scholarly journals Controlling Height with Temperature

1998 ◽  
Vol 8 (4) ◽  
pp. 535-539 ◽  
Author(s):  
Robert Berghage

Temperature management has emerged as an important tool for plant height control in greenhouse production systems. This is particularly important in vegetable transplant production where chemical controls for plant height are limited or not legal. Plant height is a function of the number of nodes and the length of each internode, and both are strongly influenced by greenhouse temperatures. Node number, or formation rate, is primarily a function of the average greenhouse temperature, increasing as the average temperature increases. Internode length is strongly influenced by the relationship between the day and night temperature, commonly referred to as DIF (day temperature - night temperature). As DIF increases, so does internode length in most plant species studied. Although the nature and magnitude of temperature effects vary with species, cultivar, and environmental conditions, these two basic responses can be used to modify transplant growth. Although data are limited, controlling transplant height with temperature does not appear to adversely influence plant establishment or subsequent yield.

HortScience ◽  
1995 ◽  
Vol 30 (7) ◽  
pp. 1465-1466
Author(s):  
Mark S. Strefeler

The influence of temperature and genotype on plant height, internode length, and morphological development of 20 cultivars of Pelargonium ×hortorum Bailey were determined by growing plants under one of three day–night temperature regimes (18/18C, 18/24C, and 24/18C). Temperature regime influenced internode length and plant height regardless of plant genotype. Internode length and plant height increased as the day–night temperature differential (DIF) increased from –6 to 6C. Average internode length increased from 5.3 ± 0.2 mm for –6C DIF to 6.3 ± 0.2 mm for +6C DIF. Genotypes differed for average internode length (4.2 to 8.7 mm) and plant height (54 to 95 mm). Node count increased as average daily temperature (ADT) increased. Node counts were 11.2 at 18/18C (ADT = 18), 11.9 at 24/18C (ADT = 20.3), and 12.1 at 18/24C (ADT = 21.8). Genotype × temperature interactions were not significant for the recorded traits. This study demonstrates that DIF is an effective height control strategy, regardless of geranium genotype, and that DIF combined with the selection of genetically short cultivars may eliminate the need for chemical height control in the commercial production of geraniums.


1992 ◽  
Vol 10 (4) ◽  
pp. 232-235
Author(s):  
David R. Brown ◽  
D. Joseph Eakes ◽  
Bridget K. Behe ◽  
Charles H. Gilliam

Abstract Moisture stress was compared to B-nine (daminozide) as a method of height control for annual bedding plant transplants. Three plant species, ‘Big Boy’ tomato, ‘California Wonder’ pepper and ‘Janie Gold’ marigold, were grown in 132 cm3 (8.05 in3) cell packs containing one of 2 commercial media, Fafard #3 or Pro-Mix BX. Treatments included moisture stress (MS), 2 concentrations of B-nine (2500 ppm applied twice and 5000 ppm once), and an untreated control. Method of height control and medium type had an interactive influence on height for each of the 3 species. Moisture stress tomato and marigold were shorter in the Fafard #3 medium compared to those in the Pro-Mix BX medium. Regardless of medium, MS tomato and marigold transplants were shorter or similar in size to the most effective B-nine treatment, 2500 ppm applied twice. Moisture stress and the B-nine treatments for pepper plants grown in the Fafard #3 medium reduced plant height similarly compared to the controls. However, when pepper plants were grown in the Pro-Mix BX medium, only B-nine treatments reduced plant height compared to the controls. Treatments producing short plants did not reduce node number, hence plants appeared fuller than treatments with tall plants. Shoot dry weights for MS tomato and marigold were less than those of plants receiving the other height control treatments, regardless of medium type. Plants of all 3 species grown in the Fafard #3 medium had less shoot dry weight than Pro-Mix BX plants across the 4 height control treatments.


1991 ◽  
Vol 116 (2) ◽  
pp. 232-237 ◽  
Author(s):  
M.P. Kaczperski ◽  
W. H. Carlson ◽  
M.G. Karlsson

Petunia × hybrids `Snow Cloud' plants were grown under 25 temperature combinations ranging from 10 to 30C and at photosynthetic photon flux levels of 100 or 200 μmol·s-1·m-2 (6.5 and 13 mol·day-1·m-2, respectively). Days to flower-was a quadratic function of average temperature, with 25C being the optimum temperature for minimal tire-e to flower at 200 μmol·s-1·m-2. Plant height increased “linearly and average internode length increased quadratically as day temperature increased. The number of lateral shoots decreased quadratically as average temperature increased, and the average length of each shoot decreased quadratically as day temperature increased.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 506B-506
Author(s):  
Hope K. Onken ◽  
Terri W. Starman

