrobial activity against crop-damaging microorganisms. Ethanol-based extracts, abundant in diterpenes, were meticulously analyzed. Notably, BHmN contained cis-abienol, while both accessions featured α-CBT diol, as confirmed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). TLC-Bioautography and microdilution assays unveiled substantial antifungal activity. The growth inhibition percentages correlated with extract ...
Dry land systems spread all over the world and comprise 41.3% of the terrestrial area, which host... more Dry land systems spread all over the world and comprise 41.3% of the terrestrial area, which host 34.7% of the global population, so it is convenient to propose crops able to grow there. Jatropha curcas is a plant adapted to arid and semiarid regions as well as sub-humid conditions, being a potential source of biodiesel. The challenge is to understand the physiology of J. curcas, which enables it to live under saline and drought conditions. The seeds of J. curcas used came from Ciego de Ávila Province, Cuba. Seven-day-old seedlings were cultivated in 1.5 L pots with half strength Hoagland solution for 42 days under semi-controlled conditions. NaCl added to solutions in pots provided 75 or 150 mM treatments for 240 h before measurements. Leaf growth, net photosynthesis and stomatal pore area were affected by 150 mM NaCl. Non-photochemical quenching of leaves was only changed by 150 mM NaCl after 24 h; the electron transport rate had a tendency to decrease in leaves under saline condi...
En un experimento llevado a cabo en un suelo Vertisol del Valle del Río Cauto en Cuba se evaluó e... more En un experimento llevado a cabo en un suelo Vertisol del Valle del Río Cauto en Cuba se evaluó el efecto del exceso de agua sobre el desarrollo del sistema radical de seis genotipos de caña de azúcar. Se uso un diseño de parcelas divididas, donde la presencia o no de exceso de agua en el suelo era la parcela y los genotipos eran las subparcelas. Los tratamientos fueron 12 y consistieron en los genotipos C86-12, C86-456, C90-317, C87-51, C1051-73 y C12078, sometidos o no al exceso de agua en el suelo. Se encontró que la Intensidad del Estrés (IE), redujo en un 17% la profundidad radical en el primer ciclo, mientras que para la primera soca se redujo en un 11%, con marcada diferencia entre genotipos. Los genotipos menos afectados fueron C86-12, C86-456 y C90-317, lo
This paper originates from an address at the 8th International Symposium on Nitrogen Fixation wit... more This paper originates from an address at the 8th International Symposium on Nitrogen Fixation with Non-Legumes, Sydney, NSW, December 2000 In sugarcane propagation the sett pieces are routinely heated at 50˚C before planting to control the xylem pathogen Leifsonia xyli ssp. xyli. To determine whether this treatment also affects the diazotrophic endophyte, Gluconacetobacter diazotrophicus, found in the intercellular solution of cane parenchyma, cultures of this bacterium were similarly heated. The nitrogenase activity of the heated cultures was monitored by measurement of hydrogen evolution. Activity was destroyed in cultures heated directly at 45 or 50˚C for 2 h. In contrast, when sett pieces were first heated for 2 h at 50˚C, G. diazotrophicus could still be isolated from the intercellular fluid, and these cultures showed considerable nitrogenase activity. There was no difference in leaf nitrogen content of plants grown in nitrogen-poor soil from setts either heated or unheated. It...
When abundant precipitations are associated to physical edaphic problems then excesses of water m... more When abundant precipitations are associated to physical edaphic problems then excesses of water may appear in soils of agricultural interest, affecting dissimilarly to the morfophysiology of the crop plants. The experiment was a split plot design at random in complete blocks with five repetitions in a Typic Hapluster soil. The presence or absence of the soil flooding was considered like plots and the genotypes like sub-plots. Stomatal density and stomatal length were measured in 10-mo old sugar cane plants in two crop cycles, plant cane and first ratoon. The stress intensity was determined. It was proven that the stress intensity inverted increased the stomatal density at a 9.0 % in plant cane and first ratoon, while the stomatal length in excess of water in soil was reduced at 12.0 % for both crop cycles, with important differences among the studied genotypes. Inverse correlations were detected between stomatal density and stomatal length. It concluded that the oxygen deficiency in flooding soil induces morphologic changes in the stomatal density and length with wide differentiation among genotypes in plant cane and first ratoon crops cycles.
