El cultivo de ajipa. Una posible alternativa para la producción de hidratos de carbono, proteína y aceite en un sistema de agricultura sostenible

28 páginas, 6 figuras, 2 tablas, 14 referencias. Colección: Agricultura. Serie: Cultivos industriales.Puede descargarse online en https://www.juntadeandalucia.es/servicios/publicaciones/detalle/49368.htmlLa ajipa, cuyo nombre científico es Pachyrhizus ahipa (Wedd.) Parodi, es una planta de la familia Leguminosas ya cultivada por los Incas durante el período precolombino, junto con especies muy habituales y mucho más conocidas para nosotros, como el maíz y el pimiento. De la importancia de la ajipa durante el período Inca dan cuenta los hallazgos arqueológicos de restos de raíces en enterramientos humanos (Paracas-Necrópolis), y las representaciones en cerámica y bordados de distintas culturas (Mochica, Nasca).Los trabajos realizados fueron financiados mayoritariamente con fondos del proyecto de la Unión Europea AHIPA (FAIR6 CT98-4297)Peer reviewe

Efecto de la fuente de nitrógeno en la distribución de asimilados y composición de savia en ajipa (Pachyrhizus ahipa (Wedd.) Parodi)

7 páginas, 4 figuras, 1 tabla y 17 referencias. Trabajo presentado en el VI Simposium Nacional - II Ibérico sobre nutrición mineral de las plantas, Sevilla, del 12 al 15 de Noviembre de 1996. Entidades colaboradoras Junta de Andalucía, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Sociedad Española de Fisiología Vegetal, El Monte, Caja de Huelva y Sevilla y Gat Fertiliquidos. Editores Científicos: Rafael Sarmiento Solís, Eduardo O. Leidi Montes y Antonio Troncoso de Arce. (Instituto de Recursos Naturales y Agrobiología de Sevilla).[EN]:Ahipa (Pachyrhizus ahipa (Wedd.) Parodi) is a legume root crop of Andean origin which accumulates carbohydrates of industrial interest in its tuberous roots and rotenone in leaves and seeds. The aim of this work was the study of lhe effect of N source (nitrate vs symbiotic N2, fixation) on growth, assimilate partitioning and xylem sap composition. The treatments consisted in: (a) plants inoculated with an specific Rhizobium strain irrigated wilh a N free nutrient solution (T-N2); and (b) non inoculated plants irrigated with a nutrient solution contai ning 4 mM NO3K (T-NO3). Main differences in growth and assimilate allocation were observed between plants grown in different treatments: N2,-fixing plants showed an increased earliness and reduced tuberous root growth in comparison with NO3-fed plants . Dry matter allocation into leaves and shoots was higher in NO -fed plants lhan in N2-fixing plants. Nitrogen concentration in leaves, stems and roots was higher in N2-fixing plants than in NO3-fed plants. At early growth stages, main xylem sap nitrogenous solutes were amino acids and amides. At flowering, N2-fixing plants showed high concentratÍon ofureides (allantoin+allantoic acid) and the amino acid L-canavanine[ES]:La ajipa (PachyrhiZlls ahipa (Wedd) Parodi), leguminosa de origen andino, se caracteriza por la acumulación de hidratos de carbono de interés industrial en sus raíces tuberosas y la presencia de rotenona en hojas y semillas. En este trabajo hemos estudiado el efecto de la nutrición nitrogenada (fijación simbiótica de N2 ó N mineral) sobre el crecimiento, partición de asimilados y composición de savia de xilema. Los tratamientos consistieron en: (a) plantas inoculadas con una cepa especifica de Rhizobium spp. (T-N2) y (b) plantas no inoculadas (T-NO3). Las planta se cultivaron en perlita/vermiculit y se regaron con solución de Hewitt sin N (T-N2) o 4 mM NO3K (T-NO3). Se observaron importantes diferencias debidas a la fuente de N: las plantas T-N, presentaron una mayor precocidad en la floración y fructificación y un menor desarrollo de la raíz tuberosa en comparación con las plantas T-NO2. La acumulación de materia seca en hojas y tallos de las plantas también fue superior en las plantas T-NO3. La concentración de N en hojas, tallos y raices fue superior en la plantas T-N2. En estadios tempranos de crecimiento, los componentes principales de savia de xilema, en ambos tratamientos. eran aminoácidos y amidas. En floración, las plantas T-N2, presentaban altas concentraciones de ureidos (alantoina+ácido alantoico) y el principal aminoácido transportado era L-canavanina.Sección de Nutrición Mineral de la Sociedad Española de Fisiología Vegetal y Instituto de Recursos Naturales y Agrobiología de Sevilla, CSIC.Peer reviewe

Estudios fisiológicos y genéticos de estirpes de Rhizobium meliloti con vistas a la producción de inoculantes

