Effects Of Root Zone Temperature Research Articles

Effects of root zone temperature and light intensity on plant growth, flowering and fruit quality of plant factory ‘festival’ strawberry (Fragaria × ananassa Duch.)

Effects of root zone temperature and light intensity on plant growth, flowering and fruit quality of plant factory ‘festival’ strawberry (Fragaria × ananassa Duch.)

Controlling root zone temperature improves plant growth and pigments in hydroponic lettuce.

Air and root zone temperatures are important environmental factors affecting plant growth and yield. Numerous studies have demonstrated that air temperature strongly affects plant growth and development. Despite the extensive literature on air temperature, comprehensive studies on the effects of root zone temperature (RZT) on plant growth, elemental composition, and pigments are limited. In this study, we carefully observed the effects of RZT in red leaf lettuce to understand its effect on lettuce growth and pigment content. Lettuce (Lactuca sativa, red leaf cultivar 'Red Fire') was grown hydroponically in a plant factory with artificial light under three RZT treatments (15, 25, or 35 °C) for 13 days. We investigated the comprehensive effects of RZT on the production of red leaf lettuce by metabolome and ionome analyses. The 25 °C RZT treatment achieved maximum shoot and root dry weight. The 35 °C RZT decreased plant growth but significantly increased pigment contents (e.g. anthocyanins, carotenoids). In addition, a RZT heating treatment during plant cultivation that changed from 25 to 35 °C RZT for 8 days before harvest significantly increased shoot dry weight compared with the 35 °C RZT and significantly increased pigments compared with the 25 °C RZT. The 15 °C RZT resulted in significantly less pigment content relative to the 35 °C RZT. The 15 °C RZT also resulted in shoot and root dry weights greater than the 35 °C RZT but less than the 25 °C RZT. This study demonstrated that plant growth and pigments can be enhanced by adjusting RZT during different stages of plant growth to attain enhanced pigment contents while minimizing yield loss. This suggests that controlling RZT could be a viable method to improve lettuce quality via enhancement of pigment content quality while maintaining acceptable yields.

The effect of root zone temperature at low nitrogen level of nutrient solution on sweet pepper

Low temperatures can inhibit plant growth and development, and cause physiological problems by damaging membrane lipids, proteins, and nucleic acids. A factorial experiment based on a complete randomized design with five replicates investigated the effect of root zone temperature and nitrogen ratio on sweet pepper seedlings in soilless culture. Treatments include root zone temperature (15, 25 (optimum), and 35 °C) and different nitrogen levels: 50, 75, and 100% (optimum) of N Johnson nutrient solution. The results showed that growth parameters including root fresh weight, shoot dry weight, and root volume reduced more at 15 °C with nitrogen level reduction compared with 35 °C. Photosynthetic characteristics like photosynthetic rate, transpiration, mesophyll conductivity, and photosynthetic water use efficiency were not affected by nitrogen levels at 25 and 35 °C. Also, higher photosynthetic traits, including greenness index, photosynthesis rate, and mesophyll conductance, were obtained with N50% at 15 °C. Shoot phenol increased by 55% at N 50% compared with N 100% at 35 °C. Sweet peppers seedlings were more sensitive to high root zone temperature of 35 °C. Heat stress and nitrogen deficiency in the root zone ambient led to poor growth, lower photosynthetic capacity, higher phenolic compound, lower nitrate reductase activity, and higher nitrogen compound in evaluated seedlings. Nitrate reductase activity was affected by heat stress and significantly decreased at 35 °C. The phosphorous and potassium concentration was reduced by nitrogen reduction at 35 °C. Conclusively, a lower nitrogen level in the nutrient solution can be used for sweet pepper seedlings’ growth if the temperature of the nutrient solution is decreased to 15 °C.

Effects of Root Zone Temperatures on the Germination of Bell Peppers and Tomatoes

Effects of Root Zone Temperatures on the Germination of Bell Peppers and Tomatoes

Root-zone Temperature Effects on Spinach Biomass Production Using a Nutrient Film Technique System

Root-zone temperature (RZT) is closely related to nutrient transportation and biomass production. However, its influence on biomass production and dry matter distribution remains unknown, especially in year-long production greenhouses. We explore the potential of RZT as an environmental control method to promote spinach field production by quantifying the effects of RZT to increase spinach production. Three RZT treatments using a nutrient film technique (NFT) system quantified and evaluated the effects of spring, summer, and winter spinach cultivation. We investigated the growth characteristics, total aboveground dry matter, and fraction of dry matter distribution to the leaf and root (which corresponded with yield). The RZT effects on total aboveground dry matter varied with the average air temperature inside the greenhouse. The total aboveground dry matter correlated positively with RZT in optimal air temperature conditions (15–20 °C). The dry matter-to-leaves ratio of the spinach did not correlate significantly with RZT in suboptimal (5 °C < air temperature < 15 °C) or supraoptimal (20 °C < air temperature) conditions. Therefore, RZT can promote biomass accumulation. We suggest RZT provides a feasible method for controlling the dry matter distribution fraction. Further research into the functional role of RZT will support hydroponic growers in improving crop yield.

