The effects of two applications of foliar sprays made from kelp (Macrocystis intearifolia Bory) on growth of beans (Phaseolus vulgaris L.) under three moisture regimes were investigated. Date of kelp harvest had little effect on plants grown in water excess or deficit conditions, although means for kelp collected in spring tended to be higher. On soils maintained near field capacity, spray made from kelp collected in July resulted in increases in some bean yield components beyond the effects of kelp collected in spring or fall. The effect of storage of liquefied kelp at room temperature was also investigated and found to be soil moisture dependent. Leaf and root weights of plants grown in field capacity and dry soil respectively were lower for plants treated with kelp aged for 118 days compared to plants treated with kelp stored for longer or shorter durations. In wet soil conditions, the effect of sprays on plant height was reduced by storage of the liquefied kelp. Kelp extracts were fractionated by solvent partition. The butanolic fraction was shown to increase significantly many yield variables under wet soil conditions. This fraction had cytokinin-like activity in two bioassay systems, and contained substances co-eluting with isopentenyl adenine and zeatin in column, thin layer, and gas-liquid chromatography systems. Non-significant increases for some plant yield components resulting from application of unfractionated kelp paralleled these increases. A kelp fraction with undefined constituents increased some yield variables of plants grown in field capacity soil, as did a fraction with auxin and gibberellin-like activities in bioassay. The presence of inhibitors in the kelp was indicated by significantly lower pod yields under dry soil conditions, and a reduction in cytokinin-like bioassay activity when increasing amounts of kelp were assayed. The possibility that phytohormone deficits resulting from root stress are ameliorated by some components of the kelp spray is discussed. / Land and Food Systems, Faculty of / Graduate

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on April 30, 2009. Major professor: Terry Smith, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Agriculture with a specialization in Soil Science." "March, 2009." Includes bibliographical references (p. 37-40). Also available on microfiche.

Orientador: Salatiér Buzetti / Coorientador: Flávio Carlos Dalchiavon / Banca: Marco Eustáquio de Sá / Banca: Edson Lazarini / Banca: Helder Barbosa Paulino / Banca: Edson Cabral da Silva / Resumo: Pesquisas têm sido desenvolvidas na busca de identificar o melhor manejo da aplicação de manganês e zinco para a soja, contudo, não há ainda concordância nos resultados, pois a dinâmica destes nutrientes no solo é influenciada também pelo modo de aplicação. O objetivo deste estudo foi verificar a influência dos modos de aplicação de Mn e Zn sobre as características nutricionais (folhas, raízes e grãos), características produtivas (componentes de produção e produtividades de grãos), bioquímicas (fitato, aminoácidos livres e proteínas totais) e qualidade fisiológica das sementes de dois cultivares de soja, em um Latossolo Vermelho distrófico típico argiloso de Cerrado. O estudo foi realizado no Instituto Federal de Ciência e Tecnologia de Mato Grosso - Campus Campo Novo do Parecis, nos anos agrícolas 2013/14 e 2014/15. O delineamento experimental adotado foi em blocos ao acaso, com quatro repetições, em esquema fatorial 2 x 10. Os tratamentos foram compostos por dois cultivares de soja (TMG 1179RR e TMG 4182) e 10 diferentes modos de aplicação de Mn e Zn. As fontes de Mn e de Zn foram o sulfato de Mn e o sulfato de Zn, com recomendação para 5 kg ha-1 dos nutrientes, quando aplicado ao solo e de 0,5% do produto em solução, quando aplicado via foliar, sendo: T1: sem aplicação de Mn e Zn; T2: aplicação de Mn no solo; T3: aplicação de Zn no solo; T4: 1 aplicação de Mn via foliar; T5: 1 aplicação de Zn via foliar; T6: aplicação de Mn no solo + 1 aplicação de Mn via foliar; T7: aplicação de Zn no solo + 1 aplicação de Zn via foliar; T8: T2 + T3; T9: T4 + T5; T10: T6 + T7. Foram avaliados os teores de N, P, K, Ca, Mg, S, Mn, Zn, Fe e Cu nos tecidos foliares, radiculares e nos grãos de soja, além do número de vagens planta- 1, número de grãos vagem-1, número de grãos planta-1, massa de grãos planta-1, massa de 100 grãos, produtividade de grãos, teor de fitato, aminoácidos livres... / Abstract: Research has been developed trying to identify the best management of the application of manganese and zinc for soybean; however, there is still no agreement on the results, because the dynamics of these nutrients in the soil is also influenced by the application method. The objective of this study was to verify in a clayey red Oxisol (Rhodic Hapludox) Cerrado phase, the influence of the application modes of Mn and Zn on nutritional characteristics (leaves, roots and grains), productive characteristics (production components and grain yield), biochemical (phytate, free amino acids and total protein) and physiological quality of two soybean cultivars. The study was conducted at the Federal Institute of Science and Technology of Mato Grosso - Campo Novo do Parecis, Brazil, in the years 2013/14 and 2014/15 growing season. The experimental design was a randomized block design, with four replications in a 2 X 10 factorial scheme. The treatments consisted of: two soybean cultivars (GMT 1179RR and 4182 GMT) and 10 differents application methods of Mn and Zn. The sources of Mn and Zn were Mn sulfate and Zn sulfate with recommendation of 5 kg ha-1 of the nutrient when applied to soil and 0.5% of the product solution, when applied to leaves as follow. T1: without application of Mn and Zn; T2: Mn soil application; T3: Zn soil application; T4: Mn foliar application; T5: Zn foliar application; T6: Mn soil application + Mn foliar application; T7: Zn soil application + Zn foliar application; T8: T2 + T3; T9: T4 + T5; T10: T6 + T7. We evaluated the concentrations of N, P, K, Ca, Mg, S, Mn, Zn, Fe and Cu in the leaves, root and grains, and the number of pods plant- 1, number of grains pod-1, number of plant-1 grain, grain mass plant-1, weight of 100 grains, grain yield, phytate content, free amino acids, protein and physiological quality of soybean seeds. Nutritional characteristics, yield components and grain yield, in addition to biochemical... / Doutor

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 8, 2008) Includes bibliographical references.

Thesis (M.Sc. Biological Sciences)--University of Waikato, 2007. / Title from PDF cover (viewed March 17, 2009) Includes bibliographical references (leaves 107-115)

Thesis (MScAgric)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Yield and fruit quality of Citrus species relative to foliar sprays of macronutrients Marginal fruit colour and poor internal quality have been primary problems in the production of early-maturing mandarins in the Western Cape region (34 Os t 9°E). This leads to a reduction in the percentage of exportable fruit, a delay in the picking and consequent reduction in internal quality due to over-maturity. Therefore, a well-developed rind colour and internal quality of citrus are quality parameters of major importance in the fruit market. The effect of soil-applied limestone ammonium nitrate (LAN) and foliar low-biuret on fruit colour, yield and internal fruit quality of 'Mihowase' Satsuma on 'Troyer' citrange rootstock were evaluated. A significant reduction in leaf N levels was recorded where soil N has been reduced from 168 kg N/ha per annum to 126 kg Nlha per annum. Nitrogen applications influenced internal quality, although differences