Interruption Treatments Research Articles

Effects of seasonal light variation and artificial light treatments on growth and flavonoid production of Artemisia princeps cultivated in greenhouses

Artemisia princeps (Ganghwa wormwood) is a medicinal plant that produces two major flavonoids, eupatilin and jaceosidin, which are used in the treatment of gastritis and peptic ulcers. A. princeps is primarily field cultivated, which has some drawbacks, including only one cultivation period per year and variations in flavonoid production due to environmental changes. The objective of this study was to analyze the effects of seasonal light variation and artificial light treatments on the growth and flavonoid production of A. princeps grown in greenhouses for year-round production. The plants were cultivated and harvested nine times in one year under natural seasonal light conditions in greenhouses. During the winter growth period (when natural light is substantially lower), four artificial light treatments were applied during two cultivation periods, from September 2016 to January 2017: supplemental light, night interruption, low light, and low light with night interruption. The plants grown under the natural light condition in greenhouses were used as a control. After harvest, the growth of the plants was measured, and the contents of eupatilin and jaceosidin were determined. The plants had the highest biomass when the accumulated radiation and duration were highest. The growth and flavonoid production were significantly associated with accumulated radiation and light duration. The supplemental light and night interruption treatments resulted in significantly higher biomass and flavonoid production, with the night interruption treatment requiring less energy input than the supplemental light treatment. Therefore, for consistent biomass and flavonoid production of A. princeps, a night interruption treatment is suggested in greenhouse cultivation during low irradiation and short days (less than 13 h).

Long-term efficacy of imatinib mesylate in patients with advanced Tenosynovial Giant Cell Tumor

Tenosynovial giant cell tumors (TGCT), are rare colony stimulating factor-1(CSF-1)-driven proliferative disorders affecting joints. Diffuse-type TGCT often causes significant morbidity due to local recurrences necessitating multiple surgeries. Imatinib mesylate (IM) blocks the CSF-1 receptor. This study investigated the long term effects of IM in TGCT. We conducted an international multi-institutional retrospective study to assess the activity of IM: data was collected anonymously from individual patients with locally advanced, recurrent or metastatic TGCT. Sixty-two patients from 12 institutions across Europe, Australia and the United States were identified. Four patients with metastatic TGCT progressed rapidly on IM and were excluded for further analyses. Seventeen of 58 evaluable patients achieved complete response (CR) or partial response (PR). One- and five-year progression-free survival rates were 71% and 48%, respectively. Thirty-eight (66%) patients discontinued IM after a median of 7 (range 1–80) months. Reported adverse events in 45 (78%) patients were among other edema (48%) and fatigue (50%), mostly grade 1–2 (89%). Five patients experienced grade 3–4 toxicities. This study confirms, with additional follow-up, the efficacy of IM in TGCT. In responding cases we confirmed prolonged IM activity on TGCT symptoms even after discontinuation, but with high rates of treatment interruption and additional treatments.

Growth regulation and off-season flowering through night breaks in Chrysanthemum morifolium Ramat cv. Anmol

The photoperiodic night interruption to schedule efficient flowering time in Chrysanthemum morifolium Ramat cv. Anmol according to demand of its flowers in the market was monitored. The influence of six night interruption treatments i.e. control, <5 second flash, 30, 60, 90 and 120 min were studied on the morphological development of Chrysanthemum morifolium Ramat cv. Anmol. The results revealed that the plant height, number of branches, leaves and root suckers per plant were positively affected with increased duration of night interruption. The flowering time was significantly delayed from mid December to end of February (two months) and number of flowers per plant increased as the duration of night interruption was increased from control to 120 min. Therefore, the night interruption durations studies were helpful to schedule the sustainable flowering time in Chrysanthemum cultivar Anmol by around two months with better plant growth.

