Bud Burst Percentage Research Articles

Significance of the root connection on the dormancy release and vegetative bud burst of Norway spruce (<i>Picea abies</i>) seedlings in relation to accumulated chilling

The effect of cutting the root connection by detaching the shoot from the root system on dormancy release and vegetative bud burst was examined in 2-year-old seedlings of Norway spruce ( [L.] Karst.). Seedlings were transferred at 1–4 week intervals between October and January from outdoor conditions to experimental forcing in a heated greenhouse. Before forcing, half of the seedlings were cut above ground line, and the detached shoots were forced with their cut ends placed in water. The intact seedlings were forced with their root system remaining intact in the pots. Vegetative bud burst was observed visually. Cutting the root connection slightly increased days to bud burst in the forcing conditions, however, no consistent effect on bud burst percentage was found. Our preliminary seedling data suggest that using detached tree material in dormancy release experiments may have a small effect on bud burst date but it will evidently not lead to drastically erroneous conclusions. Further studies, using different seed lots, are needed to assess the effect of detaching on the dormancy release and bud burst, especially in adult trees.Picea abies

Impacts of contrasting light on bud burst and on RwMAX1 and RwMAX2 expression in rose

Bud burst is a crucial factor in plant architecture and is strongly induced by light. In Rosa sp., this light effect was correlated with the growth of axillary buds and RwMAX1 and RwMAX2 expression within buds. In this paper, we investigated whether strigolactone pathway is involved in the regulation of axillary bud in response to light intensity. Hence, young roses were subjected to two contrasting light intensity regimes: high/high and high/low. The phenotype was characterized in both conditions and the expression of RwMAX1 and RwMAX2 genes was measured in the basal, middle and apical parts of rose primary branch. Light treatments showed a strong impact on axillary bud. The percentage of bud burst was severely reduced in the treatment high/low compared to the treatment high/high in all branch parts. In addition, the expression of RwMAX1 and RwMAX2 was strongly inhibited by high/high light regime and was conversely correlated with the rate of bud burst. In in vitro-grown axillary buds supplied with sucrose, glucose and fructose, RwMAX1 expression was significantly stimulated whereas that of RwMAX2 was significantly inhibited. Our results suggest that although RwMAX1 and RwMAX2 expression can be regulated by light, this expression does not explain the ability of bud burst.

Adaptability and stability of 34 peach genotypes for leafing under Brazilian subtropical conditions

This study aimed to evaluate adaptability and stability for leafing of peach genotypes in a subtropical climate. The design was completely randomized with three replicates (trees) and five branches per replicate in a factorial arrangement of 34×4 for genotypes and years, respectively. The beginning of budburst (5%), final budburst (75%) and fruit-bearing shoots formed at 45 days after the end of the budburst were evaluated for four years (2007–2010). The number of hours of temperature below 7.2°C or 12°C or above 20°C from May to August was recorded. Adaptability and stability analyses were performed using GGE biplot methodology. ‘Cascata 1063’, ‘Cascata 1303’, ‘Conserva 1187’, ‘Conserva 1223’, ‘Conserva 1396’, ‘Kampai’, ‘Libra’ and ‘Santa Áurea’ were the peach tree genotypes with the greatest adaptability and stability for budburst trait. For fruit-bearing shoots formed, the genotypes ‘Conserva 1127’, ‘Conserva 1216’ and ‘Conserva 681’ had the greatest adaptability and stability. A high percentage of budburst does not necessarily lead to a high percentage of fruit-bearing shoots development. ‘Âmbar’, ‘Bonão’, ‘Conserva 655’, ‘Kampai’, ‘Libra’, ‘Rubimel’ and ‘Santa Áurea’, showed a good percentage of budburst and development of fruit-bearing shoots, remained stable for both traits and are considered the best adapted.

