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1.
The flowering responses of Brunonia australis (blue pincushion) and Calandrinia sp. to vernalization, photoperiod, temperature and plant age were investigated to provide a foundation for manipulating flowering in these potential potted plants. Plants were vernalized at 4.8 °C for 0, 3 or 6 weeks at the plant age of 1–4 or 8–14 leaves. Following vernalization, plants were grown at 25/10 or 35/20 °C (day/night) under short days (11 h, ambient daylight averaged 380 ± 44 μmol m−2 s−1) or long days (16 h) provided by an additional 5 h night break (21:00–2:00 h at <4.5 μmol m−2 s−1 from incandescent lamps), for 85 days. This is the first work to investigate flowering of these ornamental species. Both species showed enhanced flowering following vernalization and a quantitative requirement for long days. The reduction of the time until the first visible inflorescence (Brunonia) or flower (Calandrinia) buds by 8–13 days was affected by vernalization for 3 or 6 weeks, respectively. Long days were effective for reducing the time to first visible floral bud and increasing the number of inflorescence or flowers per plant for both species. For Brunonia, LDs replaced vernalization when applied to plants with 1–4 leaves. Raising temperature from 25/10 to 35/20 °C increased the number of flowers per plant of Calandrinia by 2–2.5-fold for plants with 1–4 or 8–14 leaves respectively.  相似文献   

2.
The effects of night interruption (NI) were examined on the vegetative growth and flowering of Cymbidium ‘Red Fire’ and ‘Yokihi’. Plants were grown under 9/15 h ambient light/dark (control), 9 h ambient light plus night interruption (22:00–02:00 h) with low light intensity at 3–7 μmol m−2 s−1 (LNI) and 9 h ambient light plus NI with high light intensity at 120 μmol m−2 s−1 (HNI) conditions. The number of leaves, leaf length, number of pseudobulbs and pseudobulb diameter increased in both LNI and HNI compared to controls for both cultivars. While none of the control plants flowered within 2 years, 100% of the ‘Yokihi’ and 80% of the ‘Red Fire’ plants grown under HNI condition flowered. In the LNI group, 60% of the plants flowered in both cultivars. Plants in the HNI group showed a decreased time to visible inflorescence and flowering than those in the LNI group. The number of inflorescences and florets were greater in the plants grown under HNI than those in the LNI group. The tallest plants at flowering were in the HNI group in both cultivars. NI with low light intensity can be used effectively to promote flower induction with increased growth rate during the juvenile stage in Cymbidium. To obtain high quality plants, however, NI with high light intensity strategies should be considered.  相似文献   

3.
The effects of application method and concentration of gibberellic acid (GA3), paclobutrazol and chlormequat on black iris performance were assessed. Plants (10 cm high, 4 ± 1 leaves) were sprayed with 125, 250, 375 or 500 mg L−1 or drenched with 0.25, 0.5, 1 or 2 mg L−1 GA3. In a second experiment, the plants were sprayed with 100, 250, 500 or 1000 mg L−1 or drenched with 0.25, 0.5, 1 or 2 mg L−1 paclobutrazol. Other plants were sprayed with 250, 500, 1000 or 1500 mg L−1 or drenched with 100, 250, 375 or 550 mg L−1 chlormequat. In each experiment, the control treatment consisted of untreated plants. Results indicated that the tallest plants (37.3 cm) in the GA3 experiment were those sprayed with 250 mg L−1. The most rapid flowering (160 days after planting) occurred when a 375 mg L−1 GA3 spray was used, whereas flowering was delayed to 200 days using 1 mg L−1 GA3 drench. Drenching with 1 mg L−1 GA3 increased height of the flower stalk by 7 cm compared to the control. Though relatively slow to flower, plants drenched with 1 mg L−1 GA3 had long and rigid stalks, which were suitable as cut flowers. Number and characteristics of the sprouts were not affected by GA3. All paclobutrazol sprays resulted in leaf falcation. A 500 or 1000 mg L−1 paclobutrazol spray resulted in severe and undesirable control of plant height, drastic reduction in stalk height and weight, and delayed flowering. Plants drenched with 0.25 or 1 mg L−1 paclobutrazol were suitable as pot plants. Chlormequat reduced plant height only at the highest drench concentration, which also reduced flowering to 70%. No leaf falcation was observed with GA3 or chlormequat. Chemical names: ( ± )-(R*,R*)-beta-((4-chlorophenyl)methyl)-alpha-(1,1,-dimethylethyl)-1H-1,2,4,-triazol-1-ethanol (paclobutrazol); (2-chloroethyl) trimethylammonium chloride (chlormequat).  相似文献   

