Transport and post-harvest handling of flowers both cut and potted is one of the greatest challenges in the horticulture industry (REDMAN et al., 2002). Ethylene-induced flower abscission is responsible for the loss of crops (KIM et al., 2007). Flower abscission is greater when plants are transported (ABEBIE et al., 2005). This limits the sale of flowers and potted plants to areas close to the site of production and prevents export opportunities. South Africa is home to many spectacular species with great horticultural potential (RICE et al., 2011). Unfortunately however, development of a number of these species for export is difficult due to transport-induced flower abscission. Transport-induced flower abscission is a problem experienced by Dr Gert Brits, a breeder of Plectranthus in Stellenbosch in South Africa. In this study a number of Dr Brits’s Plectranthus varieties were used as model plants to understand the process of transport-induced flower abscission and develop a protocol for the prevention of such abscission. Flow cytometry was used to determine the ploidy levels of each of the varieties. It was important to be aware of this during the experiments as varieties with different ploidy levels have been reported to behave differently under stressful environmental conditions. Of the eight varieties examined, three were diploid (2n), one was triploid (3n), three were tetraploid (4n) and one was a mixopliod (2n/4n) variety. To determine the effects of packaging plants during transport and the effects of darkness on flower abscission, plants were packaged into perspex chambers and kept either in a 16 h photoperiod or in darkness for 96 h. Every 24 h the number of open and unopened flowers that had abscised was recorded. Both packaging and darkness increased flower abscission of open and unopened flowers in all eight varieties. Four varieties preferentially abscised open flowers; while the remaining four preferentially abscised unopened flowers. All eight varieties were exposed to different concentrations of ethylene (0, 0.1, 0.25 0.5, 1 and 2 μll-1) to determine their level of ethylene sensitivity. All of the Plectranthus varieties were determined to be extremely sensitive to ethylene. With 100% flower abscission occurring within 24 h at 1 and 2 μll-1 in all varieties. In order to determine what internal changes were causing this increase in flower abscission under these conditions, the changes in the expression of key ethylene biosynthetic enzymes, cytokinin content and carbohydrates in the flowers were examined. ACS and ACO are the two key enzymes in the ethylene biosynthetic pathway (JOHNSON & ECKER, 1998). Changes in the levels of mRNAs coding for these two enzymes were examined when plants were packaged and put into the dark. In general there was an upregulation of the ethylene biosynthetic pathway and in turn this may have increased ethylene production by the plants under simulated transport conditions. However, the changes were not large enough to be solely responsible for the increased flower abscission observed under simulated transport conditions. The concentrations of 43 cytokinins were measured in pedicle tissue from plants which had been kept in the dark for 0, 24, 48, 72 and 96 h. Of the 43 cytokinins measured 21 were below the level of detection. Concentrations for the remaining 22 cytokinins at each of the time points were examined and it was found that in general cytokinin concentrations increase when plants are packaged and put into the dark. DHZ-type cytokinins remained stable during the 96 h continuous dark monitoring period, with most of the changes observed in the tZ and iP types. Peaks in cytokinin concentrations are often followed by an increase in flower abscission, indicating that an increase in cytokinin concentrations may be one of the factors causing the increase in transport-induced flower abscission. Only glucose and fructose were detected in peduncle tissue. Changes in glucose and fructose over 24 h in the greenhouse and over 0, 24, 48, 72 and 96 h in simulated transport conditions were measured. During the day, glucose and fructose levels increased towards the afternoon and evening and decreased in the early morning. This is consistent with studies conducted on other species (ALONI et al., 1996). When plants were put into the dark, glucose and fructose levels increased slightly at 24 h and then decreased to levels similar to those measured in control plants. Although there were changes in glucose and fructose level in simulated transport conditions, they were very slight and it is unlikely that these changes are not responsible for the transport-induced flower abscission. These results suggest that the observed transport-induced flower abscission is the result of increased cytokinin concentrations and expression of ACO and ACS genes when plants are packaged and put into the dark. These changes in turn cause an increase in ethylene production by the plants, and the build-up of ethylene in the transport container causes flowers to abscise. Ethylene perception by the plant is the step which could be targeted to prevent flower abscission. A number of ethylene antagonists block the ethylene receptors in the plant and in so doing prevent the receptors from binding ethylene and transducing the abscission signal. 1-MCP isone such ethylene antagonist. To test whether 1-MCP could be used for the prevention of flower abscission in Plectranthus, plants were placed in sealed perspex chambers in the light and in the dark and treated with 100 nll-1 1-MCP for a single 6 h treatment, or for 6 h every day prior to continuous exposure to ethylene. 1-MCP treatment greatly reduced ethylene- and transport-induced flower abscission when plants were treated continuously, but reduced flower abscission for the first 24 h when pre-treated with a single 6 h exposure to 1-MCP.Transport-induced flower abscission in Plectranthus is the result of exposure to ethylene. The increase in ethylene production by the plants in transport conditions is likely due to an upregulation of the ethylene biosynthetic pathway and an increase in cytokinin concentrations or movement in the pedicle tissue. This transport-induced flower abscission can be prevented by continuous treatment with 100 nll-1 1-MCP during the transport period. By using 1-MCP plants can be transported for up to 4 d and the opportunity for export is made possible. / Thesis (Ph.D.)-University of KwaZulu-Natal, Piertermaritzburg, 2013.

