scholarly journals ROOT GROWTH OF MAGNOLIA GRANDIFLORA HORT, `ST, MARY AFTER EXPOSURE TO ROOT-ZONE TEMPERATURE TREATMENTS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1080G-1080
Author(s):  
Chris A. Martin ◽  
Dewayne L. Ingram
Keyword(s):  
Root Growth ◽  
Treatment Period ◽  
Root Length ◽  
Root Zone ◽  
Dry Weight ◽  
Total Root Length ◽  
Root Zone Temperature ◽  
Magnolia Grandiflora ◽  
Root Dry Weight ◽  
Zone Temperature

Root growth of Magnolia grandiflora Hort. `St. Mary' was studied for 16 wk after an 8-wk exposure period to 30°, 34°, 38°, or 42°±0.8°C root-zone temperature (RZT) treatments applied 6 hr daily, Immediately after the RZT treatment period, total root length was similar for trees exposed to 30°, 34°, and 38°C and was reduced 45% at 42° compared to 38°C. For weeks eight and 18 of the post-treatment period, response of total root length to RZT was linear. Total root length of trees exposed to 28°C was 247% and 225% greater than those exposed to 42°C RZT at week eight and 16, respectively. Root dry weight from the 42°C RZT treatment was 29% and 48% less than 38° and 34°C RZT treatment, respectively, at week eight. By week 16, root dry weight as a function of RZT had changed such that the 42°C RZT was 43% and 47% less than 38° and 34°C RZT, respectively. Differences in root growth patterns between weeks eight and 16 suggest that trees were able to overcome the detrimental effects of the 38°C treatment whereas growth suppression by the 42°C treatment was still evident after 16 wk. Previous exposure of tree roots to supraoptimal RZT regimens may have long-term implications for suppressing growth and lengthening the establishment period of trees in the landscape,

scholarly journals ROOT GROWTH OF MAGNOLIA GRANDIFLORA HORT, `ST, MARY AFTER EXPOSURE TO ROOT-ZONE TEMPERATURE TREATMENTS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1080g-1080
Author(s):  
Chris A. Martin ◽  
Dewayne L. Ingram
Keyword(s):  
Root Growth ◽  
Treatment Period ◽  
Root Length ◽  
Root Zone ◽  
Dry Weight ◽  
Total Root Length ◽  
Root Zone Temperature ◽  
Magnolia Grandiflora ◽  
Root Dry Weight ◽  
Zone Temperature

Root growth of Magnolia grandiflora Hort. `St. Mary' was studied for 16 wk after an 8-wk exposure period to 30°, 34°, 38°, or 42°±0.8°C root-zone temperature (RZT) treatments applied 6 hr daily, Immediately after the RZT treatment period, total root length was similar for trees exposed to 30°, 34°, and 38°C and was reduced 45% at 42° compared to 38°C. For weeks eight and 18 of the post-treatment period, response of total root length to RZT was linear. Total root length of trees exposed to 28°C was 247% and 225% greater than those exposed to 42°C RZT at week eight and 16, respectively. Root dry weight from the 42°C RZT treatment was 29% and 48% less than 38° and 34°C RZT treatment, respectively, at week eight. By week 16, root dry weight as a function of RZT had changed such that the 42°C RZT was 43% and 47% less than 38° and 34°C RZT, respectively. Differences in root growth patterns between weeks eight and 16 suggest that trees were able to overcome the detrimental effects of the 38°C treatment whereas growth suppression by the 42°C treatment was still evident after 16 wk. Previous exposure of tree roots to supraoptimal RZT regimens may have long-term implications for suppressing growth and lengthening the establishment period of trees in the landscape,

scholarly journals Root Growth of Southern Magnolia Following Exposure to High Root-zone Temperatures

HortScience ◽  
1991 ◽  
Vol 26 (4) ◽  
pp. 370-371 ◽  
Author(s):  
Chris A. Martin ◽  
Dewayne L. Ingram
Keyword(s):  
Root Growth ◽  
Root Length ◽  
Root Zone ◽  
Dry Weight ◽  
Growth Patterns ◽  
Total Root Length ◽  
Root Zone Temperature ◽  
Magnolia Grandiflora ◽  
Root Dry Weight ◽  
Zone Temperature

Root growth of southern magnolia (Magnolia grandiflora Hort. `St. Mary') was studied for 16 weeks after an 8-week exposure to 30, 34, 38, or 42 ± 0.8C root-zone temperature (RZT) treatments applied for 6 hours daily. Immediately after RZT treatments, total root length of trees responded negatively to increased RZT in a quadratic pattern and the shoot and root dry weight of trees was similar. However, 8 and 16 weeks after RZT treatments, total root length responded linearly in a negative pattern to increased RZT, and shoot and root dry weight responded negatively to increased RZT in a linear and quadratic pattern, respectively. Root dry weight of trees exposed to 42C RZT treatment was 29% and 48% less than 38 and 34C RZT treatments, respectively, at week 8. By week 16, root dry weight as a function of RZT had changed such that the 42C RZT was 43% and 47% less than 38 and 34C RZT, respectively. Differences in root growth patterns between weeks 8 and 16 suggest that trees were able to overcome the detrimental effects of the 38C treatment, whereas growth suppression by the 42C treatment was still evident after 16 weeks.

