scholarly journals The Effects of Conditioning Strawberry Plug Plants under Altered Red/Far-red Light Environments

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1263-1267 ◽  
Author(s):  
Brent L. Black ◽  
Harry J. Swartz ◽  
Gerald F. Deitzer ◽  
Bryan Butler ◽  
Craig K. Chandler
Keyword(s):  
Production System ◽  
Day Treatment ◽  
Red Light ◽  
Field Performance ◽  
Cold Climate ◽  
Plant Performance ◽  
First Year ◽  
Greenhouse Production ◽  
Plastic Films ◽  
Short Day

The effect of altered red/far-red light environment on subsequent field performance of strawberry plug plants was tested. Two wavelength-selective plastic films were compared to neutral shade and full-sun control for conditioning `Chandler' strawberry plug plants before transplanting to a winter production system. The following year, plug plants of `Chandler', `Sweet Charlie', and `Allstar' were conditioned under the same treatments, with the addition of a continuous incandescent light and a short-day photoperiod, and plant performance was followed in the winter production system in Florida, a cold-climate annual hill system in Maryland, and in a low-input greenhouse production system. During the first year, the red light-filtering film slightly advanced fruiting in Florida. However, during the second year, the effect of the red light-filtering film was not significant, and a short-day treatment resulted in a greater reduction in runnering and increased early crown and flower development. For June-bearing strawberry plants maintained above 20 °C, altering the red/far-red environment did not consistently advance flowering.

Frost hardiness, height, and dormancy of 15 short-day, nursery-treated interior spruce seed lots

2000 ◽  
Vol 30 (7) ◽  
pp. 1096-1105 ◽  
Author(s):  
C DB Hawkins ◽  
K B Shewan
Keyword(s):  
Picea Glauca ◽  
Day Treatment ◽  
Field Performance ◽  
Seed Orchard ◽  
Frost Hardiness ◽  
Control Treatment ◽  
Short Day ◽  
Physiological Processes ◽  
Interior Spruce ◽  
Day Nursery

Fifteen seed lots, five each from natural-stand, seed-orchard, and full-sib collections, of interior spruce (Picea glauca (Moench) Voss, Picea engelmannii Parry ex Engelm., and their naturally occurring hybrids) were sown in February 1993. One half of each seed lot received an ambient photoperiod (control) treatment, while the other half got a blackout (short-day) treatment. All seedlings were grown under ambient photoperiod except during the 17 days of blackout. Frost hardiness assessments were done between July and May. Blackout treatment was effective in regulating height and promoting frost hardiness in all seed lots, particularly vigorous ones. Seed lots originating from high latitude or elevation were more frost hardy both at fall lift and spring planting. Full-sib seed lots from similar latitude displayed no elevational frost-hardiness trend. Blackout treatment promoted seedling dormancy (estimated with days to bud break) at lift, but it had little or no effect on dormancy at planting. Seedling dormancy and frost hardiness were acquired and lost differently, suggesting that they are independent physiological processes. Blackout treatment significantly reduced new roots at planting in all lots. This could retard early field performance and negate the apparent utility of blackout treatment.

scholarly journals An Assessment of Storability of Norway Spruce Container Seedlings in Freezer Storage as Affected by Short-Day Treatment

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 692
Author(s):  
Johanna Riikonen ◽  
Jaana Luoranen
Keyword(s):  
Norway Spruce ◽  
Day Treatment ◽  
Field Performance ◽  
Matter Content ◽  
Dry Matter Content ◽  
Freezer Storage ◽  
Short Day ◽  
Chilling Hours ◽  
The Impact ◽  
The Relationship

Determination of safe times at which to transfer seedlings to freezer storage is problematic in forest tree nurseries. The present study aimed to determine the relationship between pre-storage frost hardiness (FH) of different plant parts, dry matter content (DMC), chilling hours (the sum of hours when temperature was between −5 °C and +5 °C), and post-storage vitality, and the impact of short-day (SD) treatment on these relationships. One and a half year old control seedlings and SD-treated seedlings of Norway spruce were transferred to freezer storage (−3 °C) on five occasions during autumn. On each occasion, the FH of buds, needles, stem, and roots, as well as DMC, were determined, and chilling hours were calculated. The vitality of the freezer-stored seedlings was determined through their root growth capacity in the subsequent spring, and through the field performance of the seedlings (shoot growth and seedling damage) at the end of the following two growing seasons. Seedlings were considered to be storable when the FH of the needles was at least −25 °C, and the FH of the roots was about −10 °C in both treatments. Early storage reduced the vitality of the seedlings. SD treatment did not advance the storability of the seedlings, although it alleviated some of the negative effects of early storage by improving the FH of needles and stem, but not that of the roots. The DMC value, indicating storability, was higher for SD-treated seedlings than for control seedlings. When data from five experiments conducted in Suonenjoki were combined, it was found that the relationship between accumulation of chilling hours and needle FH was dependent on nursery treatment and assessment year, which reduces the reliability of using chilling hours in predicting the storability of Norway spruce seedlings. The predicted climate change may complicate the fall acclimation of seedlings. New, user-friendly methods for determining storability of seedlings are urgently needed.

