Growth analysis, photosynthate partition and nodulation in bean and soybean / Análise de crescimento, partição de fotoassimilados e nodulação em feijão e soja

Photoassimilate partition and allocation among plant organs varies throughout their development and is also influenced by factors inherent to the genotype and the environment. Nodulation in the soybean-diazotrophic bacteria interaction is more effective than in the bean-diazotrophic bacteria interaction. This investigation studied growth and photoassimilate partitioning throughout the bean and soybean cycles and inferred how much it could affect the nodulation of the roots. For this purpose, an experiment with two treatments was carried out, soybean (cultivar BRS GO - 7760 - RR) and bean (cultivar BRS Estilo), with four replications, conducted in pots and entirely randomized. The seeds were inoculated with commercial rhizobia specific for bean and soybean LeguMax® (Novozymes-Turfal). Plants were analyzed throughout their cycles based on leaf area and dry mass of all organs, including nodules. Mathematical models were fitted to the data and based on them, the instantaneous physiological indicators of growth were estimated, and the percentages of photoassimilate partition among organs were evaluated. Crop growth rate, relative growth rates, net assimilation rate as well as net photosynthesis rate had higher values in soybean compared to bean, following the pattern of leaf area and total dry mass. For both species, the highest rates occurred at the beginning of the cycle, decreasing with age. Unlike the bean, soybean has a high capacity to supply photosynthates to all of its organs throughout its entire cycle, favoring the maintenance of nodule growth and explaining its greater capacity for nitrogen assimilation.

Durante o desenvolvimento das plantas a partição e alocação de fotoassimilados variam entre os seus órgãos, e dependem de fatores inerentes ao genótipo e ao meio ambiente. A nodulação é mais efetiva na interação soja-bactéria diazotrófica do que na interação feijão-bactéria diazotrófica. Esta pesquisa tem como objetivo estudar o crescimento e a partição de fotoassimilados ao longo dos ciclos do feijão e da soja e inferir o quanto isso pode afetar a nodulação das raízes. Para tanto, foi instalado um experimento com dois tratamentos, soja (cultivar BRS GO - 7760 - RR) e feijão comum (cultivar BRS Estilo), com quatro repetições, conduzido em vasos e inteiramente ao acaso. As sementes foram inoculadas com inoculantes comerciais específicos para feijão e soja LeguMax® (Novozymes-Turfal). Plantas foram coletadas ao longo de seus ciclos e medidas as áreas foliares e as massas secas de todos os órgãos, incluindo nódulos. Modelos matemáticos foram ajustados aos dados e, com base neles, foram estimados os indicadores fisiológicos instantâneos do crescimento e, também, foram avaliadas as porcentagens de partição de fotoassimilados entre os órgãos. A taxa de crescimento das culturas (CGR), as taxas de crescimento relativo (RGR), a taxa líquida de assimilação (NAR) e a taxa líquida de fotossíntese (Pn) apresentaram maiores valores na soja em relação ao feijoeiro. Para ambas as culturas as maiores taxas ocorreram no início do ciclo, decrescendo ao longo do ciclo cultural. Diferentemente do feijoeiro a soja tem alta capacidade de suprir de fotoassimilados a todos os seus órgãos ao longo de todo o seu ciclo, o que favorece o maior crescimento dos seus nódulos, justificando a sua maior capacidade na captura do N2 atmosférico.

Multiple Effect of Different Plant Growth Promoting Microorganisms on Beans (Phaseolus vulgaris L. ) Crop

Abstract We evaluated the effect of combined Rhizobium tropici, Trichoderma asperellum and plant growth-promoting rhizobacteria (PGPR) in beans crop. The hypothesis that strains of T. asperullum, R. tropici and PGPR combined could improve growth, biomass accumulation and beans yield was tested under greenhouse and field conditions. The treatments consisted of control, mineral nitrogen application and inoculation, isolated and associated with the following microorganisms: Rhizobium tropici, Bacillus subtilis, Trichoderma asperellum and Burkholderia sp. 10N6. Results were evaluated by shoot dry weight (SDW) and root dry weight (RDW), number of nodules and yield components. In greenhouse environment all the microorganisms behaved similarly, and the treatments inoculated with Burkholderia sp. 10N6 (IBu) and R. tropici (IR) stood out regarding the production components. In field conditions the treatments IR and IRTBa presented the highest values of SDW and RDW. Our results suggest that inoculation with R. tropici, T. asperellum and PGPR may promote beans growth and bring benefits to shoot and root accumulation, increase the number of nodules as well as improve yield components, contributing to a sustainable agriculture.

