Bud Break Period Research Articles

Evoluția fenofazelor de dezvoltare a unor specii de arbuști fructiferi în Republica Moldova

The paper presents the results of the study carried out regarding the development of the phenological phases of plant development of some species of fruit bushes in the Central area of the Republic of Moldova (the period of bud break, flowering and fruit ripening). It was established that the phenological phases of the studied species: raspberry (Rubus idaeus), black currant (Ribes nigrum), red currant (Ribes rubrum) and white currant (Ribes niveum), gooseberry (Ribes grossularia L.), Josta (Ribes x nidigrolaria), blackberry (Rubus caesius L.), sea buckthorn (Hippophae rhamnoides L.), honeysuckle (Lonicera kamtschatica), blueberry (Vaccinium corymbosum L.), dogwood (Viburnum opulus L.), chokeberry (Aronia melanocarpa Elliott), rose hip (Rosa rugosa Thunb), most of them having an early start in vegetation, which coincides with March, flowering takes place in April, and ripening – in June–July. Exceptions are: honeysuckle, with the earliest vegetation (03–09.03), flowering between 30.03 and 26.04 and ripening fruits in the second half of May (19–25.05); raspberries enter vegetation later (09–21.04), bloom on throughout May, and ripening takes place staggered in June, remontant raspberry varieties begin to bloom in July and ripens staggered in August; blackberry, with the latest onset of vegetation and the latest flowering (18.05–04.06), thus avoiding late spring frosts. Ripening takes place in stages at the beginning of July.

Water Regime Monitoring of the Royal Walnut (Juglans regia L.) Using Sap Flow and Dendrometric Measurements.

Changes in the distribution of annual rainfall totals, together with the increase in temperature over the last 40 years, are causing more frequent periods of drought, and plants are more often exposed to water stress. The aim of this study was to monitor the effect of different water regimes (irrigated and non-irrigated) of individuals of walnut tree (Juglans regia L.) in a private orchard located in the West of Slovakia. Our research was focused on dendrometric and sap flow measurements in the period from 28 March to 2 June 2019. The results showed differences in the sap flow of walnut trees during the budbreak period: when trees were irrigated, sap flow in the diurnal cycle was around 130 g·h−1 (20.48%), higher than in the non-irrigated treatment. Dendrometric differences between the irrigated and non-irrigated treatments were not significant. The sap flow data in the flowering period of the irrigated variant were slightly higher at 150 g·h−1 (35.62%) than non-irrigated. Dendrometric differences were more significant when the difference between the variants was more than 1.5 mm. Continuation of this research and analysis of the data obtained in the coming years will allow us to evaluate the effects of the environment on fruit trees in the long term.

The effect of climate on Burgundy vintage quality rankings

Aim: Based on consensus rankings from prominent rating authorities, we examined the importance of a suite of climatic variables, organized by winegrape phenological stage, in distinguishing between high- and low-ranked vintages in Burgundy.Methods and Results: Vintage ratings of Burgundy wines acquired from 12 sources were evaluated to develop consensus rankings for red and white wines from 1961–2015. Climate variables (air temperature, precipitation, degree-day accumulations, etc.) were organized by mean phenological stage and compared between good and poor vintages using Mann-Whitney U tests and multivariate stepwise discriminant function analysis. High temperatures, particularly during the growing season, were found to be the most consistently important climatic factor in distinguishing good-quality vintages from poor-quality vintages. The best red vintages had a greater diurnal temperature range during the growing season, whereas the top white vintages were not distinguished by unusually warm conditions, but the bottom-ranked white vintages were particularly cool and wet. The impact of rainfall varied across the growing season, with top-ranked Burgundy wines benefitting from rainfall during the bud break period and dry conditions during the ripening phase.Conclusions: The most important climatic factor in distinguishing between top- and bottom-ranked vintages is growing season temperature, especially high diurnal temperature range (for reds) and high average maximum temperatures (for whites). Good Burgundy vintages are more likely when there is ample rainfall during the bud break period in April and dry conditions during the véraison and ripening phases.Significance and Impact of the Study: As viticulturalists adapt to regional climate trends, a better understanding of how specific climate variables affect wine quality becomes increasingly important in viticulture management.