Thesis (Ph. D.)--Miami University, Dept. of Botany, 2004. / Title from second page of PDF document. Includes bibliographical references (p.70-79).

Thesis (MScAgric) -- University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Postharvest berry split and abscission are prevailing physiological disorders that negatively impact on the quality of table grapes exported from South Africa. Inferior grape quality due to these disorders results in a considerable decline in consumer confidence in the branded product, which leads to a drop in demand, and consequently, lower prices. Since information concerning postharvest factors influencing postharvest berry split and abscission is limited, the search for reliable methods to adequately control these problems remains elusive. In an attempt to obtain the required information, the influence of harvest temperature, harvest maturity, perforated liners, field heat removal prior to packing, delay periods before and after packing, storage duration and the elevation of storage temperature on the development of berry split and abscission in 'Thompson Seedless' (Vitis vinifera Linnaeus) table grapes was investigated. Changes in abscission related factors during berry development, and the influence of pre-and postharvest ethylene inhibitors on the development of berry abscission in 'Waltham Cross' table grapes, was also studied. Berry split was aggravated by packing 'Thompson Seedless' grapes at high pulp temperatures of approximately 30°C, especially if the grapes were packed in non-perforated bags. The incidence of berry split could be reduced by between 80 and 90% by packing grapes in perforated instead of non-perforated liners. Perforated bags also reduced levels of S02 damage. However, due to significantly more moisture loss from grapes in perforated bags, compared to non-perforated bags, the risk of higher fruit and stem desiccation and softer berries existed. Optimum size and density of perforations needs to be determined to reduce berry split without excessive loss of moisture from the grapes, and S02gas from the air space surrounding the product. The influence of harvest temperature and liner type on berry abscission was not conclusive. Advanced maturity increased grape resistance to berry split. However, grapes harvested too mature were prone to stem desiccation and the development of Botrytis decay. The occurrence of berry abscission also appeared to increase with advanced harvest maturity. Consequently, to ensure optimal post-storage quality, 'Thompson Seedless' grapes should be harvested as soon as horticultural maturity has been reached, which appears to be at approximately 18°Brix. Field heat removal for 1.5 hours at 19°C prior to packing had no beneficial or adverse effect on berry split and abscission. Delay periods prior to packing aggravated berry abscission, but did not influence berry split significantly. Grapes delayed for 12 hours showed a significant increase in berry abscission and Botrytis decay, compared to grapes delayed for only 3 or 8 hours. Considering that the absence of fungal decay is the most important quality prerequisite in table grapes, it is of vital importance to pack grapes with as short a delay period as possible. Grapes packed in non-perforated liners and delayed for different durations after packing, before the onset of forced-air cooling (FAC), showed significant differences regarding the incidence of berry split. Grapes delayed for 18 hours had significantly higher levels of berry split directly after the delay period, compared to grapes delayed for 6 or 12 hours. No significant difference in berry abscission occurred between grapes delayed for different periods. To minimise the amount of berry split, FAC should be applied as rapidly as possible after the packing of grapes in non-perforated liners. Two storage related factors significantly influenced the incidence of berry split in 'Thompson Seedless' grapes during cold storage significantly, viz. the duration of storage at -O.soC,and the increase in temperature after low temperature storage. Berry split increased almost linearly with prolonged storage at -O.soC. An elevation of storage temperature from -O.soC to 10°C any time during the cold storage period, further aggravated the split problem. Consequently, the reduction of berry split in 'Thompson Seedless' table grapes during cold storage requires (a) the shortest possible cold storage period, and (b) good temperature management throughout distribution, from initiation of cooling until the final point of sale. The grape berry abscission potential, as quantitatively indexed by the measurement of the fruit removal force (FRF), showed significant changes during berry development of 'Waltham Cross' table grapes, from 27 to 111 days after full bloom (OAFB). This showed that at certain stages of fruit growth, 'Waltham Cross' grapes are more prone to berry abscission. At 27 OAFB, when the berries had an average diameter of 6.6mm, the grape bunches showed a significantly higher potential for berry abscission, compared to grapes sampled at a later stage. 