Aquaporins (AQP) are membrane bound proteins that facilitate the movement of water and other small neutral solutes across cellular membranes. Plant aquaporins belong to a large family of highly conserved proteins called the Membrane Intrinsic Protein (MIP) superfamily. In many plant species the expression of aquaporin genes and their regulation has been linked to water stress. Grapevines respond to water stress with a variety of physiological mechanisms, including the susceptibility to xylem embolism. The formation of embolised vessels can lead to a reduction in hydraulic conductivity of the xylem. Recently, it has been hypothesised that aquaporins may contribute to the water movement required for embolism recovery of xylem vessels thus restoring the hydraulic pathway. Molecular and physiological techniques have been combined to study the putative role of plasma membrane and tonoplast membrane aquaporins in response to water stress induced xylem embolism in two cultivars of grapevine (Vitis vinifera cv. Chardonnay and Grenache). Water-stress induced cavitation was measured in the stems and petioles of pot grown grapevines of a drought tolerant (Grenache) and a drought sensitive variety (Chardonnay) by the detection of ultrasonic acoustic emissions (UAEs) over both a drying and diurnal cycle. Vulnerability curves were generated by correlating the UAEs with the leaf water potential (ψL). Varietal differences in cavitation vulnerability and hydraulic properties were observed. Grenache was more susceptible to water-stress induced xylem embolism than Chardonnay, and displayed a higher hydraulic capacity (measured by maximum hydraulic conductivity). This is most likely due to anatomical differences of the xylem vessels. Chardonnay displayed vulnerability segmentation, with cavitation occurring first in the petiole and later in the stem, before developing into “runaway” cavitation under severe water stress. Vulnerability segmentation was not observed in Grenache, with both petioles and stems equally vulnerable to the formation of xylem embolism. Under severe water stress, Grenache did not develop runaway cavitation indicating that they must have some mechanism to prevent the onset of runaway cavitation. To determine the role of aquaporins, candidate genes were identified, by screening a Vitis vinifera cv. Cabernet Sauvignon cDNA library, for aquaporin cDNAs encoding members of the Plasma membrane Intrinsic Protein (PIP) and Tonoplast Intrinsic Protein (TIP) subfamilies. The screen resulted in the identification of 11 full-length and two partial aquaporin cDNAs. Sequence analyses of these cDNAs reveal five are homologous to PIP2 aquaporins, six to PIP1 and two to the TIP aquaporins. Functional expression of the fulllength AQP cDNAs in Xenopus oocytes showed PIP2 members have significantly higher water permeability compared to PIP1 aquaporins. VvPIP2;1 showed very high water permeability which was reduced by acidic cytosolic pH, as has been reported for other members of the PIP2 family. Transcript analysis of some of these aquaporin genes provides preliminary evidence that aquaporins may contribute to differences in the hydraulic response of these two grapevine varieties to conditions of water stress. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1313316 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2008

Made available in DSpace on 2014-06-11T19:23:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-06-09Bitstream added on 2014-06-13T19:49:54Z : No. of bitstreams: 1 veiga_eb_me_botib.pdf: 401901 bytes, checksum: c2273887ae81585d294979b1077f218d (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Aqui analisamos as diferenças entre plantas irrigadas e não irrigadas de três espécies congenéricas de Styrax que apresentam distribuições geográficas distintas no cerrado, Brasil. Styrax ferrugineus mostrou condutância estomática (gs) não-responsiva à deficiência hídrica do solo aplicada em plantas envasadas. Isso pode explicar as maiores eficiências de trocas gasosas e fotoquímicas encontradas em S. ferrugineus, uma espécie bem adaptada ao cerrado sensu stricto (s. str.) que é um tipo de vegetação savânica. S. camporum, que é amplamente distribuída nas áreas de cerrado sensu lato (s.l.), foi a única espécie que aumentou as eficiências de uso da água nos dias de maior deficiência hídrica. Tal resultado distingue S. camporum de S. pohlii, uma espécie de mata, uma vez que ambas as espécies diminuíram gs durante os dias de maior estresse hídrico. Em contraste a outros estudos, nós propomos que características medidas instantaneamente podem detectar performances não-plásticas aos estresses ambientais, o que auxilia explicar as distintas distribuições geográficas de espécies congenéricas no cerrado / Here we analyzed the differences