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Sample records for budbreak

  1. EARLY BUD-BREAK1 (EBB1) defines a conserved mechanism for control of bud-break in woody perennials

    Science.gov (United States)

    Busov, Victor; Carneros, Elena; Yakovlev, Igor

    2016-01-01

    Bud-break is an environmentally and economically important trait in trees, shrubs and vines from temperate latitudes. Poor synchronization of bud-break timing with local climates can lead to frost injuries, susceptibility to pests and pathogens and poor crop yields in fruit trees and vines. The rapid climate changes outpace the adaptive capacities of plants to respond through natural selection. This is particularly true for trees which have long generation cycle and thus the adaptive changes are significantly delayed. Therefore, to devise appropriate breeding and conservation strategies, it is imperative to understand the molecular underpinnings that govern dormancy mechanisms. We have recently identified and characterized the poplar EARLY BUD-BREAK 1 (EBB1) gene. EBB1 is a positive regulator of bud-break and encodes a transcription factor from the AP2/ERF family. Here, using comparative and functional genomics approaches we show that EBB1 function in regulation of bud-break is likely conserved across wide range of woody perennial species with importance to forestry and agriculture. PMID:26317150

  2. Evaluation of winter temperatures on apple budbreak using grafted twigs

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    Fernando José Hawerroth

    2013-09-01

    Full Text Available Temperature is the main climate factor related to induction, maintenance and dormancy release in apple (Malus domestica Borkh.. The inadequate chilling exposure in apples causes budbreak problems, resulting in decrease in yield potential. Thus, the knowledge of physiological principles and environmental factors determining the dormancy phenomenon, especially winter temperature effects, it is necessary for the efficient selection of cultivars in a productive region. In addition, it is indispensable to adapt the orchard management aiming to decrease the problems caused by lack chilling during winter. The objective of this study was to evaluate the influence of different thermal conditions during the dormancy period on budbreak of apple cultivars. One-year-old twigs of 'Castel Gala' and 'Royal Gala' cultivars, grafted on M7 rootstock, were submitted to temperatures of 5, 10 and 15ºC for different exposure periods (168; 336; 672; 1,008 and 1,344 hours. After treatments execution, the plants were kept in a greenhouse at 25ºC. Budbreak was quantified when accumulated 3,444; 6,888; 10,332; 13,776; 17,220 and 20,664 GDHºC after temperature treatments. The cultivars responded differently to temperature effect during the winter period. The temperature of 15ºC during winter shows a greater effectiveness on 'Castel Gala' apple budbreak while in the 'Royal Gala' apples the temperatures of 5 and 10ºC show better performance. 'Castel Gala' cultivar (low chilling requirement may supply its physiological necessities, may be capable to budburst, even when subjected to higher temperatures in relation to 'Royal Gala' apples (high chilling requirement.

  3. Nut crop yield records show that budbreak-based chilling requirements may not reflect yield decline chill thresholds

    Science.gov (United States)

    Pope, Katherine S.; Dose, Volker; Da Silva, David; Brown, Patrick H.; DeJong, Theodore M.

    2015-06-01

    Warming winters due to climate change may critically affect temperate tree species. Insufficiently cold winters are thought to result in fewer viable flower buds and the subsequent development of fewer fruits or nuts, decreasing the yield of an orchard or fecundity of a species. The best existing approximation for a threshold of sufficient cold accumulation, the "chilling requirement" of a species or variety, has been quantified by manipulating or modeling the conditions that result in dormant bud breaking. However, the physiological processes that affect budbreak are not the same as those that determine yield. This study sought to test whether budbreak-based chilling thresholds can reasonably approximate the thresholds that affect yield, particularly regarding the potential impacts of climate change on temperate tree crop yields. County-wide yield records for almond ( Prunus dulcis), pistachio ( Pistacia vera), and walnut ( Juglans regia) in the Central Valley of California were compared with 50 years of weather records. Bayesian nonparametric function estimation was used to model yield potentials at varying amounts of chill accumulation. In almonds, average yields occurred when chill accumulation was close to the budbreak-based chilling requirement. However, in the other two crops, pistachios and walnuts, the best previous estimate of the budbreak-based chilling requirements was 19-32 % higher than the chilling accumulations associated with average or above average yields. This research indicates that physiological processes beyond requirements for budbreak should be considered when estimating chill accumulation thresholds of yield decline and potential impacts of climate change.

  4. Detecting QTLs and putative candidate genes involved in budbreak and flowering time in an apple multiparental population.

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    Allard, Alix; Bink, Marco C A M; Martinez, Sébastien; Kelner, Jean-Jacques; Legave, Jean-Michel; di Guardo, Mario; Di Pierro, Erica A; Laurens, François; van de Weg, Eric W; Costes, Evelyne

    2016-04-01

    In temperate trees, growth resumption in spring time results from chilling and heat requirements, and is an adaptive trait under global warming. Here, the genetic determinism of budbreak and flowering time was deciphered using five related full-sib apple families. Both traits were observed over 3 years and two sites and expressed in calendar and degree-days. Best linear unbiased predictors of genotypic effect or interaction with climatic year were extracted from mixed linear models and used for quantitative trait locus (QTL) mapping, performed with an integrated genetic map containing 6849 single nucleotide polymorphisms (SNPs), grouped into haplotypes, and with a Bayesian pedigree-based analysis. Four major regions, on linkage group (LG) 7, LG10, LG12, and LG9, the latter being the most stable across families, sites, and years, explained 5.6-21.3% of trait variance. Co-localizations for traits in calendar days or growing degree hours (GDH) suggested common genetic determinism for chilling and heating requirements. Homologs of two major flowering genes, AGL24 and FT, were predicted close to LG9 and LG12 QTLs, respectively, whereas Dormancy Associated MADs-box (DAM) genes were near additional QTLs on LG8 and LG15. This suggests that chilling perception mechanisms could be common among perennial and annual plants. Progenitors with favorable alleles depending on trait and LG were identified and could benefit new breeding strategies for apple adaptation to temperature increase. PMID:27034326

  5. Detecting QTLs and putative candidate genes involved in budbreak and flowering time in an apple multiparental population

    Science.gov (United States)

    Allard, Alix; Bink, Marco C.A.M.; Martinez, Sébastien; Kelner, Jean-Jacques; Legave, Jean-Michel; di Guardo, Mario; Di Pierro, Erica A.; Laurens, François; van de Weg, Eric W.; Costes, Evelyne