Optimum root zone temperature of photosynthesis and plant growth depends on air temperature in lettuce plants.

The present study clearly showed that the optimum root zone temperature of photosynthesis and plant growth was affected by air temperature, and that optimization of root zone temperature depending on an air growth temperature by cooling systems could lead to improvement of plant production. Temperature is one of the critical factors affecting plant growth and yield production. Both air and root zone temperatures can strongly affect growth and development of plants. However, studies on the effects of root zone temperature on plant growth parameters along with air temperature are still limited. In the present study, the effects of air and root zone temperature on plant growth, physiological parameters and photosynthetic characteristics of lettuce plants were investigated to optimize the air and root zone temperature to achieve the best growth conditions for lettuce plants. Two air temperature treatments (30/25 and 25/20°C at day/night temperature) and five root zone temperature treatments (15, 20, 25, 30 and 35°C) were applied in this study. The present study showed that the maximum plant growth of lettuce plants was higher in air temperatures at 30/25°C than in 25/20°C. When the plants were grown at an air temperature of 30/25°C, the optimum root zone temperature appeared to be 30°C. However, when the plants were grown at an air temperature of 25/20°C, the optimum root temperature decreased and appeared to be 25°C. Furthermore, plants grown under air temperature of 30/25°C showed greater CO2 assimilation rate, stomatal conductance, electron transport rate (ETR) at high light, and lower non-photochemical quenching (NPQ) at high light than those of 25/20°C. These results suggest that it is necessary to control and adjust the root zone temperature based on the air temperature.

Effect of Root Zone Temperature on Germination and Growth of Paprika Seedlings

Effect of Root Zone Temperature on Germination and Growth of Paprika Seedlings

EFFECT OF ROOT ZONE TEMPERATURE ON NUTRIENT UPTAKE IN SOILLESS CULTIVATION SYSTEMS

The main objective of this research is to evaluate the Effect of root zone temperature on nutrient uptake in soilless cultivation systems and to obtain the best reused rate for nutrients after treatment and Fertigation management in closed soilless culture systems and Fertilizer calculator for each element’s at long time of plant. The experiment was carried out in a multi-Spanish agricultural greenhouse covered with polyethylene film and aspects covered with fiberglass. There is a cooling system for evaporation (pad and fan), a heating system roots and a control in the irrigation and fertilization process. Agricultural soil is composed of bitmous, perlite and vermiculite. The obtained results indicated that the closed soilless culture systems with intermittent irrigation and heating the root zone (T1) the best from than all treatments systems closed soilless culture systems with intermittent irrigation (T2), closed soilless culture systems with irrigation once and heating the root zone (T3) and closed soilless culture systems with irrigation once (T4) in terms of uptake nutrients (Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca) and Magnesium (Mg) and The best absorption of water was the treatment of the closed soilless culture systems with intermittent irrigation and heating the root zone and the best growth parameters which include plant height, internode length, stem diameter, number of leaves, leaf area, mass of fruit and yield was the treatment of the closed soilless culture systems with intermittent irrigation and heating the root zone.

Potential host range and the effect of temperature on the pathogenicity of Phytophthora pseudocryptogea and its close relatives

Phytophthora pseudocryptogea, a member of clade 8a of the Phytophthora phylogenetic tree, was formally described in 2015 as a close relative of P. cryptogea and P. erythroseptica. The potential host range of this newly described species and its close relatives was investigated in this study. Thirty species of herbaceous plants and nine species of woody plants were inoculated and monitored for development of foliar symptoms and root rots. Also, we inoculated the detached twigs of 21 tree species, fruit of six plant species, tubers of potato, and roots of carrot and sugar beet. Our results showed P. pseudocryptogea, P. cryptogea and P. erythroseptica had different potential host ranges, though all were pathogenic on some plant species such as pistachio, tomato, potato, eggplant, spinach and clover. Additionally, some plant species were able to discriminate P. pseudocryptogea from P. cryptogea including cucumber, melon, watermelon, alfalfa, soybean, cabbage, green pepper, and rice. These plants showed susceptibility to P. pseudocryptogea and resistance to P. cryptogea. Different species showed different virulence levels on detached tree twigs; however, almost all species caused severe rot on all tested fruits, tubers and roots. Investigation of the effects of root-zone temperature on the virulence of species showed that a temperature of 20 °C in increased root rot and root colonization in P. pseudocryptogea and P. erythroseptica, while P. cryptogea caused the most root rot and colonization at 25 °C.