Efficiency of night interruption treatments with red and far-red light-emitting diodes (LEDs) in preventing bud set in Norway spruce seedlings

Terminal bud set can be prevented by interrupting night with short pulses of light when the natural photoperiod is too short to maintain growth. Norway spruce (Picea abies Karst.) seedlings originating from 61°N and 64°N were grown in growth chambers under conditions that mimic growth conditions in a heated greenhouse in early spring in Finland (experiment 1) or under constant growth conditions (experiment 2). The seedlings were exposed to the following night interruption (NI) treatments using light-emitting diodes (LEDs) that generated red (R, peak at 660 nm) and far-red (FR, peak at 735 nm) wavelengths in 20 s pulses at 15 min intervals: (i) red light alone (R); (ii) R combined with FR (R + FR); and (iii) control (no NI treatment). The R + FR treatment was more effective in preventing terminal bud set than the R treatment. Seedling responses depended on the provenance and growth conditions. The R treatment reduced the proportion of seedlings with terminal buds in the 61°N seedlings and delayed bud set in the 64°N seedlings. The fluctuating growth conditions or longer dark period between the photoperiod and NI treatments reduced the efficiency of the R + FR treatment. A combination of R and FR LEDs with adequate light intensity and duration is suitable for intermittent NI treatment in Norway spruce seedlings.

Effect of duration of night interruption on growth and flowering of Chrysanthemum cv. Kikiobiory

The study was conducted to determine the effect of duration of night interruption using incandescent bulbs on sustained quality flower production of potted standard Chrysanthemum cv. Kikiobiory. The different night interruption (NI) treatments i.e. control, <5 sec. flash, 30-, 60-, 90- and 120- min. significantly (p<0.05) affected allthe vegetative and floral parameters. The plant height, number of leaves and root suckers per plant increased with the increase duration of NI treatments with maximum at 120- min. NI (90.42 cm, 34.75 and 12.10, respectively). The days taken to flower bud appearance, colour break stage and full bloom were delayed, whereas flower quality with respect to duration of flowering and flower diameter were deteriorated with increase in duration of NI treatments. The days taken to flower bud appearance, colour break stage and full bloom were highest at 120- min. NI (136.84, 183.22 and 202.25 days, respectively) which delayed the flowering by 63.94 days, where full bloom flower appeared in March. There was reduction in duration of flowering and flower diameter with increased NI duration with lowest at 120 min. NI (7.83 days and 15.69 cm). It was observed that increase (120 min.) in night interruption increased the vegetative growth and delayed the flowering; however, flower quality was deteriorated. Thus, it was concluded that 60 min. NI improved flower quality with sustained flower production in potted Chrysanthemum cv. Kikiobiory.

Responses of Norway spruce seedlings to different night interruption treatments in autumn

Photoperiodic lighting can be used in late summer to prevent height growth cessation and terminal bud formation in nurseries growing forest tree species in Nordic countries. To create guidelines for using the method in container nurseries growing Norway spruce (Picea abies (L.) Karst.) and to test the use of light-emitting diode (LED) technology, we exposed first-year, nursery grown seedlings to the following night interruption (NI) treatments from 10 July 2014 onwards (00:00–03:00): (i) no lighting, (ii) 1 min lighting at intervals of 30 min, (iii) 1 min lighting at intervals of 15 min, and (iv) 3 h continuous lighting. Light intensities (LI) of 10, 25, and 70 μmol photosynthetically active radiation (PAR) m−2·s−1 were used. Growth, formation of terminal buds, and winter damage of the seedlings were measured. All NI treatments prevented growth cessation at LI of 25 and 70 μmol PAR·m−2·s−1, but the intermittent treatments were less effective at a LI of 10 μmol PAR·m−2·s−1. The treatments of duration longer than 1 min at intervals of 30 min did not provide any additional increase in shoot growth but predisposed the seedlings to frost injury during autumn and winter. Both seed origins used in this experiment responded similarly to the NI treatments.

Responses of plant growth rate to nitrogen supply: a comparison of relative addition and N interruption treatments

Responses of plant growth rate to nitrogen supply: a comparison of relative addition and N interruption treatments

Responses of plant growth rate to nitrogen supply: a comparison of relative addition and N interruption treatments