'Waltham Cross' has inherently straggly bunches with bare shoulders. Therefore, any abscission during berry development will aggravate the problem. Consequently, it is of vital importance that any adverse factors such as moisture stress be avoided, especially during the period when 'Waltham Cross' grapes appear to be very susceptible to berry abscission. Of all parameters measured, moisture loss showed the best correlation with abscission. Grapes harvested with total soluble solids (TSS) of 12.3°Brix, 83 OAFB, had a significantly higher abscission potential than grapes harvested more mature. Therefore, by harvesting 'Waltham Cross' grapes at optimum maturity, at a TSS of approximately 16.4°Brix, berry abscission can be reduced to a great extent. It was evident that at veraison, the metabolism of grape berries changes drastically, and additional to the rapid increase in sugars and the rapid decrease in acidity, a decrease in FRF occurs. Preharvest sprays of ReTain™ (a derivative of aminoethoxyvinylglycine), which inhibits ethylene synthesis, showed no promise as a means to reduce postharvest berry abscission. A postharvest treatment with EthylBloc® (1-methylcyclopropene), which inhibits ethylene action, only reduced berry abscission during one season. / AFRIKAANSE OPSOMMING: Die fisiologiese defekte korrelbars en los korrels wat algemeen voorkom tydens opberging van sekere tafeldruif-kultivars, het 'n negatiewe invloed op tafeldruiwe wat uitgevoer word vanaf Suid-Afrika. Minderwaardige kwaliteit as gevolg van hierdie defekte het 'n aansienlike afname in verbruikers-vertroue tot gevolg wat aanleiding gee tot 'n ooreenkomstige afname in aanvraag en prys van die produk. Inligting rakende na-oes faktore wat die voorkoms van korrelbars en los korrels beïnvloed is beperk, en geen gewaarborgde metode bestaan om hierdie twee defekte volkome te beheer nie. In 'n poging om dié gewenste inligting te bekom, is ondersoek ingestel na die effek van oes-temperatuur, oes-rypheid, geperforeerde sakke, veldhitte verwydering voor verpakking, vertragingsperiodes voor en na verpakking, tydsduur van opberging, en die verhoging van die opbergingstemperatuur, op die voorkoms van korrelbars en los korrels by 'Thompson Seedless' (Vitis vinifera Linnaeus) druiwe. Daar is ook ondersoek ingestel na veranderings in afsnoering verwante faktore tydens korrel-ontwikkeling, en die invloed van vooren na-oes toedienings van etileen inhibeerders op die ontwikkeling van los korrels by 'Waltham Cross'tafeldruiwe. Korrelbars is vererger deur 'Thompson Seedless' met hoë pulptemperature van ongeveer 29.5°C te verpak, veral indien dit in 'n riie-geperforeerde sak verpak is. Die voorkoms van korrelbars kon tussen 80 en 90% verminder word deur 'Thompson Seedless' druiwe in geperforeerde sakke te verpak, in plaas van nie-geperforeerde sakke. Geperforeerde sakke het ook S02 skade op die druiwe verminder. Tog, as gevolg van betekenisvol meer vogverlies vanaf druiwe in geperforeerde sakke as vanaf druiwe in nie-geperforeerde sakke, bestaan die risiko van meer stingel-uitdroging en minder ferm korrels indien druiwe in geperforeerde sakke verpak word. Optimale grootte en digtheid van perforasies moet bepaal word om korrelbars te verminder, maar sonder oormatige vogverlies vanaf die druiwe en oormatige verlies aan S02. Die invloed van oes-temperatuur en sak-tipe op los korrels was nie oortuigend nie. Gevorderde oes-rypheid het die druif se weerstand teen korrelbars verhoog. Daarteenoor was druiwe wat té ryp geoes is, meer gevoelig vir stingel-uitdroging en Botrytis bederf. Dit wilook voorkom of die voorkoms van los korrels toeneem met gevorderde rypheid. Dus, om optimum kwaliteit na opberging te verseker, moet 'Thompson Seedless' geoes word sodra hortologiese rypheid bereik word, wat blyk om by 'n totale opgeloste vaste stof-inhoud (TOVS) van ongeveer 18°Brix te wees. Veldhitte verwydering voor verpakking, vir 1.5 uur by 19°C, het geen effek gehad op die voorkoms van korrelbars en los korrels nie. 'n Vertragingsperiode voor verpakking het die los korrel-probleem vererger, alhoewel dit geen betekenisvolle invloed op die voorkoms van korrelbars gehad het nie. Druiwe wat vir 12 uur voor verpakking vertraag is, het betekenisvol meer los korrels en Botrytis bederf getoon, in vergelyking met druiwe wat slegs 'n vertragingsperiode van 3 of 8 uur ondergaan het. Aangesien die afwesigheid van bederf die belangrikste kwaliteits-vereiste vir tafeldruiwe is, is dit van kardinale belang om druiwe so gou as moontlik na oes te verpak. Druiwe, verpak in nie-geperforeerde sakke, wat vir verskillende periodes vertraag is voor geforseerde-lug verkoeling, het betekenisvolle verskille getoon betreffende die voorkoms van korrelbars. Druiwe vertraag vir 18 ure voor verkoeling, het betekenisvol meer korrelbars getoon, soos gemeet onmiddellik na die vertragingsperiode, in vergelyking met druiwe wat slegs vir 6 of 12 ure vertraag was. Geen betekenisvolle verskille in los korrels het voorgekom tussen druiwe wat verskillende vertragingsperiodes ondergaan het nie. Om korrelbars te verminder, moet geforseerde-lug verkoeling so gou as moontlik na verpakking van druiwe in nie-geperforeerde sakke toegepas word. Twee opbergings-verwante faktore beïnvloed die voorkoms van korrelbars by 'Thompson Seedless' druiwe tydens koelopberging, naamlik die tydsduur van opberging by -O.soC,asook 'n styging in temperatuur vanaf -O.soC tot 1DoC. Korrelbars het feitlik liniêr toegeneem met verlengde opberging by -O.soC. 