scholarly journals Air and Water Temperature Effects on Growth of Lettuce in a Hydroponic System

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 586b-586
Author(s):  
Helen Thompson ◽  
Robert Langhans
Keyword(s):  
Crop Production ◽  
Root Zone ◽  
Dry Weight ◽  
Root Zone Temperature ◽  
Hydroponic System ◽  
Air Temperatures ◽  
Control Growth ◽  
Water Plants ◽  
Final Harvest ◽  
Zone Temperature

This research explored cool crop production in various climate zones using CEA facilities and hydroponics ponds to control growth rate and quality through root zone temperature control. The precise controls were used to vary air and water temperatures to study the temperature gradient between root and shoot zones. Effect of this gradient was measured by growth rates and final harvest dry weights. Lactuca sativa L. cv. Ostinata seedlings were germinated and grown 11 days in a growth chamber and moved to greenhouse ponds. Air temperatures chosen were 17, 24, and 31°C. These were constant for the 24 days that lettuce grew in the ponds with a 5°C decrease for 14 hours. during the night. Water temperatures of the three ponds in the greenhouse were set and maintained at 17, 24, and 31°C. Maximum final harvest weights were obtained at 24°C air/water 24°C. Final weights for the 17 and 31°C water setpoint were comparable at 24°C air. The 31 °C air /water inhibited quality and final dry weight, while 17 and 24°C water produced equivalent dry weights at 31°C air. At 31°C air heads were tighter at 17 than at 24°C, and loose at 31°C. At air 17 °C maximum weight was at 24°C water and minimum at 31°C water. At 17°C air, the 24°C water plants were of good quality, with thicker leaves but visibly smaller than the 31°C water crop. Significant differences in harvest dry weights were shown at each 7-day harvest beginning on day 14, due to both air and water setpoint factors and there was significant interaction between them.

scholarly journals GROWTH RESPONSE OF SNAPDRAGON ANTIRRHINUM MAJUS TO NIGHT AIR TEMPERATURES AND ELEVATED ROOT-ZONE TEMPERATURES

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1160b-1160
Author(s):  
Khin San Wai ◽  
S.E. Newman
Keyword(s):  
Air Temperature ◽  
Growth Response ◽  
Root Zone ◽  
Dry Weight ◽  
Antirrhinum Majus ◽  
Root Zone Temperature ◽  
Shoot Dry Weight ◽  
Air Temperatures ◽  
Diffusive Resistance ◽  
Zone Temperature

The response of Antirrhinum majus (snapdragon) cultivars (`Tampicoi' and `Rainier White') to night air temperatures (10C and 20C) and elevated root-zone temperature (26C and ambient) was studied. Height of plants grown with a heated root-zone were greater, compared to unheated at both night temperatures for both cultivars. Shoot dry weight of `Tampico' plants was reduced by heated root-zone temperature at 20C night air temperature. Raceme length was greater with heated root-zone temperature compared to unheated at 10C night air temperature. Days to flower were shorter with heated compared to unheated root-zone at both night air temperatures for both cultivars. Stomatal diffusive resistance was greater on plants with unheated compared to heated root-zone temperature at 10C night air temperature for `Rainier White'.

scholarly journals Elevated Air Temperatures Cause Foliar Bleaching of Ivy Geranium ‘Beach’ and ‘Butterfly’

HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 411-415 ◽  
Author(s):  
Ritu Dhir ◽  
Richard L. Harkess ◽  
Guihong Bi
Keyword(s):  
Root Zone ◽  
Foliar Spray ◽  
Weight Ratio ◽  
Dry Weight ◽  
Fresh Weight ◽  
Root Zone Temperature ◽  
Iron Chelate ◽  
Air Temperatures ◽  
Ivy Geranium ◽  
Zone Temperature

