Absorption of Water and 32P through Suberized and Unsuberized Roots of Loblolly Pine

1975 ◽  
Vol 5 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Hsu-Ho Chung ◽  
Paul J. Kramer
Keyword(s):  
Nutrient Solution ◽  
Loblolly Pine ◽  
Mineral Nutrition ◽  
Woody Plants ◽  
Root Systems ◽  
Root Surface ◽  
P Uptake ◽  
Mineral Nutrients ◽  
Vacuum Pump ◽  
Root Segments

Measurements were made of the rate of intake of water and 32P through suberized and unsuberized roots and root segments from seedlings of Pinustaeda L. under a pressure gradient of 31 cm Hg (41 kPa), produced by use of a vacuum pump. Water and 32P intake through suberized root segments from seedlings in storage was only 11% of the intake through unsuberized segments from roots grown in nutrient solution. Water intake through entirely suberized root systems grown in nutrient solution was about 71% and 32P uptake about 58% of those through root systems grown in nutrient solution but with 40–50% of their surface unsuberized. Uptake of water and 32P through root segments and root systems grown in vermiculite was intermediate between that for seedlings grown in nutrient solution and that for dormant root systems. Removal of all unsuberized root surface reduced the total root surface by 42%, water uptake by 54%, and 32P uptake by 70% per seedling. These results indicate that absorption of water and mineral nutrients through suberized roots may play an important role in the water economy and mineral nutrition of woody plants.

scholarly journals A functional–structural model of upland rice root systems reveals the importance of laterals and growing root tips for phosphate uptake from wet and dry soils

2020 ◽  
Vol 126 (4) ◽  
pp. 789-806 ◽  
Author(s):  
Pieterjan De Bauw ◽  
Trung Hieu Mai ◽  
Andrea Schnepf ◽  
Roel Merckx ◽  
Erik Smolders ◽  
...  
Keyword(s):  
Root System ◽  
Structural Model ◽  
Upland Rice ◽  
Root Systems ◽  
P Uptake ◽  
Small Scale ◽  
P Availability ◽  
Root Tips ◽  
Root Segments ◽  
Plant P Uptake

Abstract Background and Aims Upland rice is often grown where water and phosphorus (P) are limited. To better understand the interaction between water and P availability, functional–structural models that mechanistically represent small-scale nutrient gradients and water dynamics in the rhizosphere are needed. Methods Rice was grown in large columns using a P-deficient soil at three P supplies in the topsoil (deficient, sub-optimal and non-limiting) in combination with two water regimes (field capacity vs. drying periods). Root system characteristics, such as nodal root number, lateral types, interbranch distance, root diameters and the distribution of biomass with depth, as well as water and P uptake, were measured. Based on the observed root data, 3-D root systems were reconstructed by calibrating the structural architecure model CRootBox for each scenario. Water flow and P transport in the soil to each of the individual root segments of the generated 3-D root architectures were simulated using a multiscale flow and transport model. Total water and P uptake were then computed by adding up the uptake by all the root segments. Key Results Measurements showed that root architecture was significantly affected by the treatments. The moist, high P scenario had 2.8 times the root mass, double the number of nodal roots and more S-type laterals than the dry, low P scenario. Likewise, measured plant P uptake increased >3-fold by increasing P and water supply. However, drying periods reduced P uptake at high but not at low P supply. Simulation results adequately predicted P uptake in all scenarios when the Michaelis–Menten constant (Km) was corrected for diffusion limitation. They showed that the key drivers for P uptake are the different types of laterals (i.e. S- and L-type) and growing root tips. The L-type laterals become more important for overall water and P uptake than the S-type laterals in the dry scenarios. This is true across all the P treatments, but the effect is more pronounced as the P availability decreases. Conclusions This functional–structural model can predict the function of specific rice roots in terms of P and water uptake under different P and water supplies, when the structure of the root system is known. A future challenge is to predict how the structure root systems responds to nutrient and water availability.

Hydraulic Properties of Pine and Bean Roots With Varying Degrees of Suberization, Vascular Differentiation and Mycorrhizal Infection.

1982 ◽  
Vol 9 (5) ◽  
pp. 559 ◽  
Author(s):  
R Sands ◽  
EL Fiscus ◽  
CPP Reid
Keyword(s):  
Loblolly Pine ◽  
Root Systems ◽  
Hydraulic Conductance ◽  
Root Surface ◽  
Root Surface Area ◽  
Mycorrhizal Infection ◽  
Vascular Differentiation ◽  
Hydraulic Behaviour ◽  
Pine Seedlings ◽  
Axial Conductance