'n Styging in temperatuur vanaf -O.SoCtot 1DoCop enige tydstip gedurende die koelopbergingsperiode, het korrelbars verder vererger. Dus, om korrelbars by 'Thompson Seedless' tydens opberging tot die minimum te beperk, moet die tydsduur van opberging so kort as moontlik wees, en moet die koue ketting regdeur die distribusie-proses gehandhaaf word, vanaf inisiëring van verkoeling tot en met die uiteindelike verkoop van die produk. Die afsnoerings-potensiaal van druiwe, soos kwantitatief geïndekseer is deur meting van die vrug-verwyderings-vermoë (VVV), het betekenisvol verander gedurende korrel-ontwikkeling van 'Waltham Cross' tafeldruiwe, vanaf 27 tot 111 dae na volblom (DNVB). Dit het getoon dat 'Waltham Cross' druiwe by sekere stadiums van vrug-groei meer gevoelig is vir korrel afsnoering. By 27 DNVB, wanneer die korrels 'n gemiddelde deursnee van 6.6mm gehad het, het die druiwe 'n betekenisvolle hoër potensiaal vir afsnoering getoon, in vergelyking met druiwe wat op 'n latere stadium getoets is. 'Waltham Cross' is inherent geneig tot yl trosse met kaal skouers, gevolglik sal enige afsnoering tydens korrel-ontwikkeling die probleem vererger. Dus is dit van kardinale belang dat enige nadelige faktor, soos byvoorbeeld vogstres, vermy moet word, veral gedurende periodes wanneer dit wil voorkom of 'Waltham Cross' baie vatbaar is vir korrel afsnoering. Van al die parameters wat gemeet is, het vogverlies die beste korrelasie met korrel afsnoering getoon. Druiwe wat 83 DNVB, by 'n TOVS van 12.3°Brix geoes is, het 'n betekenisvol hoër potensiaal vir korrel afsnoering getoon, in vergelyking met druiwe wat ryper geoes is. Dus, deur 'Waltham Cross' druiwe by optimum rypheid te oes, by 'n TOVS van ongeveer 16.4°Brix, kan korrelbars in 'n groot mate verminder word. Tydens verelson, wanneer die metabolisme van die druiwe drasties verander, was daar gepaardgaande met die drastiese toename in TOVS en die drastiese afname in totale titreerbare sure (TSS), ook 'n afname in Voor-oes bespuitings met ReTain™, wat etileen sintese inhibeer, het geen potensiaal getoon om los korrels by 'Waltham Cross' te verminder nie. 'n Na-oes behandeling met EthyIBloc®, wat etileen werking inhibeer, het slegs korrel afsnoering in een van die seisoene effens verminder.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-02-27T12:29:47Z No. of bitstreams: 1 PGPV16MA202.pdf: 1955049 bytes, checksum: c0487ee4e5b4f8232b76bbf8e973a9c4 (MD5) / Made available in DSpace on 2018-02-27T12:29:47Z (GMT). No. of bitstreams: 1 PGPV16MA202.pdf: 1955049 bytes, checksum: c0487ee4e5b4f8232b76bbf8e973a9c4 (MD5) Previous issue date: 2016-03-28 / FUMDES / The apple tree is a temperate fruit species with deciduous habit, where is observed the fall of the leaves at the end of the growing season. This physiological process is known as senescence, and is important for regulating the growth and development of apple plants, having a central role in the devolopment of the buds and flowering in the next cycle. In regions with autumn and winter with mild temperatures, the processes of maturation and leaf fall are delayed and may not often occur. Due to the great variability of climatic conditions for apple cultivation, many questions and hypotheses are formulated on the need to carry out the defoliation of the plants when that does not occur naturally in the fall. The objective of this research was to evaluate the effects of different concentrations of abscisic acid (ABA) in young apple trees 'Granny Smith' and 'Fuji Suprema', and adult plants in productive age 'Daiane' and 'Fuji Suprema' aiming to follow ecophysiological effects of ABA on its efficiency in inducing senescence of leaves, budbreak, nutrient levels in tissues, C/N ratio and productivity. The experiments were conducted during the fall, in a commercial orchard of apple trees in Fraiburgo, SC and in a experimental orchard in Caçador, SC, in the years of 2013 and 2014. On apple youg plants, ABA was effective in promoting the senescence of leaves. Exogenous application of ABA was effective in senescence of adult plants leaves of 'Daiane' and 'Fuji Suprema'. Was observed an increased sensitivity to treatment with ABA, regardless of concentration adopted in cv. Daiane. According with leaf analyzes, was noted that the N concentration in leaves decreases