    2016-01-01

    In temperate trees, growth resumption in spring time results from chilling and heat requirements, and is an adaptive trait under global warming. Here, the genetic determinism of budbreak and flowering time was deciphered using five related full-sib apple families. Both traits were observed over 3 years and two sites and expressed in calendar and degree-days. Best linear unbiased predictors of genotypic effect or interaction with climatic year were extracted from mixed linear models and used for quantitative trait locus (QTL) mapping, performed with an integrated genetic map containing 6849 single nucleotide polymorphisms (SNPs), grouped into haplotypes, and with a Bayesian pedigree-based analysis. Four major regions, on linkage group (LG) 7, LG10, LG12, and LG9, the latter being the most stable across families, sites, and years, explained 5.6–21.3% of trait variance. Co-localizations for traits in calendar days or growing degree hours (GDH) suggested common genetic determinism for chilling and heating requirements. Homologs of two major flowering genes, AGL24 and FT, were predicted close to LG9 and LG12 QTLs, respectively, whereas Dormancy Associated MADs-box (DAM) genes were near additional QTLs on LG8 and LG15. This suggests that chilling perception mechanisms could be common among perennial and annual plants. Progenitors with favorable alleles depending on trait and LG were identified and could benefit new breeding strategies for apple adaptation to temperature increase. PMID:27034326

  6. Estimation of chilling requirement and effect of hydrogen cyanamide on budbreak and fruit characteristics of 'superior seedless' table grape cultivated in a mild winter climate

    International Nuclear Information System (INIS)

    The chilling requirement and optimum time for hydrogen cyanamide (HC) application were determined for Superior Seedless table grape grown in southern Tunisia, an arid mild winter region. The reliability of five models to predict chilling accumulation for this cultivar was also investigated. In mid-November, current season shoots were excised and subjected to artificial chilling at 7 deg. C for different lengths of time. Each time, half the shoots were treated with a 2% (v/v) aqueous solution of HC, the others were sprayed with distilled water. Thereafter, these shoots were forced to budburst. Rest intensity gradually declined due to chilling accumulation. We estimated that the cultivar needed approx. 440 hours (h) of chilling, or chilling requirement (CR), to overcome endodormancy. During two dormant seasons, estimation of chilling accumulation showed that the Positive Chill Unit model was the most suitable to predict rest completion for Superior Seedless grown under our climatic conditions. Using this model, we found that the variety's CR was not always met by mid-February. In both laboratory and field trials, HC was most effective in enhancing and advancing budbreak if applied when approx. 2/3 of the cultivar's CR were met. Moreover, by this application berry weight and diameter were increased and fruit maturity was advanced. Our study indicated that HC (2%) was effective in advancing budbreak and fruit maturity of Superior Seedless table grape although its effectiveness depended on application date. (author)

  7. Fenologia, brotação de gemas e produção de frutos de macieira em resposta à aplicação de cianamida hidrogenada e óleo mineral Phenology, budbreak and apple fruit production by hydrogen cyanamide and mineral oil application

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    Fernando José Hawerroth

    2009-01-01

    Full Text Available A aplicação de indutores de brotação é uma das principais estratégias de manejo utilizadas para minimizar os problemas da falta de frio em frutíferas de clima temperado. Em razão da influência dos indutores de brotação sobre a resposta produtiva das plantas, a mensuração de seus efeitos ao longo do ciclo produtivo torna-se importante. Assim, o presente trabalho foi desenvolvido no ciclo 2007/2008, em Caçador/SC, objetivando avaliar diferentes combinações de cianamida hidrogenada e óleo mineral sobre a fenologia, brotação de gemas e produção de frutos em macieiras. O delineamento experimental foi em blocos casualizados, com seis repetições compostas de uma planta, seguindo arranjo fatorial (5x2, com cinco níveis de indutor de brotação (1. testemunha; 2. óleo mineral 3,2%; 3. óleo mineral 3,2% + cianamida hidrogenada 0,20%; 4. óleo mineral 3,2% + cianamida hidrogenada 0,39%; 5. óleo mineral 3,2% + cianamida hidrogenada 0,59% e duas cultivares (Imperial Gala e Fuji Suprema. A aplicação dos indutores de brotação antecipou e reduziu o período de florescimento, aumentando a coincidência de florescimento das cultivares Imperial Gala e Fuji Suprema. Os indutores de brotação uniformizaram e aumentaram a brotação de gemas axilares e terminais, obtendo-se máxima brotação na cultivar Imperial Gala com 0,44% de cianamida hidrogenada e 3,2% de óleo mineral. O aumento da concentração de cianamida hidrogenada revelou a tendência de diminuir a frutificação efetiva. Observaram-se respostas diferenciadas entre tratamentos quanto à produção e à massa média dos frutos, podendo ser atribuídas ao predomínio da produção de frutos em distintas estruturas de frutificação.The budbreak promoters application is one of main management strategies used to decrease the problems of insufficient winter chilling on temperate fruit trees. Because the influence of budbreak promoters on productive behaviour of plants

  8. Actinidia DRM1 - An Intrinsically Disordered Protein Whose mRNA Expression Is Inversely Correlated with Spring Budbreak in Kiwifruit

    Science.gov (United States)

    Wood, Marion; Rae, Georgina M.; Wu, Rong-Mei; Walton, Eric F.; Xue, Bin; Hellens, Roger P.; Uversky, Vladimir N.

    2013-01-01

    Intrinsically disordered proteins (IDPs) are a relatively recently defined class of proteins which, under native conditions, lack a unique tertiary structure whilst maintaining essential biological functions. Functional classification of IDPs have implicated such proteins as being involved in various physiological processes including transcription and translation regulation, signal transduction and protein modification. Actinidia DRM1 (Ade DORMANCY ASSOCIATED GENE 1), represents a robust dormancy marker whose mRNA transcript expression exhibits a strong inverse correlation with the onset of growth following periods of physiological dormancy. Bioinformatic analyses suggest that DRM1 is plant specific and highly conserved at both the nucleotide and protein levels. It is predicted to be an intrinsically disordered protein with two distinct highly conserved domains. Several Actinidia DRM1 homologues, which align into two distinct Actinidia-specific families, Type I and Type II, have been identified. No candidates for the Arabidopsis DRM1-Homologue (AtDRM2) an additional family member, has been identified in Actinidia. PMID:23516402

  9. Necessidade de frio para quebra de dormência de gemas de caquizeiro 'Fuyu' Chill requirement for budbreak of japanese persimmon cv. Fuyu