Beiträge zur Tabakforschung International/Contributions to Tobacco Research
Nitrogen (N) fertilizers have a decisive influence on the yield and quality of tobacco. Yield, pe... more Nitrogen (N) fertilizers have a decisive influence on the yield and quality of tobacco. Yield, percentage of plant N, wrapper leaf quality, and nicotine content are all important quality characteristics in tobacco growing. This work is an attempt to provide a tool for optimizing mineral N nutrition for Cuban cigar tobacco, using a strategy that links N supply with leaf N concentration and wrapper yield. Similar approaches developed worldwide have mainly involved Virginia and Burley tobacco types but not Cuban cigar tobacco. The objective of the current work is to identify the effects of fertilizer N levels and timing of application on each of the mentioned quality factors for shade grown Cuban cigar tobacco. Another purpose is to explore the usefulness of a quick method of assessing the N status of plants based on measuring leaf transmission at two different wavelengths (650 and 940 nm). The experiments were done in the main tobacco growing area of Cuba (Vueltabajo). In each experim...
EFECTOS DE Brevibacillus bortelensis B65 SOBRE LA GERMINACIÓN Y EL DESARROLLO DE POSTURAS DE HORT... more EFECTOS DE Brevibacillus bortelensis B65 SOBRE LA GERMINACIÓN Y EL DESARROLLO DE POSTURAS DE HORTALIZAS EN FASE DE SEMILLERO Effects of Brevibacillus borstelensis B65 on germination and seedlings development of horticulture crops ABSTRACT. Eggplant (Solanum melongena L) and pepper (Capsicum annum) are priorities of organic foodstuffs programs in Santiago de Cuba. Seedlings of both, eggplant and pepper are cultivated under organic substrates made of earthworm castings, vegetal residues and soil, which supplies key nutrients but are lacking of plant hormones that may be supplied by plant growth promoting rhizobacteria. In the present research, the effects of a biological formulation made with the rhizobacteria strain Brevibacillus borstelensis B65 on germination and growth of eggplant and pepper seedlings sowed under organic treatment were evaluated. Eggplant and pepper seeds were treated and not (control) with the bacterial formulation and transferred into an organic substrate mixtur...
Proline, glicine betaíne and total soluble proteincontents were determined in 12 Cuban wheat vari... more Proline, glicine betaíne and total soluble proteincontents were determined in 12 Cuban wheat varieties, of T.aestivum and T. durum species, growing under salineconditions. Thus, two experimental variants were conductedbased on a concentrated nutrient solution. The first treatmentbecame salty with NaCl to an electric conductivity of 8 dS.m-1and the control treatment without applying NaCl. This testwas performed under hidropony conditions and treatmentswere applied from sowing time until 45 days after seedgermination, when determinations were recorded. Data obtainedin the control and stress treatments were compared by t-studenttest for 5 and 1 % significant levels. As a result, an importantincrement of proline content was obtained in most varieties,the accumulation in foliage being bigger than in roots. Glicinebetaíne content was highly significant just in wheat varietiesof T. durum species. Total soluble protein content showed arather variable behaviour, even among varieties from the...
The intercellular spaces of sugarcane (Saccharum officinarum L.) stem parenchyma are filled with ... more The intercellular spaces of sugarcane (Saccharum officinarum L.) stem parenchyma are filled with solution (determined by cryoscanning microscopy), which can be removed aseptically by centrifugation. It contained 12% sucrose (Suc; pH 5.5.) and yielded pure cultures of an acid-producing bacterium (approximately 104 bacteria/mL extracted fluid) on N-poor medium containing 10% Suc (pH 5.5). This bacterium was identical with the type culture of Acetobacter diazotrophicus, a recently discovered N2-fixing bacterium specific to sugarcane, with respect to nine biochemical and morphological characteristics, including acetylene reduction in air. Similar bacteria were observed in situ in the intercellular spaces. This demonstrates the presence of an N2-fixing endophyte living in apoplastic fluid of plant tissue and also that the fluid approximates the composition of the endophytes's optimal culture medium. The apoplastic fluid occupied 3% of the stem volume; this approximates 3 tons of flui...