Enemigos naturales nativos de mosca blanca (Hemiptera: Aleyrodidae) en el cultivo de ejote francés en Chimaltenango, Guatemala / tive natural enemies of whitefly (Hemiptera: Aleyrodidae) in French bean crop in Chimaltenango, Guatemala

El complejo de mosca blanca (Hemiptera: Aleyrodidae) incluye algunas de las principales plagas del ejote francés (Phaseolus vulgaris L.). Dentro de las cuales, Bemisia tabaci es vector del virus del mosaico dorado que afecta la calidad y rendimiento del cultivo, con pérdidas hasta del 100% y un control difícil debido a la resistencia adquirida por las plagas hacia algunos agroquímicos. El ejote francés ocupa el segundo lugar entre de los productos no tradicionales de exportación de Guatemala. Su manejo agronómico ha sido principalmente a través del control químico, el cual afecta insectos y otros organismos que no son el objetivo del control, tales como: polinizadores, insectos benéficos, humanos y fauna silvestre. Los objetivos del estudio fueron: determinar la presencia de enemigos naturales nativos de la mosca blanca e identificar las especies de mosca blanca presentes en el cultivo del ejote francés en Chimaltenango. Para el estudio se establecieron cuatro parcelas de 300 m², se realizaron muestreos semanales durante dos ciclos del cultivo. En cada parcela se muestrearon cinco sitios y en cada sitio cinco plantas. Las especies de parasitoides nativos encontrados fueron: Encarsia Formosa Gahan, Eretmocerus eremicus Rose y Zolnerowuch y Amitus fuscipennis MacGown y Nebeker, la especie más abundante fue A. fuscipennis. Los depredadores identificados fueron Chrysoperla carnea (Stephens) e Hippodamia convergens Guerin-Meneville. La especie más abundante fue H. convergens. Estas especies podrían ser herramientas valiosas para ser empleadas en programas de control biológico, producciones orgánicas o en programas de manejo integrado de plagas.

The whitefly complex (Hemiptera: Aleyrodidae) includes some of the main pests of the French green bean (Phaseolus vulgaris L.). Among which, Bemisia tabaci is a vector of the golden mosaic virus that affects the quality and yield of the crop, with losses up to 100% and difficult control due to the resistance acquired by pests towards some agrochemicals. The French green bean ranks second among the non-traditional export products of Guatemala. Its agronomic management has been mainly through chemical control, which affects insects and other organisms that are not the objective of the control, such as: pollinators, beneficial insects, humans and wildlife. The objectives of the study were: to determine the presence of natural enemies native to the whitefly and identify the species of whitefly present in the cultivation of the French bean in Chimaltenango. For the study, four 300 m² plots were established, weekly sampling was carried out during two crop cycles. Five sites were sampled on each plot and five plants on each site. The native parasitoid species found were: Encarsia Formosa Gahan, Eretmocerus eremicus Rose and Zolnerowuch and Amitus fuscipennis MacGown and Nebeker, the most abundant species was A. fuscipennis. The predators identified were Chrysoperla carnea (Stephens) and Hippodamia convergens Guerin-Meneville. The most abundant species was H. convergens. These species could be valuable tools to be used in biological control programs, organic productions or in integrated pest management programs.