eight days after the treatment with ABA compared to control plants. The ABA anticipates the beginning of sprouting and full bloom / A macieira é uma fruteira de clima temperado de hábito caducifólio, ou seja, ocorre a queda das folhas no final do ciclo vegetativo. Esse processo fisiológico, conhecido como senescência e abscisão, é importante para a regularização do crescimento e desenvolvimento das plantas de macieira, sendo fundamental para o favorecimento da brotação e floração no ciclo seguinte. Em regiões de outono e inverno amenos, os processos de maturação e queda das folhas são retardados, podendo muitas vezes não ocorrer. Pela grande variabilidade das condições climáticas para cultivo da macieira, muitos questionamentos e hipóteses são formulados referentes à necessidade de realização da desfolha das plantas quando essa não ocorre naturalmente durante o outono. O objetivo dessa pesquisa foi avaliar os efeitos de diferentes concentrações de ácido abscísico (ABA) em mudas de macieiras ‘Granny Smith’ e ‘Fuji Suprema’, e em plantas adultas em idade produtiva de ‘Daiane’ e ‘Fuji Suprema’ visando acompanhar os efeitos ecofisiológicos e da sua eficiência na indução da senescência das folhas, brotação, teores de nutrientes nos tecidos, relação C/N e produtividade. Os experimentos foram conduzidos, durante o outono, em pomar comercial de macieira em Fraiburgo, SC, e pomar experimental em Caçador, SC, nos anos de 2013 e 2014. Em plantas jovens de macieira o ABA foi efetivo em promover a senescência das folhas. A aplicação exógena de ABA mostrou-se eficaz na senescência das folhas de plantas adultas das cultivares Daiane e Fuji Suprema. Percebeu-se maior sensibilidade ao tratamento com ABA, independentemente da concentração adotada, na cv. Daiane. A concentração de N nas folhas diminui oito dias após o tratamento com ABA em relação às plantas controle. O ABA antecipa o início das brotações e a plena floração

Made available in DSpace on 2016-12-06T17:42:05Z (GMT). No. of bitstreams: 1 PGPV14DA006.pdf: 2258194 bytes, checksum: 11c3c8a7148c0f9fa9b1f7bd89ddfa6f (MD5) Previous issue date: 2014-04-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Defoliation processo d apples trees in the Brazilian conditions occurs naturally throughout autumm. The period is critical to controlo f leaf disease in postharvest. This disease cause premature defoliation and other diseases can to start their infection through injuries of fall leaf. Apart from the physical, the phenomenon on falling leaves involves anatomical and biochemical changes in the base the petiole, called the abscission zone. The objective of this research was to evaluate the effects of defoliation with 1 g L¯¹ ethephon, AVG 0,06 g L¯¹, calcium chloride 23 g L¯¹ and abscisic acid (ABA) 1,5 g L¯¹ in mature apple trees Fuji Standart and Fuji Raku Raku . A method to observe the formation of na abscission layer, and characterize the process was definwed. To follow ecophysiological effects of ethephon and ABA, the activity of peroxidase enzyme and total protein, temporal falling leaves and functionality characterization based on the presence of chlorophyll and nitrogen translocation were determined. The experiments of defoliation were consucted during autumm in comercial apple orchards in Vacaria, RS, in 2011 and 2012 and in Region of Maule, San Clemente, in Chile in 2013. Defoliants as ethephon, AVG, calcium chloride and ABA caused the diferente defoliation progresso n Fuji Standart . The spraying of defoliants in mid-april caused no effect on the buds differentiation and phenology of apple trees. In the situation of drought during summer and fall in the second year, defoliation with ethephon in Vacaria was equal to treatment with ABA in Chile. However, ethephon and calcium chloride as defoliant may affect fruit set and yield of Fuji Standart apple trees. The most effective defloiants were ethephon and ABA. Early spraying of ABA and ethephon on Fuji Raku Raku accelerated senescence process by promoting early defoliation compared to the control. Peroxidase enzyme was found in leaf abscission processo f Fuji Raku Raku . The peak of peroxidase enzyme ocurred in less than 24 hours after ABA spray, whereas to ethephon treatment peak was about 24 hours. Chlorophyll contente, obtained by a chlorophyll meter (SPAD 502) served to assess the functionality of the apple leaves on postharvest. SPAD index below 40 indicate senescente leaves, in the processo f formation of abscission layer. Ethephon and ABA, evenanticipating defoliation, allowed translocation of nitrogen and delas on phenological stages was not observed on apple trees. The processo f leaf abscission zone in apple trtees was observed and characterized by method in this research. The abscission zone occurs in proximal parto f petiole, with flattened and lignificated cells. The formation of the abscission layer occrus toward adaxial to abaxial surface, epidermis toward vascular tissues / O processo de