4.
In a number of woody perennial species a decrease in gibberellins concentrations in the apical meristems is required for floral initiation to occur. In Rhododendron, applied gibberellins inhibit flowering and gibberellin biosynthesis inhibitors promote flowering. However, unlike previous reports on other Rhododendron cultivars, Rhododendron cv. Hatsugiri is a faculatitive LDP. It was therefore unknown how gibberellins regulate flowering in this cultivar and if non-inductive short daylengths stimulate the productions of endogenous gibberellins to suppress flowering. By inhibiting floral initiation while not stimulating vegetative growth we found applications of GA5 to best match the natural response of Rhododendron cv. Hatsugiri under short-day regimes. GA5-mediated effects on flowering have previously been reported to be due to conversion to GA6, however, GA5 was found to be present in tissue samples at up to 0.57 ng g−1 FW, while GA6 was never found. In addition, foliar applications of [14C] GA5 were not found to have metabolised to GA6. In line with the hypothesis that gibberellins inhibit floral initiation in short days in Rhododendron cv. Hatsugiri, the concentration of GA20, a precursor to many bioactive gibberellins, was higher in leaf tissues from plants in short days, compared to those in permissive long days when analysed using GC–MS.  相似文献   

5.
The formation of flower buds in Clerodendrum seems not to be affected by day length, but the development of the buds is delayed in long days. When long days were established by means of low-intensity illumination with incandescent lamps, few flowers developed and the stems elongated considerably even at a day length of 16 hours. When fluorescent lamps were used for day-length extension, short shoots with many flowers were obtained even in 24-hour days. Flower development was also delayed by gibberellic acid (GA3), but promoted by chlormequat both in short and long days. Shoot elongation was retarded by chlormequat and promoted by GA3.Plants obtained from commercial greenhouses varied considerably with respect to growth and flowering. By selection a clone was obtained which flowered richly on short shoots. Shoot elongation stopped when flowering began. A ‘negative’ selection gave rise to a clone which flowered sparsely and in which shoot elongation was not influenced by flowering.  相似文献   

6.
The effects of photoperiod (10, 12, 16, 20 or 24 h), day-temperature (12, 15, 18, 24 or 30 °C), the number of short days (14, 21 or 28 days), plant age (4, 8 or 12 weeks) and their interactions on flower and inflorescence emergence were investigated in strawberry cv. Korona. No flowers emerged in plants exposed to photoperiods of 16, 20 or 24 h or to a short-day treatment for 14 days. All plants exposed to short days at daily photoperiods of 10 or 12 h for 21 days or longer, emerged flowers at temperatures between 12 and 18 °C. A further increase in temperature led to a drastic decrease in the total number of flowers per plant. A short-day treatment (10 or 12 h photoperiod) of 28 days resulted in highest numbers of inflorescences and flowers per plant, while a short-day treatment of 21 days resulted in the highest numbers of flowers per inflorescence. Complete flower induction was observed in only 4-week-old runner plants. The number of inflorescences and the number of flowers per inflorescence increased with plant age. However, the start of flowering was delayed with increasing plant age.  相似文献   