Comparative responses of soybean (Glycine max), sicklepod (Senna obtusifolia), and Palmer amaranth (Amaranthus palmeri) to root zone and aerial temperatures

Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Shawn R. Wright ◽  
Harold D. Coble ◽  
C. David Raper ◽  
Thomas W. Rufty
Keyword(s):  
Leaf Area ◽  
Root Zone ◽  
Dry Weight ◽  
Palmer Amaranth ◽  
Dry Matter Accumulation ◽  
Weed Species ◽  
Root Zone Temperature ◽  
Root Dry Weight ◽  
Aerial Temperature ◽  
Zone Temperature

Experiments were conducted to compare germination efficiencies and vegetative growth of soybean and the competing weed species, sicklepod and Palmer amaranth, over a range of temperatures in the root zone and aerial environments. From genetic origins we hypothesized that the weeds would have a higher temperature optimum, which would help explain competitive interactions seen in the southeastern U.S. Germination experiments indicated that germination efficiency of the weeds was much more sensitive to low temperature than soybean, being markedly inhibited below 18 C. Similarly, experiments in an automated, temperature-controlled hydroponic system revealed that the weed species were less tolerant of low root zone temperature but more tolerant of high root zone temperature than soybean. At 16 C, dry weight of soybean was 74% of the control dry weight at 24 C, whereas dry weights of sicklepod and Palmer amaranth were 5 and 20% of the control, respectively. At 32 C, soybean root dry weight was only 80% of the 24 C treatment, whereas root dry weight of the weed species was not significantly different. When plants were grown at a low aerial temperature, growth of all plants was strongly inhibited] but the negative effects were somewhat more severe in the weed species than with soybean. An increase in aerial temperature from 26/22 C to 34/30 C (day/night) had a positive influence on dry matter accumulation of the weed species, stimulating sicklepod 150 to 200% and Palmer amaranth 150 to 1,600% compared to their respective controls, whereas soybean remained at about 80 to 90% of the control. All species grew taller with increasing temperature. Leaf area of the weeds increased but leaf area of soybean did not increase. Consistent with our original hypothesis, the results clearly show that the weeds, which originate from warm geographical regions, respond more negatively than soybean to low temperatures in the growth environment but more positively to high temperatures. The temperature characteristics help to explain why the intensity of weed pressure increases as the soybean growing season progresses, even after canopy closure.

scholarly journals Copper Hydroxide Controls Root Distribution In Container-Grown Carpentaria Palm

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 271D-271
Author(s):  
Sven E. Svenson ◽  
Timothy K. Broschat
Keyword(s):  
Root Growth ◽  
Growth Pattern ◽  
Root Length ◽  
Root Distribution ◽  
Dry Weight ◽  
Total Root Length ◽  
Copper Hydroxide ◽  
House Paint ◽  
Root Dry Weight ◽  
Medium Interface

The influence of copper hydroxide [Cu(OH)2] application to interior container surfaces on root growth at the container-medium interface was studied using Carpentaria palm [Carpentaria acuminata (H. Wendl. & Drude) Becc.]. Cu(OH)2 (0, 100, 200, or 400 g) was mixed with one liter of either white latex house paint, or NuFilm-17 surfactant, and applied to all surfaces inside 0.5 liter containers. Plants were grown in untreated containers, in containers treated with paint or NuFilm-17 only, or in containers treated with Cu(OH)2 in paint (100 g rate only) or NuFilm-17 (100, 200 or 400 g per liter). When applied in paint or NuFilm-17, Cu(OH)2 reduced root growth at the container-medium interface, controlling the circular growth pattern commonly observed in container-grown plants. Controlling circling root growth at the soil-container interface did not influence shoot or root dry weight, but did reduce total root length. Application of Cu(OH)2 with paint was unsightly, while application with NuFilm-17 was almost unnoticeable.

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 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 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.

Phosphorus efficiency in pasture species. VII. Relationships between yield and P uptake in two accessions of white clover

1991 ◽  
Vol 42 (7) ◽  
pp. 1271 ◽  
Author(s):  
GJ Blair ◽  
DC Godwin
Keyword(s):  
Root Growth ◽  
White Clover ◽  
Root Length ◽  
Dry Weight ◽  
Application Rate ◽  
P Uptake ◽  
Extension Rate ◽  
Root Extension ◽  
Root Dry Weight ◽  
P Application

Lack of data on root growth and relationships between root parameters and P uptake are major limitations to understanding and modelling P efficiency in crop and forage plants. An experiment was conducted whereby two accessions of white clover (Trifolium repens, Chiswick and Ladino) were grown in pots in a P deficient soil fertilized with a low (P5 [kg ha-1]) or high (P40) P application rate. Plants were harvested at 10, 16, 22, 28, 34 and 40 days after transplanting and tops harvested and roots recovered from the pots. Detailed measures of root members were made at 10, 16 and 22 days and these correlated with P uptake. Dry weight of tops of accessions was the same between the two rates of P until day 28. At 40 days, the tops yield of Ladino was higher than Chiswick at P40. Root dry weight increased with increasing P application rate and time from day 16 onwards. Significant differences in root growth only occurred at the 16 and 34 day harvests at P5. Ladino tended to have a greater mean P uptake over time than did Chiswick at both P levels. P uptake was found to be positively correlated with shoot and root dry weight, root length, root number, root volume and surface area, and negatively correlated with mean root diameter and mean length per root. Root extension rate at low P in Ladino was greater than that in Chiswick, which may explain the greater P uptake by Ladino at low P at later harvests in this experiment. The changes in length, diameter and number of roots in the two accessions examined in this study, with time, in response to P, reflect some form of coordination. Chiswick tended to produce many short roots whilst Ladino fewer long roots. Only small differences in P uptake per unit root length were measured, which suggest that total root length or root extension rate is the primary determinant of total P uptake in these accessions of white clover.

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