Germinação de Phaseolus aureus contaminados com diferentes fontes de cromo (VI) / Germination of Phaseolus aureus contaminated with different sources of chromium (VI)

O excesso de Cr nas plantas pode provocar inibição no crescimento das plantas, clorose nas folhas, desequilíbrio nutricional e alteração na germinação das sementes, sendo também altamente tóxico para humanos. Objetivou-se avaliar a germinação de sementes de feijão submetidas a diferentes fontes de Cr, em câmara germinadora durante 9 dias. As fontes de Cr utilizadas: cromato de potássio e dicromato de potássio, em 128 subamostras em soluções de concentrações crescentes de Cr (0, 5,10, 20, 45, 90, 200 e 400 mg L-1). Realizou contagem de sementes normais, anormais e mortas. Conclui-se que sementes de feijão submetidas ao dicromato de potássio germinam 47,5% em média, sem efeitos prejudiciais ao seu desenvolvimento, com apenas 0,87% de sementes anormais e 1,6% em média de sementes mortas, ambas com tolerância de até 400 mg L-1.

Respuesta del simbiosistema frijol (Phaseolus vulgaris L.) y Rhizobium tropici CIAT899 ante el efecto alelopático de Ipomoea purpurea L. Roth / Responses of the common bean (Phaseolus vulgaris L.) and Rhizobium tropici CIAT899 symbiosystem to induced allelopathy by Ipomoea purpurea L. Roth

La alelopatía es un fenómeno que involucra la producción de metabolitos secundarios que influyen en el crecimiento de las plantas, pero este potencial alelopático ha sido poco estudiado en la simbiosis rizobio-leguminosa. Esta investigación tuvo los siguientes objetivos: 1) evaluar el potencial alelopático de lixiviados acuosos de Ipomoea purpurea L. Roth en la germinación de semillas y en el crecimiento radical de plántulas de frijol (Phaseolus vulgaris L.); 2) determinar el efecto de estos lixiviados en el crecimiento in vitro de Rhizobium tropici CIAT899, y 3) evaluar el potencial alelopático de I. purpurea en el crecimiento, la fisiología y la nodulación de frijol en simbiosis con R. tropici. Tanto el lixiviado acuoso de raíz como el de la parte aérea de I. purpurea estimularon la germinación de semillas de frijol y la elongación radical. El crecimiento in vitro de R. tropici fue inhibido al aplicar los 2 tipos de lixiviado. La presencia de I. purpurea tuvo un efecto negativo en el crecimiento y en las respuestas fisiológicas de las plantas de frijol, que fue atenuado cuando las plantas fueron inoculadas con Rhizobium tropici; no obstante, la nodulación asociada a esta bacteria fue afectada en presencia de la planta alelopática. Los resultados indican que la simbiosis de rizobios en las raíces de frijol es un elemento importante en la atenuación de los danos producidos por la planta alelopática I. purpurea.

Allelopathy is a phenomenon that involves the production of secondary metabolites that influence the growth of plants and microorganisms; however, this alellopathic effect has been scarcely studied on the rhizobia-legume symbiosis. The aims of this research were 1) to assess the allelopathic potential of aqueous extracts of Ipomoea purpurea L. Roth on seed germination and root length of common bean seedlings (Phaseolus vulgaris L.), 2) to determine its effects on the in vitro growth of Rhizobium tropici CIAT899, and 3) to evaluate the allelopathic potential of I. purpurea on the growth, nodulation and physiology of common bean plants inoculated with R. tropici. After 48 h, 15% of the aqueous root extract of I. purpurea stimulated seed germination, whereas 4% of the aqueous shoot extracts stimulated such germination. Both the root or shoot extracts stimulated seed germination and e root length. In vitro growth of R. tropici was inhibited as a result of the application of both aqueous extracts. The presence of I. purpurea negatively affected both the growth and physiological responses of common bean plants, and this effect was attenuated after the inoculation of R. tropici; nevertheless, this allelopathic plant affected root nodulation. Our results suggest that the symbiosis of rhizobia and roots of common bean plants is an important element for attenuating the negative effects caused by the allelopathic plant.