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    Rudival Faquim

    2007-01-01

    Full Text Available Objetivou-se, no presente trabalho, determinar a necessidade de frio para a quebra da dormência das gemas de caquizeiro 'Fuyu'. As coletas de ramos foram realizadas em cinco datas (26-04, 14-05, 21-06, 19-07 e 16-08. Foram aplicados nos ramos cinco tratamentos de frio adicional (0; 168; 336; 504; 672 h de frio em geladeira à temperatura de 4ºC a 7ºC. A avaliação da dormência foi feita pelo teste biológico de estacas de nós isolados por meio do tempo médio para brotação (TMB, velocidade de brotação (VB, taxa final de brotação (TF e taxa de brotações vigorosas (TBV. O delineamento experimental adotado foi o completamente casualizado, num esquema fatorial 5 x 5 (cinco datas e cinco tempos de exposição ao frio, com três repetições. Foram realizados testes separadamente com gemas terminais e com gemas laterais. A quebra de dormência de gemas laterais e terminais de ramos de caquizeiro 'Fuyu' ocorreu no mês de agosto, após o tratamento com 504 h de frio, de 4ºC a 7ºC, obtendo-se 100% de gemas brotadas.This work aimed to evaluate the chill requirement for bud break of Japanese persimmon cv. Fuyu. The branches were collected in five dates (April 26th; May 14th; June 21st; July 19th, and August 16th and received five chill treatments (0, 168, 336, 504, 672 h in the refrigerator (4ºC to 7ºC. The evaluation of dormancy was observed by the biological test of single node cuttings by following variables: average time for budburst (TMB, velocity of budburst (VB, final rate of budburst (TF and rate of vigorous budburst (TBV. The experimental design was a factorial entirely randomized with five dates and five periods of chill treatment with three replications. Terminal and lateral buds were analyzed individually. The bud break of terminal and lateral buds of Japanese persimmon cv. Fuyu occurred in August after the treatment with 504 h of chill (4ºC to 7ºC, when 100% of budburst was obtained.

  10. AN INVESTIGATION ON THE BUD-BREAK AND GROWTH OF CUTTINGS OF 420 A AND 5 BB AMERICAN VINE ROOTSTOCKS IRRADIATED WITH DIFFERENT GAMMA DOSES

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    Alper DARDENIZ

    2006-02-01

    Full Text Available Viticulture is an important and intensive agricultural branch in Çanakkale province and also in Turkey. Different American vine rootstocks are widely used against phylloxera in our country. Plant breeders have been using gamma radiation for creating new varieties of crops and for obtaining broad genetic diversity for years. In this study, four different doses of gamma rays were applied to 420 A and 5 BB American vine rootstocks when the buds on the cuttings were at the dormant stage. Then, effects of different gamma radiation doses on the cuttings of 420 A and 5 BB American vine rootstocks were investigated. The aim of the research was to study the effect of different gamma radiation doses on some growth parameters of cuttings of 420 A and 5 BB, and to determine the GR50 dose. The results obtained were statistically elaborated by TARIST.

  11. AN INVESTIGATION ON THE BUD-BREAK AND GROWTH OF CUTTINGS OF 420 A AND 5 BB AMERICAN VINE ROOTSTOCKS IRRADIATED WITH DIFFERENT GAMMA DOSES

    OpenAIRE

    Dardeniz, Alper; TAYYAR, Şemun

    2005-01-01

    Viticulture is an important and intensive agricultural branch in Çanakkale province and also in Turkey. Different American vine rootstocks are widely used against phylloxera in our country. Plant breeders have been using gamma radiation for creating new varieties of crops and for obtaining broad genetic diversity for years. In this study, four different doses of gamma rays were applied to 420 A and 5 BB American vine rootstocks when the buds on the cuttings were at the dormant stage. Then, ef...

  12. A rapid transcriptional activation is induced by the dormancy-breaking chemical hydrogen cyanamide in kiwifruit (Actinidia deliciosa) buds

    Science.gov (United States)

    Walton, Eric F.; Wu, Rong-Mei; Richardson, Annette C.; Davy, Marcus; Hellens, Roger P.; Thodey, Kate; Janssen, Bart J.; Gleave, Andrew P.; Rae, Georgina M.; Wood, Marion; Schaffer, Robert J.

    2009-01-01

    Budbreak in kiwifruit (Actinidia deliciosa) can be poor in locations that have warm winters with insufficient winter chilling. Kiwifruit vines are often treated with the dormancy-breaking chemical hydrogen cyanamide (HC) to increase and synchronize budbreak. This treatment also offers a tool to understand the processes involved in budbreak. A genomics approach is presented here to increase our understanding of budbreak in kiwifruit. Most genes identified following HC application appear to be associated with responses to stress, but a number of genes appear to be associated with the reactivation of growth. Three patterns of gene expression were identified: Profile 1, an HC-induced transient activation; Profile 2, an HC-induced transient activation followed by a growth-related activation; and Profile 3, HC- and growth-repressed. One group of genes that was rapidly up-regulated in response to HC was the glutathione S-transferase (GST) class of genes, which have been associated with stress and signalling. Previous budbreak studies, in three other species, also report up-regulated GST expression. Phylogenetic analysis of these GSTs showed that they clustered into two sub-clades, suggesting a strong correlation between their expression and budbreak across species. PMID:19651683

  13. Candidate genes associated with bud dormancy release in blackcurrant (Ribes nigrum L.

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    Hedley Peter E

    2010-09-01

    Full Text Available Abstract Background The detrimental effects of mild winter temperatures on the consistency of cropping of blackcurrant (Ribes nigrum L. in parts of Europe have led to increasing interest in the genetic control of dormancy release in this species. This study examined patterns of gene expression in leaf buds of blackcurrant to identify key differential changes in these profiles around the time of budbreak. Results Using leaf bud tissue of blackcurrant, a cDNA library was generated as a source of blackcurrant ESTs for construction of a custom microarray, which was used to identify differential gene expression during dormancy release. Gene activity was lowest in early stages of dormancy, increasing to reach a maximum around the time of budbreak. Genes with significantly changing expression profiles were clustered and evidence is provided for the transient activity of genes previously associated with dormancy processes in other species. Expression profiling identified candidate genes which were mapped onto a blackcurrant genetic linkage map containing budbreak-related QTL. Three genes, which putatively encode calmodulin-binding protein, beta tubulin and acetyl CoA carboxylase respectively, were found to co-localise with budbreak QTL. Conclusions This study provides insight into the genetic control of dormancy transition in blackcurrant, identifying key changes in gene expression around budbreak. Genetic mapping of ESTs enabled the identification of genes which co-localise with previously-characterised blackcurrant QTL, and it is concluded that these genes have probable roles in release of dormancy and can therefore provide a basis for the development of genetic markers for future breeding deployment.