between treatments were too small to be of commercial importance. Despite tree appearance being more yellow in some years where N was predominantly applied as foliar spray, no consistent reduction in fruit size or yield was found. There were no clear significant differences in fruit colour, probably due to the fact that leaf N-Ievels were still within or below the norms suggested for Satsuma. The effect of Seniphosf , a mineral mixture of 31Og/L P20S, 56g/L CaO and 30g/L total N, and mono-potassium phosphate (MKP) [52% P20Sand 34% K20] on fruit colour, yield and internal fruit quality of mandarins, viz., 'Mihowase' Satsuma and 'Nules' Clementine on 'Troyer' citrange rootstock were evaluated. Seniphos'" and MKP applied during autumn colour break also did not influence fruit colour, yield and internal fruit quality, viz., juice content (%), total soluble solids (TSS), titratable acid (TA) and TSS:TA ratio of 'Nules' Clementine and 'Mihowase' Satsuma. In the Citrusdal region of South Africa (Western Cape Province), rind roughness is a general problem which often limits the percentage of exportable fruits. The effect of foliar mono-potassium phosphate (MKP) applied at 3% or 5% and urea ammonium phosphate (UAP) at 2% at 4 or 6 weeks, respectively, after full bloom (AFB) on yield, internal and external fruit quality (rind texture) of Citrus spp on rough lemon rootstock were evaluated. MKP and UAP had no consistent effect on yield, juice content (%), TSS, TA and TSS:TA ratio of 'Nouvelle' tangor, 'Valencia' orange, 'Shamouti' midseason and 'Oroval' Clementine. MKP and UAP sprays significantly, but inconsistently improved rind texture of 'Nouvelle' tangor, 'Shamouti' midseason and 'Valencia' orange. However, no positive effect was found on rind texture of 'Oroval' Clementine and 'Eureka' lemon. Inconsistent effects ofMKP and UAP sprays were also found on % leafN, P and K. / AFRIKAANSE OPSOMMING: Opbrengs en vrugkwaliteit van sitrus spesies relatief tat blaar toedienings van makroelemente Marginale vrugkleur en swak interne kwaliteit is die prim ere produksieprobleme in vroee seisoen mandaryne in die Wes-Kaap (34 Os 19°E). Die gevolg is 'n lae persentasie uitvoerbare vrugte omdat die oesdatum uitgestel word wat 'n afname in interne kwaliteit veroorsaak weens oorrypheid. Goed ontwikkelde skilkleur en interne kwaliteit is dus van groot belang vir bemarking van die vrugte. Grond-toegediende kalksteen-ammonium-nitraat (KAN) en lae biuret ureum se effek op vrugkleur, oesgrootte en interne vrugkwaliteit van 'Mihowase' Satsuma op 'Troyer citrange' onderstamme is ge-evalueer. 'n Betekenisvolle afname van die N viakke in die blare is gevind nadat grondtoediening van N vanaf 168 kg N/ha/jaar na 126 kg N/ha/jaar venninder is. N toedienings het interne kwaliteit beinvloed, maar die verskille tussen die behandelings was nie van kornmersiele waarde nie. Al was die boomvoorkoms geler in sommige jare waarin N hoofsaaklik as blaarvoedings toegedien is, was daar nie konstante afnames in vrug-of oesgrootte nie. Daar was geen betekenisvolle verskille in vrugkieur nie, waarskynlik omdat die blaarvlakke van N steeds binne die nonne daarvoor in Satsumas was. Die effek van Seniphos ('n minerale mengsel van 310g/L P20S, 56g/L CaO en 30g/L totaal N en monokaliumfosfaat (MKP) [52% P20S en 34% K20] op vrugkleur, oesgrootte en interne vrugkwaliteit van 'Mihowase' Satsumas en 'Nules' Clementine op Troyer citrange onderstarnme is geevalueer. Seniphos en MKP, toegedien tydens kleurbreek in die herfs, het ook nie skilkleur of interne vrugkwaliteit (sappersentasie, totale oplosbare vaste stowwe (TOV), suurheid (TS) en TOV:TS) betekenisvol bemvloed nie. In die Citrusdal-omgewing in die Wes-Kaap Provinsie (Suid-Afrika) is skilgrofheid 'n algemene probleem wat die hoeveelheid uitvoerbare vrugte beperk. Die effek van blaartoegediende MKP teen 3 