Diss. (sammanfattning) Ultuna : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

FARIAS, Gabriel Castro . Biometria e respostas fisiológicas de feijão-de-corda inoculado com fungos endofíticos dark septate sob estresse salino.2014. 54 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2014. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-07-04T16:34:16Z No. of bitstreams: 1 2014_dis-gcfarias.pdf: 672852 bytes, checksum: 622eef235cbb6f63c8a3c3415a004221 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-07-04T16:35:16Z (GMT) No. of bitstreams: 1 2014_dis-gcfarias.pdf: 672852 bytes, checksum: 622eef235cbb6f63c8a3c3415a004221 (MD5) / Made available in DSpace on 2016-07-04T16:35:16Z (GMT). No. of bitstreams: 1 2014_dis-gcfarias.pdf: 672852 bytes, checksum: 622eef235cbb6f63c8a3c3415a004221 (MD5) Previous issue date: 2014 / With the increasing of areas degraded by soil salinization process, is necessary to increase of agricultural investments to be able to reach a production acceptable. In order to reduce such inputs, studies of microorganisms involved in the production process are becoming more constant. The objective of this study was to evaluate the associations between endophytic fungi Dark Septate and cowpea plants when irrigated with water of different salinities, analyzing biometrics, gas exchange, nutrient content and accumulation of organic solutes in the leaves. Cowpea plants were grow in containers of five liters under greenhouse conditions and subjected to four different electrical conductivity of irrigations water (1.2; 2.2; 3.6; 5.0 dS m-1). Were used for the inoculation strains B’2 and 21W and treatments were as follows: F1 – plants that were not inoculated; F2 – plants inoculated with strains 21W and F3 – plants inoculated with strain B’2. during the experiment was measured gas exchange and at the end of the experiment the plant were collected and determinate the leaf area, shoot dry mass, root dry mass, concentration of the foliar nutrients and organic solutes, and was made the determination colonization of roots by the fungus. The salinity caused significant reductions in biomass, leaf area and leaf gas exchange, however, the presence of the endophytic fungi provided a large tolerance to the adverse effects of salinity. There was a larger accumulation of calcium, sodium, clore and phosphorus in cowpea leaves with increasing salinity and decrease in the leaves of nitrogen and potassium. The presence of the fungus in the plant provided a foliar phosphorus and nitrogen. / Com o crescimento das áreas degradadas pelo processo de salinização dos solos se faz necessário o aumento do uso de insumos para que seja possível atingir uma produção aceitável. Visando a redução de tais insumos, estudos sobre microrganismos envolvidos no processo produtivo são cada vez mais constantes. O objetivo deste trabalho foi avaliar a resposta das associações entre fungos endofíticos Dark Septate e plantas de feijão-de-corda quando irrigado com águas de diferentes salinidades, analisando-se a biometria, troca gasosas, teores foliares de nutrientes e o acúmulo de solutos orgânicos nas folhas. As plantas de feijão-de-corda foram cultivadas em vasos de 5 litros, sob condições de casa de vegetação e submetidas a quatro diferentes condutividades elétricas da água de irrigação (1,2; 2,2; 3,6 e 5,0 dS m-1). Para a inoculação foram utilizados as linhagens B’2 e 21W e os tratamentos foram os seguintes: F1 – plantas que não foram inoculadas; F2 – plantas inoculadas com a linhagem 21W e F3 – plantas inoculadas com a linhagem B'2. Durante a condução do experimento mediu-se as trocas gasosas e ao final do experimento as plantas foram coletadas e determinou-se a sua área foliar, massa seca da parte aérea, massa seca das raízes teores de nutrientes e solutos orgânicos foliares, bem como foi feita a determinação de colonização nas raízes pelo fungo. A salinidade provocou reduções significativas na biomassa, área foliar e trocas gasosas, contudo, a presença do fungo endofítico proporcionou uma maior tolerância aos efeitos negativos da salinidade. Houve um maior acúmulo de cálcio, sódio, cloro e fósforo em folhas de feijão-de-corda com o aumento da salinidade e uma diminuição dos teores de nitrogênio e potássio. A presença do fungo na planta proporcionou maior teor foliar de fósforo e nitrogênio.