Endogenous auxin regulates the sensitivity of Dendrobium (cv. Miss Teen) flower pedicel abscission to ethylene

2007 ◽  
Vol 34 (10) ◽  
pp. 885 ◽  
Author(s):  
Karnchana Rungruchkanont ◽  
Saichol Ketsa ◽  
Orawan Chatchawankanphanich ◽  
Wouter G. van Doorn
Keyword(s):  
Abscission Zone ◽  
Flower Buds ◽  
Flower Stalk ◽  
Gene Encoding ◽  
Ethylene Sensitivity ◽  
Floral Buds ◽  
Ethylene Removal ◽  
Highly Correlated ◽  
Floral Bud ◽  
Flower Abscission

Dendrobium flower buds and flowers have an abscission zone at the base of the pedicel (flower stalk). Ethylene treatment of cv. Miss Teen inflorescences induced high rates of abscission in flower buds but did not affect abscission once the flowers had opened. It is not known if auxin is a regulator of the abscission of floral buds and open flowers. The hypotheses that auxin is such a regulator and is responsible for the decrease in ethylene sensitivity were tested. Severed inflorescences bearing 4–8 floral buds and 4–6 open flowers were used in all tests. The auxin antagonists 2,3,5-triiodobenzoic acid (TIBA, an inhibitor of auxin transport) or 2-(4-chlorophenoxy)-2-methyl propionic acid (CMPA, an inhibitor of auxin action) were applied to the stigma of open flowers. Both chemicals induced high flower abscission rates, even if the inflorescences were not treated with ethylene. The effects of these auxin antagonists virtually disappeared when the inflorescences were treated with 1-methylcyclopropene (1-MCP), indicating that the abscission induced by the auxin antagonists was due to ethylene. Removal of the open flowers at the distal end of the pedicel hastened the time to abscission of the remaining pedicel, and also resulted in an increase in ethylene sensitivity. Indole-3-acetic acid (IAA) in lanolin, placed on the cut surface of the pedicel, replaced the effect of the removed flower. Treatments that promoted abscission of open flowers up-regulated a gene encoding a β-1,4-glucanase (Den-Cel1) in the abscission zone (AZ). The abundance of Den-Cel1 mRNA was highly correlated with β-1,4-glucanase activity in the AZ. The results show that auxin is an endogenous regulator of floral bud and flower abscission and suggest that auxin might explain, at least partially, why pedicel abscission of Dendrobium cv. Miss Teen changes from very ethylene-sensitive to ethylene-insensitive.

High floral bud abscission and lack of open flower abscission in Dendrobium cv. Miss Teen: rapid reduction of ethylene sensitivity in the abscission zone

2006 ◽  
Vol 33 (6) ◽  
pp. 539 ◽  
Author(s):  
Kanokpon Bunya-atichart ◽  
Saichol Ketsa ◽  
Wouter G. van Doorn
Keyword(s):  
Abscission Zone ◽  
Flower Opening ◽  
Open Flower ◽  
Rapid Reduction ◽  
Ethylene Sensitivity ◽  
Floral Buds ◽  
Endogenous Ethylene ◽  
Ethylene Insensitivity ◽  
Floral Bud ◽  
Flower Abscission