The excessive use of synthetic chemicals in agriculture demands sustainable alternatives to comba... more The excessive use of synthetic chemicals in agriculture demands sustainable alternatives to combat crop-affecting microorganisms. Plant-derived secondary metabolites have garnered attention as promising candidates with antimicrobial properties. This study investigates the antimicrobial potential of tobacco plants, specifically non-commercial accessions Nic 1015 (“TI 1341”) and BHmN, recognized for their rich bioactive compounds. Our objectives encompassed the extraction of leaf surface compounds and the assessment of their in vitro antimicrobial activity against crop-damaging microorganisms. Ethanol-based extracts, abundant in diterpenes, were meticulously analyzed. Notably, BHmN contained cis-abienol, while both accessions featured α-CBT diol, as confirmed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). TLC-Bioautography and microdilution assays unveiled substantial antifungal activity. The growth inhibition percentages correlated with extract ...
Dry land systems spread all over the world and comprise 41.3% of the terrestrial area, which host... more Dry land systems spread all over the world and comprise 41.3% of the terrestrial area, which host 34.7% of the global population, so it is convenient to propose crops able to grow there. Jatropha curcas is a plant adapted to arid and semiarid regions as well as sub-humid conditions, being a potential source of biodiesel. The challenge is to understand the physiology of J. curcas, which enables it to live under saline and drought conditions. The seeds of J. curcas used came from Ciego de Ávila Province, Cuba. Seven-day-old seedlings were cultivated in 1.5 L pots with half strength Hoagland solution for 42 days under semi-controlled conditions. NaCl added to solutions in pots provided 75 or 150 mM treatments for 240 h before measurements. Leaf growth, net photosynthesis and stomatal pore area were affected by 150 mM NaCl. Non-photochemical quenching of leaves was only changed by 150 mM NaCl after 24 h; the electron transport rate had a tendency to decrease in leaves under saline condi...
En un experimento llevado a cabo en un suelo Vertisol del Valle del Río Cauto en Cuba se evaluó e... more En un experimento llevado a cabo en un suelo Vertisol del Valle del Río Cauto en Cuba se evaluó el efecto del exceso de agua sobre el desarrollo del sistema radical de seis genotipos de caña de azúcar. Se uso un diseño de parcelas divididas, donde la presencia o no de exceso de agua en el suelo era la parcela y los genotipos eran las subparcelas. Los tratamientos fueron 12 y consistieron en los genotipos C86-12, C86-456, C90-317, C87-51, C1051-73 y C12078, sometidos o no al exceso de agua en el suelo. Se encontró que la Intensidad del Estrés (IE), redujo en un 17% la profundidad radical en el primer ciclo, mientras que para la primera soca se redujo en un 11%, con marcada diferencia entre genotipos. Los genotipos menos afectados fueron C86-12, C86-456 y C90-317, lo
This paper originates from an address at the 8th International Symposium on Nitrogen Fixation wit... more This paper originates from an address at the 8th International Symposium on Nitrogen Fixation with Non-Legumes, Sydney, NSW, December 2000 In sugarcane propagation the sett pieces are routinely heated at 50˚C before planting to control the xylem pathogen Leifsonia xyli ssp. xyli. To determine whether this treatment also affects the diazotrophic endophyte, Gluconacetobacter diazotrophicus, found in the intercellular solution of cane parenchyma, cultures of this bacterium were similarly heated. The nitrogenase activity of the heated cultures was monitored by measurement of hydrogen evolution. Activity was destroyed in cultures heated directly at 45 or 50˚C for 2 h. In contrast, when sett pieces were first heated for 2 h at 50˚C, G. diazotrophicus could still be isolated from the intercellular fluid, and these cultures showed considerable nitrogenase activity. There was no difference in leaf nitrogen content of plants grown in nitrogen-poor soil from setts either heated or unheated. It...
When abundant precipitations are associated to physical edaphic problems then excesses of water m... more When abundant precipitations are associated to physical edaphic problems then excesses of water may appear in soils of agricultural interest, affecting dissimilarly to the morfophysiology of the crop plants. The experiment was a split plot design at random in complete blocks with five repetitions in a Typic Hapluster soil. The presence or absence of the soil flooding was considered like plots and the genotypes like sub-plots. Stomatal density and stomatal length were measured in 10-mo old sugar cane plants in two crop cycles, plant cane and first ratoon. The stress intensity was determined. It was proven that the stress intensity inverted increased the stomatal density at a 9.0 % in plant cane and first ratoon, while the stomatal length in excess of water in soil was reduced at 12.0 % for both crop cycles, with important differences among the studied genotypes. Inverse correlations were detected between stomatal density and stomatal length. It concluded that the oxygen deficiency in flooding soil induces morphologic changes in the stomatal density and length with wide differentiation among genotypes in plant cane and first ratoon crops cycles.
