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 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'.

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 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 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 Plant Factories Are Heating Up: Hunting for the Best Combination of Light Intensity, Air Temperature and Root-Zone Temperature in Lettuce Production

2021 ◽  
Vol 11 ◽  
Author(s):  
Laura Carotti ◽  
Luuk Graamans ◽  
Federico Puksic ◽  
Michele Butturini ◽  
Esther Meinen ◽  
...  
Keyword(s):  
Light Intensity ◽  
Air Temperature ◽  
Dry Matter ◽  
Root Zone ◽  
Incident Light ◽  
Photon Flux ◽  
Dry Matter Content ◽  
Fresh Weight ◽  
Root Zone Temperature ◽  
Zone Temperature

This study analyzed interactions among photon flux density (PPFD), air temperature, root-zone temperature for growth of lettuce with non-limiting water, nutrient, and CO2 concentration. We measured growth parameters in 48 combinations of a PPFD of 200, 400, and 750 μmol m–2 s–1 (16 h daylength), with air and root-zone temperatures of 20, 24, 28, and 32°C. Lettuce (Lactuca sativa cv. Batavia Othilie) was grown for four cycles (29 days after transplanting). Eight combinations with low root-zone (20 and 24°C), high air temperature (28 and 32°C) and high PPFD (400 and 750 μmol m–2 s–1) resulted in an excessive incidence of tip-burn and were not included in further analysis. Dry mass increased with increasing photon flux to a PPFD of 750 μmol m–2 s–1. The photon conversion efficiency (both dry and fresh weight) decreased with increasing photon flux: 29, 27, and 21 g FW shoot and 1.01, 0.87, and 0.76 g DW shoot per mol incident light at 200, 400, and 750 μmol m–2 s–1, respectively, averaged over all temperature combinations, following a concurrent decrease in specific leaf area (SLA). The highest efficiency was achieved at 200 μmol m–2 s–1, 24°C air temperature and 28°C root-zone temperature: 44 g FW and 1.23 g DW per mol incident light. The effect of air temperature on fresh yield was linked to all leaf expansion processes. SLA, shoot mass allocation and water content of leaves showed the same trend for air temperature with a maximum around 24°C. The effect of root temperature was less prominent with an optimum around 28°C in nearly all conditions. With this combination of temperatures, market size (fresh weight shoot = 250 g) was achieved in 26, 20, and 18 days, at 200, 400, and 750 μmol m–2 s–1, respectively, with a corresponding shoot dry matter content of 2.6, 3.8, and 4.2%. In conclusion, three factors determine the “optimal” PPFD: capital and operational costs of light intensity vs the value of reducing cropping time, and the market value of higher dry matter contents.

scholarly journals GROWTH AND N AND C METABOLITES OF TOMATO IN RESPONSE TO ROOTS WARM DURING THE DAY AND COLD AT NIGHT, OR VICE VERSA

HortScience ◽  
1996 ◽  
Vol 31 (6) ◽  
pp. 914C-914
Author(s):  
Yong-Zhan Ma ◽  
Martin P.N. Gent
Keyword(s):  
Root Zone ◽  
Plant Size ◽  
Mineral Elements ◽  
N Accumulation ◽  
Root Zone Temperature ◽  
Relative Growth ◽  
Free Sugars ◽  
C And N ◽  
Light Concentration ◽  
Zone Temperature

How are C and N metabolites affected by a root-zone temperature (RZT) in phase or out of phase with the photoperiod? Tomato (Lycopersicon esculentum Mill.) was grown with an air temperature of 20C, and RZT that was in phase with a 12-h photoperiod, 28C in the light and 12C in the dark, or out of phase, 12C in the light and 28C in the dark. Seedlings were grown in flowing solution containing 200 μm NO3 and excess amount of other mineral elements. The flow rate increased with plant size. After 8 days, plants were harvested at the end of the day and at the end of the night. The relative growth rate (day–1) was slightly greater for in-phase (0.19) than out-of-phase RZT (0.17) and less than that at a constant air and RZT of 24C (0.22). RZT affected N accumulation and partitioning of C and N metabolites. Cool roots contained more NO3 and free sugars than warm roots. Leaves had less NO3 in the light than in the dark, and NO3 in leaves of plants with an out-of-phase RZT was depleted in the light. Concentration of free amino acids and protein was greater and the amount of starch was less in leaves of plants with in-phase RZT.

scholarly journals Photosynthetic Responses of Creeping Bentgrass to Reduced Root-zone Temperatures at Supraoptimal Air Temperature

2002 ◽  
Vol 127 (5) ◽  
pp. 754-758 ◽  
Author(s):  
Qingzhang Xu ◽  
Bingru Huang ◽  
Zhaolong Wang
Keyword(s):  
Soil Temperature ◽  
Chlorophyll Content ◽  
Air Temperature ◽  
Root Zone ◽  
Creeping Bentgrass ◽  
Rubisco Activity ◽  
Root Zone Temperature ◽  
Single Leaf ◽  
Soil Temperatures ◽  
Zone Temperature

High air and soil temperatures are major factors limiting growth of cool-season grasses. A previous study by the authors reported that a soil temperature reduction of only 3 °C when air temperature was maintained at 35 °C significantly improved shoot and root growth of creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.) Farw. (syn. A. palustris Huds.)]. This study was designed to investigate the responses of photosynthetic activities of creeping bentgrass to lowered root-zone temperatures from the supraoptimal level when shoots were exposed to high air temperature. Two cultivars of creeping bentgrass, `L-93' and `Penncross', were exposed to the following air/root-zone temperature regimes in growth chambers and water baths: 1) optimal air and soil temperatures (20/20 °C, control); 2) lowering soil temperature by 3, 6, and 11 °C from 35 °C at high air temperatures (35/32, 35/29, and 35/24 °C); and 3) high air and soil temperatures (35/35 °C). Soil temperature was reduced from 35 °C by circulating cool water (18 °C) in water baths at variable flow rates. Both cultivars had similar responses to high or low root-zone temperatures with high air temperature. High air and root-zone temperatures caused significant reductions in canopy photosynthetic rate (Pcanopy), single-leaf photosynthetic rate (Pleaf), leaf chlorophyll content, photochemical efficiency (Fv/Fm), and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, beginning on day 1 of high air and soil temperature stress for Pcanopy and Pleaf, and day 7 for chlorophyll content, Fv/Fm, and Rubisco activity. The 3 °C reduction in root-zone temperature at high air temperature had no effect on those photosynthetic parameters, except chlorophyll content. Reducing root-zone temperature by 6 °C or 11 °C while maintaining air temperature at 35 °C significantly improved Pcanopy, Poleaf, leaf chlorophyll content, Fv/Fm, and Rubisco activity. Single leaf photosynthetic rate at 35/24 °C was not different from the control level, but Pcanopy at 35/24 °C was lower than the control level. A reduction in root-zone temperature enhanced canopy and single-leaf photosynthetic capacity even though shoots were exposed to supraoptimal air temperature, which could contribute to improved turfgrass growth.

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