We studied the abscission of floral buds and open flowers in cut Dendrobium inflorescences. Abscission of floral buds was high and sensitive to ethylene in all cultivars studied. Many open flowers abscised in most cultivars, but cv. Willie exhibited only small amount of floral fall and cv. Miss Teen none. Applied ethylene (0.4 μL L–1 for 24 h at 27°C) greatly hastened abscission of open flowers in most cultivars, but had only a small effect in cv. Willie and no effect in cv. Miss Teen. Flower fall, if it occurred, was completely inhibited by 1-methylcyclopropene (1-MCP), showing that it was regulated by endogenous ethylene. Ethylene production from the abscission zones was low in all cultivars studied. In cv. Miss Teen the abscission zone changed from highly ethylene sensitive to completely insensitive in ~30 h, coinciding with floral opening. Removal of the floral buds somewhat reduced abscission in open flowers, but the lack of open flower abscission in cv. Miss Teen could not be explained by higher bud fall. The ovary did not grow in the (unpollinated) flowers, showing that lack of abscission in cvv. Willie and Miss Teen was not due to parthenocarpy. Flower removal in cv. Miss Teen had no effect on ethylene sensitivity of the abscission of the remaining pedicel. However, removal of the distal 2 cm of the 3-cm-long pedicels dramatically increased ethylene sensitivity. This suggests that the pedicel is important for the low ethylene insensitivity of abscission, in this cultivar. It is concluded that the abscission zones in the cvv. Willie and Miss Teen, in contrast with the other cultivars investigated, became rapidly insensitive to ethylene at the time of flower opening. At least part of the ethylene sensitivity in Miss Teen seems to be due to a factor in the pedicel.

scholarly journals The Effect of Timing of Dormex Application on Blueberry Leafing and Flower Mortality

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 601e-601 ◽  
Author(s):  
D. Scott NeSmith ◽  
Gerard Krewer
Keyword(s):  
Fruit Crops ◽  
Flower Buds ◽  
Calendar Time ◽  
Vaccinium Ashei ◽  
Hydrogen Cyanamide ◽  
Bud Development ◽  
Floral Buds ◽  
Stage 4 ◽  
Southern Highbush ◽  
Floral Bud

Leaf bud development is a problem on many blueberry cultivars grown throughout the Southeast. Dormex (50% hydrogen cyanamide) has shown potential in accelerating leaf and floral bud development of some fruit crops, but its usage on blueberries has not been thoroughly explored. A greenhouse experiment was conducted to examine the effects of timing Dormex applications on `Climax' rabbiteye blueberry (Vaccinium ashei) and `Oneal' southern highbush blueberry (V. corymbosum). Plants were subjected to low and moderate chilling conditions and were forced under greenhouse conditions. Dormex timings were: 1)1 day after forcing (DAF), 2) 3 DAF, 3) at 10% stage 3 floral buds, 4) at 30% to 50% stage 3 floral buds, 5) at 10% to 30% stage 4 floral buds, 6) control (no Dormex). All Dormex applications were applied at a rate of 2% product. Results showed that Dormex both increased and accelerated leaf bud break as compared to the control. However, flower buds at stage 3 of development or beyond were very susceptible to chemical burn by the product. The data indicate that timing of Dormex applications on blueberries should be based on rate of plant development rather than calendar time. Additional research is needed to most effectively use the product to aid blueberry leaf development.

scholarly journals NOTES ON THE EGG AND YOUNG LARVA OF ALARIA FLORIDA

1871 ◽  
Vol 3 (4) ◽  
pp. 76-76 ◽  
Author(s):  
W. Saunders
Keyword(s):  
Young Larva ◽  
Flower Buds ◽  
Flower Stalk ◽  
Evening Primrose ◽  
Young Leaves

On the 4th of July I found a number of eggs of this beautiful moth on the evening primrose, Œnothera Lamarckiana. They were found attached to the stalks of the young flower buds; to the sides of the calyx of the flower, and also to the young leaves at their base. The eggs were quite firmly fastened among the long stout hairs with which the cuticle of the calyx and flower stalk is covered.

