The root growth response to heterogeneous nitrate supply differs for Lupinus angustifolius and Lupinus pilosus

2001 ◽  
Vol 52 (4) ◽  
pp. 495 ◽  
Author(s):  
V. Dunbabin ◽  
Z. Rengel ◽  
A. Diggle
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Root System ◽  
Nutrient Solution ◽  
Growth Response ◽  
Second Order ◽  
Lupinus Angustifolius ◽  
Average Growth ◽  
First Order ◽  
Tap Root

Little is known about the ability of legume root systems to respond to the heterogeneous supply of nitrate. A split-root nutrient solution experiment was set up to compare the root growth response of 2 lupin species, Lupinus angustifolius L. (dominant tap root and primary lateral system) and L. pilosus Murr. (minor tap root and well-developed lateral root system), to differentially supplied nitrate. These 2 species represent the extremes of the root morphology types present across the lupin germplasm. Nutrient solution containing low (250 M) or high (750 M) nitrate was supplied either uniformly, or split (high and low) between the upper and lower root system. The average growth rate and total root length of L. pilosus was 1.7 times that of L. angustifolius. For both species, the increased proliferation of roots in a high nitrate zone was accompanied by a decrease in root growth in the low nitrate zone, giving approximately the same total growth as the uniform low nitrate treatment. This correlative growth rate response was 15% larger for the first-order branches of L. pilosus than L. angustifolius. While few second-order branches grew for L. angustifolius, the second-order laterals of L. pilosus showed a 2-fold correlative root growth and branching response to the split treatments, with no difference in growth between the uniform high and low nitrate treatments. The second-order laterals thus proliferated in response to the differential supply of nitrate and not the absolute concentration. While the growth rate and branching of the second-order laterals of L. pilosus exhibited a typical correlative response, first-order branching was inhibited in all split treatments, regardless of whether the roots were in the high or low nitrate zone. This response was not seen in L. angustifolius. The difference in the root growth response of the 2 root system types to differentially supplied nitrate suggests a potential in the lupin germplasm for developing a line capable of greater nitrate capture from the soil profile.

Effects of Temperature on Root Morphology and Ectendomycorrhizal Development in Pinusresinosa Ait.

1975 ◽  
Vol 5 (2) ◽  
pp. 171-175 ◽  
Author(s):  
Hugh E. Wilcox ◽  
Ruth Ganmore-Neumann
Keyword(s):  
Root Growth ◽  
Root System ◽  
Root Morphology ◽  
Root Systems ◽  
Second Order ◽  
Root Temperature ◽  
First Order ◽  
Effects Of Temperature

Seedlings of Pinusresinosa were grown at root temperatures of 16, 21 and 27 °C, both aseptically and after inoculation with the ectendomycorrhizal fungus BDG-58. Growth after 3 months was significantly influenced by the presence of the fungus at all 3 temperatures. The influence of the fungus on root growth was obscured by the effects of root temperature on morphology. The root system at 16 and at 21 °C possessed many first-order laterals with numerous, well developed second-order branches, but those at 27 °C had only a few, relatively long, unbranched first-order laterals. Although the root systems of infected seedlings were larger, the fungus increased root growth in the same pattern as determined by the temperature.

Root Morphology and Secretion of two subtropical tree species to NH4+-N and NO3–-N Deposition

2020 ◽  
Author(s):  
Rui Zhang ◽  
Yi Wang ◽  
Zhichun Zhou
Keyword(s):  
Root Growth ◽  
Root System ◽  
Root Morphology ◽  
Tree Species ◽  
Southern China ◽  
N Deposition ◽  
Fibrous Root ◽  
Nitrogen And Phosphorus ◽  
Root Absorption ◽  
Tap Root

