PRECOCIOUS FLOWERING OF ARIZONA CYPRESS WITH GIBBERELLIN

1965 ◽  
Vol 43 (8) ◽  
pp. 923-927 ◽  
Author(s):  
Richard P. Pharis ◽  
Manfred D. E. Ruddat ◽  
Cornell C. Phillips ◽  
Erich Heftmann

Extremely early flowering (production of staminate strobili 88 days from germination) of Arizona cypress (Cupressus arizonica Greene) was obtained with foliar application of gibberellin A3 commencing at age 55 days. Trials with differing concentrations of gibberellin at various ages indicated that flower bud differentiation depends on both age and gibberellin concentration, younger seedlings requiring more exogenous gibberellin. Simultaneous application of two growth retardants (AMO-1618 and B-995) had no effect upon the number of flowers, but flower size was increased where B-995 and gibberellin were given together. The period of time between initial spraying and first visible appearance of staminate strobili is 23 to 25 days. On most plants 60 to 80% of the growing vegetative meristems are changed into flower buds within 60 days of the initial treatment, often resulting in over 500 flower buds on one plant. The pollen is viable.

2013 ◽  
Vol 36 (1-2) ◽  
pp. 83-94 ◽  
Author(s):  
Franciszka Jaumień

The growth of trees sprayed in spring with chlormequat is weaker, and their elongation growth ends 2 - 3 weeks earlier than that of unsprayed trees. Trees with growth inhibited by chlormequat set flower buds on the spurs and in the subapical part of long shoots. The course of flower bud differentiation starts in the second half of July and is similar to that in the apple tree.


2019 ◽  
Vol 20 (14) ◽  
pp. 3557 ◽  
Author(s):  
Yu Han ◽  
Aoying Tang ◽  
Jiayao Yu ◽  
Tangren Cheng ◽  
Jia Wang ◽  
...  

Rosa chinensis is one of the most popular flower plants worldwide. The recurrent flowering trait greatly enhances the ornamental value of roses, and is the result of the constant formation of new flower buds. Flower bud differentiation has always been a major topic of interest among researchers. The APETALA1 (AP1) MADS-box (Mcm1, Agamous, Deficiens and SRF) transcription factor-encoding gene is important for the formation of the floral meristem and floral organs. However, research on the rose AP1 gene has been limited. Thus, we isolated AP1 from Rosa chinensis ‘Old Blush’. An expression analysis revealed that RcAP1 was not expressed before the floral primordia formation stage in flower buds. The overexpression of RcAP1 in Arabidopsis thaliana resulted in an early-flowering phenotype. Additionally, the virus-induced down-regulation of RcAP1 expression delayed flowering in ‘Old Blush’. Moreover, RcAP1 was specifically expressed in the sepals of floral organs, while its expression was down-regulated in abnormal sepals and leaf-like organs. These observations suggest that RcAP1 may contribute to rose bud differentiation as well as floral organ morphogenesis, especially the sepals. These results may help for further characterization of the regulatory mechanisms of the recurrent flowering trait in rose.


1967 ◽  
Vol 45 (9) ◽  
pp. 1519-1524 ◽  
Author(s):  
Richard P. Pharis ◽  
William Morf

Induction of staminate and ovulate strobili was obtained on western red cedar (Thuja plicata Donn) by foliar application of gibberellin A3. Staminate strobili could be induced as early as age 4 months after 3.5 months of treatment under long-day conditions, but further development of the strobilus required a photoperiodic sequence of long-day — short-day — long-day. Induction of the ovulate strobilus may also have occurred under long-day conditions at an early age, but development did not become apparent until the above photoperiodic sequence had been given. Age at this time was 12 months. It is concluded that induction and development of the strobilus is under photoperiodic as well as hormonal control.Foliar application of gibberellin A3 and a gibberellin A4/A7 mixture to pygmy cypress (Cupressus pygmaea Sarg.), Portuguese cypress (Cupressus lusitanica Mill.), and Arizona cypress (Cupressus arizonica Greene) at age 7–9 months resulted in induction of staminate strobili on all plants. Length of time to flowering varied both with species of plant and gibberellin. Application of gibberellin A3 to Arizona and Portuguese cypress seedlings resulted in production of ovulate as well as staminate strobili at ages 21 and 10 months respectively. Mourning cypress (Cupressus funebris Endl.) still in a juvenile needle stage at age 9 months has proved unresponsive to foliar application of gibberellin A3 for at least 100 days.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 491e-491
Author(s):  
Darren L. Haver ◽  
Ursula K. Schuch