desfolha de macieiras nas condições brasileiras ocorre naturalmente durante todo outono. O período é crítico para o manejo fitossanitário de pós-colheita para o controle de manchas foliares que causam desfolha precoce e de outras doenças que iniciam sua infecção através da lesão da queda da folha. Além de físico, o fenômeno de queda das folhas envolve transformações anatômicas e bioquímicas na base do pecíolo, chamada zona de abscisão. O objetivo desta pesquisa foi avaliar os efeitos da desfolha com etefon 1g L-1, AVG 0,06 g L-1, cloreto de cálcio 23 g L-1 e ácido abscísico (ABA) 1,5 g L-1, em macieiras Fuji Standard e Fuji Raku Raku em idade produtiva. Juntamente foi definido um método para observar a formação da camada de abscisão, e caracterizar este processo. Para acompanhar os efeitos ecofisiológicos do etefon e ABA, foi determinada a atividade das proteínas totais e enzima peroxidase, a queda temporal das folha, e a caracterização da sua funcionalidade com base na presença de clorofila e translocação de nitrogênio. Os experimentos de estudo da desfolha foram conduzidos, durante o outono, em pomares comerciais de macieira em Vacaria, RS, nos anos 2011 e 2012 e no Chile, na região de Maule, em San Clemente, em 2013. Como desfolhantes o etefon, o AVG e o cloreto de cálcio e o ABA causaram diferente progresso da desfolha em Fuji Standard . A pulverização de desfolhante em meados de abril, não causou efeito na diferenciação das gemas e na fenologia das plantas. Na situação de estiagem durante o verão e o outono no segundo ano, a desfolha com etefon em Vacaria foi igual ao tratamento com ABA no Chile. Porém, os defolhantes etefon e cloreto de cálcio podem afetar o pegamento das frutas e a produtividade da macieira cv, Fuji Standard. Os desfolhantes mais eficazes foram etefon e ABA. Quando se avaliou o efeito do ABA e etefon em Fuji Raku Raku , a senescência das folhas foi acelerada, promovendo a desfolha antecipada em comparacão com a testemunha. A enzima peroxidase foi constatada no processo de abscisão foliar de Fuji Raku Raku e teve seu pico de atividade em menos de 24 horas depois da aplicacão no tratamento de ABA, enquanto que etefon foi cerca de 24 horas. Os valores do teor de clorofila, obtidos por um medidor de clorofila (SPAD 502), serviram para estimar a funcionalidade das folhas de macieira após a colheita das frutas. Índices SPAD abaixo de 40 indicam folhas senescentes, em processo de formação da camada de abscisão. Etefon e ABA mesmo antecipando a desfolha, permitiram a translocação de nitrogênio e não causaram atrasos nos estágios fenológicos da macieira. O método utilizado para o estudo da abscisão permitiu observar e caracterizar a zona de abscisão foliar em macieiras durante todo o processo. Observou-se que a zona de abscisão ocorre na parte proximal do pecíolo, apresentando células achatadas e em processo de lignificação. A formação da camada de abscisão dá-se no sentido da face adaxial para a face abaxial, da epiderme em direção aos tecidos vasculares

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2018-11-20T12:51:53Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) TESE Roseli Farias pos banca.pdf: 1268393 bytes, checksum: 91cf602a1af2ff5a4994e991f0bf96f2 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-11-23T18:44:00Z (GMT) No. of bitstreams: 2 TESE Roseli Farias pos banca.pdf: 1268393 bytes, checksum: 91cf602a1af2ff5a4994e991f0bf96f2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-11-23T18:44:00Z (GMT). No. of bitstreams: 2 TESE Roseli Farias pos banca.pdf: 1268393 bytes, checksum: 91cf602a1af2ff5a4994e991f0bf96f2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-09-24 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / O raleio visa reduzir a carga de frutos da planta para equilibrar a produção e a qualidade. O raleio em pessegueiros normalmente é realizado de forma manual, exigindo mão de obra qualificada. O uso de produtos que atuem como raleante químico tem sido apontado como uma alternativa à prática manual em frutíferas. Neste sentido, objetivou-se com o presente trabalho avaliar o efeito de diferentes raleantes químicos aplicados em distintas épocas e concentrações em frutos de pessegueiros na região Sul do Brasil. O artigo 1, intitulado “Épocas de aplicação do metamitron no raleio químico de pessegueiros” analisou o efeito do metamitron aplicado em cinco épocas e o raleio manual na cultivar Sensação, nas safras 2015 e 2016, no município de Morro Redondo, RS. Observou-se que a aplicação do metamitron aos 40 dias após a plena floração teve a porcentagem de abscisão dos frutos, a frutificação efetiva e o número de frutos semelhantes ao do raleio manual. O artigo 2, “Raleio químico em pessegueiro ‘Maciel’ e ‘Sensação’” avaliou o efeito do metamitron, da benziladenina e do ethephon aplicados de forma isolada ou combinada no raleio de frutos, na safra de 2016, no município de Morro Redondo, RS. Verificou-se que a produção e o número de frutos por planta