INFLUENCE D’UN PRE-TRAITEMENT AU FROID ET DE LA TEMPERATURE NOCTURNE SUR LA CROISSANCE, LE DEVELOPPEMENT ET LE CONTENU EN ELEMENTS MINERAUX DE PLANTS DE POINSETTIA

1985 ◽  
Vol 65 (4) ◽  
pp. 1001-1010
Author(s):  
MICHEL SENECAL ◽  
BLANCHE DANSEREAU
Keyword(s):  
Temperature Regime ◽  
Dry Weight ◽  
Euphorbia Pulcherrima ◽  
Rapid Adaptation ◽  
Night Temperature ◽  
Flower Buds ◽  
Cold Pretreatment ◽  
Top Dry Weight ◽  
Pre Treatment ◽  
Nitrogen Phosphorus

To achieve more rapid adaptation of plants grown under a constant or split night temperature regime, two poinsettia cultivars (Euphorbia pulcherrima Willd ex. Klotzsch), Annette Hegg Dark Red (AHDR) and Annette Hegg Top White (AHTW), were given a cold pretreatment (PF). The PF was a 13 °C air temperature regime provided for 15 h a night during a 10-day period. The number of days to the first visible flower buds and to anthesis was longer for both cultivars having received a PF than the control plants (no pre-treatment). For AHDR only, plant height, top dry weight, the number and bract area were significantly lower after the PF when considering the average of the night temperature treatments. Regardless of the cultivar tested, no significant differences in bract diameter and root dry weight were observed between the control plants and those given a PF treatment. Whether the two cultivars were given a PF treatment or not, the split night temperature (TNP) of 16.3/14.2 °C caused a nonsignificant delay, from the appearance of first visible flower buds to anthesis, compared to those held at 16.7 °C. The most important delay of these parameters as well as the greatest reduction of bract area was obtained under a 10.8 °C night temperature. The TNP of 16.6/10.8 °C produced plants (PF or control), of both cultivars with a greater bract number and top dry weight. For the two cultivars given a PF treatment, the levels of nitrogen, phosphorus, calcium, and magnesium were greater when considering the means of the night temperature treatments.Key words: Euphorbia pulcherrima, cold pretreatment, night temperature, split night temperature

INFLUENCE DE TRAITEMENTS PRÉALABLES AU FROID SUR LA CROISSANCE ET LE DÉVELOPPEMENT DU POINSETTIA

1990 ◽  
Vol 70 (1) ◽  
pp. 363-368
Author(s):  
SERGE GAGNON ◽  
BLANCHE DANSEREAU
Keyword(s):  
Dry Weight ◽  
Flower Head ◽  
Euphorbia Pulcherrima ◽  
Rapid Adaptation ◽  
Night Temperature ◽  
Flower Buds ◽  
Cold Night ◽  
Head Diameter ◽  
Significant Difference ◽  
Temperature Pretreatment

To achieve more rapid adaptation of plants grown under a constant cold night temperature regime, rooted poinsettia (Euphorbia pulcherrima Willd ex. Klotzsch ’Annette Hegg Dark Red’) cuttings were given one of several cold pretreatments (TPF): either 17/13 °C or 13 °C for 5, 10, or 15 d. The influence of these TPF treatments was compared with that of control plants where the night temperature was 17 °C. There was no significant difference for the number of days to the first visible flower buds and to anthesis, for the number of flowering stems and bracts formed, for leaf area and aerial dry weight. However, the TPF treatment of 17/13 °C given for 15 d caused a significant increase in bract area, and of average flower head diameter compared to those plants given a TPF treatment of 13 °C for the same length of time.Key words: Euphorbia pulcherrima, night temperature, split night temperature, pretreatment

scholarly journals Temperature and Duration of Pretreatment Effects on Growth and Development of Geraniums

HortScience ◽  
1992 ◽  
Vol 27 (3) ◽  
pp. 216-217
Author(s):  
Serge Gagnon ◽  
Blanche Dansereau
Keyword(s):  
Leaf Area ◽  
Plant Height ◽  
Growth And Development ◽  
Dry Weight ◽  
Rapid Adaptation ◽  
Night Temperature ◽  
Flower Buds ◽  
Shoot Dry Weight ◽  
Temperature Regimes ◽  
Pretreatment Effects

Geranium seedlings (Pelargonium ×hortorum Bailey `Smash Hit Red') were given various cold pretreatments (CP) to obtain more rapid adaptation to constant or split-night temperature regimes. The six following CP were used: either 13C or 17/13C for 5, 10, or 15 days. The effect of these CP given at seedling stage was compared with that of control plants held at 17C at night. The CP did not significantly increase the time to first visible flower buds or to anthesis. The number of flowering stems, plant height, shoot dry weight, and leaf area of control plants were not significantly different from plants receiving CP.