Influence of plant growth regulators on sex differentiation and floral characteristics of pomegranate flowers: a case of brassinosteroids

The objective of the present study was to determine the effects of brassinosteroid application on the sex determination and floral growth of pomegranate flowers. Whole tress of <em>Punica granatum</em> ‘Mayhoş-8’ were sprayed with 0.001, 0.01, and 0.1 mg L<sup>−1</sup> 28-homobrassinolide (Hbr) at bud break. The selection of flowers was based on the appearance of a visible pistil/stigma and shape of the ovary of intact flowers. Grouping of bisexual flowers was based on their flower position, i.e., single, terminal, and lateral flowers, during the first flush of flowering in mid-June. Approximately 20 days and 40 days after spraying, 100 randomly chosen bisexual flowers per collection time were collected and measurements of floral parts were immediately taken. The differences between bisexual and functional male flowers were not distinct enough to assert any significant effects from the different Hbr treatments. Irrespective of treatments, the percentage of male flowers was higher than that of bisexual flowers. Hbr treatments applied at the bud break period had significant effects only on bisexual flowers that developed as single flowers. Applying 0.01 mg L<sup>−1</sup> Hbr produced comparably lower percentages of single bisexual flowers (53.4%). Although the 0.1 and 0.001 mg L<sup>−1</sup> Hbr treatments resulted in increased percentages of bisexual flowers, the difference was not significant. For the first collection time (mid-June), the effects of Hbr concentration on the size of the floral parts for bisexual flowers were only significant in ovary width and stigma diameter. As the concentration decreased, smaller ovaries were obtained. During the second flowering, application of 0.01 mg L<sup>−1</sup> Hbr considerably increased the overall sizes of floral parts in bisexual flowers. Hbr might affect the ratio of flower formation in certain positions on a branch and could influence the growth of floral parts in bisexual flowers. Further elucidation of these effects would help to better understand floral organ development in plants.

The identification of almond GIGANTEA gene and its expression under cold stress, variable photoperiod, and seasonal dormancy

Seasonal growth is characteristic for many tree species including almond. Varying conditions during the season are responsible for growth cessation, bud set, dormancy entry, cold hardening, and bud burst. Here, we report the characterization of an almond homologue of the Arabidopsis GIGANTEA (AtGI) gene (designated as PdGI, GenBank accession No. KJ502316). We propose a role for this gene in the transition to dormancy and cold acclimation. The complementary DNA (cDNA) sequence of PdGI was 4 322 bp long and contained an open reading frame of 3 512 bp. The deduced amino acid sequence of PdGI shared 76 % identity with AtGI. The expression of PdGI at ambient day/night temperatures of 22/20 oC was differentially regulated under a 16-h or 12-h photoperiod, increasing during the day and decreasing after dusk. However, this diurnal regulation was disrupted when plants were transferred to cold (12 oC) conditions. In addition, we have assessed the expression of PdGI and putative almond homologues of the downstream target genes CONSTANS (PdCO-like) and FLOWERING LOCUS T (PdFT-like) in flower buds and shoots from adult trees during the bud break period in autumn and early winter. Our results show a clear increase in transcript abundance towards anthesis, suggesting a role of these genes in flower development.

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

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.

Atividade da peroxidase durante o período hibernal de plantas de pessegueiro (Prunus persica (L.) Batsch.) cv. jubileu com e sem sintomas da morte precoce

A morte precoce do pessegueiro (Prunus persica (L.) Batsch) é uma síndrome caracterizada por um colapso da planta durante a floração ou no início da brotação, após drástica redução da temperatura. O objetivo do presente trabalho foi determinar a atividade da peroxidase (UE min-1 g-1 MF) durante o período hibernal, em gemas e ramos de plantas de pessegueiro cv. Jubileu, com e sem sintomas de morte precoce. Foram conduzidos dois experimentos separadamente, um para cada tipo de tecido, em dois pomares próximos, ambos com quatro anos de implantação, situados na região colonial de Pelotas - RS, nas localidades de Santa Helena e Cascata. As amostras foram constituídas por dois tipos de tecidos (gemas e ramos) e foram coletadas em quatro datas (11-06, 11-07, 29-07 e 05-08) durante o inverno de 2003. As determinações da atividade da peroxidase nos tecidos foram realizadas no Laboratório de Fisiologia Vegetal da Embrapa Clima Temperado. As plantas com sintomas de morte precoce apresentaram, durante a dormência, maior atividade da peroxidase nos dois tipos de tecidos, quando comparadas com as plantas sem sintomas da síndrome. Provavelmente, o desencadeamento da síndrome provoca alterações na dormência das plantas afetadas, que resultam na antecipação da retomada do crescimento das gemas e na exposição dos tecidos recém-formados aos danos causados pelas baixas temperaturas. Os níveis populacionais donematoide-anelado (Mesocriconema xenoplax) e dos nematoides do gênero Helicotylenchus sp. foram superiores nas amostras de solo coletadas na rizosfera das plantas com sintomas de morte precoce do que os verificados nas amostras coletadas das plantas sem sintomas da síndrome, resultando também na maior atividade da peroxidase em ambos os tecidos (gemas e ramos), durante o período hibernal das plantas afetadas.