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O uso de plantas tolerantes à uma importante alternativa para o enfrentamento do problema da salinidade na agricultura em regiÃes semiÃridas. O coqueiro anÃo (Cocos nucifera L.) vem se destacando como uma cultura tolerante ao estresse salino, porÃm, pouco se sabe sobre os mecanismos fisiolÃgicos que podem contribuir para o estabelecimento de mudas desta espÃcie sob condiÃÃes de salinidade. Diante do exposto, o objetivo deste trabalho foi avaliar o efeito da irrigaÃÃo com Ãguas salinas nas respostas fisiolÃgicas e morfomÃtricas na produÃÃo de mudas de coqueiro anÃo. O experimento foi conduzido no perÃodo entre dezembro de 2012 e abril de 2013, em casa de vegetaÃÃo do NÃcleo de Ensino e Pesquisa em Agricultura Urbana. Os tratamentos consistiram de cinco nÃveis de salinidade da Ãgua de irrigaÃÃo, sendo estes expressos pela condutividade elÃtrica da Ãgua (CEa), denominados: S1=0,9 (tratamento controle); S2=5,0; S3=10,0; S4=15,0 e S5=20,0 dS m-1. Os dados de crescimento e das variÃveis fisiolÃgicas (taxa de fotossÃntese, teor de clorofila e potencial hÃdrico) indicam que o coqueiro à tolerante a salinidade da agua de irrigaÃÃo de 5 dS m-1 durante a fase de produÃÃo das mudas. A retenÃÃo de Ãons potencialmente tÃxicos e os elevados teores de solutos orgÃnicos nas raÃzes, em relaÃÃo aos folÃolos, indicam que as raÃzes desempenham importante papel no mecanismo de tolerÃncia do coqueiro aos nÃveis elevados de salinidade. Os resultados permitem inferir sobre a possibilidade de uso de agua salobra com CEa atà 5 dS m-1 para produÃÃo de mudas de coqueiro anÃo, sem que haja perda na qualidade das mudas, nÃo afetando o padrÃo destas na fase de viveiramento. Portanto, o estudo revela uma alternativa de uso de Ãgua salobra promovendo uma economia de 100% de Ãgua potÃvel com qualidade para o consumo humano / The use of tolerant plants and an important alternative to face the problem of salinity in semi-arid regions. The dwarf coconut palm (Cocos nucifera L.) has emerged as a salt tolerant crop, however little is known about the physiological mechanisms that may contribute to the establishment of seedlings of this species under conditions of salinity. Given the above, the aim of this study was to evaluate the effect of irrigation with saline water on physiological and morphological responses in seedlings of dwarf coconut water. The experiment was conducted in the period between December 2012 and April 2013 in the greenhouse of the Center for Teaching and Research in Urban Agriculture of the Universidade Federal do Cearà â Brazil. The treatments consisted of five levels of salinity of irrigation water, which are expressed by the electric conductivity (ECw): S1 = 0,9 (control); S2 = 5,0; S3 = 10,0 ; S4 = 15,0 and S5 = 20,0 dS m-1. The results of growth and physiological parameters (rate of photosynthesis, chlorophyll content and water potential) indicate that the coconut is tolerant to salinity of irrigation water of 5 dS m-1 during the stage of seedlings. The retention of toxic ions and high levels of organic solutes in roots, in relation to the shoots, suggest that roots play an important role in the mechanism of tolerance of coconut to high levels of salinity. The results allow us to infer the possibility of using brackish water with ECw up to 5 dS m-1 for production of seedlings of dwarf coconut, without losing the quality of seedlings. Therefore, our results revealed an alternative for use of brackish water and to promoting economy of fresh water used for human consumption

Salinity continues to be one of the world’s most serious environmental problems in agriculture. The increasing world population and urbanization are forcing farmers to utilize marginal lands as well as poor quality water. One of the strategies in dealing with salinity is growing salt tolerant plants and there has been increased need to understand the effects of salinity on crops. Owing to its high nutritive value and wide adaptability to diverse environments, amaranth is considered a promising crop for marginal lands and semiarid regions. The objective of the study was to investigate the response of amaranth to salinity stress and evaluate stress amelioration by calcium and seed priming. Salinity tolerance during germination and early seedling growth was examined for six genotypes of amaranth (Amaranthus species) at different salt concentrations ranging from 0 to 200 mM NaCl or Na2SO4. Enhancement of germination was observed at 25 mM, while increasing salt concentrations reduced the germination percentage as well as germination rate. A.tricolor and Accession ’83 were able to germinate in 200 mM NaCl while there was no germination at 200 mM Na2SO4 in all the genotypes. Overall, Accession ’83 was the most resistant and A. hybridus the most sensitive genotype, particularly