7.
《Scientia Horticulturae》2005,103(2):167-177
The temperature and photoperiod interactions of a number of elite genotypes of Fragaria virginiana, F. x ananassa, and F. chiloensis were studied in a series of growth chamber experiments. Several parameters were evaluated including: (1) the critical day-length (CDL) for flowering of short day (SD) genotypes under 8, 9, 10, and 11 h days at 18 °C, (2) the floral and runnering response of single and multiple cropping genotypes under 8 and 16 h days at 18 °C, and (3) the effect of temperature on flower bud formation in day-neutral (DN) genotypes held at 18, 22, 26, and 30 °C under 12 h day-lengths. The same number of flowers were initiated under 15 and 30 day induction periods, regardless of photoperiod. Frederick 9, LH 50-4 and RH 30 (F. virginiana), ‘Aromas’ and ‘Tribute’ (F. x ananassa) and CFRA 0368 of F. chiloensis flowered under both long days (LDs) and SDs; while Eagle-14 (F. virginiana), ‘Fort Laramie’ and ‘Quinalt’ (F. x ananassa) flowered only under long days. While those genotypes that flowered under both LD and SD can be considered day-neutral, they varied in the degree of floral response to the two photoperiods. CFRA 0368 and Frederick 9 produced the same number of flowers under both LDs and SDs, while ‘Aromas’ and ‘Tribute’ had more flowers under LDs and RH 30 had more under SDs. Of the DN genotypes, LH 50-4 and RH 30 were the only ones that produced runners under SDs. Flowering in ‘Fort Laramie’ was least affected of any genotype by high temperature, although its dry weight was negatively impacted. Based on these data, several genotypes show promise as breeding parents: CFRA 0368 and Frederick 9 to equalize flower production under LD and SD conditions, LH 50-4 and RH 30 to produce more freely runnering DNs, and ‘Fort Laramie’ for floral heat tolerance.  相似文献   

8.
The genus Ptilotus has immense potential for ornamental horticulture but its commercial development has been hindered by propagation limitations. Poor seed quality and germination are reported. Cutting propagation is limited by cutting supply as the juvenile phase of Ptilotus is short. Micropropagation has been used in an attempt to overcome these difficulties but explants become floral in vitro and this causes plantlets to elongate. Ethephon has been used to control flowering of stock plants of many ornamental species. This study investigated the effect of ethephon applied to young (3-week-old, deflasked from tissue culture) and mature (1-year-old) Ptilotus plants in a greenhouse. A system of applying gaseous ethylene at 0, 100, 200 and 300 mg l−1 to the headspace of in vitro plantlets in glass jars was developed and the response of in vitro plantlets to ethylene studied. One-year-old Ptilotus plants were treated with 500 mg l−1 ethephon 2 days before pruning or 1 or 2 weeks after pruning. Ethephon application 2 days before pruning decreased the number of inflorescences and increased the number of shoots (compared to the control) but was phytotoxic. Ethephon applications of 150 or 300 mg l−1 applied weekly or fortnightly to 3-week-old plants deflasked from tissue culture reduced plant height and number of inflorescences and at low concentrations increased the number of new shoots. A fortnightly application at 150 mg l−1 is recommended. Previous reports on the effects of ethylene on inflorescence production on plantlets in vitro are limited. Our study showed that exposure of in vitro plantlets of P. nobilis to ethylene gas at 100 mg l−1 for 1 h significantly increased the number of shoots and plant height but this did not occur for plantlets of P. spicatus. Plantlets of P. spicatus exposed to transient ethylene at 200 and 300 mg l−1 showed significantly greater rooting (52.4%) than the control (13.6%).  相似文献   

9.
The effect of Prohexadione Calcium (Pro-Ca) and daminozide was observed on the growth characteristics and endogenous gibberellin contents of Chrysanthemum morifolium R. cv Monalisa White. Three concentrations viz. 100, 200 and 400 ppm of Pro-Ca and a single concentration of daminozide (800 ppm) were applied three times with 7 days interval on three weeks old plant under greenhouse condition. Pro-Ca suppressed the plant length up to 30.7% while daminozide inhibited up to 27.12% at optimum concentration. The chlorophyll contents and stem diameter were higher than control, while the fresh weight and flower number insignificantly reduced with such treatments. Gibberellin (GA) analysis showed that Pro-Ca and daminozide application significantly lowered bioactive GA1 content, although the amount of its immediate precursor GA20 was fractionally higher. Bioactive GA4 content was slightly higher than the control while significant difference in GA9 was found between the plants treated with Pro-Ca and daminozide. Current study showed that both early C13 hydroxylation and non-C13 hydroxylation pathways of GA biosynthesis are operational in C. morifolium.  相似文献   

