Leaf absorption, withdrawal and remobilization of autumn-applied urea-N in apple

2004 ◽  
Vol 84 (1) ◽  
pp. 259-264 ◽  
Author(s):  
S. Guak ◽  
D. Neilsen ◽  
P. Millard ◽  
N. E. Looney
Keyword(s):  
Malus Domestica ◽  
Low Temperatures ◽  
Fruit Set ◽  
Urea Solution ◽  
Flower Buds ◽  
Flower Bud ◽  
Flower Opening ◽  
Total N ◽  
Bud Growth ◽  
Flower Quality

Six-year-old well-nourished Jonagold/M9 apple (Malus domestica) trees were sprayed 7 d after harvest with a 2% urea solution enriched with 9.9% atom 15N. Through 3 d of the absorption period, leaves absorbed 19.2% of the intercepted urea 15N. This low absorption could be in part due to unfavourable conditions, i.e., low temperatures (daily mean ≈5°C) and windy conditions following treatment. During leaf senescence, 48% of the urea 15N absorbed was withdrawn from leaves and most of that (95%) remained in the treated branch section. Of this portion, 65% of the urea 15N was found in dormant bark, 29% in wood, and 6% in flower buds. In the following spring, 46% of the stored urea 15N was remobilized for growth of the flower buds when sampled at the “pink” stage of bud development. This accounted for 3.8% of total N in these tissues. This contribution did not influence flower quality, estimated by the length of the period between flower opening and petal fall and the level of fruit set. Key words: Malus × domestica, urea-15N, flower bud growth, fruit set

scholarly journals Flower Bud Stage and Chill Hours Influence the Activity of GA3 Applied to Rabbiteye Blueberry

HortScience ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 316-318 ◽  
Author(s):  
D.S. NeSmith ◽  
Gerard Krewer
Keyword(s):  
Gibberellic Acid ◽  
Growth Regulator ◽  
Flower Development ◽  
Fruit Set ◽  
Developmental Stages ◽  
Single Application ◽  
Flower Buds ◽  
Flower Bud ◽  
Vaccinium Ashei

Individual flower clusters of `Tifblue' rabbiteye blueberry (Vaccinium ashei Reade) were treated with 300 ppm GA at several flower bud stages to determine the activity of the growth regulator in promoting fruit set. Applications were made one time only at a specified stage of flower development, or once followed by a second application. A single application of GA when flower buds had elongated but corollas had not expanded (stage 5) led to the largest increase in fruit set. Two applications of GA, 10 to 18 days apart, increased fruit set compared with a single application at flower developmental stages other than stage 5. Fruit set promoted by a single spray of GA imposed on fully expanded corollas (stage 6) decreased with increasing number of chill hours (350, 520, 760, or 1150). Chemical names used: gibberellic acid (GA).

scholarly journals Dead Prunus Flower-bud Primordia Retain Deep-supercooling Properties

HortScience ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 831-832
Author(s):  
Sorkel A. Kadir ◽  
Ed L. Proebsting
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Low Temperature ◽  
Low Temperatures ◽  
Sweet Cherry ◽  
Prunus Dulcis ◽  
Flower Buds ◽  
Flower Bud ◽  
Flower Primordia ◽  
Deep Supercooling

Differential thermal analysis (DTA) was used to measure deep supercooling in flower buds of Prunus dulcis Mill., P. armeniaca L., P. davidiana (Carr.) Franch, P. persica (L.) Batsch, three sweet cherry (P. avium L.) selections, and `Bing' cherries (P. avium L.) during Winter 1990-91 and 1991-92. Low temperatures in Dec. 1990 killed many flower buds. After the freeze, dead flower primordia continued to produce low-temperature exotherms (LTEs) at temperatures near those of living primordia for >2 weeks. In Feb. 1992, cherry buds that had been killed by cooling to -33C again produced LTEs when refrozen the next day. As buds swelled, the median LTE (LTE50) of dead buds increased relative to that of living buds, and the number of dead buds that produced LTEs decreased. LTE artifacts from dead flower priimordia must be recognized when DTA is used to estimate LTE50 of field-collected samples.

scholarly journals Hydrogen Cyanamide Stimulates Early Foliation of `Misty' Southern Highbush Blueberry