at high salt concentrations. Inhibition of germination was greater in Na2SO4 than in NaCl salinity treatments. Amaranth was more salt tolerant at germination than at seedling growth. Seedling emergence, survival and growth were reduced by salinity and at much lower concentrations than at seed germination. Differences in salt tolerance were noted among the genotypes. Salinity stress was initiated at different growth stages (cotyledon stage, 2-leaf stage and 4-leaf stage) in order to determine whether tolerance of amaranth differs with the stage of development. The treatment either continued until termination of the experiment or for 14 days at each stage. Amaranth plants were less sensitive to salinity when the stress was initiated at the 4-leaf stage. Lower salt concentrations had less detrimental effects than higher concentrations when applied at the cotyledon stage. Application of low salt concentration at cotyledon stage for 14 days did not have any effect on plant growth. The results indicate that it is feasible to use saline water for growing amaranth with minimum yield losses if salt concentration, duration of exposure and time of salinization are carefully managed. Differences in salinity tolerance among amaranth genotypes were analyzed in terms of plant survival, growth, gas exchange, water use and leaf anatomical changes. A. hypochondriacus and A. cruentus showed greater tolerance to salinity since they survived in 200 mM NaCl treatment and the reduction in growth at 50 and 100 mM was lower than that of A. tricolor and Accession ’83. A. hypochondriacus and A. cruentus were more efficient water users and partitioned photosynthates towards shoot growth as opposed to the other two genotypes. Photosynthetic rate, stomatal conductance, stomatal density and apertures were reduced by salinity but were higher in A. tricolor than in A. cruentus. Salinity resulted in A. cruentus developing thicker leaves compared to A. tricolor. Productivity on saline soils can be increased by growing genotypes more tolerant to salinity. The interactive effect of salinity and water stress on amaranth plant growth was evaluated. It was found that the reduction in shoot growth was greater in plants submitted to water stress than in those submitted to salt or salt + water stress. Water use efficiency was increased while leaf water and osmotic potentials were reduced by the salinity stress treatments. In drying soil plants previously salinized had a greater degree of osmotic adjustment, so that plants were able to continue growth for a longer period compared to water stressed plants. The effect of calcium in ameliorating salt stress was investigated. Supplementary calcium, either as CaSO4 or CaCl2 ameliorated the negative effects of salinity on growth, gas exchange, membrane permeability and mineral uptake. In a separate experiment it was shown that it is feasible to mitigate the adverse effects of salinity on amaranth seed germination, seedling survival and growth by seed priming and that the positive effect of priming persisted to vegetative growth stage. Priming with CaSO4 + NaCl showed a greater positive response than priming with the individual salts. / Thesis (PhD (Plant Production andSoil Science))--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted

Der radiale Wasserfluss durch die feinen Seitenwurzeln von Schilf- und Mais ist vom radialen Teilchenfluss entkoppelt. Der radiale Wasserfluss wird bereits im Kortex der Wurzel durch den Protoplasten kontrolliert, da die Strömung auf dem apoplastischen Zellwandweg um die Protoplasten herum gegenüber der Strömung durch die Protoplasten nicht signifikant ist. Der radiale Reflexionskoeffizient der Wurzeln wird durch den Reflexionskoeffizient der Plasmamembran bestimmt. Die Feinwurzeln von Schilf- und Mais besitzen einen Reflexionskoeffizienten für Salze, Zucker, Zuckeralkohole und Polymere der sich nicht signifikant von eins unterscheidet. An intakten Wurzeln wurde dies durch die Abwesenheit von solvent drag für NaCl und Mannitol bei der Steigerung des Wasserflusses und der gleich großen hydraulischen Wirkung von osmotischen und hydrostatischen Kräften auf die Exsudation nachgewiesen. Die radialen Wände der Endodermis von Schilf- und Maiswurzeln sind keine perfekte Diffusionsbarriere. Liegen die genannten Stoffe in einer signifikanten Konzentration in der Zellwand vor permeieren sie passiv unter Umgehung der Protoplasten durch die Endodermis in die Xylemgefäße. Auch die Epidermis/Hypodermis der untersuchten Wurzeln hat die Eigenschaft einer semipermeablen Membran in der osmotische