Abstract Background: Both NH4+ and NO3– are capable of greatly influencing plants’ growth and biomass. However, the belowground responses of subtropical trees to either NH4+ or NO3– deposition remain poorly understood. Here, we discuss how these two forms of N deposition can affect root development, and experimentally analyzed how they could impact nitrogen and phosphorus absorption in two types (broadleaved with a fibrous root system vs. conifer with a tap root system) of subtropical tree species. Results: In a greenhouse in southern China, 1-year-old S. superba and P. massoniana seedlings grown on P-limited and P-normal soil were treated with NaNO3 and NH4Cl solutions of 0, 80, and 200 kg N ha–1 year–1, corresponding to the control, N80, and N200 groups, respectively. Root phenotype characteristics and metabolism ability were measured after 8 months of growth. The results showed that the root morphology and physiology variables differed significantly between the two species under different N and P treatments. Although S. superba had a larger quantity of roots than P. massoniana, both its root growth rate and root absorption were respectively lower and weaker. N addition differentially affected root growth and activity as follows: (1) NO3–-N80 and NH4+-N80 increased root growth and activity of the two species, but NH4+-N80 led to thicker roots in S. superba; (2) NO3–-N200 and NH4+-N200 had inhibitory effects on the roots of P. massoniana, for which NH4+-N200 led to thinner and longer roots and even the death of some roots; and (3) NH4+-N could promote metabolic activity in thicker roots (> 1.5 mm) and the NO3–-N was found to stimulate activity in thinner roots (0.5–1.5 mm) in the fibrous root system having a larger quantity of roots, namely S. superba. By contrast, NO3–-N and NH4+-N had an opposite influence upon functioning in the tap root system with a slender root, namely P. massoniana. Conclusion: We conclude P. massoniana has a much higher root absorption efficiency; however, nitrogen deposition is more beneficial to the root growth of S. superba.

Effects of root severing treatments on loblolly pine

1988 ◽  
Vol 18 (11) ◽  
pp. 1376-1385 ◽  
Author(s):  
William C. Carlson ◽  
Constance A. Harrington ◽  
Peter Farnum ◽  
Stephen W. Hallgren
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Root System ◽  
Loblolly Pine ◽  
Water Status ◽  
Lateral Roots ◽  
Second Order ◽  
Plant Water Status ◽  
Plant Water ◽  
First Order

Six-year-old loblolly pine seedlings were subjected to root severing treatments varying from 0 to 100% of first-order lateral roots. Separate treatments severed surface-oriented or deep-oriented roots. Plant water status was monitored periodically for several months. After all measurements were taken, gross root system structure was determined by excavation. Treatment responses were evident on all dates of measurement. Relationships between percentage of root system cut and leaf conductance or water potential were stronger when surface-oriented roots were cut than when deep-oriented roots were cut. Severing surface-oriented first-order lateral (SOFOL) roots probably resulted in greater impact on plant water status than severing deep-oriented first-order lateral (DOFOL) roots because (i) SOFOL roots had both surface-oriented and deep-oriented second-order lateral roots that could tap both surface and subsurface soil horizons for soil moisture, and (ii) the deep-oriented second-order roots (originating from the SOFOL roots) were spatially distributed over a much larger area than the DOFOL roots and thus would have access to soil water in a larger volume of soil. For SOFOL roots the relationship between percentage cut and leaf conductance or transpiration was strongly negative; for DOFOL roots, no relationship between these variables was observed. Initially water potential decreased with the percentage of roots cut in both groups; in later measurements, water potential was affected more by severing SOFOL than DOFOL roots. Calculation of soil moisture depletion by depth indicated that both surface- and deep-oriented second-order lateral roots were important for water uptake. Severing SOFOL roots significantly decreased nitrogen, phosphorus, and potassium levels in needles of the first growth flush of the year. Levels of these elements in terminal buds were not affected by severing SOFOL roots, but were significantly reduced by severing DOFOL roots. Secondary xylem production was reduced proportionately to the amount of root system cross-sectional area severed.

scholarly journals Omnibus Modeling of Listeria monocytogenes Growth Rates at Low Temperatures

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1099
Author(s):  
Vincenzo Pennone ◽  
Ursula Gonzales Barron ◽  
Kevin Hunt ◽  
Vasco Cadavez ◽  
Olivia McAuliffe ◽  
...  
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Case Fatality ◽  
Second Order ◽  
Lag Phase ◽  
Model Parameters ◽  
Growth Data ◽  
Temperature Growth ◽  
First Order ◽  
Primary Model