between irrigated and non-irrigated plants of three congeneric Styrax species that present distinct geographical distribution in the cerrado, Brazil. Styrax ferrugineus showed an unresponsive stomatal conductance (gs) to the soil water deficit applied to potted plants. This may explain the great gas exchange and photochemical efficiencies found in Styrax ferrugineus, which is well adapted to the cerrado sensu stricto (s. str.), a savanna-type vegetation. S. camporum, which is widely distributed in the cerrado sensu lato (s. l.) areas, was the only species that presented increased water use efficiencies on the days of maximum water deficit. Such result distinguishes S. camporum from S. pohlii, which is a forest species, since both species decreased their gs during the days of maximum water stress. In contrast to other studies, we propose that instantaneously measured traits may detect non-plastic performances to environmental stresses, which helps to explain distinct geographical distributions of congeneric species in the cerrado

Resumo: A realização do trabalho objetivou desenvolver uma técnica comercial de aplicação do ácido giberélico via pulverização foliar para o controle da floração de orquídeas Phalaenopsis, Cattleya e Brassocattleya, além da redução do tempo para a primeira florada em Phalaenopsis, fatores limitantes no cultivo. Os experimentos foram realizados no Setor de Biotecnologia e Orquidicultura da Fundação Shunji Nishimura de Tecnologia, Pompéia-SP. Foram conduzidos três experimentos. Como híbridos foram utilizados Cattleya Ireni Holguim, Brassocattleya Marcela Koss, Phalaenopsis FSNT "Snow F1" e Phalaenopsis FSNT "Dai-Itigô". Para C. Ireni Holguim e Bc. Marcela Koss testaram-se 4 concentrações de GA3 (125, 250, 500 e 1.000 mg L-1) em 4 aplicações com intervalos de 7 dias via pulverização foliar, nos meses de Outubro/Novembro para Bc. Marcela Koss e Janeiro/Fevereiro para C. Ireni Holguim, em plantas adultas, além de 2 condições hídricas (sem e com estresse hídrico). Não foi possível induzir a floração em Cattleya Ireni Holguim com o uso de GA3. Para Bc. Marcela Koss, a associação da aplicação de 250 mg L-1 de GA3 e a colocação das plantas em condições de estresse hídrico induziu cerca de 83% das plantas a florescerem fora da época normal de florescimento. Na mesma concentração de GA3, porém em condições normais de irrigação, apenas 17% das plantas foram induzidas a florescer. O número e o tamanho das flores aumentaram com o aumento das concentrações de GA3 utilizadas no experimento. Também se testou a utilização do ácido giberélico (GA3) na indução floral fora de época e qualidade do florescimento de orquídeas adultas de Phalaenopsis FSNT "Snow F1", híbrido de coloração branca. Foram realizadas duas e 4 aplicações de GA3, a intervalos de 7 dias nos meses de Novembro/Dezembro. O melhor resultado ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this works was to develop a commercial technique to control blooming in orchids, via the use of foliar sprays with gibberellic acid in Phalaenopsis, Cattleya, and Brassocattleya orchids, in addition to reducing the time required for the first blooming in Phalaenopsis, which are factors that restrict growth. It was conducted three works. The influence of gibberellic acid and water stress on the induction and quality of flowering was tested in two hybrid genera of orchids, Cattleya and Brassocattleya. The experiment was conducted at the Biotechnology and Orchidculture Sector of the Shunji Nishimura Technology Foundation, in Pompéia, SP. As hybrids was use Cattleya Ireni Holguim, Brassocattleya Marcela Koss, Phalaenopsis FSNT "Snow F1" and Phalaenopsis FSNT "Dai-Itigô". In C. Ireni Holguim and Bc. Marcela Koss, four GA3 concentrations (125, 250, 500, and 1,000 mg L-1) were tested in four applications at 7 day- intervals by foliar sprays on adult plants, in addition to two humidity conditions (with or without water stress). Applications were made in October/November in Bc. Marcela Koss and January/February in C. Ireni Holguim. It was not possible to induce flowering in Cattleya Ireni Holguim with gibberellic acid. In Brassocattleya Marcela Koss, the association between 250 mg L-1 GA3 and plants grown under water stress conditions induced blooming in 83% of plants treated under adverse conditions. At the same GA3 concentration, but without water stress, only 17% of the treated plants bloomed. The number and size of flowers increased as GA3 concentration increased. Another objective of this work was to test the use of GA3 to induce off-season flowering and improve blooming quality in adult Phalaenopsis FSNT "Snow F1". Four GA3 concentrations (125, 250, 500, and 1,000 mg L-1) in 2 and 4 applications (at 7-day intervals) were tested. Spray applications were ...(Complete abstract click electronic access below) / Orientador: João Domingos Rodrigues / Coorientador: Elizabeth Orika Ono / Banca: Armando Tavares / Banca: Carmen S. F. Boaro / Mestre