Druckgradienten einen Volumenfluss erzeugen. Es wurden zwei Methoden etabliert, mit denen sich der osmotische Druck des Xylemsaftes in isolierten Feinwurzeln bestimmen lässt. Die Feinwurzeln unterschieden sich hinsichtlich des osmotischen Druckes ihres Xylemsaftes und ihrer radialen hydraulischen Leitfähigkeit stark. Die bekannte Fähigkeit der Schilfpflanzen Natriumionen an der Sprossbasis aus dem Xylem zu eliminieren muss um Chloridionen erweitert werden. Die hohe Permeabilität der Endodermis für NaCl verringert die osmotische Wirkung des Brackwassers auf die Wasseraufnahme. Die Entkopplung der Salzaufnahme vom Wasserfluss vermeidet eine exzessive Salzbelastung des Sprosses. / Radial Water fluxes are not coupled to the radial solute fluxes in fine lateral roots of mays and reed. The radial water flow is already controlled by the protoplast in the cortical parenchyma as the hydraulic conductivity of the cell wall path circumventing the protoplasts is negligible compared to hydraulic conductivity of the pathway through the protoplast. The radial reflection coefficient of the root is defined by the reflection coefficient of the plasma membrane. Therefore fine laterals of the common reed (Phragmites australis) and maize (Zea mays) therefore exhibit a reflection coefficient for salts, sugars, alditols and polymers that is not significantly different from unity. This conclusion was drawn from the absence of solvent drag for NaCl and mannitol with increasing water flux and by the observation of equality of the hydraulic effect of both osmotic and hydrostatic forces on the exudation flow in intact roots of both plants. The radial walls of the endodermis are no absolute barrier for diffusion of small osmolytes. In the presence of high cell wall concentrations, the abovementioned osmolytes passively permeated into the xylem vessels at high rates circumventing the protoplast. The epidermis/hypodermis exhibits a semipermeable barrier as well wherein osmotic forces can create a radial volume flux. Two methods were established that allow for the determination of the flow direction and the osmotic pressure of the xylem sap in isolated fine laterals. Laterals differed strongly regarding their hydraulic conductivity and the osmotic pressure of their xylem sap. The known ability of the reed plant to remove sodium ions from the ascending sap has to be expanded for chloride. The high permeability of the endodermis for NaCl reduces the osmotic force of the brackish medium on water uptake. Uncoupling of radial water from the solute fluxes avoids the excessive permeation of NaCl and its accumulation in the assimilating leaves at high rates of transpiration.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A sensibilidade à salinidade varia com o estÃdio de desenvolvimento da cultura. O feijÃo-de-corda [Vigna unguiculata (L.) Walp.] constitui uma das principais culturas, em diversas regiÃes semi-Ãridas do mundo. Avaliou-se o efeito da irrigaÃÃo com Ãgua salina, aplicada em diferentes estÃdios de desenvolvimento de plantas de feijÃo-de-corda. O experimento foi conduzido no campo, e obedeceu ao delineamento em blocos ao acaso, com cinco tratamentos (T1, T2, T3, T4 e T5) e cinco repetiÃÃes. O feijÃo-de-corda foi cultivado no espaÃamento de 0,8 m entre linhas e 0,3 m entre plantas, com duas plantas por cova. Os tratamentos utilizados foram: T1 - plantas irrigadas com Ãgua do poÃo (CEa de 0,8 dS m-1) durante todo o ciclo; T2 - Ãgua salina com CEa de 5,0 dS m-1, com aplicaÃÃo iniciada apÃs a germinaÃÃo e permanecendo atà o final do ciclo; T3 - Ãgua salina com CEa de 5,0 dS m-1, da semeadura atà 22 dias apÃs o plantio (DAP), correspondendo Ãs fases de germinaÃÃo e crescimento inicial, e Ãgua do poÃo no restante do ciclo; T4 - Ãgua salina com CEa de 5,0 dS m-1, aplicada de 23 a 42 DAP (fase de intenso crescimento vegetativo atà a prÃ-floraÃÃo), e Ãgua do poÃo nas demais fases do ciclo; T5 - Ãgua do poÃo da semeadura atà 42 DAP e Ãgua salina (CEa de 5,0 dS m- 1) aplicada a partir dos 43 DAP (floraÃÃo e frutificaÃÃo). Foram avaliadas a cobertura vegetal do solo, crescimento vegetativo, fotossÃntese, transpiraÃÃo, condutÃncia estomÃtica, produtividade, partiÃÃo de matÃria seca, os teores, os totais extraÃdos e a distribuiÃÃo dos nutrientes na planta, a eficiÃncia nutricional, eficiÃncia no uso da Ãgua e o acÃmulo de sais no solo. A irrigaÃÃo com a combinaÃÃo de Ãgua do poÃo com Ãgua salina reduziu o acÃmulo de sais no solo, em relaÃÃo ao T2. O T2 reduziu as taxas de fotossÃntese e transpiraÃÃo, em relaÃÃo ao T1. O T3 provocou reduÃÃo das trocas gasosas somente