Characters and origin of vessels with heterogenous structure in leaf and flower abscission zones

1999 ◽  
Vol 77 (2) ◽  
pp. 253-261 ◽  
Author(s):  
JP André ◽  
A M Catesson ◽  
M Liberman
Keyword(s):  
Cell Differentiation ◽  
Lycopersicon Esculentum ◽  
Secondary Xylem ◽  
Abscission Zone ◽  
Leaf Abscission ◽  
Cell Maturation ◽  
Casting Method ◽  
Plant Organs ◽  
Flower Abscission

The lifetime of many plant organs does not exceed a few weeks or a few months. These organs separate from the plant at the level of specialized abscission zones. The observation of xylem vasculature in abscission zones, a largely neglected subject, revealed original features when a vessel casting method was used. In all species of dicotyledons examined so far, flower and leaf abscission zones possessed heterogenous metaxylem vessels adjoining protoxylem and secondary xylem vessels with homogenous patterns of lignified thickenings. Heterogenous metaxylem vessel thickenings were helical, reticulate, or scalariform elements when in the abscission zone and pitted elements on the proximal and the distal sides. The origin and possible role of these vessels are considered. Data obtained on the flower abscission zone of tomato (Lycopersicon esculentum Mill.) suggest that formation of heterogenous vessels results from localized changes in the rhythm of cell differentiation and cell maturation inside the procambium-cambium continuum.Key words: abscission zone, cambium, differentiation, heterogenous vessels, procambium, vessel cast.

scholarly journals EPIP-Evoked Modifications of Redox, Lipid, and Pectin Homeostasis in the Abscission Zone of Lupine Flowers

2021 ◽  
Vol 22 (6) ◽  
pp. 3001
Author(s):  
Emilia Wilmowicz ◽  
Agata Kućko ◽  
Wojciech Pokora ◽  
Małgorzata Kapusta ◽  
Katarzyna Jasieniecka-Gazarkiewicz ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cell Wall ◽  
Redox Homeostasis ◽  
Abscission Zone ◽  
Wall Structure ◽  
Related Research ◽  
Flower Abortion ◽  
Mitogen Activated Protein ◽  
Acyl Lipids ◽  
Flower Abscission

Yellow lupine is a great model for abscission-related research given that excessive flower abortion reduces its yield. It has been previously shown that the EPIP peptide, a fragment of LlIDL (INFLORESCENCE DEFICIENT IN ABSCISSION) amino-acid sequence, is a sufficient molecule to induce flower abortion, however, the question remains: What are the exact changes evoked by this peptide locally in abscission zone (AZ) cells? Therefore, we used EPIP peptide to monitor specific modifications accompanied by early steps of flower abscission directly in the AZ. EPIP stimulates the downstream elements of the pathway—HAESA and MITOGEN-ACTIVATED PROTEIN KINASE6 and induces cellular symptoms indicating AZ activation. The EPIP treatment disrupts redox homeostasis, involving the accumulation of H2O2 and upregulation of the enzymatic antioxidant system including superoxide dismutase, catalase, and ascorbate peroxidase. A weakening of the cell wall structure in response to EPIP is reflected by pectin demethylation, while a changing pattern of fatty acids and acyl lipids composition suggests a modification of lipid metabolism. Notably, the formation of a signaling molecule—phosphatidic acid is induced locally in EPIP-treated AZ. Collectively, all these changes indicate the switching of several metabolic and signaling pathways directly in the AZ in response to EPIP, which inevitably leads to flower abscission.

scholarly journals Evaluating Ethylene Sensitivity within the Family Solanaceae at Different Developmental Stages

HortScience ◽  
2014 ◽  
Vol 49 (5) ◽  
pp. 628-636 ◽  
Author(s):  
Nichole F. Edelman ◽  
Michelle L. Jones
Keyword(s):  
High Response ◽  
Seedling Stage ◽  
Mature Plant ◽  
Flower Senescence ◽  
Plant Responses ◽  
Hypocotyl Length ◽  
Ethylene Sensitivity ◽  
The Family ◽  
Plant Stage ◽  
Flower Abscission