10.
Ethylene exposure time required to induce flowering of Guzmania lingulata Mez. ‘Anita’ was investigated by exposing plants to ethylene at 100 μl l−1 for 4, 6, 8, 10, 12, 16, or 24 h. Plants were also exposed to ethylene-free air for the same lengths of time. Plants exposed to ethylene for 4 h did not flower, but exposure for 6 h or longer resulted in 100% flowering. Suppression of endogenous ethylene synthesis by aminoethoxyvinylglycine (AVG) resulted in a longer exposure time of 20 h being required to obtain 100% flowering. This result suggests that endogenous ethylene production contributes substantially to floral induction. Ethylene treatment on a single young leaf induced flowering as well. Application of a protein synthesis inhibitor, cycloheximide, prevented flowering induced by ethylene, indicating that activation of ethylene responsive genes is followed by synthesis of new proteins involved in flowering.  相似文献   

11.
Lychnis senno is a rare and valued ornamental plant. Seed propagation is not efficient because of the low germination rate. To grow commercially L. senno in China, a protocol for in vitro germination and propagation of this species was developed. Various germination rates were obtained by treating seeds with GA3 during 1–6 months storage period. The highest germination rate reached 19.4% when seeds were treated with 250 mg/l GA3 and stored for 5 months at 4 °C. Axillary shoot proliferation was induced in the nodal segments of the seedlings on medium containing specific concentrations of BA and NAA [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. Plant 15, 473–497]. Maximum number of shoots was developed on a medium supplemented with 5 mg/l BA and 0.5 mg/l NAA, while the higher shoots were observed on a medium supplemented with 0.5 mg/l BA and 0.05 mg/l NAA. Rooting was induced in 91.7% of the regenerated explants on a half-strength MS medium supplemented with 0.5 mg/l NAA. The plantlets grew well and flowered after transfer to the greenhouse. The chromosome numbers of seedlings and propagated plants were also determined to be 2n = 2x = 24.  相似文献   

12.
The application of gibberellic acid (GA3) to the whole loquat tree from mid-May to early June and from early August to the onset of flowering, significantly reduced the number of premature flowering shoots per current shoot and per m3 of canopy, and so reduced the total number of panicles per m3 of canopy. The number of vegetative shoots per m3 of canopy was also significantly reduced by applying GA3. The response depended on the concentration applied and produced optimal results at 50 mg l−1. Differences in the number of flowers per panicle and leaves per shoot were not significantly modified by the treatment. Nevertheless, GA3 applied directly to the developing apex near to flower differentiation reduced the number of flowers per panicle by 25–35% and without modifying the morphological characteristics of the panicle. Results suggest that less sprouting of lateral buds was largely responsible for the reduction in flowering intensity caused by GA3. Best treatments reduced thinning costs (60%, approximately) of premature flowering shoots, slightly increased fruit diameter and significantly improved fruit colour and juice quality, thus advancing harvest date.  相似文献   

13.
Long day promotes flowering of Gysophila paniculata L cultivar ‘Bristol Fairy’. Repeated treatments with GA3 or GA4 + 7 in short days did not promote flowering. The long photoperiod is effective only at relatively high temperatures. At night temperatures below 12°C, the plants remain vegetative even in long days. Efficient artificial lighting is from incandescent lamps at 60–100 lux. Fluorescent lighting (Cool-White) is not effective. Lighting of 4 hours as a night-break or at the end of the night were equally effective, but 4 hours lighting as a day-extension was less effective. Whole-night lighting promoted flowering more than any of the 4-hour lighting regimes. Cyclic lighting of one third light in each cycle promoted flowering to the same extent as continuous lighting. Light intensity during the day has a decisive effect on flower production.  相似文献   