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 537C-537
Author(s):  
J.G. Williamson ◽  
R.L. Darnell
Keyword(s):  
Vegetative Growth ◽  
Fruit Set ◽  
Small Diameter ◽  
Highbush Blueberry ◽  
Full Bloom ◽  
Flower Buds ◽  
Flower Bud ◽  
Hydrogen Cyanamide ◽  
Southern Highbush ◽  
Chilling Treatment

Two-year-old, container-grown `Misty' southern highbush blueberry plants were sprayed to drip with two concentrations of hydrogen cyanamide (HCN) (20.4 g·L–1 and 10.2 g·L–1) after exposure to 0, 150, or 300 hr of continuous chilling at 5.6°C. All plants were sprayed immediately after chilling and placed in a greenhouse for several weeks. The plants were moved outdoors during flowering to increase cross-pollination from nearby `Sharpblue' blueberry plants. HCN sprays killed some of the more advanced flower buds on shoot terminals and on small-diameter wood from the previous spring growth flush. Significantly greater flower bud mortality occurred for the 20.4 g·L–1 HCN sprays than for the 10.2 g·L–1 sprays. Flower buds subjected to 0 hr of chilling were more susceptible to spray burn than flower buds receiving 150 or 300 hr of chilling. Very little flower bud death occurred with the 10.2 g·L–1 HCN rate on plants receiving 300 hr of chilling. Vegetative budbreak was advanced for both HCN treatments compared to controls, regardless of chilling treatment. HCN-treated plants were heavily foliated at full bloom, while non-treated plants had very few to no leaves during bloom. HCN may be useful for stimulating vegetative growth in some southern highbush blueberry cultivars that suffer from poor foliation during flowering and fruit set.

scholarly journals Influence of Blossom and Fruit Thinning on Peach Flower Bud Tolerance to an Early Spring Freeze

HortScience ◽  
1994 ◽  
Vol 29 (3) ◽  
pp. 146-148 ◽  
Author(s):  
Ross E. Byers ◽  
R.P. Marini
Keyword(s):  
Prunus Persica ◽  
Fruit Set ◽  
Unit Length ◽  
Early Spring ◽  
Late Winter ◽  
Flower Buds ◽  
Flower Bud ◽  
Cross Sectional ◽  
Fruit Thinning ◽  
Crop Density

Peach trees [Prunus persica (L.) BatSch.] blossom-thinned by hand were overthinned due to poor fruit set of the remaining flowers; however, their yield was equivalent to trees hand-thinned 38 or 68 days after full bloom (AFB). Blossom-thinned trees had three times the number of flower buds per unit length of shoot and had more than two times the percentage of live buds after a March freeze that had occurred at early bud swell the following spring. Blossom-thinned trees were more vigorous; their pruning weight increased 45%. For blossom-thinned trees, the number of flowers per square centimeter limb cross-sectional area (CSA) was two times that of hand-thinned trees and four times that of the control trees for the next season. Fruit set of blossom-thinned trees was increased four times. Flower buds on the bottom half of shoots on blossom-thinned trees were more cold tolerant than when hand-thinned 68 days AFB. Fruit set per square centimeter limb CSA was 400% greater the following year on blossom-thinned trees compared to controls. Removing strong upright shoots on scaffold limbs and at renewal points early in their development decreased dormant pruning time and weight and increased red pigmentation of fruit at the second picking. The number of flower buds per unit shoot length and percent live buds after the spring freeze were negatively related to crop density the previous season for trees that had been hand-thinned to varying crop densities at 48 days AFB. According to these results, blossom thinning and fruit thinning to moderate crop densities can influence the cold tolerance of peach flower buds in late winter.

The effect of summer shading on flower bud morphogenesis in apricot (Prunus armeniaca L.)