en 5% en ureum-amrnoniurn-fosfaat (UAP) teen 2%, op onderskeidelik 4 of 6 weke na volblom, is geevalueer ten opsigte van oesgrootte, interne en ekstenne (skil grofheid) vrug kwaliteit in Citrus spp op growweskilsuurlemoen onderstam. Nie MKP of UAP het konsekwente verskille getoon t.o.v. oesgrootte, sappersentasie, TOV, TS, of TOV:TS in 'Nouvelle' tangor, 'Valencia' orange, 'Shamouti' midseison of 'Oroval' Clementine nie. Skiltekstuur is egter betekenisvol, hoewel inkonsekwent, verbeter in laasgenoemde drie. Skiltekstuur van 'Oroval' Clementine en 'Eureka' suurlemoen is nie bemvloed nie. Blaarpersentasies van N, P en K is ook inkonsekwent deur MKP en UAP beinvloed.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Fruit trees are exposed to various factors that can adversely affect the production of quality fruit. These factors can directly affect the fruit and the health of the tree and can be classified according to their biotic or abiotic nature, such as pathogenic attacks and drought stress respectively. One of the cultural practices used commercially to address these stresses is the application of fungicides and bactericides. The fruit production industry is under severe pressure from consumers, retailers and environmentalists, locally and internationally, to reduce chemical applications to fruit and fruit trees. The use of natural plant defence elicitor compounds and nutrients offer a potential alternative to fungicide and bactericide sprays and may also increase fruit quality and size as result of a reduction of plant stress. Trials were conducted to evaluate the efficiency of natural plant defence elicitors i.e. salicylic acid (SA) and flavonoids, in addition to mineral nutrients and bactericide/fungicides, on peach (incidence of Xanthomonas infection), plum (induced drought stress and Mg/Mn deficiencies) and apple (Mg/Mn deficiencies) fruit and trees against specified biotic or abiotic stress factors. Trial on Prunus persica cv. ‘Sandvliet’were conducted over two seasons (2008/2009 and 2011/2012) on a commercial site, Protea Farm, in the Worcester area in the Western Cape Province. During the 2008/2009 season the SA (AlexinTM, AlexiboostTM) containing treatments were applied first at 75% petal drop at concentrations of 125 and 250 ml. 100 L-1. The copper (StCu, Cu)-containing treatment was applied at 50% petal drop, while dichlorophen (XanbacTM) treatments were applied at fruit set at concentrations of 150, 300 and 200 ml. 100 L-1. The flavonoid (CroplifeTM) treatment was applied at the start of petal drop at a concentration of 150 ml.100 L-1. During the 2011/2012 season, a new flavonoid (CropbiolifeTM) treatment, as well as potassium (K-MaxTM) treatment, were incorporated into the trial and applied at concentrations of 150 and 500 ml. 100 L-1 respectively. Additionally a SA (AlexinTM) and dichlorophen (XanbacTM) treatments that performed well during the first season, were incorporated into the second season with application times and rates similar to the first season’s protocol. In addition to fruit size and quality measurements, the percentage Xanthomonas infection was determined on the leaves and fruit of the experimental trees. The SA (AlexinTM) containing treatment significantly reduced the incidence of Xanthomonas infection on leaves and fruit compared to the control in the first season. However, results varied between the two seasons, as no significant difference from the control could be obtained in the following season. The AlexinTM treatments also significantly increased the fruit size and quality. The flavonoid (CropbiolifeTM) and K (K-MaxTM) containing treatments similarly reduced the Xanthomonas infection on leaves and fruit, as well as increasing the fruit size and quality in the second season. The dichlorophen (XanbacTM) containing treatment recorded varying results as it