  14. The seasonal timing of warming that controls onset of the growing season.

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    Clark, James S; Melillo, Jerry; Mohan, Jacqueline; Salk, Carl

    2014-04-01

    Forecasting how global warming will affect onset of the growing season is essential for predicting terrestrial productivity, but suffers from conflicting evidence. We show that accurate estimates require ways to connect discrete observations of changing tree status (e.g., pre- vs. post budbreak) with continuous responses to fluctuating temperatures. By coherently synthesizing discrete observations with continuous responses to temperature variation, we accurately quantify how increasing temperature variation accelerates onset of growth. Application to warming experiments at two latitudes demonstrates that maximum responses to warming are concentrated in late winter, weeks ahead of the main budbreak period. Given that warming will not occur uniformly over the year, knowledge of when temperature variation has the most impact can guide prediction. Responses are large and heterogeneous, yet predictable. The approach has immediate application to forecasting effects of warming on growing season length, requiring only information that is readily available from weather stations and generated in climate models. PMID:24115181

  15. Independent Control of Organogenesis and Shoot Tip Abortion are Key Factors to Developmental Plasticity in Kiwifruit (Actinidia)

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    Foster, Toshi M.; Seleznyova, Alla N.; Barnett, Andrew M.

    2007-01-01

    Background and Aims In kiwifruit (Actinidia), the number of nodes per shoot is highly variable and is influenced by genotype and environmental conditions. To understand this developmental plasticity, three key processes were studied: organogenesis by the shoot apical meristem during shoot growth; expansion of phytomers; and shoot tip abortion. Methods Studies were made of organogenesis and shoot tip abortion using light and scanning electron microscopy. The effect of temperature on shoot growth cessation was investigated using temperature indices over the budbreak period, and patterns of shoot tip abortion were quantified using stochastic modelling. Key Results All growing buds began organogenesis before budbreak. During shoot development, the number of phytomers initiated by the shoot apical meristem is correlated with the number of expanding phytomers and the mean internode length. Shoot tip abortion is preceded by growth cessation and is not brought about by the death of the shoot apical meristem, but occurs by tissue necrosis in the sub-apical zone. For most genotypes studied, the probability of shoot tip abortion is higher during expansion of the preformed part of the shoot. Lower temperatures during early growth result in a higher probability of shoot tip abortion. Conclusions Organogenesis and shoot tip abortion are controlled independently. All buds have the potential to become long shoots. Conditions that increase early growth rate postpone shoot tip abortion. PMID:17650513

  16. Climate Change and Crop Exposure to Adverse Weather: Changes to Frost Risk and Grapevine Flowering Conditions.

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    Jonathan R Mosedale

    Full Text Available The cultivation of grapevines in the UK and many other cool climate regions is expected to benefit from the higher growing season temperatures predicted under future climate scenarios. Yet the effects of climate change on the risk of adverse weather conditions or events at key stages of crop development are not always captured by aggregated measures of seasonal or yearly climates, or by downscaling techniques that assume climate variability will remain unchanged under future scenarios. Using fine resolution projections of future climate scenarios for south-west England and grapevine phenology models we explore how risks to cool-climate vineyard harvests vary under future climate conditions. Results indicate that the risk of adverse conditions during flowering declines under all future climate scenarios. In contrast, the risk of late spring frosts increases under many future climate projections due to advancement in the timing of budbreak. Estimates of frost risk, however, were highly sensitive to the choice of phenology model, and future frost exposure declined when budbreak was calculated using models that included a winter chill requirement for dormancy break. The lack of robust phenological models is a major source of uncertainty concerning the impacts of future climate change on the development of cool-climate viticulture in historically marginal climatic regions.

  17. Compounds Derived from Garlic as Bud Induction Agents in Organic Farming of Table Grape Compuestos Derivados de Ajo como Agentes Inductores de Brotación en Cultivo Orgánico de Uva de Mesa

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    Irasema Vargas-Arispuro

    2008-03-01

    Full Text Available Viticulture is one of the most important economic activities in the Northwest of Mexico. A major obstacle for the economic production is the insufficient period of chilling temperatures. This problem leads to poor budbreak, which in turn results in reduced yields. This problem is aggravated when plants are cultivated using the organic farming system, mostly because there are not organically approved restbreaking agents. In this work different products derived from garlic (Allium sativum L. were obtained and evaluated as stimulate budbreak agent of table grape (Vitis vinifera L. cvs. Flame Seedless and Perlette. The isolated compounds were chemically identified and include allicin, diallyl disulfide, diallyl trisulfide, 3-vynil-[4H]-1,2-ditiin and 2-vynil-[3H]-1,3-ditiin, S-methyl cysteine sulphoxide, dimethyl disulfide, dimethyl trisulfide and dimethyl thiosulfonate. Cuttings with six buds were used to evaluate the compounds. After compounds were applied, the cuttings were transferred to a growing chamber at 24 °C. All evaluated compounds promoted budbreak in the cuttings of Flame Seedless and Perlette. The volatile compounds from S-methyl cysteine sulfoxide promoted 100% of budbreak of both cultivars. The compounds from garlic that stimulated budbreak in grapevines in this work include sulphur in their molecule; therefore we propose that sulphur could play a key role in breaking bud dormancy of grape cultivars evaluated in this studyLa viticultura es una de las principales actividades económicas en el Noroeste de México. Entre los problemas que enfrenta esta actividad está el período de frío insuficiente, lo que lleva a una pobre brotación y consecuentemente una menor producción. Este problema se agrava cuando se cultivan plantas por el método orgánico, ya que no existen agentes inductores de brotación aprobados para uso orgánico. En este trabajo se aislaron diferentes compuestos derivados de ajo (Allium sativum L. que se evaluaron

  18. Potential effect of atmospheric warming on grapevine phenology and post-harvest heat accumulation across a range of climates

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    Hall, Andrew; Mathews, Adam J.; Holzapfel, Bruno P.