2013 ◽  
Vol 8 (1) ◽  
pp. 54-63 ◽  
Author(s):  
Susanna Bartolini ◽  
Raffaella Viti ◽  
Lucia Andreini
Keyword(s):  
Fruit Set ◽  
Prunus Armeniaca ◽  
Climatic Conditions ◽  
Regular Growth ◽  
Xylem Differentiation ◽  
Flower Bud ◽  
Primary Xylem ◽  
Floral Differentiation ◽  
Prunus Armeniaca L ◽  
Bud Growth

AbstractThe aim of this investigation was to assess whether imposed summer shading treatments in apricot (Prunus armeniaca L.) can affect the main phenological phases related to the floral morphogenesis (floral differentiation, xylogenesis), flower bud growth and quality in terms of bud capacity to set fruit. Experimental trials were carried out on fully-grown trees of ‘San Castrese’ and ‘Stark Early Orange’ cultivars characterized by different biological and agronomical traits to which shadings were imposed in July and August. Histological analysis was carried out from summer onwards in order to determine the evolution of floral bud differentiation, and the acropetal progression of primary xylem differentiation along the flower bud axis. Periodical recordings to evaluate the bud drop, blooming time, flowering and fruit set rates were performed also. These shade treatments determined a temporary shutdown of floral differentiation, slowed xylem progression up to the resumption of flower bud growth and a reduced entity of flowering and fruit set. These events were particularly marked in ‘San Castrese’ cultivar, which is well known for its adaptability to different climatic conditions. These findings suggest that adequate light penetration within the canopy during the summer season could be the determining factor when defining the qualitative traits of flower buds and their regular growth, and ultimately to obtain good and constant crops.

scholarly journals Ethephon Prolongs Dormancy and Enhances Supercooling in Peach Flower Buds

1991 ◽  
Vol 116 (3) ◽  
pp. 500-506 ◽  
Author(s):  
Edward F. Durner ◽  
Thomas J. Gianfagna
Keyword(s):  
Prunus Persica ◽  
Storage Period ◽  
Bud Dormancy ◽  
Late Winter ◽  
Flower Buds ◽  
Flower Bud ◽  
Ethephon Treatment ◽  
Bud Growth ◽  
Peach Trees ◽  
Heat Requirement

The heat requirement for flower bud growth of container-grown peach trees [Prunus persica (L.) Batsch. cvs. Redhaven and Springold] in the greenhouse varied inversely and linearly with the length of the cold-storage period (SC) provided to break bud dormancy. Ethephon reduced the rest-breaking effectiveness of the 5C treatment. Buds from ethephon-treated trees grew more slowly than buds from untreated trees upon exposure to 20 to 25C, resulting in later bloom dates. The effect of ethephon on flower bud hardiness in field-grown trees of `Jerseydawn' and `Jerseyglo' was studied using exotherm analysis after deacclimation treatments. Bud deacclimation varied with reacclimating temperature (7 or 21 C), cultivar, ethephon treatment, and sampling date. All buds were more susceptible to injury in March than in January or February. Buds reacclimated more rapidly at 21C than at 7C. `Jerseyglo' reacclimated more rapidly than `Jerseydawn'. Untreated buds were less hardy and also reacclimated more rapidly than treated buds. Ethephon enhanced flower bud hardiness in three distinct ways: 1) it decreased the mean low-temperature exotherm of pistils, 2) it increased the number of buds that supercooled after exposure to reacclimating temperatures, and 3) it decreased the rate of deacclimation, especially at 21C. Ethephon prolongs flower bud dormancy by increasing the chilling requirement. The rate at which flower buds become increasingly sensitive to moderate temperatures in late winter and spring is thus reduced by ethephon. Thus, ethephon delays deacclimation during winter and delays bloom in the spring. Chemical name used: (2-chloroethyl) phosphoric acid (ethephon).

scholarly journals (93) Vegetative and Flower Bud Development, and Fruit Set of Low-chill Peach Cultivars in North-central, Central, and Southwest Florida

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1029A-1029
Author(s):  
Todd Wert ◽  
Jeffrey G. Williamson ◽  
Robert E. Rouse
Keyword(s):  
Fruit Set ◽  
Average Length ◽  
Flower Buds ◽  
Flower Bud ◽  
North Central ◽  
Bud Development ◽  
Central Florida ◽  
Southwest Florida ◽  
Vegetative Buds ◽  
Flower Bud Development