Root zone temperature effects on potted Dahlia production

Dahlias (Dahlia × hybrida) have been a popular greenhouse crop in recent years, as increased dahlia breeding and selection has led to a new generation of dahlias, with enhanced disease resistance, leading the way for a renewed interest in the horticulture market. Vegetative or clonal dahlia production has become more popular with many new dahlia series available to producers and consumers (e.g. ‘XXL’, ‘Karma’, ‘Gallery’, ‘Dahlietta’, ‘Dalaya’, etc.). It has been observed and reported that periodic significant crop loss (complete crop loss in some cases) of vegetative dahlia crops during greenhouse production in North America in late spring, shortly before market. It is hypothesized that elevated root zone temperatures (RZT) may be to cause, rather than disease problems. The main objective of this research was to evaluate and characterize elevated RZT effects on vegetative dahlia production on different dahlia lines and cultivars. Elevated RZT treatments were applied using a hot water bath. Dahlia plants (6 replications) were subjected to one of 5 RZT treatments; 18 (control; ambient), 35, 40, 45, or 50°C. Plants were treated 5 weeks after plugs were transplanted, when significant rooting was observed. Treatments were considered ‘applied’ when the temperature in the root zone of the pot (~2.5 cm from the edge of the pot; ~5 cm from the top of the media). Root ratings based on a predetermined scale (0=brown, dead; 4=white, active) were collected before treatments were applied and weekly after treatments. Our results showed that temperature affects were cultivar dependent. One week after treatment, with the exception of the controls, for most temperature treatments, root ratings decreased in ‘Dalaya Shiva’, ‘XXL Sunset’, and ‘Dalaya Yogi’. The cultivar XXL Veracruz did not respond to treatments. For ‘Karma Naomi’, ‘Karma Sangria’, ‘Melody Gypsy’ and ‘Melody Sincerity’, RZT treatments of 45 and 50°C resulted in decreased root ratings, one week post treatment. After 2 and 3 weeks, some root ratings increased, indicating root recovery across the treatments. These results provide insight into the effects of elevated RZTs. However, treatments did not result in complete crop losses, suggesting additional factors need to be considered to explain the phenomenon.

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

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.

Impact of Rhizosphere’s Thermal Change on the Development and Production of Hydroponically Grown Cucumber under Controlled Environment

The easier and more economical control of root-zone temperature (RZT) as compared to that of other environmental factors such as air temperature could be an effective solution to temperature stress for the crop plants in hydroponics. The present study was designed to investigate the effect of root-zone temperature on the growth and yield of cucumber (Cucumis sativus L.) plants in recirculating hydroponic system under greenhouse of dimension, 9m x 30m during three cropping periods of the year in Oman viz. summer (June-August), fall (September-November) and spring (February-May) during year 2016/2017 at Directorate General Of Agriculture and Livestock Research of the Ministry of Agriculture & Fisheries located at Rumais Barka of Oman. The plants were grown in perlite medium at root-zone cooled temperatures of 22áµ’C, 25áµ’C, 28áµ’C treatments besides the control i.e. root-zone uncooled temperature of 33áµ’C as control treatment. The treatments were arranged in Complete Randomized Design (CRD) with four replications. The results indicated that the crop at root-zone temperatures of 22áµ’C and 25áµ’C gave the superior performance in terms of plant height, leaf number, chlorophyll content, leaf area cm2, fruit number/m2, yield in ton per greenhouse (t/gh), fresh and dry weight of shoot and root with significant differences between the treatments in all three periods. Fruit yield varied from 4.5t/gh to 6.4t/gh for root-zone temperature (RZT) and from 4.2 t/gh to 6.8 t/gh for the cropping periods. The higher yields of 6.4 t/gh and 6.4t/gh were found under RZT of 22áµ’C and 25áµ’C, respectively and were significantly higher (p<0.05) than that under control (33áµ’C; 4.5t/gh). In respect of cropping periods, the crop during fall period (February-May) gave higher fruit yield (6.8t/gh) than that during summer period (4.2t/gh). Â Thus the results indicated that cooling of root-zone temperature through nutrient solution is essential during high temperatures of summer (June-August) in Oman.Â

Effect of rootzone temperature on the growth, photochemical light use efficiency and rootzone ethylene accumulation of recombinant inbred lines of lettuce in a tropical greenhouse