    2016-01-01

    Carbohydrates are accumulated within the perennial structure of grapevines when their production exceeds the requirements of reproduction and growth. The period between harvest and leaf-fall (the post-harvest period) is a key period for carbohydrate accumulation in relatively warmer grape-growing regions. The level of carbohydrate reserves available for utilisation in the following season has an important effect on canopy growth and yield potential and is therefore an important consideration in vineyard management. In a warming climate, the post-harvest period is lengthening and becoming warmer, evidenced through studies in wine regions worldwide that have correlated recent air temperature increases with changing grapevine phenology. Budbreak, flowering, veraison, and harvest have all been observed to be occurring earlier than in previous decades. Additionally, the final stage of the grapevine phenological cycle, leaf-fall, occurs later. This study explored the potential for increased post-harvest carbohydrate accumulation by modelling heat accumulation following harvest dates for the recent climate (1975-2004) and two warmer climate projections with mean temperature anomalies of +1.26 and +2.61 °C. Summaries of post-harvest heat accumulation between harvest and leaf-fall were produced for each of Australia's Geographical Indications (wine regions) to provide comparisons from the base temperatures to projected warmer conditions across a range of climates. The results indicate that for warmer conditions, all regions observe earlier occurring budbreak and harvest as well as increasing post-harvest growing degree days accumulation before leaf-fall. The level of increase varies depending upon starting climatic condition, with cooler regions experiencing the greatest change.

  19. Coordination of Different Phenological Events during the Growing Season

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    Berninger, F.; Lemieux, J.; Zhai, L.

    2008-12-01

    In two separate studies we followed the phenological development of black spruce on different microsites and of three congeneric species (Jack pine, white birch and trembling aspen) with different growth patterns on a single site. All studies were done in the northern black spruce belt in northern Quebec (northern boreal forest). We followed several phenological points during the growing season (bud development, shoot extension, onset of the diameter growth, diameter growth, budset, end of diamter growth, maximum foliage growth, end of foliage growth, end of latewood differentiation). We hypothesized that phenological development and growth are internally regulated in trees in a way that: (1) the time that it takes to pass through a certain phenological phase is similar for all trees. (2) trees that start bud development earlier will start also diameter growth earlier (3) that growth of "early trees" will end earlier.These kind of relationships are suggested by the hormonal theory of tree growth and would be useful to understand when trees are vulnerable to different abiotic and biotic events. The different sites had a clear impact on phenology which was linked to the microclimate of the site. Bud- development of the warm site was clearly more rapid on a warmer site, separated from about 100 meters from weter colder sites. However, coordination between sites broke down and clear differences in the early stages of bud development were already less clear at the late stages of bud development. The end of growth was quite similar between the sites. Between species it became evident that different species have similar "phenological timetales" and the onset. Ranks of the species were different for budbreak and the onset of xylem development. Also, birch, the species with an earlier budbreak reached full leaf size later than aspen. In addition the often proclaimed linkage between end of extension growth and onset of latewood formation did not hold for Jack pine. The

  20. An apple rootstock overexpressing a peach CBF gene alters growth and flowering in the scion but does not impact cold hardiness or dormancy

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    Artlip, Timothy S; Wisniewski, Michael E; Arora, Rajeev; Norelli, John L

    2016-01-01

    The C-repeat binding factor (CBF) transcription factor is involved in responses to low temperature and water deficit in many plant species. Overexpression of CBF genes leads to enhanced freezing tolerance and growth inhibition in many species. The overexpression of a peach CBF (PpCBF1) gene in a transgenic line of own-rooted apple (Malus×domestica) M.26 rootstock (T166) trees was previously reported to have additional effects on the onset of dormancy and time of spring budbreak. In the current study, the commercial apple cultivar ‘Royal Gala’ (RG) was grafted onto either non-transgenic M.26 rootstocks (RG/M.26) or transgenic M.26 (T166) rootstocks (RG/T166) and field grown for 3 years. No PpCBF1 transcript was detected in the phloem or cambium of RG scions grafted on T166 rootstocks indicating that no graft transmission of transgene mRNA had occurred. In contrast to own-rooted T166 trees, no impact of PpCBF1 overexpression in T166 rootstocks was observed on the onset of dormancy, budbreak or non-acclimated leaf-cold hardiness in RG/T166 trees. Growth, however, as measured by stem caliper, current-year shoot extension and overall height, was reduced in RG/T166 trees compared with RG/M.26 trees. Although flowering was evident in both RG/T166 and RG/M.26 trees in the second season, the number of trees in flower, the number of shoots bearing flowers, and the number of flower clusters per shoot was significantly higher in RG/M.26 trees than RG/T166 trees in both the second and third year after planting. Elevated levels of RGL (DELLA) gene expression were observed in RG/T166 trees and T166 trees, which may play a role in the reduced growth observed in these tree types. A model is presented indicating how CBF overexpression in a rootstock might influence juvenility and flower abundance in a grafted scion. PMID:26981253

  1. Identification and characterization of flowering genes in kiwifruit: sequence conservation and role in kiwifruit flower development

    Directory of Open Access Journals (Sweden)

    Wang Yen-Yi

    2011-04-01

    Full Text Available Abstract Background Flower development in kiwifruit (Actinidia spp. is initiated in the first growing season, when undifferentiated primordia are established in latent shoot buds. These primordia can differentiate into flowers in the second growing season, after the winter dormancy period and upon accumulation of adequate winter chilling. Kiwifruit is an important horticultural crop, yet little is known about the molecular regulation of flower development. Results To study kiwifruit flower development, nine MADS-box genes were identified and functionally characterized. Protein sequence alignment, phenotypes obtained upon overexpression in Arabidopsis and expression patterns suggest that the identified genes are required for floral meristem and floral organ specification. Their role during budbreak and flower development was studied. A spontaneous kiwifruit mutant was utilized to correlate the extended expression domains of these flowering genes with abnormal floral development. Conclusions This study provides a description of flower development in kiwifruit at the molecular level. It has identified markers for flower development, and candidates for manipulation of kiwifruit growth, phase change and time of flowering. The expression in normal and aberrant flowers provided a model for kiwifruit flower development.