The family Solanaceae, which includes both important crop and ornamental species, is generally considered to have high sensitivity to ethylene. Our objectives were to evaluate ethylene sensitivity between accessions with the family Solanaceae and to determine whether similar sensitivity was observed in seedlings and mature plants. For the seedling evaluations, seeds were germinated and grown in the dark on filter paper saturated with 0 or 100 μM 1-aminocyclopropane-1-carboxylic acid (ACC; the immediate precursor to ethylene). The relative hypocotyl length at 100 μM ACC was compared with untreated control (0 μM) seedlings. Mature plants were treated with 0 or 10 μL·L−1 ethylene in the dark for 24 hours. Ethylene responses including flower abscission, flower senescence, and epinasty were observed and quantified. Seedlings and mature plants were classified as having no response, low, medium, or high ethylene sensitivity based on the severity of the ethylene responses observed. Sensitivity differences were observed among seedling, juvenile, and mature plants, and a range of ethylene responses and symptom severity was observed between accessions within a species. The majority of the accessions were classified as medium or high ethylene sensitivity at both the seedling and mature plant stages. Solanum melongena ‘Black Beauty’ (eggplant) had a low response to ethylene at the seedling stage and a high response at the mature plant stage, whereas Petunia ×hybrida ‘Daddy Orchid’ had a high response at the seedling stage and a low response at the mature plant stage. Peppers (Capsicum annum), tomatoes (Solanum lycopersicum), and tomatillos (Physalis ixocarpa) exhibited both floral and vegetative symptoms of ethylene damage, whereas calibrachoas (Calibrachoa ×hybrida), eggplants, nicotianas, and petunias exhibited only floral symptoms. The most common floral response to ethylene treatment was flower abscission, which was observed in almost all of the Solanum, Capsicum, and Nicotiana accessions. We consistently observed ethylene-induced epinasty in the genus Capsicum and in all of the Solanum except eggplant. Our results indicated that developmental stage influenced ethylene sensitivity, and there was not a consistent correlation between seedling and mature plant responses within the Solanaceae accessions that we evaluated.

scholarly journals Rootstock Effects on the Flowering of `Delicious' Apple. I. Bud Development

1995 ◽  
Vol 120 (6) ◽  
pp. 1010-1017 ◽  
Author(s):  
Peter M Hirst ◽  
David C Ferree
Keyword(s):  
Floral Development ◽  
Dry Weight ◽  
Growing Season ◽  
Flower Formation ◽  
Full Bloom ◽  
Floral Buds ◽  
One Year ◽  
Floral Bud ◽  
Leaf Dry Weight

Floral development was studied in buds of `Starkspur Supreme Delicious' apple trees growing on B.9, M.26 EMLA, M.7 EMLA, P.18, and seedling rootstocks. In each of 3 years, buds were sampled from the previous years growth at intervals throughout the growing season and dissected to determine whether the apex was domed, indicating the start of floral development. Number of bud scales and true leaves increased during the early part of the growing season, but remained fairly constant beyond 70 days after full bloom. The type of rootstock did not affect the number of bud scales or transition leaves, and effects on true leaf numbers were small and inconsistent. Final bract number per floral bud was similarly unaffected by rootstock. The proportion of buds in which flowers were formed was influenced by rootstock in only one year of the study, which was characterized by high temperatures and low rainfall over the period of flower formation. Bracts were observed only in floral buds, and became visible after doming of bud apices had occurred. Flowers were formed during the first 20 days in August, regardless of rootstock or year. The appendage number of vegetative buds was constant from 70 days after full bloom until the end of the growing season, but the number of appendages in floral buds increased due to the continued production of bracts. The critical bud appendage number for `Starkspur Supreme Delicious' before flower formation was 20, and was stable among rootstocks and years. Buds with diameters above 3.1 mm were generally floral, but on this basis only 65% of buds could be correctly classified. Spur leaf number, spur leaf area, and spur leaf dry weight were not good predictors of floral formation within the spur bud.

scholarly journals Flower Bud Differentiation and Development of ‘Jinsi No.4’ Jujube (Ziziphus jujuba Mill.) in Hunan Province of Southern China