14.
Post-harvest performance of cut viburnum inflorescences was examined in the present study. Harvesting viburnum at three developmental stages resulted in significant differences on flower opening rate (FOR) and flower abscission rate (FAR), but not on vase life. Harvesting at Stage III (>50% open flowers) resulted in highest flower opening percentage, whereas harvesting at Stage I (10–30% open flowers) in significantly lower flower abscission percentage. Pulsing with 20 or 40 mg/l AgNO3 for 24 h extended vase life by 1.6 and 1.9 days, respectively, compared to the controls. Furthermore, flower abscission was significantly reduced after 20 or 40 mg/l AgNO3 treatments by 51 and 62%, respectively, compared to the controls. In contrast, vase solutions containing 100 mg/l DICA or 100 and 200 mg/l methanol did not extend vase life of cut viburnum inflorescences, but significantly reduced flower abscission. Vase solutions containing 1 or 2% (w/v) sucrose negatively affected vase life, flower opening and flower abscission of viburnum inflorescence. Post-harvest treatments with 1-MCP at 10 μl/l in an ethylene-free environment resulted in extension of vase life and in significant reduction of FAR and respiration rates compared to the controls. Vase life of 1-MCP treated inflorescences was increased by 4.2 days compared to the controls. FAR of 1-MCP treated inflorescences remained significantly lower from the second to the eighth day of the vase life period.  相似文献   

15.
Lettuce plants were sprayed with gibberellin (GA3) or water at the rosette (8-leaf) stage and subsequently with water or CCC (500 or 1500 ppm) at the onset of bolting. GA3 induced rapid bolting and increased seed yield, but seed stalks were longer and thinner than those that had been sprayed with water at the same stage. Treatment with CCC (500 ppm) at bolting decreased the flower stalk height of plants that had been sprayed with water at the rosette stage, but not that of GA3 treated plants. CCC (500 ppm) increased the number of inflorescence branches per plant as well as seed yield in the autumn sown crop, but had no effect on the winter sown crop. When a higher concentration of CCC (1500 ppm) was applied at bolting, flower stalk height decreased, irrespective of whether the plants had been previously treated with GA3 or not, and seed stalk diameter increased. However, 1500 ppm CCC reduced the number of inflorescence branches per plant and mean seed yield. It is concluded therefore that although the application of 500 ppm CCC at the onset of bolting may increase seed yield in the autumn sown crop, this treatment does not improve the seed stalk strength (e.g. increasing diameter or reducing height) of GA3 treated plants. On the other hand, whereas a higher concentration of CCC (1500 ppm) improves seed stalk characteristics, it reduces seed yield.  相似文献   

16.
Dendrobium nobile Lindl. is a popular temperate Chinese orchid commonly marketed as a traditional medicinal plant. Seedlings of Dendrobium nobile Lindl. produced floral buds (33.3–34.8%) precociously on a defined basal medium (1/2 MS) containing paclobutrazol (PP333) at 0.5 mg L−1 or thidiazuron (TDZ) at 0.1 mg L−1 within 4 months of culturing. The frequency of floral buds formation can be further increased to 95.6% by growing seedlings in a PN (PP333 0.3 mg L−1 + NAA 0.5 mg L−1)-containing medium followed by transfer onto 1/2 MS medium with PP333 and TDZ (PP333 + TDZ). However, flower developed was deformed under 25 °C but it developed fully when grown in a lower temperature regime (23 °C/18 °C, light/dark) for 45 days. Under optimal condition, in vitro flowering was observed about 6 months after seed sowing.  相似文献   