foram reduzidos excessivamente, enquanto a alocação dos frutos em categorias de maior calibre aumentou, quando utilizado o produto ethephon isolado ou em combinação com o metamitron nas cultivares Maciel e Sensação. O metamitron e a benziladenina aplicados isolados ou em combinação promoveram a abscisão dos frutos e resultaram em massa e diâmetro médio dos frutos semelhantes ao raleio manual nas cultivares Maciel e Sensação. O artigo 3, “Metamitron no raleio químico de pessegueiros” teve a proposta de avaliar o efeito do metamitron aplicado em cinco épocas e cinco concentrações na cultivar Maciel, nas safras 2015 e 2016, no município de Morro Redondo, RS. Constatou-se que o raleio químico realizado mais próximo da floração e na concentração de 100 mg L-1 resultou em maior abscisão de frutos em relação ao raleio manual. O artigo 4, “Raleio químico com metamitron em pessegueiros ‘BRS Kampai’” avaliou o efeito raleante do metamitron em cinco concentrações sobre a produção e a qualidade dos frutos, nas safras 2016 e 2017, no município de Eldorado do Sul, RS. Verificou-se que a concentração de 100 mg L-1 de metamitron teve efeito similar ao raleio manual em relação à abscisão de frutos. O raleio químico, especialmente com metamitron, demonstrou ser uma prática alternativa e/ou combinatória ao raleio manual em pessegueiros. / O raleio visa reduzir a carga de frutos da planta para equilibrar a produção e a qualidade. O raleio em pessegueiros normalmente é realizado de forma manual, exigindo mão de obra qualificada. O uso de produtos que atuem como raleante químico tem sido apontado como uma alternativa à prática manual em frutíferas. Neste sentido, objetivou-se com o presente trabalho avaliar o efeito de diferentes raleantes químicos aplicados em distintas épocas e concentrações em frutos de pessegueiros na região Sul do Brasil. O artigo 1, intitulado “Épocas de aplicação do metamitron no raleio químico de pessegueiros” analisou o efeito do metamitron aplicado em cinco épocas e o raleio manual na cultivar Sensação, nas safras 2015 e 2016, no município de Morro Redondo, RS. Observou-se que a aplicação do metamitron aos 40 dias após a plena floração teve a porcentagem de abscisão dos frutos, a frutificação efetiva e o número de frutos semelhantes ao do raleio manual. O artigo 2, “Raleio químico em pessegueiro ‘Maciel’ e ‘Sensação’” avaliou o efeito do metamitron, da benziladenina e do ethephon aplicados de forma isolada ou combinada no raleio de frutos, na safra de 2016, no município de Morro Redondo, RS. Verificou-se que a produção e o número de frutos por planta foram reduzidos excessivamente, enquanto a alocação dos frutos em categorias de maior calibre aumentou, quando utilizado o produto ethephon isolado ou em combinação com o metamitron nas cultivares Maciel e Sensação. O metamitron e a benziladenina aplicados isolados ou em combinação promoveram a abscisão dos frutos e resultaram em massa e diâmetro médio dos frutos semelhantes ao raleio manual nas cultivares Maciel e Sensação. O artigo 3, “Metamitron no raleio químico de pessegueiros” teve a proposta de avaliar o efeito do metamitron aplicado em cinco épocas e cinco concentrações na cultivar Maciel, nas safras 2015 e 2016, no município de Morro Redondo, RS. Constatou-se que o raleio químico realizado mais próximo da floração e na concentração de 100 mg L-1 resultou em maior abscisão de frutos em relação ao raleio manual. O artigo 4, “Raleio químico com metamitron em pessegueiros ‘BRS Kampai’” avaliou o efeito raleante do metamitron em cinco concentrações sobre a produção e a qualidade dos frutos, nas safras 2016 e 2017, no município de Eldorado do Sul, RS. Verificou-se que a concentração de 100 mg L-1 de metamitron teve efeito similar ao raleio manual em relação à abscisão de frutos. O raleio químico, especialmente com metamitron, demonstrou ser uma prática alternativa e/ou combinatória ao raleio manual em pessegueiros.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24238号 / 農博第2517号 / 新制||農||1094(附属図書館) / 学位論文||R4||N5409(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 土井 元章, 教授 田尾 龍太郎, 准教授 中野 龍平 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

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Le sapin baumier (Abies balsamea L.), espèce favorite des producteurs d'arbres et de couronnes de Noël dans les provinces de l'Atlantique, est victime de chutes d'aiguilles sévères (abscission prématurée) après la récolte. Une série d'expériences ont été réalisées pour : (i) déterminer le rôle des racines, (ii) identifier la température et le temps d'exposition optimums permettant d'augmenter la durée de rétention des aiguilles (DRA) en post-récolte; (iii) déterminer et caractériser les changements de concentration en phytohormones en réponse à un traitement de basse température (BT); (iv) élucider l'effet interactif des facteurs génotypiques et environnementaux sur la DRA post-récolte; et (v) investiguer les dynamiques temporelles de