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

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. 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. 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. 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.

Phenology and photosynthetic traits of short shoots and long shoots in Betula grossa.

Leaf phenology, growth irradiance (i.e., photosynthetic photon flux (PPF) at the leaf surface) and photosynthetic capacity (A(area); measured at a PPF of 1000 micro mol m(-2) s(-1) and expressed on a leaf area basis) were investigated in early leaves (ELs) and late leaves (LLs) of Betula grossa Siebold & Zucc. trees. Early leaves first appeared on morphologically distinct long shoots and short shoots. The appearance of ELs, which was restricted to the bud break period, was followed by the successive appearance of LLs on long shoots only. Late leaves appeared successively until the middle of the growing season. Late leaves started to abscise around the middle of the growing season, whereas ELs on both long and short shoots did not abscise until near the end of the growing season. Solar irradiance was higher at the surface of LLs of late appearance than at the surface of either LLs of early appearance or ELs. Solar irradiance at the surface of ELs decreased after LLs appeared. In both long and short shoots, A(area) of ELs increased and then remained stable for 65-80 days before starting to decrease. Although A(area) was higher in LLs than in ELs for a short time in August, it started to decrease earlier in LLs than in ELs. Area-based nitrogen concentration (N(area)) was higher in LLs than in ELs after August. Although N(area) decreased slowly in ELs after August, it did not decrease in LLs. In both ELs and LLs, A(area)/N(area) decreased with time. The crown was thus characterized by a rapidly growing surface with young LLs having high A(area) and by shaded inner parts with ELs having stable low A(area).

Seasonal Development of Phomopsis Shoot Blight of Peach and Effects of Selective Pruning and Shoot Debris Management on Disease Incidence.

Seasonal development of shoot blight of peach caused by a Phomopsis sp. was evaluated in Oconee, Hall, and Peach counties in Georgia from April 1994 through May 1996. The frequency of infected buds in all three locations was highest during spring (mid-March to mid-May) and fall (early September to mid-October). The frequency of infected buds was highest in Hall County, which is the northernmost sampling location, followed by Oconee and Peach counties, which are located further south. During the same period of time, the effects of selective pruning and shoot debris management on disease incidence were evaluated in orchards in Oconee and Hall counties from May 1994 through May 1996. Selective pruning of infected shoots in May and October each year, following the major periods of infection, significantly reduced disease incidence during the following seasons in both locations. Disease incidence was similar regardless of whether shoot debris were left under the tree or removed from the orchard and destroyed. Our study indicates that major periods of infection of peach shoots by the Phomopsis sp. occur in the spring during the period of bud break, and in the fall when dormant buds and leaf scars are present. Additionally, our study indicates that reduction of inoculum by selectively removing infected shoots from the trees following the major periods of infection may significantly reduce disease incidence, although it may not eliminate the disease. Removal of infected shoot debris from the orchard does not appear to be necessary following pruning.

Thiol and amino acid composition of the xylem sap of poplar trees (Populus ×canadensis 'robusta')