Expressional regulation of PpDAM5 and PpDAM6, peach (Prunus persica) dormancy-associated MADS-box genes, by low temperature and dormancy-breaking reagent treatment

The present study investigated the expressional regulation of PpDAM5 and PpDAM6, two of the six peach (Prunus persica) dormancy-associated MADS-box genes, in relation to lateral bud endodormancy. PpDAM5 and PpDAM6 were originally identified as homologues of Arabidopsis SHORT VEGETATIVE PHASE/AGAMOUS-LIKE 24 identified in the EVERGROWING locus of peach. Furthermore, PpDAM5 and PpDAM6 have recently been suggested to be involved in terminal bud dormancy. In this study, seasonal expression analyses using leaves, stems, and lateral buds of high-chill and low-chill peaches in field conditions indicated that both genes were up-regulated during the endodormancy period and down-regulated with endodormancy release. Controlled environment experiments showed that the expression of both PpDAM5 and PpDAM6 were up-regulated by ambient cool temperatures in autumn, while they were down-regulated by the prolonged period of cold temperatures in winter. A negative correlation between expression levels of PpDAM5 and PpDAM6 and bud burst percentage was found in the prolonged cold temperature treatment. Application of the dormancy-breaking reagent cyanamide to endo/ecodormant lateral buds induced early bud break and down-regulation of PpDAM5 and PpDAM6 expression at the same time. These results collectively suggest that PpDAM5 and PpDAM6 may function in the chilling requirement of peach lateral buds through growth-inhibiting functions for bud break.

Chlorophyll fluorescence as a tool for evaluation of viability in freeze-stressed grapevine buds

This study examined the utility of the ratio of variable fluorescence to maximum fluorescence (Fv/Fm) to detect freezing injury on buds of two Vitis vinifera cultivars: Pinot noir and Pinot gris. Freezing treatments on buds caused a decrease both in Fv/Fm and percentage of budburst, more severely on Pinot gris than Pinot noir, specifically at the lower temperature (-20°C). Fv/Fm ratio showed a close correlation with percentage of budburst, and a threshold of the lethal Fv/Fm was proposed as an indicator of bud mortality.

Summer water stress and shade alter bud size and budburst date in three mediterranean Quercus species

Current environmental conditions are known to affect plant growth, morphology, phenology, and therefore, plant performance. However, effects of the previous-year environmental conditions can also affect plant structure by altering bud growth, and proportion and date of budburst. Here, we analysed the effects of previous-year water stress and shade on bud size, percentage, and date of budburst in seedlings of three co-occurring Iberian Quercus species in two independent experiments. Responses of apical, lateral, and basal buds were checked during an annual cycle. In the first experiment, seedlings of two evergreens (Q. coccifera L., Q. ilex subsp. ballota (Desf.) Samp.) and a deciduous-marcescent tree (Q. faginea Lam.) were grown under two levels of summer watering. In the second experiment, seedlings were grown under three light intensities. Soluble sugars and starch in shoots and roots were measured before budburst. Summer drought increased bud size of all species and advanced budburst of Q. ilex and Q. coccifera. Moderate and/or intense shade tended to reduce bud size and delay budburst in all species. These responses seem related to changes in the date of bud formation rather than to the amount of carbon reserves, which were reduced both by drought and shade. Treatments affected percentage of budburst in lateral buds, which was reduced by shade and water stress, probably leading to narrower crowns. These results show that previous-year environmental conditions are relevant for plant phenology and structure. The different responses in budburst date between the deciduous and the evergreens might alter their competition relationships at seedling stage.

STUDIES ON THE EFFECT OF SOME DORMANCY BREAKING AGENTS ON BUD BEHAVIOUR AND YIELD OF LE-CONTE PEARS

This investigation was carried out during the seasons of 2006 and 2007 to study the effect of some dormancy - breaking chemicals on bud constituents, bud break, flower fire blight infections, fruit set and yield of Le Conte pear trees. The data revealed that, spraying Le-Conte pear trees at 1st February with Dormex at 1% + mineral oil at 3% was effective for hastening the date of bud burst, enhanced the bud burst percentage and gave pronounced effect on bud constituents, flower fire blight infections, fruit set and yield. Furthermore, spraying Le-Conte pear trees with mixture of Dormex at 1% and mineral oil at 3% is an economic treatment than the use of hydrogen cyanamide alone at 4% as recommended which is rather expensive under the Egyptian conditions.