17.
In vegetatively propagated Pelargonium × hortorum plants, formation of axillary shoots and initiation of inflorescences and leaves were promoted by an increase in quantum flux density, whereas application of GA3 had a negative effect. Application of CCC caused an increase in number of axillary shoots and consequently an increase in number of inflorescences and leaves per plant.Dry weight increase was promoted by an increase in quantum flux density, unaffected by GA3 treatment, but inhibited by CCC treatment. Moreover, continuous removal of the oldest leaves reduced the number of inflorescences, leaves, axillary shoots and dry weight. The changes in inflorescence and leaf initiation could not be definitely correlated to the changes in dry weight increase.  相似文献   

18.
The effects of photoperiod (12, 13, 14, 15 or 16 h), day temperature (12, 15, 18, 24 or 27 °C) and night temperature (6, 9 or 12 °C) and their interactions on flower and inflorescence emergence were investigated by exposing 4 week old runner plants of strawberry cvs. Korona and Elsanta during a period of 3 weeks. A daily photoperiod of 12 or 13 h resulted in the highest number of plants with emerged flowers. A photoperiod of 14 h or more strongly reduced this number, while no flowers emerged at a photoperiod of 16 h. Plants exposed to photoperiods of 12 or 13 h flowered earlier and had longer flower trusses. A day temperature of 18 °C and/or a night temperature of 12 °C were optimal for plants to emerge flowers and resulted in the shortest time to flowering. A night temperature of 6 °C strongly reduced the number of plants that emerged flowers, especially when combined with lower day temperatures. Photoperiod and temperature had no effect on the number of inflorescences, all flowering plants produced on average one inflorescence. The number of flowers on the inflorescence increased with decreasing day temperature and when photoperiod was raised from 12 to 15 h. In general, ‘Korona’ was more sensitive to photoperiod and temperature as ‘Elsanta’, and had a lower optimal day temperature for flower emergence. Results of this experiment may be used to produce high quality plant material or to define optimal conditions when combining flower induction and fruit production.  相似文献   

19.
Passiflora mollissima, Passiflora tricuspis and Passiflora nov sp. are three passion fruit species occurring in Bolivia. Germination percentages and rates were determined for 11 different treatments. Per species, germination of 100 seeds was monitored every 3 days, during 90 days. Germination started after 9 days and 50% of final germination was reached within a month or less. Successful, recommended methods for P. mollissima are removing the basal point of seeds (27% germination) or removing the basal point in combination with pre-soaking seeds for 48 h in 50 ppm GA3 (18%). Pre-soaking seeds for 24 h in 400 ppm GA3 (42%) and removal of the basal point in combination with pre-soaking seeds for 48 h in 50 ppm GA3 (36%) are suggested methods to improve germination of P. nov sp. Removing the apical point of P. tricuspis seeds resulted in maximal germination (57%). No unique treatment gave satisfactory results for the three species tested. Exogenous dormancy, probably a combination of mechanical and chemical dormancy is present in the three species studied. Presence of physical dormancy was found in P. mollissima.  相似文献   

20.
Salicornia is a new vegetable crop that can be irrigated with highly saline water, even at salt concentrations equivalent to full-strength seawater. During leafy vegetable cultivation, the onset of the reproductive phase is an undesired phenomenon that reduces yield and quality and prevents year-round cultivation. Knowledge about the regulation of floral induction in the members of the tribe Salicornieae, however, is lacking. To establish year-round cultivation, we studied the flower induction of five Salicornia and two Sarcocornia varieties. Plants were grown under two day lengths, 13.5 h and 18 h, and harvested by a repetitive harvest regime. A 13.5-h day length prevented flower induction in the Israeli Salicornia varieties, but a longer day length was required to prevent flower induction in two species originating from more northern latitudes. The onset of the reproductive phase under suboptimal short day length conditions severely reduced vegetative growth and yields in Salicornia. In Sarcocornia, the repetitive harvest regime prevented flowering, making it a promising candidate for year-round cultivation. Irrigating the plants with full-strength seawater (electrical conductivity 48 dS m−1) vs. water with moderate salinity (electrical conductivity 10 dS m−1) did not change the general flowering pattern of the studied Salicornieae members.  相似文献   

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