The Intergovernmental Panel on Climate Change has predicted that there will be increases in precipitation and heat-induced drought events globally. Information on kale response to waterlogging is minimal. The purpose of this project was to identify the response of kale to three treatments of water stress: underwatering, overwatering, and waterlogging. Plant pigments analyzed displayed a varied response to underwatering and overwatering, with concentrations changing with maturity but with reductions and no changes, respectively, at full harvest maturity. Glucosinolate concentrations were also influenced by maturity and increased under waterlogging and underwatering but no differences with overwatering. Overall, water stress to any degree is not ideal for kale during production, but despite yield reductions, underwatering led to increases among phytonutrients, but increases are apparent and do not equate to increased absorption when consumed.

Flower forcing to meet holiday market can increase the value of potted flowering plants. This study was to investigate the effects of chilling and post-chilling photoperiod treatments on flowering of banana shrub and the effects of water stress, daminozide, chlormequat, and ethephon on flowering of bougainvillea. Experiments were conducted at R.R. Foil Plant Science Research Center and MSU Dorman Greenhouse at Mississippi State University (MSU), Mississippi State, MS. Results from banana shrub experiment indicated that 8-week chilling at 8 ºC was necessary for banana shrub to break bud dormancy and a tank mix of daminozide and chlormequat was able to increase the number of flower buds on banana shrub. Results from bougainvillea experiment indicated that water stress, daminozide, and chlormequat enhanced flowering. In conclusion, this study provided fundamental information to future research on flower forcing of banana shrub and bougainvillea.

Synthesis of water stress proteins (Wsp) is induced upon repeated desiccation and rehydration of immobilized cells of the desiccation-tolerant cyanobacterium <i>Nostoc commune</i> UTEX 584 (<i>Nostoc</i> 584). The Wsp polypeptides synthesized and secreted by field material of N. <i>commune</i> have been extensively characterized and shown to exist as three isoforms with molecular masses of 33, 37 and 39 kDa. In order to understand the role of Wsp in the mechanism of tolerance to water stress an attempt was made to isolate the gene(s) that encodes Wsp in <i>Nostoc</i> 584. A polyclonal antibody raised against a mixture of the isoforms was used to screen expression libraries (phage and plasmid) of <i>Nostoc</i> 584 genomic DNA fragments. This work presents the analysis of clones, isolated from the expression libraries, which cross react with Wsp antiserum. Sequencing of the DNA from one of the cross reacting clones revealed an incomplete open reading frame (ORFA) that showed strong similarity to two fructose bisphosphate aldolases, CfxA and CfxB, from the photosynthetic purple non-sulfur bacterium, <i>Rhodobacter sphaeroides</i>. A promoter region present upstream of ORFA is recognized by RNA polymerase from <i>E. coli</i>. Further upstream of the promoter lies <i>trn</i>K encoding lysyl-tRNA, identified by evident similarity to the corresponding gene from the chloroplast of the liverwort, <i>Marchantia polymorpha</i>. The remainder of the aldolase gene (<i>fba</i>) was isolated using the colony hybridization technique. Sequence analysis of DNA from the second cross reactive clone revealed six ORFs (ORFs 1 through 6).The products of ORFI and ORF2 are overproduced in this clone. The polypeptide encoded by ORFI shows very strong cross-reactivity with the polyclonal Wsp antibody, whereas ORF2 does not. Database searches using the deduced amino acid sequences of the six ORFs have provided clues to the possible identities of these ORFs. ORF6 shows correspondence with a protein, in Arabidopsis thaliana, which is induced in response to cold, abscissic acid and water stress. The common feature shared by ORFs 1 to 5 is that the highest similarities are observed with enzymes involved in carbohydrate metabolism. ORFs 1 through 5 may possibly represent a novel cluster of genes that form all or part of an operon involved in the metabolism of carbohydrates in Nostoc 584. Fructose bisphosphate aldolase (EC 4.1.2.13) is a key enzyme in carbohydrate metabolism, playing a role in glycolysis as well in the Calvin cycle of carbon dioxide fixation. The potential roles played by aldolase and the products of ORFs 1 through 5 in overall carbon metabolism of <i>Nostoc commune</i> UTEX 584 are discussed. / Ph. D.