significantly reduced the Xanthomonas infection on the fruit only in the second season. The plum trials were conducted over the 2011/2012 season on ‘Laetitia’ and ‘Songold’ plum trees, Welgevallen Experimental Farm, Stellenbosch University. Three SA (AlexinTM, AlexSal and RezistTM) containing foliar treatments were applied on the ‘Laetitia’ trees. Only two SA (AlexinTM, AlexSal) containing foliar treatments were applied on the ‘Songold’ trees. Additionally, a foliar treatment containing only K, Ca, Mg and B, was applied in both the ‘Laetitia’ and ‘Songold’ trials. All the treatments were first applied at 75% petal drop, at the same concentration of 250 ml. 100 L-1. Additionally to fruit size and quality, the mineral nutrient content of the leaves and fruit was determined. The ascorbic acid and glutathione content was determined in fruit at harvest and again after storage. None of the treatments had a positive effect on the parameters measured, except the SA (AlexinTM) containing treatments which increased the titratible acidity (TA) in both at harvest and after storage. The treatments also did not alleviate the induced stress compared to the control. The apple and plum tree trials were conducted over the 2011/2012 season in a semi-closed greenhouse, at the Welgevallen Experimental Farm, Stellenbosch. Magnesium (Mg) and Manganese (Mn) deficiencies were induced in one-year-old ‘Royal Beaut’ apple and ‘Laetitia’ plum trees planted in 10 L nursery bags, by omitting these nutrients from a standard Long Ashton soil application. Foliar treatments of Mg (MagMaxTM) and Mn (ManMaxTM) containing sprays were subsequently applied at concentrations of 250 and 75 ml. 100 L-1 respectively, after deficiency symptoms for these nutrients were visually observed. Mineral nutrient analysis of the leaves were analysed on the 13th of February for the plums and 30th of March 2012, for the apples. The Mn (ManMaxTM) containing treatment successfully overcame the Mn induced deficiency. The Mg (MagMaxTM) containing treatment did not overcome the induced Mg deficiency and was probably due to the deficient nitrogen levels in the plants, caused by an error in the initial Long Ashton nutrient solution formulation. In conclusion AlexinTM, K-MaxTM and CropbiolifeTM have shown their ability to decrease Xanthomonas infection in peaches. Additionally to their positive effect on fruit size and quality on the peaches. SA was not able to overcome the induced stress on plums, but had a positive effect on the fruit quality and size. The ManMaxTM been proven to overcome the induced Mn deficiency, while MagMaxTM was unsuccessful to overcome the Mg deficiency. / AFRIKAANSE OPSOMMING: Vrugtebome word blootgestel aan verskeie faktore wat die produksie van kwaliteit vrugte nadelig kan beïnvloed. Hierdie faktore kan ‘n direkte invloed hê op die vrugte en op die gesondheid van die boom en kan geklassifiseer word op grond van hulle biotiese of abiotiese natuur, soos patogeen infeksie en droogte stres onderskeidelik. Van die produksie praktyke wat gebruik word sluit in die toepassing van verskillende swamdoders en bakterisiede. Die vrugtebedryf is onder geweldige druk van verbruikers, die kleinhandel en omgewingsbewustes om die toediening van chemikalieë aan vrugte en vrugtebome te verminder. Die gebruik van natuurlike plant verdediging stimulerende verbindings en nutriënte, bied 'n moontlike alternatief tot die spuit van swamdoders en bakterisiede, en kan ook moontlik ʼn bydrae maak tot verbeterde vrugkwaliteit en -grootte. Proewe is uitgevoer om die effektiwiteit van die natuurlike plant verdediging stimulante, salisielsuur (SA) en flavonoïede, addisioneel tot verskillende voedingstowwe en bakterieële / swamdoders op perske, pruim en appels teen Xanthomonas infeksie, droogte stres en Mg / Mn tekorte as biotiese en abiotiese stres faktore onderskeidelik