Beiträge zur Tabakforschung International/Contributions to Tobacco Research
Nitrogen (N) fertilizers have a decisive influence on the yield and quality of tobacco. Yield, pe... more Nitrogen (N) fertilizers have a decisive influence on the yield and quality of tobacco. Yield, percentage of plant N, wrapper leaf quality, and nicotine content are all important quality characteristics in tobacco growing. This work is an attempt to provide a tool for optimizing mineral N nutrition for Cuban cigar tobacco, using a strategy that links N supply with leaf N concentration and wrapper yield. Similar approaches developed worldwide have mainly involved Virginia and Burley tobacco types but not Cuban cigar tobacco. The objective of the current work is to identify the effects of fertilizer N levels and timing of application on each of the mentioned quality factors for shade grown Cuban cigar tobacco. Another purpose is to explore the usefulness of a quick method of assessing the N status of plants based on measuring leaf transmission at two different wavelengths (650 and 940 nm). The experiments were done in the main tobacco growing area of Cuba (Vueltabajo). In each experim...
EFECTOS DE Brevibacillus bortelensis B65 SOBRE LA GERMINACIÓN Y EL DESARROLLO DE POSTURAS DE HORT... more EFECTOS DE Brevibacillus bortelensis B65 SOBRE LA GERMINACIÓN Y EL DESARROLLO DE POSTURAS DE HORTALIZAS EN FASE DE SEMILLERO Effects of Brevibacillus borstelensis B65 on germination and seedlings development of horticulture crops ABSTRACT. Eggplant (Solanum melongena L) and pepper (Capsicum annum) are priorities of organic foodstuffs programs in Santiago de Cuba. Seedlings of both, eggplant and pepper are cultivated under organic substrates made of earthworm castings, vegetal residues and soil, which supplies key nutrients but are lacking of plant hormones that may be supplied by plant growth promoting rhizobacteria. In the present research, the effects of a biological formulation made with the rhizobacteria strain Brevibacillus borstelensis B65 on germination and growth of eggplant and pepper seedlings sowed under organic treatment were evaluated. Eggplant and pepper seeds were treated and not (control) with the bacterial formulation and transferred into an organic substrate mixtur...
Proline, glicine betaíne and total soluble proteincontents were determined in 12 Cuban wheat vari... more Proline, glicine betaíne and total soluble proteincontents were determined in 12 Cuban wheat varieties, of T.aestivum and T. durum species, growing under salineconditions. Thus, two experimental variants were conductedbased on a concentrated nutrient solution. The first treatmentbecame salty with NaCl to an electric conductivity of 8 dS.m-1and the control treatment without applying NaCl. This testwas performed under hidropony conditions and treatmentswere applied from sowing time until 45 days after seedgermination, when determinations were recorded. Data obtainedin the control and stress treatments were compared by t-studenttest for 5 and 1 % significant levels. As a result, an importantincrement of proline content was obtained in most varieties,the accumulation in foliage being bigger than in roots. Glicinebetaíne content was highly significant just in wheat varietiesof T. durum species. Total soluble protein content showed arather variable behaviour, even among varieties from the...
The intercellular spaces of sugarcane (Saccharum officinarum L.) stem parenchyma are filled with ... more The intercellular spaces of sugarcane (Saccharum officinarum L.) stem parenchyma are filled with solution (determined by cryoscanning microscopy), which can be removed aseptically by centrifugation. It contained 12% sucrose (Suc; pH 5.5.) and yielded pure cultures of an acid-producing bacterium (approximately 104 bacteria/mL extracted fluid) on N-poor medium containing 10% Suc (pH 5.5). This bacterium was identical with the type culture of Acetobacter diazotrophicus, a recently discovered N2-fixing bacterium specific to sugarcane, with respect to nine biochemical and morphological characteristics, including acetylene reduction in air. Similar bacteria were observed in situ in the intercellular spaces. This demonstrates the presence of an N2-fixing endophyte living in apoplastic fluid of plant tissue and also that the fluid approximates the composition of the endophytes's optimal culture medium. The apoplastic fluid occupied 3% of the stem volume; this approximates 3 tons of flui...
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