No description available.

Interactions between host plants and aphids under water stress conditions were examined. Two controlled environment room studies, a Veld experiment and phenological modelling analysis were used to investigate three different plant-aphid relationships. The aim of these studies was to determine the results of water shortage on plant and pest populations, which are likely to result under climate change scenarios. The central hypothesis was that mild drought stress would lead to greater aphid populations through a beneficial increase of small nitrogenous molecules in the phloem sap providing improved diet quality — the Plant Stress Hypothesis (White, 1969). Myzus persicae (the peach–potato aphid) is a broad-range feeder with a preference for senescent foliage. Contrary to expectations, on young cabbage plants, Brassica oleracea var capitata, it was found to increase faster and to a greater extent on well-watered hosts. Aphids were also found to prevent osmoregulation in droughted plants. Despite this, the aphid infestation led to a drought-like response in all plants irrespective of watering regime, causing significantly reduced growth. Metopolophium dirhodum (the rose–grain aphid) overwinters as eggs on Rosa spp. but most of its life-cycle is spent on grasses and cereal crops. As with M. persicae, aphid infestation caused drought-like symptoms even in well-watered plants. The mechanism of reduction in plant health is most likely through aphid damage to the efficiency of Photosystem a within 7 days of infestation. On young barley plants, Hordeum vulgare, the rose–grain aphid was found to increase faster and to greater extent on droughted hosts. In contrast to M. persicae, the study strongly supported the Plant Stress Hypothesis, Finding that even mild water stress of approximately −0.3 MPa could lead to conditions favourable to rapid aphid population increase. The difference in the response of different species of aphids may be associated more with the levels of soluble nitrogen in their diet than specifically host plant water status. Drepanosiphum platanoidis is an aphid specific to sycamore, Acer pseudoplatanus and spends its entire life-cycle on that species. In the Veld, the total number of aphids supported by a single tree was found to correlate most strongly with soluble leaf nitrogen. In addition, the number of aphids on individual leaves was found to correlate strongly and negatively with stomatal conductance and leaf water potential. Finally, analysis of historical aphid suction-trap data was carried out. UK Rothamsted suction-traps are 12.2 m tall and sample air at 0.75 m3 s-1, with daily aphid sampling between April and November. The traps are designed to catch the largest proportion of aphids in the total insect sample and to reduce the effect of surrounding land-use on the sample. The area represented by a trap may be as much as 700 km2 (Harrington and Woiwod, 2007). The dataset is the longest and most geographically extensive for aphid populations, comprising 46 sites across Europe as of 2011. In this analysis, aphid and meteorological data from the Edinburgh East Craigs site were used. This also enabled comparison with D. platanoidis numbers collected in the Veld, which showed a strongly significant positive relationship between the two. Since the data collected in suction-traps are correlated with numbers in the Veld, aphid population analysis can be improved with use of these longer datasets, without reliance on shorter-term Veld surveys. The various population characteristics examined were found to be strongly correlated with each other, but were unconnected to data from previous years. The date of first catch was found to be significantly advancing over time, with strong influences from daily minimum temperatures and vapour pressure deficits of the air within the year. Higher temperatures with lower humidity tend to bring forward the date of first catch. Lower tends to depress the population in the summer. The overall hypothesis that mild drought would benefit aphid populations cannot be accepted, but in two cases of the experiment sections of the work there were strong relationships between aphid numbers and both leaf temperature and soil moisture. The meteorological data analysis indicates that climatic changes towards a hotter, drier climate could substantially alter population dynamics. Harrington, R. and Woiwod, I. (2007). Foresight from hindsight: The Rothamsted Insect Survey. Outlooks on Pest Management, 18, 9–14. White, T. (1969). An index to measure weather-induced stress of trees associated with outbreaks of psyllids in Australia. Ecology, 50, 905–909.