te evalueer. Die Prunus persica ‘Sandvliet’ proewe is oor twee seisoene (2008/2009 en 2011/2012) op 'n kommersiële perseel, Protea Farm, in die Worcester-area in die Wes-Kaap Provinsie, uitgevoer. Gedurende die 2008/2009 seisoen is die SA (AlexinTM, AlexiboostTM) bevattende behandelings eers toegedien by 75% blomblaarval teen konsentrasies 125 en 250 ml. 100 L-1. Die koper (StCu, Cu) bevattende behandeling is toegedien by 50% blomblaarval, terwyl die dichlorofen (XanbacTM) bevattende behandelings toegedien is by vrugset, teen konsentrasies van 150, 300 en 200 ml. 100 L-1. Die flavonoïde (CroplifeTM) behandeling is toegedien by die begin van blomblaarval teen 'n konsentrasie van 150 ml. 100 L-1. Gedurende die 2011/2012 seisoen was 'n nuwe flavonoïd (CropbiolifeTM) en ‘n kalium (K-MaxTM) behandeling toegevoeg tot die eksperiment, met ʼn toediening teen konsentrasies van onderskeidelik 150 en 500 ml. 100 L-1. Daarbenewens is die SA (AlexinTM) en dichlorofen (XanbacTM) behandeling van die 2008/2009 seisoen herhaal teen dieselfde konsentrasies en toedieningstye soos in die protokol van die eerste seisoen. Behalwe vir die bepaling van vruggrootte en –kwaliteit, is die persentasie Xanthomonas infeksie op blare en vrugte ook bepaal. Die SA (AlexinTM) bevattende behandeling het die voorkoms van Xanthomonas infeksie op die blare en vrugte betekenisvol verminder in vergelyking met die kontrole. Resultate het egter gewissel in die daaropvolgende seisoen en geen beduidende verskille tussen die behandelings is waargeneem nie. Hierdie SA-bevattende behandelings het ook tot ‘n toename in vruggrootte en -kwaliteit gelei. Die flavonoïde bevattende behandelings, (CropbiolifeTM) en K (K-MaxTM), het soortgelyke afnames in Xanthomonas infeksie op die blare en vrugte in die tweede seisoen getoon, sowel as ‘n toename in vruggrootte en -kwaliteit. Die dichlorofen (XanbacTM) bevattende behandeling het variërende resultate getoon aangesien dit slegs tot ‘n beduidende afname in Xanthomonas infeksie op die blare en vrugte in die tweede seisoen kon lei. Pruim proewe is uitgevoer in die 2011/2012 seisoen op ‘Laetitia’ en ‘Songold’ pruimbome te Welgevallen Proefplaas, Universiteit van Stellenbosch. Drie SA (AlexinTM, AlexSal en RezistTM) bevattende blaar behandelings is toegedien op die ‘Laetitia’ bome. Slegs twee SA (AlexinTM, AlexSal) blaar behandelinge is toegedien op die ‘Songold’ bome. ʼn Verdere K, Ca, Mg en B blaar behandeling is ook toegedien in beide die ‘Laetitia’ en ‘Songold’ proewe. Al die behandelings se eerste toediening het saamgeval met 75% blomblaarval, teen dieselfde konsentrasie van 250 ml. 100 L-1. Addisioneel tot vruggrootte en –kwaliteit, is die mineraal element inhoud van die blare en vrugte bepaal. Die askorbiensuur en glutatioon inhoud is bepaal in die vrugte met oes asook na opberging. Geen behandeling het 'n positiewe uitwerking op die parameters wat gemeet is getoon nie, behalwe een van die SA (AlexinTM) bevattende behandelings wat die titreerbare sure (TS) verhoog het in beide kultivars. Die behandelings kon ook nie die geïnduseerde stres verlig in vergelyking met die kontrole nie. Die appel- en pruim proewe is uitgevoer gedurende die 2011/2012 seisoen in 'n semi-geslote glashuis te Welgevallen Proefplaas, Universiteit van Stellenbosch. Magnesium (Mg) en Mangaan (Mn) tekorte is geïnduseer in een-jaar-oue ‘Royal Beaut’ appel en ‘Laetitia’ pruim bome, aangeplant in 10L kwekerysakke, deur dié elemente uit ʼn toediening van standaard Long-Ashton voedingsoplossing aan die grond weg te laat. Mg (MagMaxTM) en Mn (ManMaxTM) bevattende blaarspuite is daarna toegepas teen onderskeidelik konsentrasies van 250 en 75 ml. 100 L-1. ʼn Minerale analise van die blare is uitgevoer op 13 Februarie, op die pruime en 30 Maart 2012, op die appels. Die Mn (ManMaxTM) bevattend behandeling het die Mn-geïnduseerde tekort