na primeira mediÃÃo, enquanto, que similar aplicaÃÃo nos outros estÃdios (T4 e T5) nÃo provocou reduÃÃes significativas nas trocas gasosas das plantas. O T2 inibiu o crescimento vegetativo da planta, enquanto o T3 provocou retardo no desenvolvimento da planta. Os tratamentos T2 e T3 provocaram reduÃÃes significativas no nÃmero de vagens e na produÃÃo de sementes por planta, em relaÃÃo aos demais tratamentos. Por outro lado, os tratamentos T4 e T5 nÃo afetaram o crescimento e a produtividade da cultura, sendo que o T4 causou aceleraÃÃo no ciclo reprodutivo da cultura. Os minerais foram extraÃdos pelo feijÃo-de-corda na seguinte ordem decrescente: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, no entanto, o T2 reduziu a extraÃÃo da maioria dos elementos analisados, com exceÃÃo do Na e Cl. Os minerais Na, Cl, K, Ca, Fe e Mn permaneceram preferencialmente nas partes vegetativas enquanto N e P foram exportados em maiores proporÃÃes pelos frutos. O T3 reduziu a eficiÃncia de utilizaÃÃo da maioria dos nutrientes. O T2 reduziu a eficiÃncia agronÃmica de utilizaÃÃo de N, P e K, entretanto nÃo afetou a eficiÃncia de utilizaÃÃo dos nutrientes extraÃdos pelas plantas. / The sensitivity of crops to salinity often changes from one growth stage to another. Cowpea [Vigna unguiculata (L.) Walp.] is an important crop specie cultivated in different semi-arid regions of the world. The objective of this work was to evaluate the effect of the irrigation with saline water, applied at different growth development stages of cowpea. The experiment was set up in the field, during the dry season. A completely randomized block design, with five treatments (T1, T2, T3, T4 and T5) and five repetitions, was adopted. The distance between lines and plants were 0.8 m and 0.3 m, respectively, with two plants per hole. The treatments studied were: T1 - Groundwater with electrical conductivity (ECw) of 0.8 dS m-1 during the whole crop cycle; T2 - Saline water (ECw = 5.0 dS m-1) during the whole crop cycle, starting after germination; T3 - Saline water (ECw = 5.0 dS m-1) from sowing until the 22th day after sowing (germination and initial growth) and groundwater in remaining stages of the crop cycle; T4 - Saline water (ECw = 5.0 dS m-1) from the 23th to the 42nd day after germination (intense growth and pre-flowering), and groundwater irrigation for the remaining growth stages. T5 - Groundwater from sowing to the 42nd day after sowing and saline water (ECw = 5.0 dS m-1) during flowering and pod-filling stages. Soil coverage, gas exchange, vegetative growth and crop yield were measured. The mineral concentration and quantity of nutrient removed from the soil, as well as the nutrient use efficiency and salt accumulation in soil were also determined. The irrigation with combination of groundwater and saline water reduced the salt accumulation in soil, in relation to continuous use of saline water. The continuous application of water with ECw of 5.0 dS m-1 (T2) reduced the rates of photosynthesis and transpiration, in relation to the well water (T1). Plants of the treatment 3 showed reduction in gas exchanges only in the first measurement, while the saline water application in other growth stages (T 4 and T5) did not provoke significant reductions in leaf in the gas exchanges of the plants. It was found that the continuous use of saline water inhibits plant growth, while the irrigation with saline water during germination and initial growth causes retardation in plant development. For treatments 2 and 3, reduction in the number of pods and in seed production was verified. Irrigation with saline water from the 23rd to the 42nd day (T4) and from the 43rd to the 63rd (T5) day after sowing did not affect reproductive and vegetative growth, but the saline water application in the pre-flowering (T4) caused anticipation of reproductive cycle. Cowpea plants removed the minerals analyzed in the following decreasing sequence: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, but the continuous use of saline water (T2) reduced the total extracted for the most nutrients, except for Na e Cl. The minerals Na, Cl, K, Ca, Fe and Mn were distributed preferentially to vegetative plant parts, while the most of N and P were exported in the pods. The irrigation with saline water during germination and initial growth stage (T3) reduced the mineral use efficiency of most of analyzed nutrients. The continuous application of saline water (T2) reduced the agronomic efficiency of the fertilizer application (N, P and K), but it did not affect the nutrient use efficiency by the plants.