Listeria monocytogenes is a pathogen of considerable public health importance with a high case fatality. L. monocytogenes can grow at refrigeration temperatures and is of particular concern for ready-to-eat foods that require refrigeration. There is substantial interest in conducting and modeling shelf-life studies on L. monocytogenes, especially relating to storage temperature. Growth model parameters are generally estimated from constant-temperature growth experiments. Traditionally, first-order and second-order modeling (or primary and secondary) of growth data has been done sequentially. However, omnibus modeling, using a mixed-effects nonlinear regression approach, can model a full dataset covering all experimental conditions in one step. This study compared omnibus modeling to conventional sequential first-order/second-order modeling of growth data for five strains of L. monocytogenes. The omnibus model coupled a Huang primary model for growth with secondary models for growth rate and lag phase duration. First-order modeling indicated there were small significant differences in growth rate depending on the strain at all temperatures. Omnibus modeling indicated smaller differences. Overall, there was broad agreement between the estimates of growth rate obtained by the first-order and omnibus modeling. Through an appropriate choice of fixed and random effects incorporated in the omnibus model, potential errors in a dataset from one environmental condition can be identified and explored.

scholarly journals Understanding Root Biology for Enhancing Cotton Production

2021 ◽  
Author(s):  
Jayant H. Meshram ◽  
Sunil S. Mahajan ◽  
Dipak Nagrale ◽  
Nandini Gokte-Narkhedkar ◽  
Harish Kumbhalkar
Keyword(s):  
Root Growth ◽  
Root System ◽  
Abiotic Stresses ◽  
Root Length Density ◽  
Plant Root ◽  
Root System Architecture ◽  
Cotton Production ◽  
Tap Root ◽  
Commercial Crop ◽  
Environmental Responses

Cotton is an important commercial crop grown in India. It occupies an area of about 12.7 million hectares and is grown both in irrigated as well as rainfed tracts. In such situations, roots are very important organ for plant growth and development, since they act as anchors, providing mechanical support, and chemical extractors for the growing plant. Root length density sets the proportion of water uptake both under wet conditions and dry soils. Cotton plants with efficient root system capture water and nutrients from soil having these features of longer tap root. It is widely accepted that breeding efforts on aboveground traits are not sufficient to the necessary yield advantage. Shifting the emphasis to analyzing the root system would provide an additional means to enhance yield under changing climatic condition. Belowground image analysis studies point to the importance of root system architecture for optimizing roots and rhizosphere dynamics for sustainable cotton production. In this review, we describe the cotton root biological context in which root-environment interactions providing an overview of the root growth morphology species wise, phytohormone action that control root growth, root anatomical significance in drying soils, biotic and abiotic stresses involved in controlling root growth and environmental responses.

scholarly journals 592 PB 164 POST-TRANSPLANT ROOT GROWTH OF CITRUS PLANTS AS INFLUENCED BY PRODUCTION TIME IN NURSERY CONTAINERS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 516f-516
Author(s):  
Thomas E. Marler
Keyword(s):  
Methylene Blue ◽  
Root Growth ◽  
Root System ◽  
Nutrient Solution ◽  
Dry Weight ◽  
Two Dimensional ◽  
Rooted Cuttings ◽  
Post Transplant ◽  
Root Regeneration ◽  
Complete Nutrient Solution

An aeroponics system was used to determine root growth of Citrus aurantifolia Swingle following removal from containers. Rooted cuttings were planted in 0.46-liter containers in a 1 sand: 1 perlite medium, and watered daily and fertilized with a complete nutrient solution weekly. The plants were grown in the containers until root growth had filled the container volume. A sample of plants was removed from the bench after 86, 146, or 210 days in container production. Plants were bare-rooted and the existing root system dyed with methylene blue, and placed in the aeroponics system. The plants were maintained in the aeroponics system for 50 days, then were harvested and the roots separated into pre-existing roots and new roots. Two dimensional area and dry weight of roots were measured. Relative new root growth of plants that were maintained 210 days in the containers was less than that of plants that were removed from containers earlier. The data indicate that maintaining plants in containers for extended periods of time may reduce root regeneration following removal from containers.

scholarly journals Root Development Patterns in Field Grown Peach Trees

1993 ◽  
Vol 118 (3) ◽  
pp. 362-365 ◽  
Author(s):  
D.M. Glenn ◽  
W.V. Welker
Keyword(s):  
Root Growth ◽  
Root System ◽  
Growth Response ◽  
Prunus Persica ◽  
Surface Soil ◽  
Root Production ◽  
Mature Trees ◽  
Deep Roots ◽  
Development Patterns ◽  
Peach Trees