Short-day treatment alters Douglas-fir seedling dehardening and transplant root proliferation at varying rhizosphere temperatures

2008 ◽  
Vol 38 (6) ◽  
pp. 1526-1535 ◽  
Author(s):  
Douglass F. Jacobs ◽  
Anthony S. Davis ◽  
Barrett C. Wilson ◽  
R. Kasten Dumroese ◽  
Rosa C. Goodman ◽  
...  
Keyword(s):  
Electrolyte Leakage ◽  
Cold Hardiness ◽  
Day Treatment ◽  
Field Performance ◽  
Douglas Fir ◽  
Day Length ◽  
Root Production ◽  
Root Proliferation ◽  
Cold Temperatures ◽  
Short Day

We tested effects of shortened day length during nursery culture on Douglas-fir ( Pseudotsuga menziesii var. menziesii (Mirb.) Franco) seedling development at dormancy release. Seedlings from a 42°N source were grown either under ambient photoperiods (long-day (LD)) or with a 28 day period of 9 h light : 15 h dark photoperiods (short-day (SD)). Seedlings were periodically removed from freezer storage from January to May. Sensitivity of plant tissues to cold temperatures was investigated via electrolyte leakage at nine test temperatures ranging from 2 to –40 °C. New root growth was assessed with rhizosphere temperatures of 10, 15, 20, and 25 °C. From 2 to –13 °C, there was no difference between treatments in cold hardiness. However, at or below –18 °C, LD seedlings exhibited higher indices of damage than SD seedlings. The LT50 (temperature at which 50% cell electrolyte leakage occurred) was consistently lower for SD than LD seedlings. Rhizosphere temperature differentially influenced new root proliferation: LD seedlings had greater new root production than SD seedlings at 20 °C, whereas the opposite response was detected at 10 °C. Our results confirm photoperiod sensitivity of Douglas-fir sources from relatively low (i.e., <45°N) latitudes. Increased spring cold hardiness and greater rooting at lower rhizosphere temperatures may improve field performance potential of SD-treated seedlings.

scholarly journals 263 Photoselective Films Influence Flowering of Photoperiodic Species

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 436E-436
Author(s):  
Teresa A. Cerny ◽  
Nihal C. Rajapakse ◽  
Ryu Oi
Keyword(s):  
Plant Species ◽  
Light Quality ◽  
Red Light ◽  
Photon Flux ◽  
Crop Species ◽  
Plastic Films ◽  
Spectral Filters ◽  
Short Day ◽  
Long Day ◽  
Air Temperatures

Growth chambers constructed from photoselective plastic films were used to investigate the effects of light quality on height manipulation and flowering of photoperiodic plant species. Three types of treatment films were used; control, a far-red light intercepting film (YXE-10) and a red light intercepting film (SXE-4). The red (600-700 nm):far-red (700-800 nm) ratios and phytochrome photoequilibrium estimates for the control, YXE-10 and SXE-4 films were 1.0 and 0.71, 1.5 and 0.77, and 0.71 and 0.67, respectively. The photosynthetic photon flux was adjusted to uniformity among chambers using neutral density filters. Spectral filters did not effect minimum and maximum air temperatures. Experiments were conducted using quantitative long day (Antirrhinum majus and Petunia × hybrida), quantitative short day (Zinnia elegans and Dendranthema × grandiflorum) and day-neutral (Rosa × hydrida) plant species under natural short-day conditions. Plants produced under the YXE-10 filters were significantly shorter than the control plants, while plants produced under the SXE-4 films had similar or increased height compared to the control plants. However, both height response and flowering times varied with the crop species. Flowering time of Rosa × hybrida plants was uniform among all treatments. Flowering of quantitative long-day plants was delayed by at least 10 days under the YXE-10 film and was most responsive to the filtered light. Flowering of quantitative short-day plants was delayed by 2 days under the YXE-10. Days to flower for plants produced under the SXE-4 film were similar to the control plants for all species tested.

scholarly journals 199 Influence of Photoperiod, Temperature, and Growth Regulators on Growth and Flowering of Helichrysum and Brachycome

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 476D-476
Author(s):  
Jessica Phillips ◽  
James M. Garner ◽  
Allan M. Armitage
Keyword(s):  
Flowering Time ◽  
Constant Temperature ◽  
Growth Regulators ◽  
Day Treatment ◽  
Growth Index ◽  
Greenhouse Production ◽  
Short Day ◽  
Linear Decrease ◽  
Extended Day ◽  
Temperature And Growth