EFFECT OF SPRAYING OF THOMPSON SEEDLESS GRAPEVINES WITH HYDROGEN CYANAMIDE ON BUD BEHAVIOUR

Dormex at 0, 2, 3 and 5% was sprayed on 1 or 7 or 14 January during two seasons 2006 and 2007 on 15 years old Thompson Seedless grapevines, planted at 2 X 2 meter in a loamy clay soil on three dates. The results of the two experimental seasons indicated that, the response of Thompson Seedless grapevines to (Dormex) treatments varied according to the concentration and spraying date. Budburst percentage generally increased from the basal to distal of bud location. The percentages of budburst, time budbreak and the vegetative growth were markedly increased respectively compared to control. There beneficial results concerning an advancement in date of bud burst, an increase in the percentage of buds developed to vegetative growth and appearance of flowering. The best results were obtained by 5% hydrogen cyanamide applied on the first of January in both season.

Rootstock effect on budburst of ‘Premier’ low-chill peach cultivar

Abstract To determine the effect of rootstock with different chilling requirements on the bud break of the low-chill ‘Premier’ peach cultivar (150 CH), the trees grafted on ‘Newbelle’ (150 CH) and ‘O’Henry’ (750 CH) seedling rootstocks were forced in a glasshouse after being subjected to 100, 200 and 300 CU chilling. The percentage of flower bud burst was slightly higher on ‘Newbelle’ than on ‘O’Henry’, although the difference was not significant. There was little leaf bud burst with 100 CU chilling on both rootstocks. With 200 and 300 CU chilling, the percentage of leaf bud burst and the total leaf number per tree was higher on the ‘Newbelle’ than on the ‘O’Henry’ rootstocks.

The role ofDiaporthe perjunctain delayed budburst and death of grapevine buds

Diaporthe perjuncta has been associated with Phomopsis cane and leaf spot disease of grapevine in Australia. Both D. perjuncta and Phomopsis viticola cause bleaching of cane and, for this reason, diagnosis of the two fungi is often confused in the vineyard. P. viticola causes leaf spots and shoot lesions in the growing season, whereas more recent studies have indicated that D. perjuncta might not be a pathogen. Field studies were conducted to assess the role of D. perjuncta in delayed budburst and death of grapevine buds. Over three seasons (1999–2001), vines were assessed at four vineyards in South Australia for percentage of budburst and incidence of D. perjuncta. A D. perjuncta-specific probe, pT1P180, was used to detect D. perjuncta in unburst buds, cane and shoots on spurs having buds that failed to burst. D. perjuncta was detected in both bleached and non-bleached cane. Although there was a significant association between the incidence of D. perjuncta and buds that failed to burst in 1999 only, overall bud burst was normal in all vineyards and bud loss was not a concern. Bunch number and shoot growth was not affected. Mites were considered as a possible factor in damage to unburst buds, but it was more likely that failure of buds to burst was related to physiological or environmental effects. D. perjuncta did not adversely affect grapevine productivity and cannot be regarded as a pathogen of grapevine.

Bud burst in Norway spruce (Picea abies): preliminary evidence for age-specific rest patterns

This study examines the effect of chilling and photoperiod on rest completion and bud burst in Norway spruce [Picea abies (L.) Karst.] using twigs from both 15-year-old (“young trees”) and 56-year-old (“old trees”) trees. The material was transferred between September and May from outdoors to experimental forcing conditions with four different photoperiods. The bud burst percentage of the twigs from young trees generally increased in all photoperiods until the end of the year. After that it decreased until vernal equinox (March 20) and then increased steeply towards spring. This new observation of transient rest completion during autumn suggests that young trees have (I) a transient time window during late autumn when ontogenetic development is possible, and (ii) a secondary rest culminating approximately at the time of vernal equinox. In twigs from old trees the transient rest completion was much weaker as the bud burst percentages generally remained under 20 during autumn and winter. At vernal equinox there were no burst buds in twigs from the old trees in any photoperiod and after that the bud burst percentage increased basically in the same manner as in the young trees. The bud burst percentage of the twigs from young trees was generally higher as the photoperiod increased. However, no evidence for absolute long photoperiod requirement of rest completion was observed.