Universidad de Granada, Facultad de Ciencias. Leída el 12-07- 198

Nitrogen and phosphorus availability limit N2 fixation in bean

Availability of nitrogen (N) and phosphorus (P) might significantly affect N2 fixation in legumes. The interaction of N and P was studied in common bean (Phaseolus vulgaris), considering their effects on nodulation and N2 fixation, nitrate reductase activity, and the composition of N compounds in xylem sap. The effect of N on the uptake of P by plants was estimated by analysing rhizospheric pH and P concentration in xylem sap and in plant shoots. Inoculated bean plants were grown in pots containing perlite/vermiculite in two experiments with different amounts of P and N. In a third experiment, bean plants were grown on two soil types or on river sand supplied with different concentrations of N. At harvest, shoot growth, number of nodules and mass, and nitrogenase activity were determined. Xylem sap was collected for the determination of ureides, amino acids, nitrate and phosphate concentration. At low nitrate concentration (1 mM), increasing amounts of P promoted both nodule formation and N2 fixation, measured as ureide content in the xylem sap. However, at high nitrate concentration (10 mM), nodulation and N2 fixation did not improve with increased P supply. Glutamine and aspartate were the main organic N compounds transported in the xylem sap of plants grown in low nitrate, whereas asparagine was the dominant N compound in xylem sap from plants grown in high nitrate. Nitrate reductase activity in roots was higher than in shoots of plants grown with low P and high N. In both soils and in the sand experiment, increased application of N decreased nodule mass and number, nitrogenase activity and xylem ureides but increased the concentration of asparagine in xylem sap. Increasing P nutrition improved symbiotic N2 fixation in bean only at low N concentrations. It did not alleviate the inhibitory effect of high nitrate concentration on N2 fixation. A decrease in plant P uptake was observed, as indicated by a lower concentration of P in the xylem sap and shoots, correlating with the amount of N supplied. Simultaneously with the specific inhibition of N2 fixation, high nitrate concentrations might decrease P availability, thus inhibiting even further the symbiotic association because of the high P requirement for nodulation and N2 fixation.This work was partially supported by Project SC93–070 (INIA-MAPA).Peer Reviewe

Ahipa (Pachyrhizus ahipa [Wedd.] Parodi): An alternative legume crop for sustainable production of starch, oil and protein

Ahipa (Pachyrhizus ahipa [Wedd.] Parodi) is a tuberous root producing legume which can be used for the production of raw materials such as starch, sugar and protein in a sustainable agriculture system. In this study, we studied root and pod production of available landraces grown at two different locations for making preliminary yield assessments and analyzed root and seed composition to determine production of raw materials. Important variation in root and pod growth and harvest index was observed among accessions. Some landraces showed higher potential for root production than others, with a higher potential for seed production. Root dry matter ranged from 16.3 to 21.1%. Root starch content ranged 38.6-54.4%, while a wider variation in root sugar content was observed (21.8-51.4%). Seeds had high protein (25.2-31.4%) and high oil contents (18.7-22.4%). Free amino acid concentration in roots was quite high (0.26-0.41%), with asparagine as the main amino-N compound. An important accumulation of canavanine, amino acid structural analog of arginine, was found in seeds of some accessions. With low nutritional requirements and high pest resistance, which underlines the low environmental impact, ahipa reaches root and seed yield similar to other root or pulse crops. Since of its yield and root and seed components (starch, sugar, proteins, oil), which could be improved by breeding, the ahipa appears a promising alternative to other traditional sources of raw materials. © 2002 Elsevier Science B.V. All rights reserved.This work was supported by European Union FAIR Grant CT98-4297 AHIPA.Peer Reviewe

Interaction effects between Rhizobium strain and bean cultivar on nodulation, plant growth, biomass partitioning and xylem sap composition

The interaction Rhizobium/Phaseolus was studied under controlled conditions using commercial bean cultivars and different Rhizobium strains. Plant growth (Shoot and pods), symbiotic parameters (nodule number and nodule mass) and N solutes (ureides; amino acids and nitrate) in xylem sap were determined. A significant variation of plant growth in response to inoculation with Rhizobium strains was observed. Inoculation with different strains affected biomass (shoot and pod growth) and N concentration in shoots, as a result of differences in N2 fixation rates, but also affected the harvest index, significant differences were observed in the concentration of N solutes in the xylem sap. The genotype of bean cultivar had an important effect on the symbiotic effectiveness of different strains, affecting variables like number and mass of nodules, and the concentration of N solutes in xylem sap. An interaction cultivar x strain effect was observed for plant growth, symbiotic parameters and ureides and aminoacids in sap. The results suggest the need to search for specific strain/cultivar combinations in order to maximize the N2 fixation capacity in beans. Because of the variation in sap ureide and amino acid concentration, the ureide method for N2 fixation assessment would require calibration for each Rhizobium/Phaseolus combination.Peer Reviewe