Xylem sap of poplar trees was collected by vacuum extraction. Samples were taken year round and concentrations of thiols as well as amino acids were determined. Throughout the season glutathione was the predominant thiol in the xylem sap of poplar trees with concentrations ranging from 0.1 to 13 μM. Cysteine and γ-glutamylcysteine concentrations were 0.1–4 and 0.01–3 μM, respectively. The glutathione content was subject to strong seasonal fluctuations. Highest amounts of glutathione (13 μM) were observed in March, immediately before flowering of the catkins. Like γ-glutamylcysteine and cysteine, glutathione values reached further maxima at the onset of budbreak and leaf expansion in April and May. Also the amino acids investigated (glutamine, asparagine, glutamic acid, methionine, arginine) showed strong seasonal fluctuations in the xylem sap of poplar, with glutamine being the most abundant organic nitrogen compound (max. 13 mM). Highest amounts of amino acids were detected during April and May, the period of budbreak and leaf expansion, presumably owing to an increased degradation of storage protein. The sulfur-containing amino acid methionine was present in high amounts during the early growing season. It appeared to be the dominant reduced sulfur compound translocated in the xylem sap of poplar trees in April and May, whereas glutathione was the predominant organic sulfur compound in the xylem sap in March. The significance of storage and mobilization of reduced sulfur and organic nitrogen compounds for development of reproductive (catkins) and vegetative tissue (leaves and sprouts) in poplar trees is discussed. Key words: xylem sap, amino acid, thiol, transport, storage, mobilization.

Vegetative and reproductive behaviour of kiwifruit as related to cane length

Abstract In southern Italy (Bari, lat. 41°07′) mature kiwifruit vines (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson cv. Hayward) on pergolas were subjected to different winter pruning treatments over 3 consecutive years (1986–88) in order to study the effects of cane length on vegetative and reproductive behaviour. Three treatments were achieved by pruning canes to 6, 12, and 18 buds, and cane numbers were adjusted to leave the same number of buds (400 ± 30) on each vine. The data collected showed that: (1) the mean percentage budbreak decreased as cane length increased; (2) the budbreak period in plants with short canes was 8.7 days, whereas with long canes it was 3.7 days; (3) the number of fruits per winter bud ranged from 1.5 (canes with 6 buds) to 2.6 (canes with 12 buds); (4) the mean fruit weight was 92.9 g in plants with short canes (6 buds each), 88.5 g in plants with 12 buds/cane, and 81.5 g in those with 18 buds/cane; (5) at winter pruning the mean weight of woody material removed...

Improving flowering of kiwifruit in climatically marginal areas using hydrogen cyanamide

Application of hydrogen cyanamide (H 2NC  N; Dormex ®) more than doubled the average flowering intensity when applied to 8 kiwifruit ( Actinidia deliciosa (A. Chev.) C.F. Laing et A.R. Ferguson) orchards in the Western Cape. All pollinated flowers set fruit and this represented a potential doubling of production. There appeared to be some interaction between concentration and application time. Concentration had a much greater influence than application time. Three and 4% hydrogen cyanamide gave the highest flowering intensities. Application 5, 4 or 3 weeks before natural bud break gave equally good results, however, the vines showed increasing sensitivity to hydrogen cyanamide with decreasing time to bud break. The increased flowering intensity was brought about mainly by a more compact bud break period, which increased the proportion of flower-bearing (reproductive) shoots, as well as by an increase in the number of flowers on individual shoots. Overall bud break percentages were increased as well, but this had a smaller influence than the altered flower development pattern. The low chilling cultivar ‘Abbott’ was more sensitive to the chemical than cultivar ‘Hayward’ and showed phytotoxicity at the higher concentration (4%). The mature vines were naturally more productive, but showed a lower response to hydrogen cyanamide than the young vines. Mature vines generally had higher average flower numbers per reproductive shoot. The response to hydrogen cyanamide appeared to be greater in the orchards that received higher winter chilling accumulation.

Effect of applied growth regulators on cone production in Douglas-fir, and relation of endogenous growth regulators to cone production capacity

Extracts of buds and young shoots of a good cone-producing clone of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were tested for cone production effect on seed orchard Douglas-fir trees chosen for their history of poor cone production. Other metabolites, including gibberellin 4/7, arginine, and abscisic acid were also tested. Growth regulator levels in good and poor cone-producing clones of Douglas-fir were compared over the period of bud break and shoot elongation.No evidence was obtained for the presence of growth regulators critical to cone production in purified extracts from ramets of the good cone-producing clone. Applied gibberellin 4/7 increased male and female cone production. Crude extracts of a good cone-producing clone increased male cone bud production. Arginine and abscisic acid had no effect.Bioassays indicated that growth regulator levels in buds and young shoots changed greatly with stage of development but were similar in good and poor cone-producing clones.