Brotação e fertilidade de gemas em uvas sem sementes no Vale do São Francisco

Com o objetivo de avaliar a porcentagem de brotação e índice de fertilidade de gemas de cinco variedades de uvas sem sementes em cinco diferentes datas de poda, realizou-se um experimento no Campo Experimental de Bebedouro, da Embrapa Semi-Árido, em Petrolina-PE. O delineamento experimental foi em parcelas subdivididas, constituídas por cinco variedades de uvas sem sementes como tratamentos principais e cinco diferentes épocas de poda como tratamentos secundários, utilizando-se dez repetições constituídas por uma planta. As variedades utilizadas foram Perlette, Thompson Seedless, Marroo Seedless, Catalunha e Superior Seedless, e as épocas de poda foram: 18 e 19/12/2000; 18 a 21/06/2001; 23 a 29/10/2001; 29/01 a 05/02/2002 e 08 a 12/04/2002. As variáveis estudadas foram a porcentagem de brotação e o índice de fertilidade real das gemas determinado pela razão número de cachos por número de gemas. A fertilidade real de gemas foi analisada entre a 1ª e 10ª gema da vara. Os maiores valores médios para brotação e fertilidade foram observados nas variedades Marroo Seedless e Perlette, sendo que as podas realizadas nos meses de junho de 2001 e abril de 2002 favoreceram o aumento da brotação e da fertilidade das gemas na maioria das variedades.

New contribution to the survey of the acrotony theory on the branch of one year grapevine: III - Role of buds and leaves in development, application in the vineyard of results obtained in laboratory and greenhouse

<p style="text-align: justify;">The respective influences of the bud and leaves on stimulation of acrotony phenomenon was studied. Defoliation (all leaves at the stage budbursted + 30 days) and various bud ablation were made : buds 9, 10 ; 7, 8, 9, 10 ; 5, 6, 7, 8, 9, 10 ; 3, 4, 5, 6, 7, 8, 9, 10.</p><p style="text-align: justify;">Concerning the phenomen of acrotony, the role of apical bud and leaves developped on at 10 and 30 days after budburst were determined.</p><p style="text-align: justify;">The effect produced by excision of the apical buds shows that the two subadjacent buds were developped. All decapitation did not increase the percentage of budbreak.</p><p style="text-align: justify;">In all decapitations, the subadjacent buds were developped however, buds below were inhibed. The effect produced by excision of leaves in the second stage of development did not promote budbreak.</p><p style="text-align: justify;">On 10 bud canes, auxins synthesized in the developing young leaves seem to exercise their inhibiting effect on the budbreak of the subjacent buds.</p><p style="text-align: justify;">Cytokinins managed by the means of our operatory mode seem to reach the subjacents buds, modify the expression of the ramification of the canes with regard to the system usual acrotony and limit the inhibition basipetally. The budburst of the canes at a temperature of 18°C seems to be more important than that at 30°C day/ 20°night. Thus, the acrotony phenomenon decreases. When the apical branches are in second phase of growth, the size of the leaves become large. It seems that the leaves would exercise their inhibitions on the subjacent buds by the slant of the synthesized gibberillins and auxins. Cytokinins have no further role to play during this phase of growth and do not thwart anymore the inhibition. In the vineyard, the ANA treatment is totally inhibiting at 20 and 50 mg/l doses. In contrast, the 6BAP treatment at 20 mg/l shortly before budburst increases the budburst percentage for Muscatel of Italy.</p><p style="text-align: justify;">When the last treatment is performed during 25 days followed by a cytokinin treatment we notice budburst. The mechanism of these different growth regulators on the acrotony phenomenon has been discussed .</p>

The effects of hydrogen cyanamide on budburst and fruit maturity of ‘Thompson Seedless’ grapevine