Controles alternativos para el gorgojo del frijol Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae) / Alternate controls for the bean weevil Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae)

Las especies del género Quercus son de importancia ecológica y económica dentro de los bosques donde se desarrollan. Pueden encontrarse desde zonas cálidas y secas hasta selvas lluviosas. Estos bosques, también son reconocidos por presentar alto grado de endemismo y gran número de interacciones ecológicas. Sin embargo, en Guatemala las especies de encino han sido poco estudiadas y están fuertemente amenazadas; a pesar de poseer un alto potencial para aprovechamiento, manejo y uso en la restauración de ecosistemas. Este estudio se orientó hacia la actualización de la riqueza y distribución geográfica de las especies de encino para Alta Verapaz, Baja Verapaz y Petén, a partir de la revisión de registros en herbarios nacionales, bases de datos en línea de herbarios extranjeros y colectas de campo. Se registraron 19 especies de encinos en Alta Verapaz, Baja Verapaz y Petén, nueve especies más de las reportadas previamente, actualizándose los rangos de distribución departamental de 18 especies a excepción de Quercus sapotifolia Liebm. De las especies registradas, 16 se encuentran con algún grado de amenaza, según el Listado de Especies Amenazadas y listas rojas de UICN. También se identificaron vacíos de información acerca de la distribución de estas especies dentro de remanentes boscosos importantes en los departamentos evaluados. Se espera que a partir de este estudio se incrementen los esfuerzos por comprenden la riqueza y distribución de las especies de encino para Guatemala.

Quercus species represent one of the genera with ecological and economic importance within the forests where they develop, since these can be found from warm and dry zones to rain forests. Oak forests also exhibit high endemism levels and a large number of ecological interactions. However, oak species in Guatemala have been briefly studied, although they represent a genus highly threatened and with a high potential for use, handling and ecosystem restoration. This study was oriented towards the actualization of richness and geographical distribution of the oak species in Alta Verapaz, Baja Verapaz and Peten from reviewing records in National Herbariums, online databases of foreign Herbariums and field collection. A total of 19 oak species in Alta Verapaz, Baja Verapaz and Peten were recorded, nine more species of those previously reported, updating the departmental distribution ranges of 18 species except Quercus sapotifolia Liebm. Of the species recorded, 16 were listed with some degree of threat according to the national List of Threatened Species and the IUCN Red List of Threatened Species. Our results evidenced that the oak species were located in important forest remnants in all of the departments evaluated. It is expected from this study to increase the efforts to understand the oak species richness and species distributions patterns for Guatemala.

Varieties of lima bean shows different growth responses when inoculated with Bacillus sp. a plant growth-promoting bacteria / Variedades de feijão-fava exibem diferentes respostas de crescimento quando inoculadas com Bacillus sp. uma bactéria promotora de crescimento em plantas

Plant growth-promoting bacteria (PGPB) comprise of soil microorganisms that cause positive effects on plant growth. The hypothesis according to which the inoculation of lima bean with PGPB Bacillus stimulates vegetative growth, which may result in a higher plant productivity, was tested. Thus, this study aimed to evaluate the effects of inoculation of two varieties of lima bean (branca and boca de moça) with Bacillus sp., UFPEDA 472 strain, based on plant growth responses. The experiment was conducted in a greenhouse using a completely randomized design. Three treatments were applied separately to each lima bean variety: the first used inoculation with Bacillus, one was submitted to nitrogen supplementation, and one was the absolute control (non-inoculated plants). The following variables were evaluated: absolute and relative growth rate, root length, stem diameter, fresh and dry mass of shoots and roots, shoot:root ratio and total chlorophyll. The results showed that lima bean displayed better growth responses when inoculated with Bacillus sp. UFPEDA 472 in relation to the treatment with nitrogen and/or non-inoculated plants. When inoculated with PGPB Bacillus, the lima bean var. branca was superior to boca de moça in terms of root length and root dry mass. The lima bean var. boca de moça inoculated with Bacillus sp. UFPEDA 472 was superior to branca in terms of absolute growth rate, stem diameter, fresh and dry mass of shoot, shoot:root ratio and total chlorophyll. In general, the lima bean var. boca de moça inoculated with Bacillus shows a better growth performance. Our results suggest that growth responses of lima bean varieties branca and boca de moça are related with a positive interaction with the PGPB Bacillus.