Attachment of bacteria to the roots of higher plants

Abstract Attachment of soil bacteria to plant cells is supposedly the very early step required in plant-microbe interactions. Attachment also is an initial step for the formation of microbial biofilms on plant roots. For the rhizobia-legume symbiosis, various mechanisms and diverse surface molecules of both partners have been proposed to mediate in this process. The first phase of attachment is a weak, reversible, and unspecific binding in which plant lectins, a Ca 12 -binding bacterial protein (rhicadhesin), and bacterial surface polysaccharide appear to be involved. The second attachment step requires the synthesis of bacterial cellulose fibrils that cause a tight and irreversible binding of the bacteria to the roots. Cyclic glucans, capsular polysaccharide, and cellulose fibrils also appear to be involved in the attachment of Agrobacterium to plant cells. Attachment of Azospirillum brasilense to cereals roots also can be divided in two different steps. Bacterial surface proteins, capsular polysaccharide and flagella appear to govern the first binding step while extracellular polysaccharide is involved in the second step. Outer cell surface proteins and pili are implicated in the adherence of Pseudomonas species to plant roots

Tolerancia simbiótica a nitrato de distintas leguminosas

7 páginas, 6 tablas y 15 referencias.-- Trabajo presentado en el VI Simposium Nacional - II Ibérico sobre nutrición mineral de las plantas, Sevilla, del 12 al 15 de Noviembre de 1996.-- Entidades colaboradoras Junta de Andalucía, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Sociedad Española de Fisiología Vegetal, El Monte, Caja de Huelva y Sevilla y Gat Fertilíquidos.-- Editores Científicos: Rafael Sarmiento Solís, Eduardo O. Leidi Montes y Antonio Troncoso de Arce.-- (Instituto de Recursos Naturales y Agrobiología de Sevilla).[EN]: The effect of mineral nitrogen on N2 fixation, nodulation and shoot dry weight of four legume species was evaluated in a greenhouse experiment. Two different soils were amended with NO3K to raise 40 and 30 ppm of N-NO3. Seeds of each species were inoculated, at sowing time, with speciflc high N2 fixers rhizobia (lO(elevado a 9) cells/seed). From the data it was concluded that common bean (Phaseolus vulgaris L.) and field pea (Pisum sativum) were simbiotically less tolerant to nitrate than soybean (Glycille max (L.) Merr) and overall white lupin (Lupinus albus)[ES]: Se estudió la respuesta simbiótica de cuatro leguminosas: altramuz (Lupinus albus ev. Multolupa), guisante (Pisum sativum cv. Aphile), soja (Glycine max (L.) Merr. cv . Williams) y judia (Phaseolus vulgaris L. cv. Canellini), cada una inoculada con su microsimbionte específico, a tres concentraciones de nitrato en el suelo (O, 40 Y 80 ppm, como NO3K) bajo condiciones controladas en invernadero. Las distintas especies se cultivaron en dos suelos diferentes de la provincia de Sevilla: uno francolimoso, de la Vega del Guadalquivir (Finca Exptal. CIFA-Las Torres) y, otro arcilloso de la Sierra Norte (Castilblanco de los Arroyos). A efectos comparativos, la judía también se cultivó en arena lavada con los mismos tratamientos nitrogenados. La tolerancia simbiótica se evaluó mediante la determinación de los siguientes parámetros peso seco y contenido en N de la parte aérea, número y peso seco de nódulos, actividad nitrogenasa (reducción de acetileno; ARA) y análisis de compuestos nitrogenados en savia xilemática . Del análisis de los resultados puede concluirse que la judía y el guisante son simbioticamente más sensibles a la presencia de nitrato en el medio de crecimiento; mientras que la soja y, sobre todo el altramuz, son más tolerantes.Este trabajo ha sido financiado por la D.G.L.F.A., Consejeria de Agricultura y Pesca, Junta de Andalucia, con la ayuda puente al Proyecto INIA 96/65.Peer reviewe

Microbials for Agriculture: Why Do They Call Them Biostimulants When They Mean Probiotics?

There is growing interest in using plant-beneficial microorganisms to partially replace chemicals and help reduce the environmental impact of agriculture. Formulated microbial products or inoculants for agriculture contain single strains or a consortium of live microbes, well characterized and biosafe, which can contribute to the growth, health, and development of a plant host. This concept conforms to the definition of probiotics. However, some plant-growth-promoting microorganisms (PGPMs) have been considered a category of biostimulants since some years ago, despite the traditional concept of biostimulants involves substances or materials with no fertilizer value, which in minute amounts promote plant growth. The inclusion of PGPMs together with substances has also involved a significant distortion of the classical concept of biostimulants. Regulations such as the recent EU Fertilizing Products Regulation (EU No. 2019/1009) have incorporated the new definition of biostimulants and included microbials as a subcategory of biostimulants. We discuss that this regulation and the forthcoming European harmonized standards disregard some key features of microbial products, such as the live, true biological nature of their active principles. The factors that determine the complex functional compatibility of plant–microbe associations, and important biosafety issues that concern the intentional release of microbes into the environment, seem to be also ignored. We anticipate that by equating microbials to chemicals, the biological nature of microbial products and their specific requirements will be underestimated, with pernicious consequences for their future development and success