2017 ◽  
Vol 11 (1) ◽  
pp. 9-15
Author(s):  
Feng Zou ◽  
Jinghua Duan ◽  
Huan Xiong ◽  
Deyi Yuan ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Southern China ◽  
Paraffin Section ◽  
Hunan Province ◽  
Flower Bud ◽  
Floral Organs ◽  
Floral Buds ◽  
Final Yield ◽  
Ziziphus Jujuba ◽  
Single Flower ◽  
Floral Bud

Ziziphus jujuba Mill. is one of the most important fruit crops and has been cultivated in China for more than 4000 years. Z. jujuba fruit is rich in nutritional and medicinal values. Compared to other wood fruits, Z. jujuba is unique in its flowering and fruiting characteristics. Floral buds differentiation and formation of Z. jujuba is an essential process that affects yield. Z. jujuba ‘Jinsi No.4’ blooms profusely, yet its final yield is low. In this study, the floral bud differentiation and development of ‘Jinsi No.4’ were examined by paraffin section. Results showed that the floral buds of ‘Jinsi No.4’ differentiated in the current year and started from early April. The duration of a single flower differentiation was short, taking only 7 days for maturation of flowers buds. Floral bud differentiation of ‘Jinsi No.4’ can be divided into six stages, i.e., pre-differentiation, initial differentiation, sepal differentiation, petal differentiation, stamen differentiation, and pistil differentiation. Flower development experienced seven stages, i.e., alabastrum, alabastrum break, sepal flattening, petal flattening, stamen flattening, filament withering, and ovule swelling. Dysplasia was observed in some floral organs in Z. jujuba ‘Jinsi No.4’, suggesting that the dysplasia of floral organs may be one of the main reasons for low yields. Our findings on flower bud development in ‘Jinsi No.4’ will contribute to its production and flowering management in Hunan area of southern China.

scholarly journals THE DEVELOPMENT OF CUSTARD APPLE FLOWER BUD UNDER NITROGEN AND POTASSIUM NUTRITION

2016 ◽  
Vol 38 (2) ◽  
Author(s):  
IVAN VILAS BÔAS SOUZA ◽  
ABEL REBOUÇAS SÃO JOSÉ ◽  
JOSÉ CARLSON GUSMÃO DA SILVA ◽  
MARINÊS PEREIRA BOMFIM ◽  
JECILENE SILVA DE JESUS
Keyword(s):  
Apple Tree ◽  
Block Design ◽  
Annona Squamosa ◽  
Summer Period ◽  
Flower Buds ◽  
Flower Bud ◽  
Potassium Nutrition ◽  
Floral Buds ◽  
National Market ◽  
Custard Apple

ABSTRACT The custard apple tree (Annona squamosa L.), has increased in cultivation due to good prices in the national market. However, there are few studies regarding the fruit’s nutrition. The aim of this study was to verify the influence of N and K levels in developing the flower buds in two growing cycles, corresponding to the time of high temperatures (spring-summer) and another milder season (autumn-winter). The experiment was conducted in a rural property located in the municipality of Anagé, Bahia, installed in a randomised complete block design with 3 blocks, arranged in a factorial 4 x 4, obtained by the combination of the following levels of N (0, 16.875, 33.750 and 67.500 g plant-1) in the form of urea and K (0, 22.5, 45.0 and 90.0 g plant-1) in the form of potassium chloride, applied every fifteen days (every fortnight / every two weeks). It was evaluated the vigor of floral buds, measured by determining its weight and the length of them. At the end of the study it was concluded that the vigor of the floral buds tended to increase with elevated levels of nitrogen in the coldest period of the year (dry season with low in temperature). In the spring-summer period (rainy season and high temperature) the vigor of the flower buds was reduced as they increased the doses of N. Potassium did not affect the vigor of the flower buds in these considered periods. There was no interaction between N and K levels for the vigor of the flower buds.

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