Bactérias promotoras de crescimento em plantas (BPCP) compreendem microrganismos do solo que causam efeitos positivos no crescimento vegetal. A hipótese de que a inoculação de feijão-fava com BPCP Bacillus estimula o crescimento vegetativo, o qual pode resultar em uma maior produtividade vegetal, foi testado. Assim, este estudo objetivou avaliar o efeito da inoculação de duas variedades de feijão-fava (branca e boca de moça) com Bacillus sp., estirpe UFPEDA 472, baseado em respostas de crescimento vegetal. O experimento foi conduzido em casa de vegetação usando um delineamento completamente ao acaso. Três tratamentos foram aplicados separadamente à cada variedade de feijão-fava: o primeiro utilizou a inoculação com Bacillus sp. UFPEDA 472, um foi submetido à suplementação com nitrogênio e um foi o controle absoluto (plantas não inoculadas). As seguintes variáveis foram avaliadas: taxa de crescimento absoluto e relativo, comprimento das raízes, diâmetro do caule, massa fresca e seca da parte aérea e raízes, relação parte aérea:raiz e clorofila total. Os resultados mostram que o feijão-fava exibiu melhores respostas de crescimento quando inoculadas com Bacillus sp. UFPEDA 472 em relação ao tratamento com nitrogênio e/ou às plantas não inoculadas. Quando inoculado com Bacillus sp. UFPEDA 472, o feijão-fava var. branca foi superior à boca de moça em termos de comprimento e massa seca das raízes. O feijão-fava var. boca de moça inoculado com Bacillus sp. UFPEDA 472 foi superior à branca na taxa de crescimento absoluto, diâmetro do caule, massa fresca e seca da parte aérea, relação

Symbiotic potential and survival of native rhizobia kept on different carriers

Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N₂ fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7^T and Rhizobium calliandrae LBP2-1^T and of the reference strain Rhizobium etli CFN42^T. A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1^T, 167% for strain CFN42^T and 219% for strain ITTG R7^T) than for the other carriers after 240 days, except for CFN42^T kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42^T was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7^T was kept on PSB. The nitrogenase activity was the highest for ITTG R7^T kept on PEAT (4911 μmol C₂H₄ per fresh weight nodule h⁻¹); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them.

Bioinformatics based structural characterization of glucose dehydrogenase (gdh) gene and growth promoting activity of Leclercia sp. QAU-66

Glucose dehydrogenase (GDH; EC 1.1. 5.2) is the member of quinoproteins group that use the redox cofactor pyrroloquinoline quinoine, calcium ions and glucose as substrate for its activity. In present study, Leclercia sp. QAU-66, isolated from rhizosphere of Vigna mungo, was characterized for phosphate solubilization and the role of GDH in plant growth promotion of Phaseolus vulgaris. The strain QAU-66 had ability to solubilize phosphorus and significantly (p < 0.05) promoted the shoot and root lengths of Phaseolus vulgaris. The structural determination of GDH protein was carried out using bioinformatics tools like Pfam, InterProScan, I-TASSER and COFACTOR. These tools predicted the structural based functional homology of pyrroloquinoline quinone domains in GDH. GDH of Leclercia sp. QAU-66 is one of the main factor that involved in plant growth promotion and provides a solid background for further research in plant growth promoting activities.

Phosphate solubilizing ability of Emericella nidulans strain V1 isolated from vermicompost.