Orientador: Rinaldo César de Paula / Banca: Miguel Luiz Menezes Freitas / Banca: Susi Meire Maximino Leite / Banca: Sérgio Valiengo Valieri / Banca: Pedro Luís da Costa Aguiar Alves / Resumo: O presente trabalho teve por objetivo avaliar o desempenho e a divergência genética entre 18 clones de Eucalyptus spp. submetidos a quatro regimes de irrigação (RI1 irrigação diária; RI2 irrigação a cada dois dias; RI3 irrigação a cada quatro dias; RI4 irrigação a cada seis dias). O experimento foi implantado em casa de vegetação no delineamento em blocos casualizados, no esquema fatorial 18 x 4 (18 clones e quatro regimes de irrigação), com quatro repetições, e conduzido por 73 dias. Foram avaliadas características de crescimento como: incremento relativo em altura (IR-ALT), em diâmetro do coleto (IR-DC), em número de folhas (IR-NF), em área foliar (IR-AF), em matéria seca de folha (IR-MSF), em matéria seca de caule (IR-MSC) e em matéria seca de raíz (IR-MSR); relação raiz-parte aérea (RPA) e fisiológicas: taxa líquida de fotossíntese (A), condutância estomática (gs), transpiração (E), teor relativo de clorofila total, eficiência quântica do fotossistema II (Fv/Fm) e potencial hídrico foliar (yf). As avaliações fisiológicas foram realizadas um dia antes (AI) e um dia após a irrigação (DI) de cada tratamento, em intervalos regulares de 11 e 13 dias, respectivamente, ocasião em que coincidia a irrigação (12 dias) em todos os regimes hídricos. Quanto ao estudo da divergência genética, foi usada como medida de dissimilaridade a distância generalizada de Mahalanobis (D2), aplicando-se em seguida o método hierárquico de agrupamento de Ligação Média Entre Grupos (UPGMA) e também o algoritmo de otimização de Tocher. Adicionalmente, foi feito o estudo da importância relativa dos caracteres para a divergência usando a técnica de Componentes Principais. Observou-se que todas as características avaliadas apresentaram diferenças significativas tanto entre os clones quanto entre os regimes hídricos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objectives of this work was to evaluate the growth and physiological traits and genetic divergence among 18 Eucalyptus spp. clones submitted to four irrigation regimes (RI1 - daily; RI2 - every two days; RI3 - every four days; RI4 - every six days). The experiment was carried out in a greenhouse, in a randomized block design, and a factorial scheme 18 x 4 (18 clones and four irrigation regimes) with four replications during 73 days. It was evaluated the growth traits: relative increment at height (RI-H), collar diameter (RI-CD), number of leaves (RI-NL), leaf area (RI-LA), dry mater of the leaves (RI-DML), stem (RI-DMS) and roots (RI-DMR), the root-shoot ratio (RSR); and physiological traits: net photosynthesis (A), stomatal conductance (gs), transpiration (E), relative chlorophyll content of total (U.R.), quantum efficiency of Photosystem II (Fv/Fm) and leaf water potential (yf). The physiological evaluations were performed one day before (BI) and one day after the irrigation (AI) in each treatment, in regulate intervals of 11 and 13 days, respectively, when the irrigation (12 days) coincided with every irrigation regimes. The genetic divergence it was used as dissimilarity measure the generalized Mahalanobis distance, using the hierarchical method of grouping of Unweighted Arithmetics Average (UPGMA) and Tocher’s optimization method. In addition, it was done the study of relative importance of traits to the divergence using the Principal Components technique. It was observed that all traits evaluated presented significant difference among genotypes and water regimes. The estimates of genotypic determination coefficient presented values over 0.85 for growth traits and between 0.28 and 0.87 for physiological ones. The clones generally presented reduction in their traits as the frequency of irrigation was decreased, although in variable proportions among them... (Complete abstract, click electronic access below) / Doutor