l'accumulation de l'acide abscissique (ABA) induite par les basses températures et évaluer l'effet de l'ABA sur la DRA. Les semis de sapin baumier soumis à 5°C durant au moins 6 h ont présenté une DRA supérieure de 11 jours et la présence de racines a eu un effet synergique retardant l'abscission des aiguilles. Lorsque soumis à 5°C durant 48 h, la concentration foliaire en ABA des semis a augmenté de 2,5 fois (2007 ng g⁻¹ DW) et l'acide gibbérellique GA₄₄ a diminué de 3,5 fois (9,85 ng g⁻¹ DW). Le traitement BT n'a eu aucun effet sur les phytohormones dans les racines. Parmi les deux génotypes (AB-NSD-184 et AB-NSD-004) étudiés dans le verger Debert en Nouvelle-Ecosse, une corrélation négative fut observée entre la DRA post-récolte des branches échantillonnées et les facteurs climatiques choisis (moyenne des heures de photopériode quotidienne (PP) et moyenne des températures maximales quotidiennes) (R²=0,75; P=0,001) ainsi qu'avec les concentrations foliaires en ABA (R²=0,38; P=0,001) chez le génotype ABNSD- 184 seulement. Une DRA maximale de 180 jours et minimale de 41 jours furent observées respectivement en octobre et juin. Les conditions environnementales ont fortement modulé les effets du traitement BT sur la RDA post-récolte. La déshydratation a accéléré l'abscission des aiguilles, et le traitement BT appliqué sous conditions lumineuses a compensé pour les effets de la déshydratation et a augmenté la RDA de 30 jours. De tels avantages n'ont pas été observés lorsque le traitement fut appliqué dans l'obscurité. Les bénéfices physiologiques découlant du traitement BT ne furent présents que sous un faible déficit de pression de vapeur (DPV; < 0,87 kPa). Sous DPV élevé (> 1,30 kPa), BT a diminué la RDA de 35% (45 jours), réduit de moitié la teneur en eau relative des aiguilles, et augmenté de 4 fois le potentiel hydrique du xylème. Les changements temporels de la concentration foliaire en ABA ont différé entre les génotypes et I l l l'ABA a augmenté avec le temps après récolte. L'apport d'ABA via le xylème à des concentrations > 95 uM a provoqué l'abscission des aiguilles. Cependant, une concentration entre 2,5 et 7,5 uM d'ABA acheminée via le xylème durant 15 jours a prolongé la DRA de 20 jours. Ni les concentrations élevées d'ABA (12,5 uM), ni l'inhibition de la synthèse de l'ABA n'ont augmenté la DRA. Les bénéfices du traitement BT sur la durée de rétention des aiguilles implique des changements de l'ABA foliaire et cette réponse a varié en fonction des génotypes et des conditions environnementales.

Fruit abscission is a natural occurrence in cotton. Fruiting retention is very important since yields are highly correlated with number of bolls produced. There are many factors contributing to the abscission of squares by cotton, including environmental conditions, heavy boll load, diseases, and insect feeding. An experiment was designed to evaluate the compensation capacity of cotton at various levels of square removal using two cotton cultivars at two planting dates over two Virginia locations; the effect of mechanical square removal on cotton yield components and quality; and to evaluate the use and effectiveness of COTMAN in tracking major phenological stages PHS, FF, and Cutout of cotton at various rates of square removal. In 1998, DPL 51 was planted on May first at the Tidewater Agricultural Research and Extension Center in Suffolk, Virginia. This was an ideal location, planting date, and variety, so in 1999, the experiment was expanded to ascertain whether cotton would have the same compensation capacity in less ideal conditions. In 1999, two varieties were planted, DPL 51 (early maturing) and DPL 5111 (late maturing), on two planting dates (two weeks apart), and in a location outside the traditional cotton growing region, the Southern Piedmont AREC in Blackstone, Virginia. Five levels of manual desquaring treatments (0%, 12-15%, 20-25%, and 30-40% of first position squares, and 20% of small bolls [Suffolk, 1999 only]) were used in both years. The physiological progress of the crop was monitored using the COTMAN cotton monitoring system and compared to the Target Development Curve (TDC). Over both years, there were no significant differences in boll numbers or yield among any of the square removal treatments. Comparison of fruiting curves with the TDC showed that in both 1998 and 1999, the influence of square removal in excess of 30-40% resulted in a lower apogee and premature cut-out. Also, though not statistically significant, yield was greatly reduced at the 30-40% square removal rate, often by as much as 448 kg/ha. In many cases, a lower level of square removal (varying between the 12-15% and the 20-25% rates) seemed to stimulate the growth and development of the crop. It may also contribute to a higher level of square retention. The results of this study suggest that cotton plants will compensate for up to 30% of first position square loss, with no reduction in yields. / Master of Science