Bacterial endophytes are the organisms that live inside the plant for a full or a part of their life cycle. Endophytic bacteria have captured the interest of agriculture industry due to their plant beneficial properties, such as synthesis of phytohormones, solubilization of soil nutrients, and alleviation of biotic and abiotic stresses. Several studies have reported that stress tolerant endophytic bacteria can work with a similar performance as non-stressed conditions when inoculated to the plants under stressed conditions. Combination of abiotic stresses such as salinity, drought and low nitrogen stress can have additive or agonistic effects on bacterial and plant growth, and their interactions. However, very few studies have reported the impact of combined stress on endophytic bacterial assisted plant growth promotion. Therefore, understanding the underlying mechanisms of endophytic bacterial assisted plant’s tolerance abiotic stresses may provide the means of better exploiting the beneficial abilities of endophytic bacteria in agricultural production. Thus, the aim of this thesis was to study the stress tolerance mechanisms, beneficial characteristics, and plant growth promotion characteristics of endophytic bacteria under individual and combined abiotic stresses. Transcriptome analysis of endophytic bacteria revealed that tolerance mechanisms to deal with one kind of stress is different than concurrent stresses. Salinity and drought stress largely modulated the genes involved in flagellar assembly and membrane transport, showing reduced motility under stress conditions to preserve the energy. Additionally, bacterial endophyte that can fix nitrogen was studied with maize plant growth promotion under drought and low nitrogen stress conditions. The results suggested that diazotrophic bacterial endophyte can promote plant growth under moderate individual and combined stress conditions. Plant growth promoting endophytic bacteria can be utilized as an efficient tool to increase crop production under individual and concurrent abiotic stresses.

Zur Aufklärung des Wirkungsmechanismus der toleranzerhöhenden Wirkung gegenüber Salinität des Pflanzenwurzeln besiedelnden PGPR Bacillus subtilis wurden bakterielle Stoffwechselprodukte der Stämme FZB24 und FZB41 bei der Testpflanze Tomate unter dem Einfluss von hohem Salzstress getestet. Das Kulturfiltrat mit der Gesamtheit der von B. subtilis produzierten Stoffwechselprodukte zeigte im axenischen Test zur Ermittlung des Wachstums nach 7-tägiger Behandlung der Sämlinge und nachfolgender Kultivierung unter Salzstress eine gewisse toleranzerhöhende Wirkung bei 0,1 %-Konzentration. Zur Produktaufschlüsselung wurde das Kulturfiltrat über Adsorberharz und HPLC fraktioniert. Diese Fraktionen, sowie die aus dem Kulturfiltrat nach 19 h Fermentation wurden ebenfalls bei Sämlingen axenisch getestet. Fraktionen mit verschiedenen Proteinen und Peptiden, die von B. subtilis produziert werden, zeigten teilweise eine konzentrationsabhängige Wirkung hinsichtlich der Wachstumsstimulierung und zugleich Toleranzerhöhung gegenüber Salzstress, weshalb nachfolgend ein Peptidextrakt aus B. subtilis einer Testung im axenischen System unterzogen wurde. Der Peptidextrakt zeigte gleichfalls eine erkennbare konzentrationsabhängige Wirkung. Mit gleichem Testsystem wurden Auxin-Präkursoren und Auxin selbst, die als Stoffwechselprodukte von B. subtilis nachgewiesen sind, sowohl als Wurzelbehandlung, wie auch als Blattbehandlung bei Sämlingen geprüft. Zusätzlich wurde die Wirkung der Auxine auf den Wassergehalt der Sämlinge unter Salzstress, sowie die Adventivwurzelbildung von Hypokotylsegmenten aus etiolierten Sämlingen in An- und Abwesenheit von Salinität getestet. Darüber hinaus wurde die Aufnahme und der Transport von Auxinen, ebenfalls bei Sprosssegmenten aus etiolierten Sämlingen in An- und Abwesenheit von Salinität geprüft. Schließlich wurde die Wirkung der Auxine auf das Wachstum und den Wassergehalt in einer Hydrokultur im Gewächshaus unter Salzstress ermittelt. Die Ergebnisse zeigen, dass namentlich Auxin-Präkursoren und z. T. Auxin als Stoffwechselprodukte von B. subtilis eine Erhöhung der Salzstresstoleranz bei der Testpflanze herbeiführen können, wenngleich die Wirkung auf die Salztoleranz sehr differenziert und unterschiedlich stark ausgeprägt war. Der vorhandene Effekt vor allem der Auxin-Präkursoren wird als offenbar bedeutendster Mechanismus für die wachstumsstimulierende und zugleich toleranzerhöhende Wirkung gegenüber Salinität des Rhizobakteriums bei Wurzelbesiedlung und Interaktion mit dem pflanzlichen Stoffwechsel diskutiert. / To find out the mode of tolerance increasing action against salinity of the plant root colonizing PGPR Bacillus subtilis, bacterial metabolites of the strains FZB24 and FZB41 were studied in the test plant tomato under the influence of high salinity. Because the culture filtrate with the whole range of produced metabolites by B. subtilis showed to a certain extent a tolerance increasing action at dilution of 0,1 % in axenic plant growth tests after 7 days treatment of seedlings and subsequent cultivation under salt stress, it has been fractionated with adsorber resin and HPLC. These