  2. Identification and characterization of flowering genes in kiwifruit: sequence conservation and role in kiwifruit flower development

    Science.gov (United States)

    2011-01-01

    Background Flower development in kiwifruit (Actinidia spp.) is initiated in the first growing season, when undifferentiated primordia are established in latent shoot buds. These primordia can differentiate into flowers in the second growing season, after the winter dormancy period and upon accumulation of adequate winter chilling. Kiwifruit is an important horticultural crop, yet little is known about the molecular regulation of flower development. Results To study kiwifruit flower development, nine MADS-box genes were identified and functionally characterized. Protein sequence alignment, phenotypes obtained upon overexpression in Arabidopsis and expression patterns suggest that the identified genes are required for floral meristem and floral organ specification. Their role during budbreak and flower development was studied. A spontaneous kiwifruit mutant was utilized to correlate the extended expression domains of these flowering genes with abnormal floral development. Conclusions This study provides a description of flower development in kiwifruit at the molecular level. It has identified markers for flower development, and candidates for manipulation of kiwifruit growth, phase change and time of flowering. The expression in normal and aberrant flowers provided a model for kiwifruit flower development. PMID:21521532

  3. Adaptation of lodgepole pine and interior spruce to climate: implications for reforestation in a warming world.

    Science.gov (United States)

    Liepe, Katharina J; Hamann, Andreas; Smets, Pia; Fitzpatrick, Connor R; Aitken, Sally N

    2016-02-01

    We investigated adaptation to climate in populations of two widespread tree species across a range of contrasting environments in western Canada. In a series of common garden experiments, bud phenology, cold hardiness, and seedling growth traits were assessed for 254 populations in the interior spruce complex (Picea glauca, P. engelmannii, and their hybrids) and for 281 populations of lodgepole pine (Pinus contorta). Complex multitrait adaptations to different ecological regions such as boreal, montane, coastal, and arid environments accounted for 15-20% of the total variance. This population differentiation could be directly linked to climate variables through multivariate regression tree analysis. Our results suggest that adaptation to climate does not always correspond linearly to temperature gradients. For example, opposite trait values (e.g., early versus late budbreak) may be found in response to apparently similar cold environments (e.g., boreal and montane). Climate change adaptation strategies may therefore not always be possible through a simple shift of seed sources along environmental gradients. For the two species in this study, we identified a relatively small number of uniquely adapted populations (11 for interior spruce and nine for lodgepole pine) that may be used to manage adaptive variation under current and expected future climates. PMID:26834833

  4. Drought during canopy development has lasting effect on annual carbon balance in a deciduous temperate forest.

    Science.gov (United States)

    Noormets, Asko; McNulty, Steve G; DeForest, Jared L; Sun, Ge; Li, Qinglin; Chen, Jiquan

    2008-01-01

    * Climate change projections predict an intensifying hydrologic cycle and an increasing frequency of droughts, yet quantitative understanding of the effects on ecosystem carbon exchange remains limited. * Here, the effect of contrasting precipitation and soil moisture dynamics were evaluated on forest carbon exchange using 2 yr of eddy covariance and microclimate data from a 50-yr-old mixed oak woodland in northern Ohio, USA. * The stand accumulated 40% less carbon in a year with drought between bud-break and full leaf expansion (354 +/- 81 g C m(-2) yr(-1) in 2004 and 252 +/- 45 g C m(-2) yr(-1) in 2005). This was caused by greater suppression of gross ecosystem productivity (GEP; 16% = 200 g) than of ecosystem respiration (ER; 11% = 100 g) by drought. Suppressed GEP was traced to lower leaf area, lower apparent quantum yield and lower canopy conductance. The moisture sensitivity of ER may have been mediated by GEP. * The results highlight the vulnerability of the ecosystem to even a moderate drought, when it affects a critical aspect of development. Although the drought was preceded by rain, the storage capacity of the soil seemed limited to 1-2 wk, and therefore droughts longer than this are likely to impair productivity in the region. PMID:18537894

  5. Effects of elevated ozone on CO2 uptake and leaf structure in sugar maple under two light environments

    International Nuclear Information System (INIS)

    The interactive effects of ozone and light on leaf structure, carbon dioxide uptake and short-term carbon allocation of sugar maple (Acer saccharum Marsh.) seedlings were examined using gas exchange measurements and 14C-macroautoradiographic techniques. Two-year-old sugar maple seedlings were fumigated from budbreak for 5 months with ambient or 3 × ambient ozone in open-top chambers, receiving either 35% (high light) or 15% (low light) of full sunlight. Ozone accelerated leaf senescence, and reduced net photosynthesis, 14CO2 uptake and stomatal conductance, with the effects being most pronounced under low light. The proportion of intercellular space increased in leaves of seedlings grown under elevated ozone and low light, possibly enhancing the susceptibility of mesophyll cells to ozone by increasing the cumulative dose per mesophyll cell. Indeed, damage to spongy mesophyll cells in the elevated ozone × low light treatment was especially frequent. 14C macroautoradioraphy revealed heterogeneous uptake of 14CO2 in well defined areole regions, suggesting patchy stomatal behaviour in all treatments. However, in seedlings grown under elevated ozone and low light, the highest 14CO2 uptake occurred along larger veins, while interveinal regions exhibited little or no uptake. Although visible symptoms of ozone injury were not apparent in these seedlings, the cellular damage, reduced photosynthetic rates and reduced whole-leaf chlorophyll levels corroborate the visual scaling of whole-plant senescence, suggesting that the ozone × low light treatment accelerated senescence or senescence-like injury in sugar maple. (author)

  6. Cutaneous reactions simulating erythema multiforme and Stevens Johnson syndrome due to occupational exposure to a plant-growth regulator

    Directory of Open Access Journals (Sweden)

    Inamadar Arun

    2007-01-01

    Full Text Available Background: In India, hydrogen cyanamide (Dormex ® is a plant growth regulator used mainly for the bud-breaking of grapevines. The use of this chemical may result in severe cutaneous reactions simulating erythema multiforme (EM, Stevens-Johnson syndrome (SJS and toxic epidermal necrolysis (TEN. Methods: Studies were conducted on four seasonal grapevine workers who developed severe cutaneous reactions following the unprotected use of Dormex ® (hydrogen cyanamide. Results: Two of the patients had EM-like skin lesions and the other two developed SJS-TEN-like skin lesions. A latent period of 5-7 days existed between the contact with the chemical and the development of the skin lesions. The histopathological picture was suggestive of EM. All the patients responded to systemic steroids and antihistamines. Conclusions: Hydrogen cyanamide may act as a hapten, initiating cytotoxic immunological attack on keratinocytes, resulting in EM- and SJS-TEN-like clinical picture. Awareness regarding such severe cutaneous reactions due to the inappropriate handling of Dormex ® is required. The use of personal protection equipments while handling agricultural chemicals is essential.