Ethephon was applied as a foliar spray to 36-day-old petunia seedlings to determine its effectiveness at reducing apical dominance by increasing lateral shoot development. Ethephon application at rates of 125, 250 and 500 mg·L–1 to whole shoots of Petunia × hybrida `Orchid' decreased apical dominance compared to the control. The average length of a lateral shoot increased 56% as ethephon application rates increased from 0 to 500 mg·L–1. In Expt. I, ethephon-treated plants had a greater number of laterals than control plants. The number of nodes produced before the first flower bud was initiated increased from 15 to 21 as rates of ethephon increased from 0 to 500 mg·L–1. Ethephon delayed anthesis up to 10 days when applied at 500 mg·L–1 and up to 8 days when applied at 250 mg·L–1. The number of visible flower buds increased in all ethephon-treated plants compared to the control. Ethephon at 250 mg·L–1, increased shoot and root dry mass 37.9% and 20.4%, respectively, compared to untreated controls. Roots appeared healthy in both experiments, but phytotoxicity (mild chlorosis) occurred in Expt. II on plants treated with 500 mg·L–1. The experiment was repeated twice with similar results.


HortScience ◽  
2021 ◽  
pp. 1-9
Author(s):  
Yue Wen ◽  
Shu-chai Su ◽  
Ting-ting Jia ◽  
Xiang-nan Wang

The periods of flower bud differentiation and fruit growth for Camellia oleifera overlap greatly affect the allocation of photoassimilates to flower buds and fruit, resulting in obvious alternate bearing. To export the cause and mitigate alternate bearing of Camellia oleifera, the allocation of photoassimilates to buds and fruit supplied by leaves at different node positions was studied by the addition of labeled 13CO2 during the slow fruit growth stage. The fate of 13C photoassimilated carbon was followed during four periods: slow fruit growth (4 hours and 10 days after 13C labeling); rapid growth (63 days after 13C labeling); oil conversion (129 days after 13C labeling); and maturation (159 days after 13C labeling). Photosynthetic parameters and leaf areas of the leaves shared a common pattern (fifth > third > first), and the order of photosynthetic parameters of different fruit growth stages was as follows: oil conversion > maturation > rapid growth > slow growth. The most intense competition between flower bud differentiation and fruit growth occurred during the oil conversion stage. Dry matter accumulation in different sinks occurred as follow: fruit > flower bud > leaf bud. Photoassimilates from the labeled first leaf were mainly translocated to the first flower bud, and the upper buds were always differentiated into flower buds. The photoassimilates from the labeled third leaf were distributed disproportionately to the third flower bud and fruit. They distributed more to the third flower bud, and the middle buds formed either flower or leaf buds. However, the photoassimilates from the labeled fifth leaf were primarily allocated to the fruit that bore on the first node of last year’s bearing shoot, and basal buds did not form flower buds. Based on our results, the basal leaves should be retained for a high yield in the current year, and the top leaves should be retained for a high yield in the following year. Our results have important implications for understanding the management of flower and fruit in C. oleifera. The thinning of fruit during the on-crop year can promote flower bud formation and increase the yield of C. oleifera crops in the following year. During the off-year, more fruit should be retained to maintain the fruit yield. The thinning of middle-upper buds could promote more photoassimilates allocate to the fruit.


HortScience ◽  
2020 ◽  
Vol 55 (11) ◽  
pp. 1794-1798
Author(s):  
Jinxin Wang ◽  
Tao Luo ◽  
He Zhang ◽  
Jianzhu Shao ◽  
Jianying Peng ◽  
...  

Hormones have an important role in apple flower bud differentiation; therefore, it is necessary to systematically explore the dynamic changes of endogenous hormones during flower and leaf bud development to elucidate the potential hormone regulation mechanism. In this study, we first observed the buds of ‘Tianhong 2’ apple during their differentiation stage using an anatomical method and divided them into physiologically differentiated stages of spur terminal buds, flower buds, and leaf buds. Then, we determined the contents of zeatin riboside (ZR), abscisic acid (ABA), auxin (IAA), and gibberellin (GA3) in these various types of buds using an enzyme-linked immunosorbent assay. The results showed that the content of ZR and the ratio of ZR to IAA in spur terminal buds decreased significantly during physiological differentiation. The contents of ZR, IAA, and GA3 in leaf buds culminated at the initial differentiation stage. The content of ZR in flower buds was significantly higher than that in leaf buds after formation of the inflorescence primordium and sepal primordium. Before the appearance of stamen primordium, the content of GA3 in flower buds was remarkably lower than that in leaf buds. The ratios of ABA/IAA and ZR/IAA in flower buds were significantly higher than those in leaf buds before the appearance of flower organ primordium. Moreover, ABA content, ABA/ZR, and ABA/GA3 in flower buds were higher than those in leaf buds throughout the whole flower bud morphological differentiation process. Therefore, the reduced ZR content was beneficial to floral induction. The low content of GA3, and high ratios of ABA/IAA and ZR/IAA were conducive to early morphological differentiation. In addition, high ratios of ABA/GA3 and ABA/ZR were beneficial to the morphological differentiation of flower buds. Moreover, the high ABA content was beneficial to floral induction and morphological differentiation of flower buds. Our results shed light on the mechanisms of hormonal regulation of apple flower bud differentiation and could potentially strengthen the theoretical basis for artificial regulation of apple flower bud development using exogenous plant hormones.