Phosphorus is one of the key factors that regulate soil fertility. Its deficiencies in soil are largely replenished by chemical fertilizers. The present study was aimed to isolate efficient phosphate solubilizing fungal strains from Eisenia fetida vermicompost. Out of total 30 fungal strains the most efficient phosphate solubilizing one was Emericella (Aspergillus) nidulans V1 (MTCC 11044), identified by custom sequencing of β-tubulin gene and BLAST analysis. This strain solubilized 13 to 36% phosphate from four different rock phosphates. After three days of incubation of isolated culture with black Mussorie phosphate rock, the highest percentage of phosphate solubilization was 35.5±1.01 with a pH drop of 4.2±0.09. Kinetics of solubilization and acid production showed a linear relationship until day five of incubation. Interestingly, from zero to tenth day of incubation, solubility of soil phosphate increased gradually from 4.31±1.57 to 13.65±1.82 (mg kg-1) recording a maximum of 21.23±0.54 on day 45 in respect of the V1 isolate. Further, enhanced phosphorus uptake by Phaseolus plants with significant pod yield due to soil inoculation of Emericella nidulans V1 (MTCC 11044), demonstrated its prospect as an effective biofertilizer for plant growth.

Curtobacterium flaccumfaciens pv. flaccumfaciens detection in bean seeds using a semi-selective culture medium

The bacterial wilt caused by Curtobacterium flaccumfaciens pv. flaccumfaciens is currently considered one of the most important bacterial bean disease in Brazil. One of the most effective control methods against this disease is the use of healthy seeds. However, no methods are known that could be routinely used to detect this bacterium in bean seeds under Brazilian condition. The aim of this work was to evaluate qualitative and quantitative detection methods for Curtobacterium flaccumfaciens pv. flaccumfaciens in naturally-infected bean seeds, and the detection of this pathogen in thirty bean seed samples, by sowing onto a semi-selective culture medium the leachate obtained from soaked bean seeds. Both the qualitative and quantitative methods were effective for detecting the presence of the bacteria in the seeds samples analysed. The qualitative method proved more practical for rotine use; of the thirty bean seed samples analyzed by this method, fifty percent were infected with Curtobacterium flaccumfaciens pv. flaccumfaciens.

Atualmente, a murcha-de-curtobacterium, causada por Curtobacterium flaccumfaciens pv. flaccumfaciens, é considerada uma das principais doenças baterianas da cultura do feijoeiro, no Brasil. Um dos métodos eficazes de controle desta doença é o emprego de sementes sadias. Entretanto, não se tem conhecimento de métodos que possam ser utilizados em rotina para o isolamento desta bactéria em sementes de feijoeiro. O presente trabalho teve por objetivo avaliar os métodos qualitativos e quantitativos de isolamento de Curtobacterium flaccumfaciens pv. flaccumfaciens em sementes de feijoeiro naturalmente infectadas e a detecção deste patógeno em trinta amostras de sementes de feijoeiro, pela semeadura do líquido de maceração das sementes em meio de cultura semi-seletivo. Tanto o método quantitativo quanto o quantitativo foram eficazes em detectar a presença da bactéria nas amostras de sementes analisadas. O método qualitativo mostrou-se mais prático para o uso em rotina e das trinta amostras de sementes de feijoeiro analisadas por este método cinqüenta porcento delas estavam infectadas com Curtobacterium flaccumfaciens pv. flaccumfaciens.

Study on ground water characteristics and the effects of discharged effluents from textile units at Karur District.

A study was made on the physico-chemical characteristics of water samples mixed with effluent discharged from textile industries at Chellandipalayam (Site--I), Senaparatti (Site--II) and Pasupathipalayam (Sites--III and IV) revealed the elevated levels of Ca, Mg, Na, Cr, K, Ni, Cu, Zn, CO3, SO4, NO3 and Cl- . The concentrations of these ions exceeded the limit prescribed by ISI. The increase in the concentrations of ions was revealed by higher values of electrical conductivity (EC). Water at these sites was found to be hard, brackish and unsuitable for drinking purpose. In all these sites, the seed germination of rice alone was significantly affected among the other crops tested. Irrigation of crops with ground water notably lowered the quantity of reserve food in rice, wheat (starch), and sugarcane (sugar), indicating the interference of their metabolic pathway by polluted ground water.