scholarly journals POINSETTIA GROWTH AND DEVELOPMENT IN RESPONSE TO DAY-NIGHT TEMPERATURE REGIME AND UNICONAZOLE.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1074c-1074
Author(s):  
Richard J. McAvoy
Keyword(s):  
Leaf Area ◽  
Temperature Regime ◽  
Dry Weight ◽  
Plant Canopy ◽  
Night Temperature ◽  
Specific Leaf Weight ◽  
Leaf Weight ◽  
Temperature Regimes ◽  
Potting Medium ◽  
Total Plant

Poinsettias, Euphorbia pulcherrima Willd. cvs Lilo and Diva Starlight, were exposed to either warm day-cool night or cool day-warm night greenhouse temperature regimes. Day time temperatures were imposed between 900 to 1600 HR. Within each temperature regime, poinsettias were grown single stem or pinched and drenched with either 0.04 or 0.08 mg a.i. uniconazole per 1.6 1 pot or grown as untreated controls. Light levels (PAR) and potting medium and plant canopy temperatures were continuously monitored.Over the course of the study, the day-night temperature differential (DIF), in the plant canopy, averaged 4.2C in the warm day regime and -1.4C in the cool day regime. The average daily temperature was lower (16.9C) in the warm day regime than in the cool day regime (18.7C).DIF treatment significantly affected final leaf area, leaf and total plant dry weight, leaf area ratio and specific leaf weight, The DIF treatment by cultivar interaction was significant for final poinsettia leaf area, stem, leaf and total plant dry weight, break number and average break length. Uniconazole significantly affected final plant height, stem and total plant dry weight, break number, average break length and specific leaf weight. Uniconazole by DIF treatment effects were not significant,

scholarly journals Growth of Cyclamen as Affected by Day and Night Temperatures

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 466G-467
Author(s):  
Meriam Karlsson ◽  
Jeffrey Werner
Keyword(s):  
Dry Weight ◽  
Flowering Plants ◽  
Flower Size ◽  
Night Temperature ◽  
Flower Number ◽  
Cyclamen Persicum ◽  
Flower Buds ◽  
Average Daily Temperature ◽  
Positive Difference ◽  
Significant Difference

The growth of Cyclamen persicum Mill. `Laser Scarlet' and `Sierra Scarlet' was evaluated for plants grown at day/night temperature differences of +9, +3, 0, –3 or –9°C. The day temperature was maintained for the duration of the 16-hr photoperiod and the day and night temperatures were selected to provide an average daily temperature of 16°C. The plants were grown at the specific temperatures starting 15 weeks from seeding until flowering. Total daily irradiance was 10 mol/day per m2. There was no significant difference in time to flower for plants of `Laser' (115 10.3 days from transplant). Flower buds appeared earlier above the foliage for `Sierra' plants grown at negative differences of 3 or 9°C (113 11.4 days) compared to plants grown at constant 16C (124 9.7 days). At flowering, plants grown with a positive difference of 9°C were significantly taller (22 1.9 cm for `Laser' and 24 2.0 cm for `Sierra') than the plants at 16C (19 1.9 cm for `Laser' and 21 2.1 cm for `Sierra'). Plants of `Laser' grown at +3C difference were also taller (21 2.1 cm) than the control plants at 16°C. Plant dry weight was larger for plants of both `Laser' and `Sierra' grown with +9°C. There were no differences in flower number or flower size among plants within each cultivar grown at the different temperature conditions.

Response of Eckespoint Lilo poinsettia to nitrite, substrate pH and etridiazole in a subirrigation system

1994 ◽  
Vol 74 (1) ◽  
pp. 151-154
Author(s):  
Theo J. Blom ◽  
Brian D. Piott
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Key Words ◽  
Nitrification Inhibitor ◽  
Dry Weight ◽  
Euphorbia Pulcherrima ◽  
Nitrite Concentration ◽  
Top Dry Weight ◽  
Substrate Ph ◽  
Complete Nutrient Solution

Poinsettias (Euphorbia pulcherrima Willd. 'Eckespoint Lilo') were grown in pH-adjusted (4.5, 5.5 or 6.5) sphagnum peat substrates and subirrigated using a complete nutrient solution with three concentrations of nitrite (0, 1.75 and 3.5 mol m−3). The substrate also was either treated with a nitrification inhibitor (etridiazole) or remained untreated. There was a linear decrease in leaf and bract areas, top dry weight, plant height and root growth with increasing nitrite concentration. This response occurred at a rate of 10% mol−1 NO2− m−3 at a substrate pH of 4.5 or 5.5 and 6% mol−1 NO2 m−3 at a substrate pH of 6.5. Leaf and bract areas and top dry weight were greater at pH 4.5 than at pH 6.5. Etridiazole did not affect the response of plant growth to nitrite and (or) substrate pH. Key words: Aaterra, 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazole, subirrigation, terrazole, truban