Effect of a Dormant Application of Surfactants on Bud Development and Disease Control in Selected Deciduous Fruit Plants1

Abstract Spray treatment a single dormant application of high concentrations of anionic (Triton CS7) and nonionic (Triton N57 and Triton X100) surfactants caused up to 5 days delay in bud break in apple (Malus domestica Borkh.), but had less effect on grape (Vitis spp.) and peach (Prunus persica (L.) Batsch) and none on pear (Pyrus spp.). Surfactants tended to extend the bud break period but were frequently lethal to buds, particularly at concentrations of 3% and 5% active ingredient. In field studies, surfactants delayed the early stages of flower bud development but not bloom of apple or peach and did not control apple scab caused by Venturia inaequalis (Cke.) wint. or powdery mildew caused by Podosphaera leucotricha (Ell & Ev.) Salm.

Gibberellins, Abscisic Acid, and Related Inhibitors in Branches and Bleeding Sap of Birch (Betula pubescens Ehrh.)

Summary The main acidic inhibitor in wood, bark and bleeding sap has been identified by GC-MS and ORD to be ABA1). The ABA level was high during dormancy (wood 1.5, bark 2.2 mg/kg fr. w.) and low after breaking of buds (wood 0.02, bark 0.08 mg/kg fr. w.). In the period of bud break the ABA level decreased continuously in the wood but reached a maximum in the bark. Bleeding sap contained 40 ng ABA/ml, which apparently is leached off the xylem storage. Additionally, a neutral inhibitor has been detected showing a high content during winter dormancy (wood 2.4, bark 10.4 mg ABA-eq/kg fr. w.) and a lower one after bud break (wood 1.7, bark 7.8 mg ABA-eq/kg fr. w.). It consists of different components, one of which seems to be an ABA conjugate, apparently ABA glucosyl ester. In wood, bark and bleeding sap a GA has been detected chromatographically similar to GA3. In addition, the bark contained a GA4/7 like compound, and the wood a neutral GA conjugate during sap streaming. The GA content of the branches was very low during dormancy and increased at sap streaming period.

Cone-Induction Response of Douglas Fir to Form of Nitrogen Fertilizer and Time of Treatment

Cone production increases of 2.5, 5.0 and 1.5 times that of control were obtained the year following treatment with 400 lb nitrate nitrogen per acre (1 lb/acre = 1.12 kg/ha), applied 6 weeks before vegetative bud break, at the start of bud break, and 10 days after the midpoint of the bud break period, respectively, on 20-year-old Douglas fir (Pseudotsugamenziesii (Mirb.) Franco.). Cone counts of 15, 26, 72, 142 and 155 were obtained from 0, 200, 400, 800 and 1600 lb nitrate nitrogen per acre, applied to 13-year-old trees during early bud break. Ammonium nitrogen, applied at the same rates and times, was ineffective for stimulation of cone production on either age of tree. There were no differences in rate of accumulation of total nitrogen in buds and foliage, shoot-growth responses, or total number of buds per shoot due to form of nitrogen. Nitrate treatment enhanced cone production through a reduction in bud failure during the shoot elongation period. These results suggest responses are not primarily due to improved mineral nutrition, but to a specific chemical stimulation from critically timed changes in type of nitrogen metabolism. Possible influences of temperature and rainfall on natural cone crop periodicity and on proper timing of nitrate treatment are discussed.

Effect of soil and air temperature on soluble sugars and growth of white spruce (Picea glauca) seedlings

Qualitative and quantitative analyses of soluble sugars were conducted on needle and root samples of 17-month-old white spruce seedlings grown for the last 5 months at 50°, 70°, 80°, 90°, and 100 °F soil temperatures under continuous light in a greenhouse at an air temperature of 70 °F. Additional samples were taken when seedlings grown under these conditions were transferred for 1 month to a cold room at 34 °F under continuous light. Shoot and root growth was also studied on newly germinated seedlings exposed to soil–air temperatures of 65°–70°, 70°–70°, 80°–70°, and 90°–70 °F under continuous light for 8 months.An increase in sugars per unit dry weight, a greater apical growth, and a higher shoot–root ratio were associated with the 50°–70 °F and 65°–70 °F soil–air temperatures. The seedlings exposed for 1 month to soil–air temperatures of 34°–34 °F showed a considerable increase of soluble sugars, especially of the higher oligosaccharides from the raffinose family, when compared with those grown at 70 °F air temperature and varying soil temperatures. When seedlings are exposed to low temperatures, even at the period of budbreak, the change in the composition and amount of sugars is similar to that established under natural conditions in the fall.