This paper investigates the effects of uptake of nitrate and the availability of internal N reserves on growth rate in times of restricted supply, and examines the extent to which the response is mediated by the different pools of N (nitrate N, organic N and total N) in the plant. Hydroponic experiments were carried out with young lettuce plants (Lactuca sativa L.) to compare responses to either an interruption in external N supply or the imposition of different relative N addition rate (RAR) treatments. The resulting relationships between whole plant relative growth rate (RGR) and N concentration varied between linear and curvilinear (or possibly bi-linear) forms depending on the treatment conditions. The relationship was curvilinear when the external N supply was interrupted, but linear when N was supplied by either RAR methods or as a supra-optimal external N supply. These differences resulted from the ability of the plant to use external sources of N more readily than their internal N reserves. These results show that when sub-optimal sources of external N were available, RGR was maintained at a rate which was dependent on the rate of nitrate uptake by the roots. Newly acquired N was channelled directly to the sites of highest demand, where it was assimilated rapidly. As a result, nitrate only tended to accumulate in plant tissues when its supply was essentially adequate. By comparison, plants forced to rely solely on their internal reserves were never able to mobilize and redistribute N between tissues quickly enough to prevent reductions in growth rate as their tissue N reserves declined. Evidence is presented to show that the rate of remobilization of N depends on the size and type of the N pools within the plant, and that changes in their rates of remobilization and/or transfer between pools are the main factors influencing the form of the relationship between RGR and N concentration.

Flowering of Herbaceous Perennials under Various Night Interruption and Cyclic Lighting Treatments

Six long-day species of herbaceous perennials were grown under six night-interruption (NI) photoperiod treatments to determine their relative effectiveness at inducing flowering. Photoperiods were 9-hour natural days with NI provided by incandescent lamps during the middle of the dark period for the following durations: 0.5, 1, 2, or 4 hours; 6 minutes on, 54 minutes off for 4 hours (10% or 6/54 cyclic lighting); or 6 minutes on, 24 minutes off for 4 hours (20% or 6/24 cyclic lighting). For five species, the experiment was repeated with more mature plants; for the sixth, Rudbeckia fulgida Ait. `Goldsturm', following a cold treatment of 8 weeks at 5 °C. The species generally showed a quantitative flowering response to the NI duration until a saturation duration was reached; as the length of the uninterrupted night break increased, flowering percentage, uniformity, and number and plant height increased and time to flower decreased. Minimum saturation durations of NI were 1 hour for Coreopsis grandiflora Hogg ex Sweet `Early Sunrise' and Hibiscus moscheutos L. `Disco Belle Mixed', 2 hours for Campanula carpatica Jacq. `Blue Clips' and Coreopsis verticillata L. `Moonbeam', and 4 hours for unchilled R. fulgida `Goldsturm'. Echinacea purpurea Moench `Bravado' flowered similarly across all lighting treatments. The 6/24 cyclic lighting regimen induced flowering comparable to that under a continual 4-hour NI for four of the six species and the cold-treated R. fulgida `Goldsturm'. Flowering under the 6/54 regimen was generally incomplete, nonuniform, and delayed compared to that under saturation duration treatments. Three of five species flowered earlier when more mature plants were placed under the NI treatments. Cold-treated R. fulgida `Goldsturm' flowered more rapidly than unchilled plants and the saturation duration of NI decreased to 1 hour.

Photoperiod and Temperature Interact to Affect Gomphrena globosa L. and Salvia farinacea Benth. Development

Gomphrena globosa L. `Gnome Pink' and Salvia farinacea Benth. `Victoria Blue' were grown under different photoperiod treatments with day and night temperatures ranging from 15 to 30°C ± 1°C air temperature for 14 weeks after germination or until anthesis. Days to anthesis and leaf number were lowest when plants were grown under 9 hr of daylight and daylight plus 4-hr day extension from 1700–2100 HR (100 μmol·m–2·s–1 from high-pressure sodium lamps) for Gomphrena and Salvia, respectively. Days to anthesis decreased as temperature increased from 15 to 25°C with Gomphrena. Further increasing night temperature from 25 to 30°C delayed flowering and increased leaf number below the first flower of Gomphrena, but hastened flowering of Salvia. Plant height and internode elongation were greatest and least in the night interruption (2 μmol·m–2·s–1 from incandescent lamps from 2200–0200 HR) and continuous light (daylight plus 100 μmol·m–2·s–1 from high-pressure sodium lamps) treatments, respectively. Implications of these data with respect to classification of Gomphrena and Salvia flower induction are discussed and revised production schedules are presented.