verlig. Die Mg (MagMaxTM) bevattende behandeling het nie die geïnduseerde Mg-tekort verlig nie. Dit is moontlik toe te skryf aan die stikstof tekort in die plante wat te wyte was aan ʼn foutiewe Long Ashton voedingsoplossing formulasie wat aanvanklik toegedien is. Ten slotte het AlexinTM, K-MaxTM en CropbiolifeTM getoon dat hul die vermoë het om Xanthomonas infeksie te verminder, asook om vruggrootte en kwaliteit in perskes te verbeter. SA was nie in staat om die geïnduseerde stres op pruime te oorkom nie, maar het 'n positiewe uitwerking op die vruggroote en kwaliteit gehad. ManMaxTM het getoon dat dit ʼn geïnduseerde, visuele Mn tekort kan oorkom, terwyl MagMaxTM onsuksesvol was om die Mg-tekort te oorkom

Orientador: Renato de Mello Prado / Coorientador: Cassiano Garcia Roque / Coorientador: Rita de Cassia Felix Alvarez / Banca: Rilner Alves Flores / Banca: Jairo Osvaldo Cazetta / Resumo: A deficiência de boro é um fator limitante na produção do algodoeiro, mas o excesso pode induzir à toxicidade. Nas duas desordens nutricionais de boro, o acréscimo de silício, via foliar ou radicular, pode aliviar esses efeitos, mas essas informações não são conhecidas nas plantas de algodão. Objetivou-se (a) inicialmente, verificar a fonte e a concentração de Si aplicada via foliar que resulta em maior acúmulo do elemento nas plantas de algodão; (b) definir a concentração crítica do boro na solução nutritiva que induz à deficiência e à toxicidade do micronutriente nas plantas de algodão, e (c) verificar o efeito do silício, aplicado via foliar e radicular, como agente mitigador dos efeitos deletérios da deficiência e da toxicidade de boro no algodoeiro. Foram desenvolvidos três experimentos em plantas de algodão transgênico cultivados em sistema semi-hidropônico em casa de vegetação. O primeiro experimento foi com concentrações de Si via foliar em diferentes fontes do elemento. O segundo experimento foi com concentrações de B na solução nutritiva. Com os resultados destes experimentos, obtiveram-se a concentração foliar de Si e a fonte mais adequada, e a concentração de B na solução nutritiva, que induz a suficiência, deficiência e toxicidade. Diante destes resultados, realizou-se o terceiro experimento, onde foram avaliados Si aplicado via foliar e radicular, e o controle (sem Si) em plantas de algodão sob deficiência, suficiência e toxicidade de B. A aplicação foliar de Si... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Boron deficiency is a limiting factor for cotton production, but boron excess may induce toxicity. In the two nutritional disorders of boron, the addition of silicon by leaf or root application can alleviate these effects but this information is unknown in cotton plants. The objective of this study was to (a) initially verify the source and concentration of Si applied in the leaf that results in greater accumulation of the element in the cotton plants; (b) define the critical concentration of boron in the nutrient solution that induces the deficiency and toxicity of the micronutrient, and (c) to verify the effect of silicon, applied by leaf and root, as a mitigating agent of the deleterious effects of boron deficiency and toxicity in cotton. Three experiments were carried out on cotton plants cultivated in a soilless growing system. The first experiment was with concentrations of Si by leaf application with different sources of the element. The second experiment was with concentrations of B in the nutrient solution. With the results of these experiments, we got the more adequate Si foliar source and concentration; and the concentration of B in nutrition solution that induces to sufficiency, deficiency and toxicity. The third experiment was done to verify the effects of apply silicon by leaf and root and control (without Si) in cotton plants under deficiency, sufficiency and toxicity of B. The application of Si is viable for cotton, since it increased the accumulation of Si, t... (Complete abstract click electronic access below) / Mestre