SummaryThe effect of hydrogen cyanamide (H2CN2) on budburst and fruit maturity of `Thompson Seedless' grapes was examined. Nine year old vines of cv. Thompson Seedless grafted on R.110 rootstock and supported on overhead tendone trellis (parral), were treated with either 2% or 4% of H2CN2, 53 and 67 d before expected budbreak and compared with unsprayed vines. The earliest treatment with 4% H2CN2 enhanced budbreak and advanced fruit maturity by 17 d. However, the same concentration applied 53 d before natural budbreak advanced the date of maturity by only 4 d. All the treatments increased significantly the percentage of budburst compared with the control. H2 CN2 had no significant effect on yield, but a positive effect on fruit quality. A higher index of maturity was obtained by the treatment: 4% H2CN2, 67 d before budbreak. All the treatments of H2CN2 induced more uniform budburst compared with the control. The best uniformity was obtained by the earliest spray using the higher concentration (4%).

Improving Production of MM.106 Apple Rootstock Stools using Hydrogen Cyanamid Dormancy-breaking Agent

Dormex (aqueous solution of 48% hydrogen Cyanamid) was applied by the end of December at 2%, 4%, and 6% in the first season and at 3%, 4%, and 5% in the second season to 1-year-old shoots of MM.106 apple rootstock. Dormex at 4%, 5%, and 6% increased significantly the percentage of bud burst, stool diameter, stool length, internode length, and leaf area; moreover, it decreased the number of days required to reach 50% bud burst. However, Dormex at 4% and 6% enhanced the stool Grand Period of Growth (GPG) by 1 and 2 months, respectively, compared with the untreated plants. Dormex treatments resulted in a significant increase in stool content of N, Ca, and Zn.

数種の日本原産野生ブドウの芽の休眠と内生ＡＢＡおよび新梢内水分含量との関係

The intensity of bud dormancy, water content, and the endogenous levels of ABA-like substances in shoots of several wild grape species native to different regions of Japan were compared with those of Vitis labruscana Bailey, cultivar 'Muscat Bailey A', from September to December.The onset of endodormancy (rest) in V. coignetiae Pulliat and V. amurensis Rupr., which are wild species of the more northern origin, was earlier than that in other wild species. Furthermore, the water content decreased during a period of bud dormancy, whereas, the levels of ABA-like substances increased sharply in October for these two wild species. In V. shiragai Makino and the cultivar 'Muscat Bailey A', the period of the deepest dormancy occurred in November. The water content of their shoots decreased gradually and the levels of ABA-like substances increased as the intensity of bud dor-mancy deepened. The period of the deepest dormancy of V. kiusiana Momiyama and V. sp. (tentative name Shiohitashibudo) was not well-defined, because these wild species ex-hibited low percentages of bud burst during the study period. Changes in shoot water content of these two species paralleled the changes in percentage of bud burst. However, the level of ABA-like substances in these wild species peaked in November. The period of the deepest dormancy in V. ficifolia Bunge var. ganebu Hatusima, which is of subtropical origin, occurred in November, but its intensity was lighter than that of other wild spe-cies. Its shoots also had higher water content and low ABA-like substances.The results show that the onset and intensity of bud dormancy differed among the wild grape species and, generally, low shoot water content and high level of ABA-like subst-ances coincided with the time of deepest dormancy.

A COMPARISON OF POST-BUDDING TREATMENTS OF CACAO IN THE NURSERY

The percentage of bud burst, survival and growth was influenced by the budding site and post-budding treatment. Cacao (Theobroma cacao L.) seedlings budded at the cotyledonary node performed better than those budded at the eighth node above the cotyledon. Scions patch budded at the cotyledonary node performed best if four to eight leaves were left above the bud patch and the rest of the stem excised. Poor treatments were total leaf removal and decapitation two to three inches above the bud, bending the stock plant stem and removal of the apical bud.

BREAKING THE REST PERIOD IN BLACK CURRANTS WITH GIBBERELLIC ACID AND LOW TEMPERATURE

A single application of gibberellic acid (GA) was successful in breaking the rest period of black currants in September, October and November, while chilling for 2 weeks was insufficient to be effective.The highest percentage of bud burst was obtained by GA application immediately after defoliation. Delay in GA application after defoliation decreased and delayed plant response because penetration of GA was hindered. Multiple and very early GA applications immediately after taking the plants into the glasshouse caused shedding of undeveloped buds.