Effect of rootzone temperature on the growth, photochemical light use efficiency and rootzone ethylene accumulation of recombinant inbred lines of lettuce in a tropical greenhouse

Effect of Root-Zone Temperature on the Growth and Fruit Quality of Hydroponically Grown Strawberry Plants

<p>It has been reported that soil temperature modulates the growth and quality of many leafy vegetables and some fruit vegetables; however, this effect has not been sufficiently reported for strawberry plants. Here using a deep flow technique hydroponic system, we investigated the effect of various root-zone temperatures (10 °C, 20 °C, and 30 °C) on the plant growth and fruit quality of strawberry plants grown at an air temperature of 20 °C. The high root-zone temperature treatment (30 °C) decreased oxygen consumption and cell viability of the roots, resulting in withering of most of the plants after 2 months of treatment. In contrast, roots exposed to low temperature (10 °C) showed higher biomass production than those exposed to ambient condition (20 °C), whereas leaf growth was only slightly influenced. The biomass of reproductive organs, such as inflorescences and fruits, were increased in plants treated with a low root-zone temperature, suggesting the activation of reproductive growth by low temperature. However, the contents of ascorbic acid and sugar in fruits were not significantly influenced by the cooling of the root-zone, although the fruit maturation period was significantly prolonged by low temperature. These data indicate that manipulation of root-zone temperature could alter the vegetative and reproductive growth of hydroponically grown strawberry plants.</p>

Diurnal root zone temperature variations affect strawberry water relations, growth, and fruit quality

To test the hypothesis that the effect of daily root zone temperature (RZT) variations would affect strawberry plant performance, root systems of Control ‘Albion’ strawberry plants Treatment 1 (T1) were maintained at 20°C (no stress), while plants in other treatments were exposed to different diurnal temperature swings about the daily mean of 20°C. In treatment 2 (T2), temperature swing was 5°C (mild) which had a total variation of 10°C (Tvar-10) with a minimum of 15°C and maximum of 25°C, treatment 3 (T3) had a variation about the mean of 10°C (moderate) with a total variation of 20°C (Tvar-20) with a minimum of 10°C and maximum of 30°C, or 15°C (severe) swings about the mean in treatment 4 (T4) with a diurnal total variation of 30°C (Tvar-30) with a minimum of 5°C and maximum of 35°C. Leaf area and shoot dry weight of plants in the severe treatment were 30% lower than Controls. Root dry weight in the severe treatment was 30% lower than in the mild treatment. Fruits in the moderate and severe treatments were 22% smaller than in the mild treatment. Fruit soluble sugar content was elevated slightly by RZT fluctuation. Shoot concentrations of N, Mg, Fe, B, Zn were not affected by RZT, but there were small differences in concentrations of P, K, Ca, Mn, and Cu. Nutrient uptake of N and Ca were not affected, but P, K and Mg were about 35% less in Tvar-20 and Tvar-30. RZT variation had no effect on chlorophyll content or number of leaves, maximum carboxylation rate, photosynthetic electron transport rate, maximum CO2 assimilation rate, or fluorescence parameters (Fv/Fm and ϕPSII). There was little effect of RZT on predawn or midday stem water potential (SWP), but the SWP was substantially lowered in the severe treatment at mid-morning when RZT was about 5°C and air vapor pressure deficit was at its daily maximum. We attributed the reduced shoot and root growth to the transient reduction in SWP when RZT was near 5°C. Overall, the consequences of diurnal RZT fluctuations for strawberry production appear to be small if the minimum temperature is above 7°C.

The effect of root-zone temperature on temperature difference between leaf and air in tomato plants

The effect of root-zone temperature on temperature difference between leaf and air in tomato plants

Elevated Root-Zone Temperature Modulates Growth and Quality of Hydroponically Grown Carrots

Air and soil temperatures strongly influence the growth and quality of crops. However, in root vegetables, such as carrot, few experiments aimed at regulating growth and quality by manipulating root-zone temperature have been reported. We investigated the effect of root-zone temperatures (20&degC, 25&degC, 29&degC, and 33&degC) on carrot growth and components using a hydroponic system. High root-zone temperatures for 14 days reduced shoot and rootgrowth and water content. In contrast, total phenolic compounds and soluble-solid content increased in tap roots under high-temperature treatment. Root oxygen consumption was upregulated after 7 days under high-temperature treatment. These results suggest that high root-zone temperatures induce drought-like stress responses that modulate carrot biomass and components. High root-zone temperature treatments administered to hydroponically grown crops may be a valuable tool for improving and increasing the quality and value of crops.