Photoperiod and Temperature Interact to Affect Viola × wittrockiana Gams. Development

Viola × wittrockiana Gams. cvs `Delta Pure Rose' and `Sorbet Yellow Frost' were grown under different photoperiod and temperature treatments (12–24 ± 2°C) for different lengths of time at different stages of development during the first 6 weeks after germination. Plants were grown with ambient light (≈9 hr) at 16°C before and after treatments. Days to anthesis and leaf number were lowest when plants were grown under night interruption from 2200–0200 hr (2 μmol·m–2·s–1 from incandescent lamps) and daylight plus continuous light (100 μmol·m–2·s–1 from high-pressure sodium lamps) for `Sorbet Yellow Frost' and `Delta Pure Rose', respectively. Days to anthesis decreased as temperature increased from 12 to 24°C. Plant height and internode elongation were greatest and least in the night interruption and continuous light treatments, respectively. Branching decreased as temperature increased from 12 to 24°C. Implications of these data with respect to classification of Viola × wittrockiana flower induction and development of prefinished seedlings is discussed.

Photoperiod and Temperature Interact to Affect Petunia × hybrida Vilm. Development

Petunia × hybrida Vilm. cvs. `Purple Wave', `Celebrity Burgundy', `Fantasy Pink Morn', and `Dreams Red' were treated with temperature and photoperiod treatments for different lengths of time at different stages of development during the first 6 weeks after germination. Plants were grown with ambient light (≈8–9 hr) at 16°C before and after treatments. Flowering was earliest and leaf number below the first flower was lowest when plants were grown under daylight plus 100 μmol·m–2·s–1 continuous light (high-pressure sodium lamps). Flowering did not occur when plants were grown under short-day treatment (8-hr daylight). Plants grown with night interruption lighting from 2200–0200 HR (2 μmol·m–2·s–1 from incandescent lamps) flowered earlier, and with a reduced leaf number compared to plants grown with daylight + a 3-hr day extension from 1700–2000 HR (100 μmol·m–2·s–1 using high-pressure sodium lamps). Plant height and internode elongation were greatest and least in night interruption and continuous light treatments, respectively. `Fantasy Pink Morn' and `Purple Wave' were the earliest and latest cultivars to flower, respectively. Flowering was hastened as temperature increased from 12 to 20°C, but not as temperature was further increased from 20 to 24°C. Branching increased as temperature decreased from 24 to 12°C. Implications of data with respect to classification of petunia flower induction and pre-fi nishing seedlings are discussed.

Determining the Critical Photoperiod for Flowering of Several Herbaceous Perennial Species

Twenty-four herbaceous perennial species were treated at 5C for 0 or 15 weeks. Critical photoperiods for flower initiation and development with and without a cold treatment were determined. Photoperiods were 10, 12, 14, 16, and 24 h of continuous light and 9 h plus a 4-h night interruption. Continuous photoperiodic treatments consisted of 9-h natural days extended with light from incandescent lamps. Response to cold and photoperiod varied by species; Scabiosa caucasica `Butterfly Blue' flowered without a cold treatment under all photoperiods after 8 to 10 weeks of forcing, but plant height increased from 14 to 62 cm as daylength increased. Rudbeckia fulgida `Goldsturm' flowered without cold after 13 to 15 weeks of forcing, but only under 16 hours of continuous light and night interruption treatments. Heuchera sanguinea `Bressingham Hybrids' did not flower without cold under any photoperiod but did flower under all photoperiods with cold. The only Lavendula angustifolia `Munstead Dwarf' plants that flowered without cold were those under 24-h continuous light; ≈60% flowered. After cold, some lavender plants flowered under all photoperiods, and the flowering percentage increased with increasing daylength.

Effect of Extended Photoperiod on Budbreak, Overwinter Survival, and Carbohydrate Levels of Acer rubrum ‘October Glory’ Rooted Cuttings

Abstract Acer rubrum L. ‘October Glory’ cuttings taken on 15 June 1984 were subjected to short day (SDT) (800-1700 HR) or short day plus night interruption treatments (NIT) (800-1700 plus 2200-200 HR) from 25 July until 22 Oct. 1984. Additional cuttings taken on 14 Aug. were subjected to the same photoperiod treatments from 10 Sept, until 22 Oct. For the 15 June cuttings, the NIT treatment induced significantly greater percent budbreak than the SDT, but did not induce significantly greater overwinter survival. Cuttings of 15 June that broke bud under NIT had significantly greater stem length and dry weight than cuttings that broke bud under SDT. SDT and NIT cuttings of 15 June that broke bud had significantly greater percent root carbohydrates, total grams of carbohydrates, and percent overwinter survival then cuttings that did not break bud. For the 14 Aug. cuttings, 1% of the cuttings broke bud, yet 95% (SDT) and 90% (NIT) of the cuttings survived the winter, and no difference in cutting carbohydrate levels, except stem starch, existed between the two treatments.