fractions, as well as fractions from the culture filtrate after 19 h fermentation were tested also by seedlings in axenic culture. Fractions with different proteins and peptides, which were produced by B. subtilis, showed partly activities also depending of concentration with regard to the growth stimulation and at the same time tolerance increase against salt stress. Following also a peptide extract from B. subtilis was examined in the axenic plant test system, showing similarly a visible action depending of concentration. In the same test system there were tested further auxin precursors and auxin itself, which are known metabolites of B. subtilis, on seedlings both by root treatment and leaf treatment. Additionally was studied the action of auxins on the water content of the seedlings under salt stress, as well as on the adventitious root formation of hypokotyl segments from etiolated seedlings, in presence and absence of salinity. Finally it was studied the uptake and transport of auxins in segments of stems from etiolated seedlings in presence and absence of salinity. Lastly it was tested the action of auxins on plant growth and water content in a hydroponic cultivation under greenhouse conditions and salt stress. The results show that particularly auxin precursors and partly auxin as metabolites of B. subtilis can induce an increase in the salt stress tolerance of the test plant, although the action on the salt tolerance was differentiated and variable in its extent. The existing effect firstly of the auxin precursors is discussed as obviously main mechanism for the plant growth stimulating and at the same time tolerance increasing action of the rhizobacterium against salinity by root colonization and interaction with the plant metabolism.

From the Proceedings of the 1973 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 4-5, 1973, Tucson, Arizona / A change in groundwater quality, averaging approximately +0.13 millimhos electrical conductivity and +35 ppm chloride per year, has been documented between 1940 and 1972 with data from ten long -term sample wells. The decrement in the water quality of the surficial aquifer seems to be attributable to four major mechanisms. An increase in salinity may be expected from leakage of saline water from the artesian aquifer. Such leakage would be stimulated by pumping- caused reduction of confining pressure, and by the puncture of the cap beds by deep wells. Water reaching the aquifer from natural recharge may contribute salts to the system. Such recharging water, if passed through soluble beds, could contribute to the salt. Lateral movement of water through similar deposits may be a contribution, and the concentration and infiltration of agricultural water could also add to aquifer salinity. The economic analysis of the Safford Valley, based on the modeling of a "Representative Farm" analog, indicates that cotton will remain economical to produce on the basis of the projected salinity trends, for a significant time beyond limits of prediction. The analysis indicates that the optimum salt-resistant crops for the area are being cultivated, and, of these, alfalfa will cease to be productive in large areas of the valley by 1990. The entire valley will not produce alfalfa for profit by 2040. The methodologies shown in the paper indicate how pumping influences salinity change and outline salinity control recommendations for the area.

NEVES, Antônia Leila Rocha. Irrigation of cowpea with saline water at different growth stages and their effects on the plant and soil. 2008. 119 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola. 2008 / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-13T14:53:10Z No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-13T14:57:22Z (GMT) No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) / Made available in DSpace on 2016-06-13T14:57:22Z (GMT). No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) Previous issue date: 2008 / The sensitivity of crops to salinity often changes from one growth stage to another. Cowpea [Vigna unguiculata (L.) Walp.] is an important crop specie cultivated in different semi-arid regions of the world. The objective of this work was to evaluate the effect of the irrigation with saline water, applied at different growth development stages of cowpea. The experiment was set up in the field, during the dry season. A completely randomized block design, with five treatments (T1, T2, T3, T4 and T5) and five repetitions, was adopted. The distance between lines and plants were 0.8 m and 0.3 m, respectively, with two plants per hole. The treatments studied were: T1 - Groundwater with electrical conductivity (ECw) of 0.8 dS m-1 during the whole crop cycle; T2 - Saline water (ECw = 5.0 dS m-1) during the whole crop cycle, starting after germination; T3 - Saline water (ECw = 5.0 dS m-1) from sowing until the 22th day after sowing (germination and initial growth) and groundwater in remaining stages of the crop cycle; T4 - Saline water (ECw = 5.0 dS m-1) from the 23th to the 42nd day after germination (intense growth and pre-flowering), and groundwater irrigation for the remaining growth stages. T5 - Groundwater from sowing to the 42nd day