Effect of Root-Zone Temperature on Growth and Quality of Hydroponically Grown Red Leaf Lettuce (Lactuca sativa L. cv. Red Wave)

Soil temperature influences crop growth and quality under field and greenhouse conditions; however, precise investigation using controlled cultivation systems is largely lacking. We investigated effects of root-zone temperatures on growth and components of hydroponically grown red leaf lettuce (Lactuca sativa L. cv. Red Wave) under a controlled cultivation system at 20&degC. Compared with ambient root-zone temperature exposure, a 7-day low temperature exposure reduced leaf area, stem size, fresh weight, and water content of lettuce. However, root-zone heating treatments produced no significant changes in growth parameters compared with ambient conditions. Leaves under low root-zone temperature contained higher anthocyanin, phenols, sugar, and nitrate concentrations than leaves under other temperatures. Root oxygen consumption declined with low temperature root exposure, but not with root heating. Leaves of plants under low rootzone temperature showed hydrogen peroxide production, accompanied by lipid peroxidation. Therefore, low temperature root treatment is suggested to induce oxidative stress responses in leaves, activating antioxidative secondary metabolic pathways.

Low Root Zone Temperature Limits Nutrient Effects on Cucumber Seedling Growth and Induces Adversity Physiological Response

Effects of root-zone temperatures (RZT) (12°C-RZT and 20°C-RZT) and different N, P, and K nutrient regimes on the growth, reactive oxygen species (ROS), and antioxidant enzyme in cucumber seedlings were investigated in hydroponics. Strong interactions were observed between RZT and nutrient on the dry weight (P=0.001), root length (P=0.001) and leaf area (P=0.05). Plant dry weights were suppressed at low RZT of 12°C, while higher biomass and growth of cucumber seedlings were produced at elevated RZT of 20°C under each nutrient treatment. Growth indexes (plant height, internode length, root length, and leaf area) at 12°C-RZT had less difference among nutrient treatments, but greater response was obtained for different nutrients at high RZT. RZT had larger effects (P=0.001) on cucumber seedling growth than nutrients. In addition, N was more effective nutrients to plant growth than P and K under low root temperature to plant growth. Higher hydrogen peroxide (H2O2), malondialdehyde (MDA), soluble sugar (SS) contents in leaves were observed at 12°C-RZT in all nutrient treatments than those at 20°C-RZT, indicating the chilling adversity damaged to plant growth. In general, antioxidant enzyme had larger response under low root-zone temperature. Superoxide dismutase (SOD) activities were higher in both leaves and roots while peroxidase (POD) and catalase (CAT) showed large different action in leaves and roots at both the two root-zone temperature.

Effects of root-zone temperature and N, P, and K supplies on nutrient uptake of cucumber (Cucumis sativus L.) seedlings in hydroponics

The nutrient uptake and allocation of cucumber (Cucumis sativus L.) seedlings at different root-zone temperatures (RZT) and different concentrations of nitrogen (N), phosphorus (P), and potassium (K) nutrients were examined. Plants were grown in a nutrient solution for 30 d at two root-zone temperatures (a diurnally fluctuating ambient 10°C-RZT and a constant 20°C-RZT) with the aerial parts of the plants maintained at ambient temperature (10°C–30°C). Based on a Hoagland nutrient solution, seven N, P, and K nutrient concentrations were supplied to the plants at each RZT. Results showed that total plant and shoot dry weights under each nutrient treatment were significantly lower at low root-zone temperature (10°C-RZT) than at elevated root-zone temperature (20°C-RZT). But higher root dry weights were obtained at 10°C-RZT than those at 20°C-RZT. Total plant dry weights at both 10°C-RZT and 20°C-RZT were increased with increased solution N concentration, but showed different responses under P and K treatments. All estimated nutrient concentrations (N, P, and K) and uptake by the plant were obviously influenced by RZT. Low root temperature (10°C-RZT) caused a remarkable reduction in total N, P, and K uptake of shoots in all nutrient treatments, and more nutrients were accumulated in roots at 10°C-RZT than those at 20°C-RZT. N, P, and K uptakes and distribution ratios in shoots were both improved at elevated root-zone temperature (20°C-RZT). N supplies were favorable to P and K uptake at both 10°C-RZT and 20°C-RZT, with no significantly positive correlation between N and P, or N and K uptake. In conclusion, higher RZT was more beneficial to increase of plant biomass and mineral nutrient absorption than was increase of nutrient concentration. Among the three element nutrients, increasing N nutrient concentration in solution promoted better tolerance to low RZT in cucumber seedlings than increasing P and K. In addition, appropriately decreased P concentration favors plant growth.