  7. Modeling olive-crop forecasting in Tunisia

    Science.gov (United States)

    Ben Dhiab, Ali; Ben Mimoun, Mehdi; Oteros, Jose; Garcia-Mozo, Herminia; Domínguez-Vilches, Eugenio; Galán, Carmen; Abichou, Mounir; Msallem, Monji

    2016-01-01

    Tunisia is the world's second largest olive oil-producing region after the European Union. This paper reports on the use of models to forecast local olive crops, using data for Tunisia's five main olive-producing areas: Mornag, Jemmel, Menzel Mhiri, Chaal, and Zarzis. Airborne pollen counts were monitored over the period 1993-2011 using a Cour trap. Forecasting models were constructed using agricultural data (harvest size in tonnes of fruit/year) and data for several weather-related and phenoclimatic variables (rainfall, humidity, temperature, Growing Degree Days, and Chilling). Analysis of these data revealed that the amount of airborne pollen emitted over the pollen season as a whole (i.e., the Pollen Index) was the variable most influencing harvest size. Findings for all local models also indicated that the amount, timing, and distribution of rainfall (except during blooming) had a positive impact on final olive harvests. Air temperature also influenced final crop yield in three study provinces (Menzel Mhiri, Chaal, and Zarzis), but with varying consequences: in the model constructed for Chaal, cumulative maximum temperature from budbreak to start of flowering contributed positively to yield; in the Menzel Mhiri model, cumulative average temperatures during fruit development had a positive impact on output; in Zarzis, by contrast, cumulative maximum temperature during the period prior to flowering negatively influenced final crop yield. Data for agricultural and phenoclimatic variables can be used to construct valid models to predict annual variability in local olive-crop yields; here, models displayed an accuracy of 98, 93, 92, 91, and 88 % for Zarzis, Mornag, Jemmel, Chaal, and Menzel Mhiri, respectively.

  8. Multi-sensor analysis of changing growing season dynamics across northwest North America since 1998

    Science.gov (United States)

    Nemani, R.; White, M.; Schwartz, M.; Saatchi, S.; Myneni, R.; Dettinger, M.; Cayan, D.

    2005-12-01

    Changes in Pacific Climate on interannual (ENSO) and decadal time scales (Pacific Decadal Oscillation, PDO)have a strong impact on a variety of biospheric processes over northwest North America, including changes in vegetation phenology, snow hydrology, summer drought and fire frequency, forest growth and crop yields. Though evidence exists for a shift in PDO in 1998, the impact of such a shift on terrestrial ecosystems is not yet known. We used a variety of satellite (AVHRR, SSM/I, GOES) and surface (NWS, SNOTEL, streamflow) networks to characterize changes in climate and ecosystem conditions between 1991-97 and 1998-04. Satellite data show that cooler sea surface temperatures during 1998-04 period led to lower atmospheric water vapor over the North Pacific, which in turn led to lower dewpoint and night minimum temperatures over northwest North America. Such climatic changes were dramatic over spring, leading to a delay in the satellite-derived onset of growing season. Modeled budbreak/flowering phases, based on observed weather data, also show a delay of 4-7 days during 1998-04 compared to 1991-97. The delay in growing season onset after 1998 was further supported by later occurrence of soil thaw and snowmelt. It is probably too early to determine if any of the observed changes are a part of the purported shift in PDO. However if they persist, climate-sensitive sectors such as viticulture, with large expansions in recent years, could face potential problems. Continuous monitoring facilitated by a variety of satellite and ground-based sensors offers an unprecedented, spatio-temporal view of changes as they happen.

  9. Application of architectural analysis and AMAPmod methodology to study dwarfing phenomenon: the branch structure of 'Royal Gala' apple grafted on dwarfing and non-dwarfing rootstock/interstock combinations.

    Science.gov (United States)

    Seleznyova, A N; Thorp, T G; White, M; Tustin, S; Costes, E

    2003-05-01

    Architectural analysis was applied to study branch development of 'Royal Gala' apple trees grafted with dwarfing and non-dwarfing rootstock/interstock combinations, which had been chosen to produce trees with a wide range of vigour. Using AMAPmod methodology, the structure of 3-year-old branches was described at four levels of representation: branch; annual shoot; growth unit; and node. Three types of growth units were distinguished: extension growth unit (vegetative unit with internode extension); vegetative spur with minimal internode extension; and fruiting spur or bourse. The aim of the analysis was to describe exactly how the rootstock/interstock combinations affected the structure building process. The number of extension growth units, vegetative spurs and fruiting spurs per annual shoot changed over the years, but this was not affected by rootstock/interstock combination. Compared with MM.106 rootstock, M.9 rootstock reduced the number of nodes per extension growth unit. In most cases, rootstock/interstock combination had no effect on the linear relationship between extension growth unit length and node number (R(2) = 0.88). Average internode length depended on unit node number, with internodes being shorter for units with fewer nodes. Thus the difference in apple branch size induced by the rootstock/interstock combinations was mainly due to a reduction in the length and number of neoformed nodes produced on extension growth units. As percentage budbreak of axillary buds on extension growth units was not affected by rootstock/interstock combination, differences in numbers of axillary annual shoots per branch were entirely due to differences in the total numbers of nodes extended during the previous year. PMID:12714365

  10. Detritivores enhance the mobilization of 137Cs from leaf-litter

    International Nuclear Information System (INIS)

    A large amount of radioactive material was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident after the disastrous earthquake and subsequent tsunami of March 2011. Since most of the Japanese land area is covered by forest ecosystems, 137Cs was mostly deposited and accumulated on the land surface of forest. The fate of radioactive materials accumulated on the leaf litters should be conscientiously monitored to understand the future distribution and the spread to the surrounding landscapes. Because the accident took place on 11 March 2011, just before the bud-break of deciduous trees, the 137Cs are highly accumulated on the surface of leaf litter on the forest floor. This accumulated 137Cs had transferred to higher trophic organisms mainly through the detritus food chain. However, on the litter surface, 137Cs considered to be strongly and immediately fixed and highly immobilized. Decomposition processes in the forest floor can re-mobilise the nutritional elements which are contained within detritus and make them available for the organisms. In the present study, the feeding effect of detritivore soil arthropods on the mobilization of 137Cs from leaf litter was experimentally examined. Furthermore, the effect of detritivores on the plant uptake of 137Cs was examined by small-scale nursery experiment. Decomposition experiment in the small microcosms was performed using a larvae of Trypoxylus dichotomus, whichis a detritivores feeding on dead plant materials such as wood debris and leaf litters. Contaminated leaf litters were collected in a forest of the Kami-Oguni River catchment in the northern part of Fukushima Prefecture. The leaf litters at A0 layers which are highly contaminated by 137Cs were utilized for the experiment. The contaminated leaf litter was fed to the larvae for ten days. The litter with larvae excreta was washed by 2 M KCl and deionized water. The 137Cs concentration was measured by germanium detectors (Seiko EG and G). As a