FERTILIZATION AND NIGHT TEMPERATURE EFFECTS ON GROWTH AND CARBOHYDRATE STATUS OF POINSETTIA

1989 ◽  
Vol 69 (1) ◽  
pp. 347-349
Author(s):  
M. SENÉCAL ◽  
B. DANSEREAU ◽  
R. PAQUIN
Keyword(s):  
Temperature Effects ◽  
Sugar Content ◽  
Dry Weight ◽  
Total Sugar ◽  
Euphorbia Pulcherrima ◽  
Night Temperature ◽  
Total Sugar Content ◽  
Carbohydrate Levels ◽  
Carbohydrate Status ◽  
Fertilizer Rates

Poinsettia (Euphorbia pulcherrima Willd ’Annette Hegg Dark Red’) were fertilized with 3.0, 4.5 or 6.0 g per 15-cm pot of Osmocote (14N-6.1P-11.6K) and were grown in greenhouses at 9, 13, or 17 °C night temperature. As the night temperature increased, the number of days to anthesis, bract number and carbohydrate levels decreased. Maximum bract mean area and minimum root dry weight were achieved at 13 °C. High fertilizer rates increased the number of days to anthesis while bract number, root and shoot dry weights, reducing and total sugar content decreased.Key words: Euphorbia pulcherrima, fertilization, night temperature, carbohydrate

scholarly journals Initial Growth of Seedlings of Mountain Laurel as Influenced by Day/Night Temperature

1992 ◽  
Vol 117 (5) ◽  
pp. 736-739 ◽  
Author(s):  
Asiah A. Malek ◽  
Frank A. Blazich ◽  
Stuart L. Warren ◽  
James E. Shelton
Keyword(s):  
Weight Ratio ◽  
Dry Weight ◽  
Root Weight ◽  
Initial Growth ◽  
Night Temperature ◽  
Root Dry Weight ◽  
Total Plant ◽  
Top Dry Weight ◽  
Leaf Photosynthetic Rate ◽  
Mountain Laurel

Seedlings of mountain laurel (Kalmia latifolia L.) were grown for 16 weeks under long-day conditions with days at 18, 22, 26, or 30C for 9 hours in factorial combination with nights at 14, 18, 22, or 26C for 15 hours. Total plant dry weight, top dry weight, and dry weights of leaves, stems, and roots were influenced by day and night temperatures. The night optimum for all dry weight categories was 22C. Dry matter production was lowest with nights at 14C. Total plant dry weight and dry weights of tops, leaves, and stems were maximized with days at 26C, but for roots the optimum was 22C. Dry weight accumulation was lower with days at 18 or 30C. Responses of leaf area were similar to that of total plant dry weight, with optimum days and nights at 26 and 22C, respectively. Within the optimal day/night temperature range of 22-26/22C for dry weights, there was no evidence that alternating temperatures enhanced growth. Shoot: root ratios (top dry weight: root dry weight) increased with day temperatures up to 30C and were highest with nights at 14 or 26C. Leaf weight ratio (leaf dry weight: total plant dry weight) decreased with increasing night temperature, and increased curvilinearly in response to day temperature with the minimum at 26C. Stem weight ratio (stem dry weight: total plant dry weight) increased with increasing day or night temperature. Root weight ratio (root dry weight: total plant dry weight) was highest with nights at 18 or 22C and decreased with days >22C. Net leaf photosynthetic rate was maximized with days at 26C.

scholarly journals Initial Growth of Seedlings of Flame Azalea in Response to Day/Night Temperature

1992 ◽  
Vol 117 (2) ◽  
pp. 216-219 ◽  
Author(s):  
Asiah A. Malek ◽  
Frank A. Blazich ◽  
Stuart L. Warren ◽  
James E. Shelton
Keyword(s):  
Leaf Area ◽  
Weight Ratio ◽  
Dry Weight ◽  
Night Temperature ◽  
Total Leaf Area ◽  
Root Dry Weight ◽  
Total Leaf ◽  
Total Plant ◽  
Top Dry Weight ◽  
Leaf Dry Weight