2019 ◽  
Vol 136 ◽  
pp. 06004
Author(s):  
Yan Huang ◽  
Bin Hou ◽  
Dong Liang ◽  
Ronghai Lu ◽  
Lei Liu ◽  
...  

In this study, 3 year-old ‘Xiahei’ grape was used as the test material. It aimed to promote the differentiation of grape flower buds with different concentrations of paclobutrazol and chlormequat chloride, and the effects of different ways of promoting the differentiation of flower buds on the germination of grape buds and fruit quality were studied. The results showed that different ways of flower bud differentiation could promote the germination of ‘Xiahei’ grape buds. In consideration of the fruiting habit, phenological period and fruit quality of different treatments, second fruits which were sprayed with 1000 times 15% paclobutrazolin had the best effect. On May 1, 2019 (One fruit sitting period) spraying grape new tip with 1000 times 15% paclobutrazol and 0.3% potassium dihydrogen phosphate, 0.1% boric fertilizer and the same fungicides, spraying again after 7 days, reagent type and concentration were same as the first time, after 10 days of the second spraying 2.5% hydrogen cyanamide was used to break dormancy of winter bud. The way could effectively promote grape secondary fruit and improve the quality of the grapes.


Author(s):  
R. SUDHAGAR, S. KAMALAKANNAN

An experiment was conducted to study the effect of growth retardants on flowering and yield parameters and shelf life of spanish jasmine. The experiment comprised of eleven treatments each replicated thrice was executed following the principles of randomized block design. The treatments included foliar spray of CCC @ 1000, 1500 and 2000 ppm, alar @ 1000, 2000 and 3000 ppm, ethrel @ 1000, 1500 and 2000 ppm, pruning and untreated control. In this study, the application of CCC 1500 ppm exerted favourable influence and enhanced the flower bud characters viz., flower bud length (2.98 cm), flower stalk length (2.36 cm) and total length of the flower (5.34 cm). The yield and yield attributes viz., hundred flower buds weight (9.90 g), flower buds yield plant-1 (4.23 kg), flower buds yield plot-1 (33.84 kg) and flower buds yield hectare-1 (14.1 t ha-1) were also found to be the maximum in the plants treated with CCC 1500 ppm. The plant growth retardants did not show any significant effect on shelf life of flowers.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 447d-447
Author(s):  
Meriam Karlsson ◽  
Jeffrey Werner

Nine-week-old plants of Cyclamen persicum `Miracle Salmon' were transplanted into 10-cm pots and placed in growth chambers at 8, 12, 16, 20, or 24 °C. The irradiance was 10 mol/day per m2 during a 16-h day length. After 8 weeks, the temperature was changed to 16 °C for all plants. Expanded leaves (1 cm or larger) were counted at weekly intervals for each plant. The rate of leaf unfolding increased with temperature to 20 °C. The fastest rate at 20 °C was 0.34 ± 0.05 leaf/day. Flower buds were visible 55 ± 7 days from start of temperature treatments (118 days from seeding) for the plants grown at 12, 16, or 20 °C. Flower buds appeared 60 ± 6.9 days from initiation of treatments for plants grown at 24 °C and 93 ± 8.9 days for cyclamens grown at 8 °C. Although there was no significant difference in rate of flower bud appearance for cyclamens grown at 12, 16, or 20 °C, the number of leaves, flowers, and flower buds varied significantly among all temperature treatments. Leaf number at flowering increased from 38 ± 4.7 for plants at 12 °C to 77 ± 8.3 at 24 °C. Flowers and flower buds increased from 18 ± 2.9 to 52 ± 11.0 as temperature increased from 12 to 24 °C. Plants grown at 8 °C had on average 6 ± 2 visible flower buds, but no open flowers at termination of the study (128 days from start of treatments).


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