Made available in DSpace on 2014-06-11T19:31:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-18Bitstream added on 2014-06-13T19:40:42Z : No. of bitstreams: 1 zucareli_v_dr_botib.pdf: 5350798 bytes, checksum: fd5318b9aeeb46f6db5812e7089c5b26 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Aspectos anatômicos, fisiológicos e bioquímicos da enxertia de maracujazeiros sobre Passiflora cincinnata Mast. 2011. 104f. Tese (Doutorado) – Instituto de Biociências, UNESP - Universidade Estadual Paulista, Botucatu-SP. A espécie Passiflora cincinnata Mast. é considerada potencialmente importante para uso como porta enxerto, uma vez que é tolerante a doenças, nematóides e seca. O presente trabalho teve como objetivos estudar aspectos da anatomia da enxertia de espécies comerciais sobre o porta enxerto Passiflora cincinnata, a influência da enxertia no crescimento inicial de maracujazeiros comerciais e, também, nas respostas ao estresse hídrico. O trabalho constou de três experimentos, no primeiro foi estudado o efeito da exertia sobre o desenvolvimento das plantas de maracujazeiros comerciais (P. edulis f. flavicarpa, P. edulis f. edulis e Passiflora alata). No segundo foram estudados aspectos relacionados à anatomia do caule na região da enxertia durante o processo de pegamento e lignificação em duas espécies de maracujazeiros comerciais (P. edulis f. flavicarpa e P. alata). No terceiro experimento foi estudado o efeito da enxertia nas respostas ao estresse hídrico durante a fase inicial de desenvolvimento das plantas de P. edulis f. edulis para compreender por meio de estudos de trocas gasosas e análises bioquímicas como o estresse hídrico pode afetar a produtividade das plantas de maracujazeiros. Foi possível observar que a influência da enxertia no crescimento inicial das plantas de maracujazeiros e nos teores de minerais foliares variou de acordo com a espécie estudada. Na anatomia foi observada compatibilidade entre o porta enxerto e as espécies copa estudadas, ocorrendo divisão e diferenciação celular já no oitavo dia após a enxertia e, aos 30 dias após a enxertia, os tecidos se apresentavam diferenciados e completamente unidos... / Anatomical, physiological and biochemical aspects related to grafting of passion fruit trees onto Passiflora cincinnata Mast. 2011. 104f. Thesis (Doctorate) – Institute of Biosciences, UNESP – São Paulo State University, Botucatu-SP. The species Passiflora cincinnata Mast. is considered potentially important as rootstock since it is tolerant to diseases, nematodes and drought. The present work aimed to evaluate anatomical aspects related to grafting of commercial species onto the rootstock Passiflora cincinnata and to determine the influence of grafting on the initial growth of commercial passion fruit trees and on the responses to water stress. The study consisted of three experiments. In the first experiment, the effect of grafting was assessed on the development of commercial passion fruit trees (P. edulis f. flavicarpa, P. edulis f. edulis and Passiflora alata). The second experiment aimed to describe aspects related to the stem anatomy in the grafting region during setting and lignification in two species of commercial passion fruit trees (P. edulis f. flavicarpa and P. alata). The third experiment was designed to study the effect of grafting on the responses to water stress during the initial development stage of P. edulis f. edulis plants and understand, using gas exchange and biochemical evaluations, how water stress can affect the productivity of passion fruit trees. The influence of grafting on the initial growth of passion fruit trees and on the leaf mineral levels varied according to the species. Considering the anatomy, there was compatibility between the rootstock and canopy species, with cell division and differentiation occurring already on the eighth day after grafting, and at 30 days after grafting tissues were differentiated and completely joined. As to gas exchange and chlorophyll fluorescence, the greatest differences were between... (Complete abstract click electronic access below)