The objective was to determine the interrelationship between root growth and plant available soil water (PAW) for young, nonbearing, and mature fruiting peach trees (Prunus persica L. Batsch) over 7 years. Root growth observed with minirhizotrons indicated that young, nonbearing trees developed new white roots throughout the growing season. The pattern of new white root growth became bimodal when the trees fruited. White root production in mature trees appeared in March, preceding budbreak, ceased in June, resumed following fruitremoval in August, and persisted through January. The appearance of white roots was inversely related to the presence of fruit and was not correlated to PAW levels in the 0 to 90 cm depth. The lack of root growth response to PAW levels was attributed to a root system that penetrated the soil to depths beyond our zone of sampling. Circumstantial evidence suggests that deep roots help maintain the surface root system when the surface soil dries.

Start current and growth rate in Smith–Purcell free-electron laser with dielectric-loaded cylindrical grating

2019 ◽  
Vol 14 (2) ◽  
pp. 149-158
Author(s):  
Zahra Rezaei ◽  
Bizhan Farokhi
Keyword(s):  
Growth Rate ◽  
Electron Beam ◽  
Wave Interaction ◽  
Forward Direction ◽  
Second Order ◽  
First Order ◽  
Minimum Value ◽  
Dielectric Grating ◽  
Cylindrical Metal ◽  
Beam Wave Interaction

Abstract We present an analytic theory for Smith–Purcell device in which a cylindrical metal–dielectric grating was derived by an annular electron beam propagating along the grating axis. A dispersion relation is obtained for azimuthally symmetric modes. Also, the first-order and second-order growth rates of the modes which are in phase with the beam are compared. It is shown that the second-order growth rate gives a more accurate description of beam–wave interaction for beams with larger thicknesses, as well as grating slots, with smaller depths and greater lengths. The start current for BWO operation of the SP-FEL is presented too. The importance of the minimum value of start current is that above it, the SP-FEL will operate as an oscillator, even in the absence of external feedback. In this case, the group velocity of the synchronous evanescent wave is negative, while the electron beam travels in the forward direction. It is shown in this paper that the dielectric and grating parameters affect the value of start current. So, by changing these parameters, the minimum value for the start current can be obtained.

Phytotoxicity, Leachability, and Site of Uptake of 2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide

Weed Science ◽  
1969 ◽  
Vol 17 (4) ◽  
pp. 441-444 ◽  
Author(s):  
Y. Eshel
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Gossypium Hirsutum ◽  
Root System ◽  
Soil Depth ◽  
The Other ◽  
Slight Reduction ◽  
Culture Solution ◽  
Other Hand ◽  
Different Soils

The toxicity, leachability, and site of uptake of the herbicide 2-chloro-2',6'-diethyl-N-(methoxymethyl) acetanilide (hereinafter referred to as CP 50144) were studied in different soils. Two inches of water leached most of the compound to a soil depth of 2 to 3 inches, when applied at rates of 1 and 2 kg/ha. The inherent toxicity of CP 50144 to cotton (Gossypium hirsutumL., var. Acala 4-42) was studied in culture solution. The herbicide was most toxic to cotton when the entire root system of the crop was exposed to soil treated with CP 50144; reduction of weight of seedlings was accompanied by severe inhibition of root growth. On the other hand, only a slight reduction in growth rate was noticed when only the shoot zone of cotton was exposed to the herbicide.

Nonlinear Analysis of Visual Evoked Potentials Elicited by Color Stimulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 315-318 ◽  
Author(s):  
K. Momose ◽  
K. Komiya ◽  
A. Uchiyama
Keyword(s):  
Visual System ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Normal Subjects ◽  
Second Order ◽  
First Order ◽  
The Relationship ◽  
Perceived Color ◽  
Second Order Nonlinearity ◽  
Visual Evoked

Abstract:The relationship between chromatically modulated stimuli and visual evoked potentials (VEPs) was considered. VEPs of normal subjects elicited by chromatically modulated stimuli were measured under several color adaptations, and their binary kernels were estimated. Up to the second-order, binary kernels obtained from VEPs were so characteristic that the VEP-chromatic modulation system showed second-order nonlinearity. First-order binary kernels depended on the color of the stimulus and adaptation, whereas second-order kernels showed almost no difference. This result indicates that the waveforms of first-order binary kernels reflect perceived color (hue). This supports the suggestion that kernels of VEPs include color responses, and could be used as a probe with which to examine the color visual system.

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