The Effect of Periodic Dark Interruptions in Long Photoperiods on Floral Induction in the Long-Day Plants Silene armeria L., annual Lunaria annua L. and Samolus parviflorus Raf.

After a basic fluorescent and incandescent illumination, a period of incandescent illumination was interrupted by 3 hours of darkness at different times, the total light period always being 16 h. After these Day Interruption (DI) treatments of various durations the plants were transferred to long day (LD) or continuous light (CL), where the numbers of days of flower-bud visibility were recorded. Compared with the uninterrupted controls, the DI-treatments generally accelerated flower formation to an extent which varied rhythmically with the moment in the photoperiod at which the DI was given. By involving the days to flower-bud visibility in LD or CL of originally vegetative plants in the evaluation of the results, the DI-effects could be explained as the reflection of rhythmically returning changes in the light requirement for flower formation in the course of the photoperiod. Relatively rapid flower formation after a certain DI treatment reflected a relatively low light requirement, and vice versa. Calculations of the inductive efficiencies of interrupted regions, defined as their inductive effect as percentages of the effect of LD or CL, confirmed this viewpoint. The rhythmic courses of the light requirement during the photoperiod could be distinguished as two types:

The Control of Flowering in Lilium longiflorum Thunb. cv. Nellie White by Cyclic or Continuous Light Treatments1

Abstract Flowering was accelerated by incandescent light day extensions of 3 minutes of light and 27 minutes of dark or longer light cycles and by 15 minutes of light and 15 minutes of dark cycles when BCJ-ruby incandescent light was given to young shoots from non-vernalized bulbs. If bulbs were vernalized for 3 weeks, cool white fluorescent light accelerated flowering as a day extension. As a night interruption, incandescent, fluorescent or BCJ-ruby incandescent cyclic light treatments accelerated flowering of shoots from vernalized or non-vernalized bulbs. Day extensions of cyclic fluorescent or BCJ-ruby light treatments of 6 minutes on and 24 off or 3 minutes on and 27 off did not mediate a phytochrome controlled flowering response and along with the fact that there was no photoreversibility between day extensions of incandescent, fluorescent or BCJ-ruby incandescent light, indicate a high energy reaction involvement in the flowering of the lily. As a night interruption treatment, a phytochrome mediated flowering response was observed with 3 minutes of light on and 27 off or 6 minutes on and 24 off cyclics of fluorescent or BCJ-ruby incandescent light treatments. However, as the light period increased to 15 minutes on and 15 off or under a continuous light cycle, there were no differences in the flowering response between fluorescent or BCJ-ruby incandescent. As night interruptions there was a reversibility response by R — FR, but not by FR — R. This indicated the simultaneous operation of the phytochrome and the high energy reaction.

Effects of Night Breaks on Floral Initiation and Development in Saccharum1

The effects of night breaks with light of different spectral compostion applied at various stages of floral development, starting before induction up to inflorescence emergence, were studied in Saccharum spontaneum L. and S. robustum L. clones. Night interruption treatments with incandescent light decreased % inflorescence emergence and delayed flowering when applied at all stages of development in S. spontaneum L. In both S. robustum L. and S. spontaneum L. clones, the degree of inhibition of flowering depended on the stages of development at which the night interruptions were applied; the early stages of differentiation of the inflorescence (initiation of inflorescence axis and branch primorda) were found to be the most sensitive. The spectral composition of the light used was also important; red, orange, and green light were generally the most inhibitory to inflorescence development, while blue, far‐red, and ultraviolet were not effective and similar to darkness. Attempts to reverse the inhibitory effect of red light by far‐red failed. Night breaks also had their maximum inhibitory effects when applied towards the end of the dark period and had minimum effects when applied at the middle of the dark period.