Bleaching of the youngest leaves of actively growing ivy geranium (Pelargonium peltatum L.) develops as the temperature increases from late spring to summer in the southeastern United States. Heat stress-induced iron deficiency has been suspected as causing this disorder. Ivy geranium ‘Beach’ (bleaching-resistant) and ‘Butterfly’ (bleaching-susceptible) were grown for 8 weeks at 24 or 31 °C average root-zone temperature and iron chelate (Fe-EDDHA, 6% Fe) was applied at 0 mg Fe (control), 0.54 mg Fe foliar spray, 1.08 mg Fe foliar spray, 54 mg Fe drench, or 108 mg Fe drench per plant at 30-day intervals. In a second experiment, ivy geranium ‘Beach’ and ‘Butterfly’ plants were grown for 6 weeks at 28 °C day/16 °C night or 36 °C day/22 °C night average air temperatures and iron chelate (Fe-EDDHA, 6% Fe) was applied at 0 mg (control) or 27 mg Fe soil drench per pot at 15-day intervals. No bleaching was observed as a result of elevated root-zone temperatures. High levels of Fe-chelate suppressed growth reducing fresh weight, dry weight, and fresh-to-dry-weight ratio in ‘Butterfly’. Elevated air temperatures severely reduced plant growth, leaf area, fresh weight, and dry weight in both cultivars. Elevated air temperature reduced chlorophyll a, carotenoids, and pheophytins in ‘Butterfly’ but not in ‘Beach’. Fe-chelate application had no effect at ambient temperature but increased chlorophyll to carotenoids ratio (Chl:Caro) at elevated air temperatures in ‘Butterfly’. Therefore, elevated air temperatures were determined to be the cause of bleaching in ivy geranium.

scholarly journals Air and Root-zone Temperatures Influence Growth and Flowering of Snapdragons

HortScience ◽  
1992 ◽  
Vol 27 (7) ◽  
pp. 796-798 ◽  
Author(s):  
Khin San Wai ◽  
Steven E. Newman
Keyword(s):  
Root Zone ◽  
Dry Weight ◽  
Cut Flower ◽  
Root Zone Temperature ◽  
Group Iii ◽  
Air Temperatures ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Temperature Time ◽  
Zone Temperature

Growth chamber studies using elevated root-zone temperatures and greenhouse studies using two root-zone and two night air temperatures were conducted to determine the effects on growth and flowering of two response groups [`Rainier White' (Group II) and `Tampico' (Group III)] of cut-flower snapdragons (Antirrhinum majus L.). Chamber-grown snapdragons with the root zone at 30C had shorter stems and a lower dry weight than those at 20C. Holding the root zone above 26C increased time to flower. Greenhouse-grown `Tampico' and `Rainier White' snapdragon stems were longer with increased root-zone temperature regardless of night air temperature. Time to flower was reduced an average of 6 days with increased root-zone temperature and 12 days when the night air was maintained at 20C. This study demonstrated that the effects of relatively low greenhouse temperatures may be offset by root-zone heat.

EMERGENCE AND SEEDLING GROWTH OF INBRED LINES OF CORN AT SUBOPTIMAL ROOT-ZONE TEMPERATURES

1987 ◽  
Vol 67 (2) ◽  
pp. 409-415 ◽  
Author(s):  
A. MENKIR ◽  
E. N. LARTER
Keyword(s):  
Zea Mays ◽  
Seedling Growth ◽  
Root Zone ◽  
Seedling Emergence ◽  
Correlation Coefficients ◽  
Dry Weight ◽  
Inbred Lines ◽  
Root Zone Temperature ◽  
Emergence Percentage ◽  
Zone Temperature

Based on the results of an earlier paper, 12 inbred lines of corn (Zea mays L.) were evaluated for emergence and seedling growth at three controlled root-zone temperatures (10, 14, and 18 °C). Low root-zone temperatures, 10 and 14 °C, were detrimental to emergence, seedling growth, and root growth of all inbred lines. Differential responses of inbred lines were observed within each temperature regime. The differences in seedling emergence among lines became smaller with increasing root-zone temperature, while the reverse was true for seedling dry weight. Simple correlation coefficients showed a significantly (P = 0.05) negative association between emergence percentage and emergence index (rate). Neither of these two emergence traits was significantly correlated with seedling dry weights. Seedling dry weights were significantly (P = 0.01) and positively associated with root dry weights. Two inbred lines exhibited good tolerance to low root-zone temperatures, viz. CO255 and RB214. A significant and positive correlation existed between emergence percentage at a root-zone temperature of 10 °C and field emergence in test with the same genotypes reported earlier. Selection at a root-zone temperature of 10 °C for a high percentage of seedling emergence, therefore, could be effective in identifying genotypes capable of germinating in cool soils. Furthermore, the significantly (P = 0.01) positive relationship between seedling dry weights at all root-zone temperatures and those from the field test suggest that strains with vigorous seedling growth in the field could be identified using low root-zone temperature regimes.Key words: Zea mays, root-zone temperature, cold tolerance

scholarly journals An Investigation of a Root Zone Heating System and Its Effects on the Morphology of Winter-Grown Green Peppers