after sowing and saline water (ECw = 5.0 dS m-1) during flowering and pod-filling stages. Soil coverage, gas exchange, vegetative growth and crop yield were measured. The mineral concentration and quantity of nutrient removed from the soil, as well as the nutrient use efficiency and salt accumulation in soil were also determined. The irrigation with combination of groundwater and saline water reduced the salt accumulation in soil, in relation to continuous use of saline water. The continuous application of water with ECw of 5.0 dS m-1 (T2) reduced the rates of photosynthesis and transpiration, in relation to the well water (T1). Plants of the treatment 3 showed reduction in gas exchanges only in the first measurement, while the saline water application in other growth stages (T 4 and T5) did not provoke significant reductions in leaf in the gas exchanges of the plants. It was found that the continuous use of saline water inhibits plant growth, while the irrigation with saline water during germination and initial growth causes retardation in plant development. For treatments 2 and 3, reduction in the number of pods and in seed production was verified. Irrigation with saline water from the 23rd to the 42nd day (T4) and from the 43rd to the 63rd (T5) day after sowing did not affect reproductive and vegetative growth, but the saline water application in the pre-flowering (T4) caused anticipation of reproductive cycle. Cowpea plants removed the minerals analyzed in the following decreasing sequence: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, but the continuous use of saline water (T2) reduced the total extracted for the most nutrients, except for Na e Cl. The minerals Na, Cl, K, Ca, Fe and Mn were distributed preferentially to vegetative plant parts, while the most of N and P were exported in the pods. The irrigation with saline water during germination and initial growth stage (T3) reduced the mineral use efficiency of most of analyzed nutrients. The continuous application of saline water (T2) reduced the agronomic efficiency of the fertilizer application (N, P and K), but it did not affect the nutrient use efficiency by the plants. / A sensibilidade à salinidade varia com o estádio de desenvolvimento da cultura. O feijão-de-corda [Vigna unguiculata (L.) Walp.] constitui uma das principais culturas, em diversas regiões semi-áridas do mundo. Avaliou-se o efeito da irrigação com água salina, aplicada em diferentes estádios de desenvolvimento de plantas de feijão-de-corda. O experimento foi conduzido no campo, e obedeceu ao delineamento em blocos ao acaso, com cinco tratamentos (T1, T2, T3, T4 e T5) e cinco repetições. O feijão-de-corda foi cultivado no espaçamento de 0,8 m entre linhas e 0,3 m entre plantas, com duas plantas por cova. Os tratamentos utilizados foram: T1 - plantas irrigadas com água do poço (CEa de 0,8 dS m-1) durante todo o ciclo; T2 - Água salina com CEa de 5,0 dS m-1, com aplicação iniciada após a germinação e permanecendo até o final do ciclo; T3 - Água salina com CEa de 5,0 dS m-1, da semeadura até 22 dias após o plantio (DAP), correspondendo às fases de germinação e crescimento inicial, e água do poço no restante do ciclo; T4 - Água salina com CEa de 5,0 dS m-1, aplicada de 23 a 42 DAP (fase de intenso crescimento vegetativo até a pré-floração), e água do poço nas demais fases do ciclo; T5 - Água do poço da semeadura até 42 DAP e água salina (CEa de 5,0 dS m- 1) aplicada a partir dos 43 DAP (floração e frutificação). Foram avaliadas a cobertura vegetal do solo, crescimento vegetativo, fotossíntese, transpiração, condutância estomática, produtividade, partição de matéria seca, os teores, os totais extraídos e a distribuição dos nutrientes na planta, a eficiência nutricional, eficiência no uso da água e o acúmulo de sais no solo. A irrigação com a combinação de água do poço com água salina reduziu o acúmulo de sais no solo, em relação ao T2. O T2 reduziu as taxas de fotossíntese e transpiração, em relação ao T1. O T3 provocou redução das trocas gasosas somente na primeira medição, enquanto, que similar aplicação nos outros estádios (T4 e T5) não provocou reduções significativas nas trocas gasosas das plantas. O T2 inibiu o crescimento vegetativo da planta, enquanto o T3 provocou retardo no desenvolvimento da planta. Os tratamentos T2 e T3 provocaram reduções significativas no número de vagens e na produção de sementes por planta, em relação aos demais tratamentos. Por outro lado, os tratamentos T4 e T5 não afetaram o crescimento e a produtividade da cultura, sendo que o T4 causou aceleração no ciclo reprodutivo da cultura. Os minerais foram extraídos pelo feijão-de-corda na seguinte ordem decrescente: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, no entanto, o T2 reduziu a extração da maioria dos elementos analisados, com exceção do Na e Cl. Os minerais Na, Cl, K, Ca, Fe e Mn permaneceram preferencialmente nas partes vegetativas enquanto N e P foram exportados em maiores proporções pelos frutos. O T3 reduziu a eficiência de utilização da maioria dos nutrientes. O T2 reduziu a eficiência agronômica de utilização de N, P e K, entretanto não afetou a eficiência de utilização dos nutrientes extraídos pelas plantas.