Orientador: Renato de Mello Prado / Coorientador: Cassio Hamilton Abreu Júnior / Banca: Fábio Olivieri de Nobile / Banca: Aguinaldo José Freitas Leal / Banca: Priscila Lupino Gratão / Banca: Mara Cristina Pessôa da Cruz / Resumo: A deficiência de boro pode afetar a eficiência nutricional e o crescimento vegetativo e reprodutivo, induzindo alterações celulares no feijão-caupi. A eficiência do fornecimento do B via foliar, na cultura pode depender da concentração adequada do micronutriente na calda de pulverização, e se associado ao sorbitol poderia potencializar a sua absorção e crescimento. Propôs-se avaliar os efeitos da deficiência de boro na planta e da adubação foliar com boro na ausência e na presença de sorbitol no crescimento e no acúmulo de boro na planta, na produção e sua mobilidade no feijão-caupi. No estudo foram realizados três ensaios no período de fevereiro/ 2014 a maio/2015. No experimento I, empregaram-se dois tratamentos com solução nutritiva sob ausência (-B) e presença de boro (+B) em dez repetições. No experimento II utilizou-se esquema fatorial 5x2, sendo cinco concentrações de B (0; 1,25; 2,5; 3,75 e 5,0 g L-1 de B), via foliar, na forma de ácido bórico, na ausência ou na presença de sorbitol (500 mmol L 1), com quatro repetições. No experimento III estudou-se a mobilidade do boro marcado (10B) absorvido pelas raízes e pelas folhas. Avaliaram-se os sintomas de deficiência de boro, o crescimento da raiz, a massa seca dos órgãos da planta e o teor de B e a produção de grãos. A deficiência de boro em plantas de feijão-caupi diminuiu a eficiência de absorção de B, embora tenha aumentado à eficiência de uso do nutriente, mas os maiores prejuízos ocorreram nas variáveis reprodutivas e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Boron deficiency can affect nutritional efficiency, as well as vegetative and reproductive growth, inducing cell changes in cowpea. Efficiency of B supply via foliar application in crops may depend on its proper concentration in spray solution, and when associated with sorbitol, it could enhance its absorption and plant growth. The aim of this study was to assess the effects of boron deficiency and foliar fertilization in the absence and presence of sorbitol on plant growth and production, and its accumulation and mobility in cowpea. In the study, three experiments were carried out from February 2014 to May 2015. Experiment I was composed of two treatments with nutrient solution under absence (−B) and presence (+B) of boron in ten repetitions. In the experiment II, a 5 × 2 factorial scheme was used, being applied via foliar five concentrations of B (0, 1.25, 2.5, 3.75 and 5.0 g L−1 of B) in the form of boric acid and in the absence or presence of sorbitol (500 mmol L−1 ), with four repetitions. In the experiment III, marked boron (10B) mobility was studied regarding its absorption by roots and leaves. Boron deficiency symptoms, root growth, dry weight of plant organs and B content and grain production were assessed. Boron deficiency in cowpea plants decreased B absorption efficiency, although it has increased nutrient use efficiency. The greatest losses occurred in reproductive variables and root growth in relation to leaves and stem production. Boron deficiency induces cellular changes such as thickening in the middle lamella and starch accumulation in leaf chloroplasts, which lead to characteristic visual symptoms for cowpea. The highest production of cowpea grains (90-100% of maximum production) occurred when B was pulverized at 2.62 g L−1 of B without sorbitol, having as a source the boric acid, on growth stages V6, R1 and R2 and foliar ... (Complete abstract click electronic access below) / Doutor