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 933
Author(s):  
Muhammad Ameen ◽  
Zhuo Zhang ◽  
Xiaochan Wang ◽  
Muhammad Yaseen ◽  
Muhammad Umair ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Ambient Temperature ◽  
Root Zone ◽  
Dry Weight ◽  
Heating System ◽  
Sustainable Growth ◽  
Control Treatment ◽  
Plant Canopy ◽  
Root Zone Temperature ◽  
Zone Temperature

The winter season in Nanjing is from December to February, with extremely low temperature and high humidity due to seasonal snowfall. During these extreme cold climatic conditions, plants have to survive severe heat stress conditions, even if they are being kept in greenhouses. The objective of this study was to investigate a heating system that can provide heat directly to the root zone instead of heating the entire greenhouse, which is a viable option to reduce energy consumption. Root zone heating could be an effective alternative for the sustainable development of plants during the winter. A novel type of root zone heating system was applied to evaluate the energy consumption during different greenhouse ambient temperature conditions, the effects of root zone heating systems on pepper plant morphology, and heat transfer rates to plant canopy in the greenhouse. The temperature treatments in root zone heating system were T-15, T-20, T-25, T-30, and a control treatment (TC) at 15 °C, 20 °C, 25 °C, and 30 °C, respectively, while TC received no heat. A simulation study was carried out to validate the root zone temperature. The results of the current investigation revealed that energy consumption has an inverse relationship to the ambient temperature of the greenhouse, while temperature gradients to the plant canopy observed from the lower to the upper part of the plant and the upper canopy experienced less temperature fluctuation as compared to the lower part of the plant. The results also showed that treatment T-20 had the maximum in terms of the leaf dry weight, stem diameter, and the number of leaves, while T-25 showed the maximum root dry weight and stem dry weight; T-30 and T-15 had minimum dry weights of plant segments among all treatments. Control treatment (TC) showed a minimum dry mass of plant. The root zone heating with optimal root zone temperature was found to be a viable and adaptable option as this leads to improved energy consumption patterns for the sustainable growth and development of plants in greenhouses during extremely low temperatures.

scholarly journals Response of Peach Seedlings to Root-zone Temperature and Root-applied Growth Regulators

HortScience ◽  
1991 ◽  
Vol 26 (7) ◽  
pp. 870-872 ◽  
Author(s):  
M. Tagliavini ◽  
N.E. Looney
Keyword(s):  
Shoot Growth ◽  
Root Zone ◽  
Dry Weight ◽  
Shoot Elongation ◽  
Fruit Production ◽  
Root Diameter ◽  
Promoting Effect ◽  
Root Volume ◽  
Root Zone Temperature ◽  
Zone Temperature

Root and shoot growth of peach seedlings was strongly suppressed when the roots were held at 8 to 10C. Shoot and root dry weights and root volume increased linearly with increasing root-zone temperature (RZT) to 22C. GA3 at 5.7 μm (2 ppm) added to the aerated full nutrient solution reversed the effect of low RZT on shoot elongation but inhibited root growth at all RZTs. Paclobutrazol (PBZ) (6.8 × 10-3μm) (2 ppb) inhibited shoot elongation at all RZTs and shoot dry weight at 16 and 22C. However, PBZ had no effect on root dry weight accumulation at any RZT. The shoot growth-promoting effect of GA3, relative to control plants, disappeared at higher RZTs, but GA3 reversed the growth-inhibiting effect of PBZ at all RZTs. PBZ increased mean root diameter at all RZTs and significantly increased root volume at 22C. These results show that growth of peach seedlings is profoundly influenced by a cool root-zone environment. The plant growth regulator effects suggest that seedling roots play an important role in whole-plant gibberellin physiology. Some possible implications for fruit production are discussed. Chemical names used: gibberellic acid (GA3); β -[(4-chlorophenyl)methyl]- α -(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol(paclobutrazol,PBZ).