Argyranthemum frutescens `Sugar Baby', Calibrachoa hybrid `Million Bells Cherry Pink', and Orthosiphon stamineus `Lavender' are three vegetatively propagated specialty annuals that are recent introductions into the floriculture industry. It is important to understand how the growth and development of these new crops is best controlled. Rooted cuttings of these three species where transplanted into 10-cm pots on 7 Oct. and the plant growth regulator treatments were applied on 19 Oct. 1999. Foliar spray treatments included ancymidol at 66 and 132, daminozide at 2500 and 5000, paclobutrazol at 20 and 40, ethephon at 500 and 1000, and uniconazole at 10 and 20 mg/L. Uniconazole medium drench treatment was applied at 1 and 2 mg/L. Control was a water foliar spray. At harvest, plant height, plant width, number of flowers, pedicle length, stem length, stem node number and internode length, and fresh and dry weights were measured. Uniconazole spray at 20 mg/L reduced plant height and width without affecting the fresh and dry weights of Argyranthemum. Flower number was increased and pedicel length was reduced. The overall plant height and width of Calibrachoa were not reduced with 20 mg /L uniconazole foliar spray, but plant form was improved by decreased internode elongation. Uniconazole foliar spray at 20 mg/L reduced Orthosiphon stem and internode length. Ethephon reduced plant height, plant width, and flower number of all species. Branching and days to flower were increased in Orthosiphon. In all species, daminozide and paclobutrazol were found to be ineffective, while ancymidol spray and uniconazole drench stunted and distorted growth.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 446e-447
Author(s):  
Joyce G. Latimer ◽  
Paul A. Thomas

Perennial bedding plant species were tested for response to single treatments of Sumagic (0, 15, 30, 45, or 60 ppm), Bonzi (0, 40, 80, 120, or 160 ppm), Cycocel (0, 750, 1500, 2250, or 3000 ppm) or B-Nine (5000 ppm, applied twice) applied during greenhouse production in Spring 1997. Plant height of both Chrysanthemum parthenium and Malva alcea had a quadratic response to Sumagic and Bonzi rates, with excessive height reductions at the lowest application rates at 4 weeks after treatment. All rates of Cycocel reduced plant height of C. parthenium and M. alcea by 33% and 40%, respectively. These species did not establish in the landscape. Verbena bonariensis was moderately responsive to Sumagic and Bonzi, but not Cycocel. Application rates of 15 and 30 ppm Sumagic or 160 ppm Bonzi provided moderate height control without landscape persistence beyond 4 weeks after planting. Leucanthemum × superbum `Alaska' was responsive to Sumagic and Bonzi, but not Cycocel or B-Nine. Rates of 15 ppm Sumagic or 40 ppm Bonzi provided moderate control without landscape persistence. Plant height of Monarda didyma `Blue Stocking' had a linear response to Sumagic and Bonzi rates. Plant height of Rudbeckia fulgida var. Sullivantii `Goldstrum' was reduced by Bonzi and Sumagic but not B-Nine or Cycocel, with recommended rates of 30 to 40 ppm Sumagic or 160 ppm Bonzi. Treatment of Sedum × `Autumn Joy' with Sumagic resulted in excessive landscape persistence of growth retardation at all rates, but Sedum was not responsive to Cycocel. Veronica alpina `Sunny Border Blue' was responsive to all rates of Cycocel, but growth retardation persisted through 12 weeks after planting.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 493B-493
Author(s):  
Pamela Korczynski ◽  
James E. Faust ◽  
Robert Klein

Paclobutrazol drenches (1 ppm, 118.4 mL per pot) were applied to Poinsettia `Freedom' Red' on 1, 11, 21, and 31 Oct. in 1997 and 1998. Plant heights were recorded twice weekly throughout the experiment, and internode length and bract area were measured at harvest. The total bract area of the three true bracts and the top three transitional bracts was reduced by 5.8%, 13.6%, 4.2%, and 2.3% for the 1, 11, 21, and 31 Oct. application dates, respectively; however, all plants were highly marketable. At the time of each drench application, the most newly unfolded leaf was marked. The internode lengths for the three internodes below this leaf and the internodes that developed after the drench application were typically between 5 and 10 mm in length, while the internode lengths of the control plants were typically 10 to 25 mm, depending on node number. Plant height increased 62, 51, 47 and 19 mm following application on the 1, 11, 21, and 31 Oct. application dates, respectively. The 1, 11, 21, and 31 Oct. drench applications reduced total stem elongation from 1 Oct. to anthesis by 64%, 49%, 28%, and 15%, respectively. Paclobutrazol drenches did not affect time to anthesis.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 486E-486
Author(s):  
James Sellmer ◽  
Craig R. Adkins ◽  
Ingram McCall ◽  
Brian Whipker