  11. Seleção de genótipos de pessegueiro F1 com baixa necessidade de frio hibernal Selection of F1 peach genotypes with low chilling requirements

    Directory of Open Access Journals (Sweden)

    Américo Wagner Júnior

    2009-12-01

    Full Text Available A baixa necessidade de frio é característica fundamental para que se possa cultivar economicamente o pessegueiro em condições de clima subtropical, devendo ser este, portanto, o principal objetivo dos programas de melhoramento nestas regiões. o objetivo deste trabalho foi avaliar e selecionar progênies de pessegueiro com baixa necessidade de frio hibernal por meio do método de ramos destacados e indicar o melhor genitor para utilização em programas de melhoramento, visando a esta característica. Foram avaliados 180 genótipos pertencentes a 25 populações de pessegueiro, sendo que o número de genótipos em cada população variou de três a dezenove. os ramos foram submetidos a 50; 100; 150; 200 e 400 unidades de frio, e, ao término de cada tratamento, os ramos foram transferidos para o interior da casa de vegetação. Após 21 dias, foram avaliados quanto às porcentagens de floração e brotação,e com os resultados obtidos, 5 populações e 29 genótipos de pessegueiro com baixa necessidade de frio hibernal foram selecionados. A cultivar Real mostrou-se eficiente na obtenção de pessegueiros com baixa necessidade de frio hibernal, quando utilizada como genitor feminino.Low chilling requirement is the main characteristic for the economic cultivation of peaches under subtropical climate conditions, therefore it should be the most important objective in breeding programs for these regions. The aim of this work was to evaluate and to select peach progenies with low chilling requirement through detached twigs methodology, to indicate a good genitor for using in the breeding program with this characteristic. A total of 180 genotypes, from 25 peach populations, were observed. The genotypes of each population varied from three to nineteen plants. The twigs were submitted to 50, 100, 150, 200 and 400 chilly units. once the treatments were concluded, the twigs were transferred to a greenhouse and after twenty one days the budbreak and

  12. Detritivores enhance the mobilization of {sup 137}Cs from leaf-litter

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Masashi; Suzuki, Takahiro [Community Ecology Lab., Biology Course, Faculty of Science, Chiba University, Chiba, 263-8522 (Japan); Ishii, Nobuyoshi [National Institute of Radiological Sciences, Chiba, 263-8555 (Japan); Ohte, Nobuhito [Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657 (Japan)

    2014-07-01

    A large amount of radioactive material was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident after the disastrous earthquake and subsequent tsunami of March 2011. Since most of the Japanese land area is covered by forest ecosystems, {sup 137}Cs was mostly deposited and accumulated on the land surface of forest. The fate of radioactive materials accumulated on the leaf litters should be conscientiously monitored to understand the future distribution and the spread to the surrounding landscapes. Because the accident took place on 11 March 2011, just before the bud-break of deciduous trees, the {sup 137}Cs are highly accumulated on the surface of leaf litter on the forest floor. This accumulated {sup 137}Cs had transferred to higher trophic organisms mainly through the detritus food chain. However, on the litter surface, {sup 137}Cs considered to be strongly and immediately fixed and highly immobilized. Decomposition processes in the forest floor can re-mobilise the nutritional elements which are contained within detritus and make them available for the organisms. In the present study, the feeding effect of detritivore soil arthropods on the mobilization of {sup 137}Cs from leaf litter was experimentally examined. Furthermore, the effect of detritivores on the plant uptake of {sup 137}Cs was examined by small-scale nursery experiment. Decomposition experiment in the small microcosms was performed using a larvae of Trypoxylus dichotomus, whichis a detritivores feeding on dead plant materials such as wood debris and leaf litters. Contaminated leaf litters were collected in a forest of the Kami-Oguni River catchment in the northern part of Fukushima Prefecture. The leaf litters at A0 layers which are highly contaminated by {sup 137}Cs were utilized for the experiment. The contaminated leaf litter was fed to the larvae for ten days. The litter with larvae excreta was washed by 2 M KCl and deionized water. The {sup 137}Cs concentration was measured

  13. Atividade de enzimas relacionadas com a mobilização de carboidratos durante a dormência da nogueira (Juglans Regia Walnut enzyme activity related with carbohydrate mobilization during dormancy period

    Directory of Open Access Journals (Sweden)

    Idemir Citadin

    2009-06-01

    Full Text Available A brotação da nogueira é dependente da mobilização de carboidratos do lenho para as gemas localizadas na porção superior dos ramos. O objetivo do trabalho foi contribuir para o entendimento do mecanismo de brotação acrótona da nogueira, em clima temperado, através da mensuração da atividade da ±-amilase (EC 3.2.1.1 e sacarose fosfato sintase (SPS - EC 2.4.1.14 relacionadas com a mobilização de carboidratos, durante o período de dormência. Para cada coleta, foram amostrados cinco ramos do ano, durante os meses de setembro a março. Em abril, próximo à retomada do crescimento ativo, foram feitas três amostragens. As partes apical, subapical e da base dos ramos foram separadas em casca, lenho (xilema e gemas. O tempo médio de brotação (TMB em condições controladas (25ºC, a umidade ponderal e a atividade das enzimas acima relacionadas foram determinadas. Os resultados obtidos reforçam a teoria de que o gradiente de brotação na nogueira se desenvolve durante a ecodormência e apresenta uma relação de dependência com a atividade da á-amilase; não está evidente a relação da atividade da SPS com a evolução do crescimento das gemas, durante a ecodormência.Juglans regia L. sprout depends on the carbohydrate mobilization from the parenchyma cells into the buds located in the upper portion of the twigs. The objective of this work was to contribute to the walnut tree sprout acrotony mechanism, in temperate climate, through the activity of alpha-amylase (EC 3.2.1.1, and Sucrose Phosphate Synthase (SPS - EC 2.4.1.14 mensuration, related to carbohydrate mobilization, during the dormancy period. From September to March, five one-year-old twigs were monthly sampled around. In April, close to budbreak, three samples were accomplished. The twigs were divided in apical, sub-apical, and base, and separated in bark, buds and wood (xylem. The average time of bud break in controlled conditions (25ºC, water content, and activity