Four low-chill peach cultivars were evaluated at three locations in Florida for vegetative and reproductive bud development and fruit set. Twenty trees (five each of `Flordaprince', `Tropicbeauty', `UFgold', and `Flordaglo') were planted at each site in Feb. 2002. Prior to budbreak in Spring 2004 and 2005, three shoots per tree of average length and diameter were selected at a height between 1.5–2.0 m and the numbers of vegetative and flower buds per node were recorded for each shoot. No consistent pattern for the number of vegetative buds per node was observed among cultivars and locations, or across years. However, 'Tropicbeauty' tended to have fewer vegetative buds per node than `Flordaprince' during both seasons, although not at all locations. Overall, the number of flower buds per node was greater for north-central Florida than for central or southwest Florida. There were no consistent tends over years and among locations for the ranked order of flower buds per node by cultivar. The percentage of nodes without flower or vegetative buds (blind nodes) was generally greatest for `Tropicbeauty' at most locations during both years. During 2005, the percentage of blind nodes was greater in central and southwest Florida than in north-central Florida. Overall, fruit set was similar between the central and north-central Florida locations. Fruit set tended to be higher for `UFGold' and `Flordaglo' than for `Flordaprince' or `Tropicbeauty'.

scholarly journals Infection Efficiency of Venturia inaequalis Ascospores as Affected by Apple Flower Bud Developmental Stage

Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 661-663 ◽  
Author(s):  
S. Sanogo ◽  
D. E. Aylor
Keyword(s):  
Developmental Stage ◽  
Venturia Inaequalis ◽  
Growth Stages ◽  
Vegetative Shoot ◽  
Flower Buds ◽  
Flower Bud ◽  
Infection Efficiency ◽  
Tight Cluster ◽  
Bud Growth

The average infection efficiency of ascospores of Venturia inaequalis deposited on cluster leaves of apple flower buds was 6 to 16%, 3 to 9%, and 0.4 to 0.6% at tight cluster, first pink, and full pink-to-bloom, respectively. No lesions were observed on flower bud cluster leaves at petal fall. However, the leaves on the vegetative shoot emerging from the flower bud were highly susceptible; the average infection efficiency of ascospores on these leaves was 6 to 21%. The infection efficiency was more variable on young cluster and vegetative shoot leaves than on developing and mature cluster leaves. Results from this study indicate that differences in infection efficiency of V. inaequalis ascospores could be identified by apple bud growth stages.

Hormone Sprays and Supplemental Light Prevent Cold-storage-induced Postharvest Leaf Chlorosis and Abscission in `Stargazer' Hybrid Lilies

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 536c-536
Author(s):  
Anil P. Ranwala ◽  
William B. Miller
Keyword(s):  
Cold Storage ◽  
Storage Temperature ◽  
Flower Longevity ◽  
Flower Bud ◽  
Flower Opening ◽  
Foliar Sprays ◽  
Leaf Chlorosis ◽  
Bud Opening ◽  
Flower Quality

Rapid leaf chlorosis and abscission limits the use of cold storage for post-production short-term holding of potted lilies. We investigated the effects of storage temperature, storage irradiance and pre-storage foliar sprays of gibberellin and/or cytokinin on postharvest leaf and flower quality of Lilium sp. `Stargazer' hybrid lilies. Storage of “puffy bud” stage plants at 4, 7, or 10 °C in dark for 2 weeks induced leaf chlorosis within 4 days in a simulated consumer environment, and resulted in 60% leaf chlorosis and 40% leaf abscission by 20 days. Cold-storage also reduced the duration of flower bud opening, inflorescence and flower longevity, and increased flower bud abortion. Providing light up to 40 μmol·m–2·s–1 during cold-storage at 4 °C significantly delayed leaf chlorosis and abscission and increased the duration of flower bud opening, inflorescence and flower longevity. Foliar sprays of ProVide (100 mg·L–1 GA4+7) and Promalin [100 mg·L–1 GA4+7 and 100 mg·L–1 benzyladenine (BA)] effectively prevented leaf chlorosis and abscission at 4 °C, while ProGibb (100 mg·L–1 GA3) and ABG-3062 (100 mg·L–1BA) were not effective. Accel (10 mg·L–1 GA4+7 and 100 mg·L–1 BA) showed intermediate effects on leaf chlorosis. Flower longevity was increased and bud abortion was prevented by all hormone formulations except ProGibb. The combination of light (40 μmol·m–2·s–1) and Promalin (100 mg·L–1 GA4+7 and 100 mg·L–1 BA) completely prevented cold-storage induced leaf chlorosis and abscission and significantly improved flower opening and overall plant quality.

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