Plant growth retardant (PGR) substrate drenches (in milligrams active ingredient) of ancymidol at 0.25, 0.5, 1, 2, or 4; paclobutrazol at 1, 2, 4, 8, or 16; and uniconazole at 0.25, 0.5, 1, 2, or 4 were applied to pampas grass (Cortaderia argentea Nees) to compare their effectiveness at chemical height control during greenhouse forcing and evaluate the residual effect on plant growth in the landscape. Cortaderia argentea plant height exhibited a quadratic dose response to paclobutrazol and uniconazole, while ancymidol-treated plants showed a linear dose effect. During greenhouse production, all rates of uniconazole reduced plant height by 56% to 71% compared to the untreated control, whereas paclobutrazol and ancymidol treatments reduced plant height by 14% to 61% and 0% to 34%, respectively. Severe height retardation was evident at 2 mg of uniconazole. By week 5 in the field all plants treated with uniconazole, paclobutrazol doses of 4, 8, or 16 mg, and with 4 mg of ancymidol were shorter than the untreated control. By week 24 in the field, all plants exhibited similar heights except plants treated with uniconazole at 1, 2, or 4 mg remained shorter than the untreated control. In conclusion, each PGR was effective in controlling plant height of Cortaderia argentea during greenhouse forcing. Furthermore, plants treated with low to moderate rates of ancymidol or paclobutrazol grew out of the regulating effect by week 5 in the landscape. These results demonstrate that PGR can be effectively and economically employed in the production of Cortaderia argentea.


2021 ◽  
Vol 13 (13) ◽  
pp. 7355
Author(s):  
Shivendra Kumar ◽  
Ramdeo Seepaul ◽  
Ian M. Small ◽  
Sheeja George ◽  
George Kelly O’Brien ◽  
...  

Brassica carinata (carinata) has emerged as a potential biofuel source due to its high erucic acid content, making it desirable for various industrial applications. Nitrogen (N) and sulfur (S) are required as primary sources of nutrition for growth and development in different oilseed crops and their utilization is interdependent. The purpose of the study was to analyze the interactive effect of N and S nutrition on the growth and other physiological activities of carinata and B. napus (napus). Four treatments, i.e., optimum NS (+N+S, 100% N and 100% S); N limited (−N+S, 0% N, 100% S); S limited (+N−S, 100% N, 0% S), and NS limited (−N−S, 0% N and 0% S) of N and S in full-strength Hoagland solution were imposed in the current study. Effect of different NS treatments was observed on vegetative traits such as number of primary and secondary branches, total leaf area, total biomass production and allocation, and physiological traits such as production of photosynthetic pigments, net photosynthesis, electron transport, and other aspects for both carinata and napus. The traits of stem elongation, number of nodes, node addition rate, internode length, number of primary and secondary branches were 60%, 36%, 50%, 35%, 56%, and 83% lower, respectively, in napus in comparison to carinata. Different NS treatments also positively influenced the production of photosynthetic pigments such as chlorophyll (Chl) a and b and carotenoids in carinata and napus. The concentration of Chla was 11% higher in napus in comparison to carinata. The rate of net photosynthesis, electron transport, and fluorescence was 12%, 8%, and 5% higher based on overall value, respectively, in napus compared to carinata. On the other hand, the overall value for stomatal conductance decreased by 5% in napus when compared to carinata. Different growth-related traits such as vegetative (plant height, node number, internode length, leaf area, number of primary and secondary branches), reproductive (pod number, pod length, seeds per pod), and photosynthetic capacity in oilseed brassicas are correlated with the final seed and oil yield and chemical composition which are of economic importance for the adoption of the crop. Thus, the analysis of these traits will help to determine the effect of NS interaction on crop productivity of carinata and napus.


2015 ◽  
pp. 45-52
Author(s):  
C. Poncet ◽  
C. Bresch ◽  
H. Fatnassi ◽  
L. Mailleret ◽  
A. Bout ◽  
...  

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