Five taxa of Helichrysum Mill. and Brachycome Cass. were recently evaluated for greenhouse production and amenity use. Preliminary studies on the influence of photoperiod, temperature, and growth regulators were conducted for H. bracteatum Vent., (syn Bracteantha bracteata) `Sunray' and `Matilda Yellow', H. apiculatum D.C, (syn Chrysocephalum apiculatum) `Golden Buttons' and Brachycome iberidifolia Benth. `Jumbo Mauve' and `Mauve Delight'. All taxa of Helichrysum were quantitative LD plants, flowering slightly more rapidly under night-break (2200-0200 HR) and extended day incandescent lighting, compared with 9-h short-day treatment. No influence of photoperiod occurred with cultivars of Brachycome. Constant temperature of 12, 20, or 28 °C were provided and all taxa demonstrated a linear decrease in flowering time as temperatures increased. The growth index (average of height and two measurements of width) was also influenced by temperature. Paclobutrazol and daminozide were applied at different concentrations and frequencies. Paclobutrazol was more effective than daminozide in both genera, and daminozide was ineffective in Brachycome.

scholarly journals Growth Control of Lisianthus by Photoselective Plastic Films

2001 ◽  
Vol 11 (4) ◽  
pp. 581-584 ◽  
Author(s):  
Sandra B. Wilson ◽  
Nihal C. Rajapakse
Keyword(s):  
Plant Height ◽  
Red Light ◽  
Growth Control ◽  
Selective Reduction ◽  
Dry Weight ◽  
Eustoma Grandiflorum ◽  
Greenhouse Production ◽  
Plastic Films ◽  
Transmission Properties ◽  
Leaf Dry Weight

Plant response to photoselective plastic films with varying spectral transmission properties was tested using lisianthus (Eustoma grandiflorum) `Florida Pink', `Florida Blue', and `Florida Sky Blue'. Films were designated YXE-10 (far-red light-absorbing film) and SXE-4 (red light absorbing film). Light transmitted through YXE-10 films reduced plant height compared to control plants by 10% (`Florida Blue'), and stem dry weight by 19% to 40%, but the response varied by cultivar. Internode length was reduced by 10% to 19% when `Florida Pink' and `Florida Sky Blue' plants were grown under YXE-10 films. Leaf and root dry weights were not affected by YXE-10 films, with the exception that `Florida Sky Blue' plants had a lower leaf dry weight than the control plants. Light transmitted through SXE-4 films increased plant height of `Florida Pink' plants by 15% but not of `Florida Blue' or `Florida Sky Blue.' Regardless of cultivar, dry weight of leaf, stem and root tissue was not affected by SXE-4 films as compared to control films. The average number of days to flower and bud number were not affected by YXE-10 or SXE-4 films, regardless of cultivar. The results suggest that selective reduction of far-red wavelengths from sunlight may be an alternative technique for greenhouse production of compact plants, but the magnitude of the response is cultivar specific.

scholarly journals Blackout Reduces Height of Easter Lily but End-of-day Red Light Treatment Using Light-emitting Diodes Does Not

2020 ◽  
Vol 30 (2) ◽  
pp. 156-162
Author(s):  
Jasmine Jenji Mah ◽  
David Llewellyn ◽  
Youbin Zheng
Keyword(s):  
Treatment Effects ◽  
Light Emitting Diodes ◽  
Day Treatment ◽  
Red Light ◽  
Lilium Longiflorum ◽  
Light Treatment ◽  
Greenhouse Production ◽  
Light Emitting ◽  
Stem Extension ◽  
Easter Lily

One principle for reducing undesirable stem extension in greenhouse production is to counteract the decrease in red-to-far red ratio that occurs naturally during twilight periods. This study evaluated three lighting treatments on the morphology of easter lily (Lilium longiflorum): 1) a 1-hour end-of-day treatment providing 20 μmol·m−2·s−1 of monochromatic red light (EOD R), 2) blackout curtains closed 45 to 75 minutes before sunset and kept closed until 0 to 60 minutes after sunrise (BO), and 3) a control with natural twilight (CTRL). Plants under the BO treatment were 11% shorter than CTRL, while plants exposed to EOD R did not differ in height compared with BO or CTRL. There were no treatment effects on any other measured parameters, including aspects of flowering.

Approach to the Reforms in Nightsoil Treatment Process Introduced Abroad

1991 ◽  
Vol 24 (5) ◽  
pp. 189-196 ◽  
Author(s):  
S. B. Guo ◽  
R. Z. Chen ◽  
G. Li ◽  
H. Y. Shoichi
Keyword(s):  
Treatment Cost ◽  
Treatment Process ◽  
Biological Process ◽  
Treatment Plant ◽  
Plant Performance ◽  
First Year ◽  
Original Design ◽  
Effluent Quality ◽  
Public Toilets

In 1987 Guangzhou Liede Nightsoil Treatment Plant started commissioning. The purpose of the plant is to dispose of 400 tons of nightsoi1 from city public toilets per day. In the first year of the commissioning a biological process was basically used according to the original design made by a Danish company. Practically it has been proved that the design is effective. The process can reduce BOD from 3800 mg/l to about 133 mg/l, or by approximately 96.5 percent. The performance of the sludge digester system is satisfactory. Because the primary investigation on characteristics of the nightsoil was insufficient there were some problems raised during the commissioning. So in the first year the effluent failed to achieve the desired quality. After the analysis of the plant performance some necessary reforms have been carried out. Now the effluent quality can stably meet the national discharge limits and the treatment cost decreases.

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