Seedlings of flame azalea [Rhododendron calendulaceum (Michx.) Torr] were grown for 12 weeks under long-day conditions with days at 18, 22, 26, or 30C for 9 hours in factorial combination with nights at 14, 18, 22, or 26C for 15 hours. Total plant dry weight, top dry weight, leaf area, and dry weights of leaves, stems, and roots were influenced by day and night temperatures and their interactions. Dry matter production was lowest with nights at 14C. Root, leaf, top, and total dry weights were maximized with days at 26C in combination with nights at 18 to 26C. Stem dry weight was maximized with days at 26 to 30C and nights at 22C. Leaf area was largest with days at 18 and 26C in combination with nights at 18 or 26C. Within the optimal, day/night temperature range of 26 C/18-26C for total plant dry weight, there was no evidence that alternating temperatures enhanced growth. Shoot: root ratios (top dry weight: root dry weight) were highest with days at 18 and 30C. Leaf area ratio (total leaf area: total plant dry weight) was highest and specific leaf area (total leaf area: leaf dry weight) was largest when days and nights were at 18C and were lower at higher temperatures. Regardless of day/night temperature, leaf weight ratio (leaf dry weight: total plant dry weight) was higher than either the stem weight ratio (stem dry weight: total plant dry weight) or root weight ratio (root dry weight: total plant dry weight). Net leaf photosynthetic rate increased with day temperatures up to 30C.

INFLUENCE DE LA TEMPÉRATURE NOCTURNE ET D’UN APPOINT DE LUMIÈRE SUR LA CROISSANCE ET LE DÉVELOPPEMENT DU Gerbera ET DU Calendula

1987 ◽  
Vol 67 (3) ◽  
pp. 871-879
Author(s):  
MICHEL SENÉCAL ◽  
BLANCHE DANSEREAU
Keyword(s):  
Dry Weight ◽  
Temperature Treatment ◽  
Winter Period ◽  
Gerbera Jamesonii ◽  
Calendula Officinalis ◽  
Night Temperature ◽  
Flower Number ◽  
Flower Bud ◽  
Top Dry Weight ◽  
Supplementary Lighting

During fall-winter and spring conditions, Gerbera jamesonii H. Bolus ex Hook. ’Happipot’ and Calendula officinalis L. ’Fiesta Gitanas’ plants were subjected to night temperatures of 9, 13, 17 and 20 °C (1700–0800 h) during the first year of experiment and were grown under supplementary lighting treatments (control, 75 and 150 μmol m−2 s−1) for 7 h per day at a temperature of 13 °C during the second year. The plant top dry weight of gerbera increased with a rise in night temperature and supplementary lighting, but the reverse tendency was noted with calendula under the night temperature treatment; increases in plant top dry weight under supplementary lighting were observed only during the fall-winter period. For both species, root dry weight showed less variation than plant top dry weight under night temperature and supplementary lighting treatments. The percentage of gerbera plants having shoots increased with a reduction of the night temperature and supplementary lighting during the fall-winter experiments. The lowering of night temperature and supplementary lighting reduced calendula flower bud abortion only during the fall-winter period. For both species, flower number was not significantly different among die night temperature treatments. Supplementary lighting enhanced flower number of calendula only. Flowering of gerbera was accelerated with a reduction of night temperature and with supplementary lighting.Key words: Calendula officinalis, Gerbera jamesonii, night temperature, supplementary lighting

INFLUENCE OF CLIPPING HEIGHT ON THE NEUTRAL CARBOHYDRATE LEVELS OF ROOT EXUDATES OF ALFALFA PLANTS GROWN UNDER GNOTOBIOTIC CONDITIONS

1972 ◽  
Vol 52 (4) ◽  
pp. 643-649 ◽  
Author(s):  
R. A. HAMLEN ◽  
F. L. LUKEZIC ◽  
J. R. BLOOM
Keyword(s):  
Root Exudates ◽  
Dry Weight ◽  
Root Tissue ◽  
Minor Components ◽  
Flower Buds ◽  
Total Sugars ◽  
Spectral Techniques ◽  
Mass Spectral ◽  
Mature Leaves ◽  
Carbohydrate Levels

Influence of clipping height on neutral carbohydrate levels in root exudates of alfalfa grown gnotobiotically was investigated by gas-chromatographic and mass-spectral techniques. Exudates were obtained from plants that were lightly clipped (removal of flower buds), intermediately clipped (15 cm), and severely clipped (removal of all but four mature leaves). Glucose, inositol, sucrose, and four unidentified (U) components were detected. Fluctuations in the level of sugars were observed in exudates from two sampling periods. Glucose and U1 were most concentrated under light clipping. Levels of inositol and sucrose were maximum under intermediate clipping. Amounts of U3 were greatest from severely clipped plants, whereas levels of U5 remained constant at all cuttings. Concentration of U4 was lowest under severe clipping. U2, present in exudates from seedling plants, was not detected. Quantities of sugars released per gram of dry weight of root tissue were greater under severe clipping. U1 was the major component, with glucose, inositol, and sucrose minor components of the total sugars.

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