scholarly journals Effect of Root-zone Temperature on Survival, Growth, and Root Morphology of Kalmia latifolia and Ilex crenata ‘Compacta’

2007 ◽  
Vol 25 (2) ◽  
pp. 73-77
Author(s):  
Amy N. Wright ◽  
Stuart L. Warren ◽  
Frank A. Blazich
Keyword(s):  
Root Morphology ◽  
Root Zone ◽  
Lateral Roots ◽  
Dry Weight ◽  
Stem Cuttings ◽  
Root Zone Temperature ◽  
Kalmia Latifolia ◽  
Percent Survival ◽  
Mountain Laurel ◽  
Zone Temperature

Abstract Root-zone temperature (RZT) is an important environmental factor affecting growth and performance of woody ornamental plants in the landscape. Research was conducted to compare the effects of RZT on survival, growth, and root morphology of a difficult-to-transplant species, mountain laurel (Kalmia latifolia L.), and an easy to transplant species, Japanese holly (Ilex crenata Thunb.). Seedlings of mountain laurel or micropropagated liners of mountain laurel (Kalmia latifolia L. ‘Sarah’) and rooted stem cuttings of Japanese holly (Ilex crenata Thunb. ‘Compacta’) were grown hydroponically for 12 weeks in controlled environment conditions under long days at 9-hr days/15-hr nights of 26/22C (79/72F) with RZTs of 16, 24, or 32C (61, 75, or 90F). Compared to 16 and 24C (61 and 75F), percent survival of mountain laurel was reduced by a RZT of 32C (90F), whereas percent survival of Compacta holly was unaffected by RZT. Root dry weight of mountain laurel was reduced 72% at 32C (90F) while top dry weight was unaffected by RZT. Top and root dry weights of Compacta holly were unaffected by RZT. Root: top ratio of mountain laurel was reduced by increasing RZT, whereas root: top ratio of Compacta holly was unaffected by RZT. Root area of mountain laurel and Compacta holly were reduced 80 and 64%, respectively, at 32C (90F) compared with 16C (61F). Number of lateral roots in the apical 2 cm (0.8 in) of primary roots of both taxa increased with increasing RZT. Results of this research indicate that reducing RZT in the landscape may increase survival and root growth of transplanted mountain laurel.

scholarly journals `Rotundifolia' Holly Growth and Nitrogen Accumulation Influenced by Supraoptimal Root-zone Temperatures

HortScience ◽  
1991 ◽  
Vol 26 (11) ◽  
pp. 1387-1388 ◽  
Author(s):  
Thomas H. Yeager ◽  
Rebecca H. Harrison ◽  
Dewayne L. Ingram
Keyword(s):  
Root Zone ◽  
Dry Weight ◽  
N Fertilization ◽  
Sand Culture ◽  
Nitrogen Accumulation ◽  
N Accumulation ◽  
Root Zone Temperature ◽  
Root Zones ◽  
Application Rates ◽  
Zone Temperature

Ilex crenata Thunb. `Rotundifolia' grown in sand culture with the root zone at 40C for 6 hours daily had smaller root and shoot dry weights after 6 weeks than plants grown with root zones at 28 or 34C. Root and shoot N accumulation (milligrams N per gram of dry weight) decreased when root-zone temperatures were increased from 28 to 40C and plants were fertilized twice dally with either 75, 150, or 225 mg N/liter. Nitrogen application rates of 150 or 225 mg·liter-1 resulted in increased root and shoot N accumulation for plants grown with root zones at either 28, 34, or 40C compared with the 75 mg N/liter treatment. Increased N fertilization rates did not alleviate reduced plant growth due to the high root-zone temperature.

scholarly journals Tomato N Metabolism with Root Zone Temperature that Is Constant, In Phase, or Out of Phase with Shoot Temperature

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 688b-688
Author(s):  
Yong-Zhan Ma ◽  
Martin P.N. Gent
Keyword(s):  
Air Temperature ◽  
Free Amino ◽  
Root Zone ◽  
Dry Weight ◽  
Light Period ◽  
Root Zone Temperature ◽  
Relative Growth ◽  
Research Initiative ◽  
N Metabolism ◽  
Zone Temperature

Tomato (Lycopersicon esculentum Mill) seedlings were grown with air temperature of 28°C light/12°C dark (12/12 hours), and either a constant, 20°C, root-zone temperature (RZT), or in-phase with air temperature, 28°C in the light and 12°C in the dark, or out-of-phase, 12°C in the light and 28°C in the dark. These treatments were applied from 17 to 25 days after germination, with 200 m \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{-}^{3}\) \end{document} in flowing nutrient solution. The relative growth rate of leaves was the greatest with constant RZT, 0.33/d, and least with out-of-phase RZT, 0.29/d. The concentration of free amino acid and protein in leaves was least for out-of-phase RZT. The \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{-}^{3}\) \end{document} concentration in leaves was the highest in the dark, intermediate in the middle of the light period, and the lowest at the end of the light period. In roots, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{-}^{3}\) \end{document} concentration showed a similar trend. This variation was greatest when RZT was varied out of phase, and least with constant RZT. At the end of the light period, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{-}^{3}\) \end{document} concentration in roots was 246, 180, and 162 μmol·g–1 dry weight for constant, in phase, and out of phase RZT, respectively. In the light, leaves of seedlings grown with out-of-phase RZT had 5 mmol·g–1 \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{-}^{3}\) \end{document}, compared to 16 mmol·g–1 with in-phase RZT Availability of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{-}^{3}\) \end{document} in the light may be the factor limiting plant growth with out-of-phase RZT. This research was supported in part by grant number 93-37100-9101 from the National Research Initiative Competitive Grants Program/USDA.

scholarly journals Effect of Cooling Root-Zone Temperature on Growth, Yield and Nutrient Uptake in Cucumber Grown in Hydroponic System During Summer Season in Cooled Greenhouse

2018 ◽  
Vol 11 (1) ◽  
pp. 47 ◽  
Author(s):  
Muthir S. Al-Rawahy ◽  
Salim A. Al-Rawahy ◽  
Yaseen A. Al-Mulla ◽  
Saleem K. Nadaf
Keyword(s):  
Nutrient Uptake ◽  
Root Zone ◽  
Growth Yield ◽  
Nutrient Concentrations ◽  
First Year ◽  
Cucumis Sativus L ◽  
Root Zone Temperature ◽  
Hydroponic System ◽  
Dry Matter Weight ◽  
Zone Temperature

Optimum cool root zone temperature positively influences the production of greenhouse vegetables grown during summer/high temperature period under hydroponics system. Hence, the effect of root-zone temperature was investigated on the growth, yield and nutrient uptake of cucumber (Cucumis sativus L.) plants grown in pots filled with perlite medium under recirculating hydroponic system in greenhouse during summer period (June-August) in two consecutive years 2016/2017 and 2017/2018 using three cooling treatments-T1 (22 ºC), T2 (25 ºC) and T3 (28 ºC) and non-cooled treatment T4 (33 ºC) as control in Randomized Complete Design (RCD). All the treatments received the same nutrient concentrations. Significant (p < 0.05) differences were observed for all the characters viz. plant height, leaf number/m2, chlorophyll content, leaf area (cm2), fruit number /m2, yield (t/gh), fresh (g) and dry matter weight (g) of shoot and root at all cooled root-zone temperatures as compared to control in both the years. Plants at cooled root-zone temperature (RZT) of 22 ºC gave high number of fruits/m2 to the extent of 180 in 2016/2017 and 220 in 2017/2018 followed by that at 25 ºC (167, 221) and 28 ºC (178, 143) as compared to those in control (33 ºC) (101,133) in both the years. Similarly, highest fruit yields were found at cooled RZT of 22 ºC (5.0 t/gh) and 28 ºC (4.7 t/gh) in the first year and 22 ºC (6.1 t/gh) and 25 ºC (6.0 t/gh) in the second year. The plants at cooled RZT responded positively and significantly (p < 0.05) in the uptake of all nutrient elements in shoots and roots in comparison with those at non-cooled RZT in both years.

Sign in / Sign up

Export Citation Format

Share Document