The hydraulic behaviour of root systems of loblolly pine seedlings conformed to the model of Fiscus (1975) and Dalton et al. (1975). The average hydraulic conductance per unit of root surface area was 1.4 × 10-6 cm s-1 bar-1. The hydraulic conductance of various parts of pine root systems was determined using root severing experiments. The average hydraulic conductance of brown (older suberized) roots was 7.55 × 10-7 cm s-1 bar-1, and that of white (newly regenerated unsuberized) roots was 1.95 x 10-6 cm s-1 bar-1. Hydraulic conductance was independent of the amount of mycorrhizal infection. The mean maximum exudation rate from detopped seedlings at zero hydrostatic pressure difference was 1.31 × 10-7 cm s-1. Axial conductance of nutrient solution by roots of bean plants and loblolly pine seedlings was measured at 25°C. Bean vessels and pine tracheids conducted at 0.4 and 0.55 times idealized Poiseuille conductance. Bean roots with differentiated vessels had 8 times more axial conductance per unit area of stele than pine roots, and 6.5 times more axial conductance than bean roots with undifferentiated vessels. Change in axial conductance of bean roots with temperature was completely explained by change in viscosity of the solution. Axial resistance was negligible in the experiments where the hydraulic conductance of whole root systems was measured.

scholarly journals Biological nitrification inhibition in maize—isolation and identification of hydrophobic inhibitors from root exudates

2021 ◽  
Author(s):  
Junnosuke Otaka ◽  
Guntur Venkata Subbarao ◽  
Hiroshi Ono ◽  
Tadashi Yoshihashi
Keyword(s):  
Root Exudation ◽  
Root Systems ◽  
Root Surface ◽  
Maize Root ◽  
Nitrification Inhibition ◽  
Isolation And Identification ◽  
N Losses ◽  
Chemical Structures ◽  
Maize Roots ◽  
Biological Nitrification

AbstractTo control agronomic N losses and reduce environmental pollution, biological nitrification inhibition (BNI) is a promising strategy. BNI is an ecological phenomenon by which certain plants release bioactive compounds that can suppress nitrifying soil microbes. Herein, we report on two hydrophobic BNI compounds released from maize root exudation (1 and 2), together with two BNI compounds inside maize roots (3 and 4). On the basis of a bioassay-guided fractionation method using a recombinant nitrifying bacterium Nitrosomonas europaea, 2,7-dimethoxy-1,4-naphthoquinone (1, ED50 = 2 μM) was identified for the first time from dichloromethane (DCM) wash concentrate of maize root surface and named “zeanone.” The benzoxazinoid 2-hydroxy-4,7-dimethoxy-2H-1,4-benzoxazin-3(4H)-one (HDMBOA, 2, ED50 = 13 μM) was isolated from DCM extract of maize roots, and two analogs of compound 2, 2-hydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (HMBOA, 3, ED50 = 91 μM) and HDMBOA-β-glucoside (4, ED50 = 94 μM), were isolated from methanol extract of maize roots. Their chemical structures (1–4) were determined by extensive spectroscopic methods. The contributions of these four isolated BNI compounds (1–4) to the hydrophobic BNI activity in maize roots were 19%, 20%, 2%, and 4%, respectively. A possible biosynthetic pathway for zeanone (1) is proposed. These results provide insights into the strength of hydrophobic BNI activity released from maize root systems, the chemical identities of the isolated BNIs, and their relative contribution to the BNI activity from maize root systems.

scholarly journals MINERAL NUTRITION OF CRISPHEAD LETTUCE GROWN IN A HYDROPONIC SYSTEM WITH BRACKISH WATER

2016 ◽  
Vol 29 (3) ◽  
pp. 656-664 ◽  
Author(s):  
HAMMADY RAMALHO E SOARES ◽  
ÊNIO FARIAS DE FRANÇA E SILVA ◽  
GERÔNIMO FERREIRA DA SILVA ◽  
RAQUELE MENDES DE LIRA ◽  
RAPHAELA REVORÊDO BEZERRA
Keyword(s):  
Nutrient Solution ◽  
Mineral Nutrition ◽  
Brackish Water ◽  
Water Source ◽  
Water Salinity ◽  
Hydroponic System ◽  
Foliar Phosphorus ◽  
Solution Preparation ◽  
Phosphorus And Potassium ◽  
Local Water

ABSTRACT Water availability in the Brazilian semiarid is restricted and often the only water source available has high salt concentrations. Hydroponics allows using these waters for production of various crops, including vegetables, however, the water salinity can cause nutritional disorders. Thus, two experiments were conducted in a greenhouse at the Department of Agricultural Engineering of the Federal Rural University of Pernambuco, to evaluate the effects of salinity on the mineral nutrition of crisphead lettuce, cultivar Taina, in a hydroponic system (Nutrient Film Technique), using brackish water in the nutrient solution, which was prepared by adding NaCl to the local water (0.2 dS m-1). A randomized blocks experimental design was used in both experiments. The treatments consisted of water of different salinity levels (0.2, 1.2, 2.2, 3.2, 4.2 and 5.2 dS m-1) with four replications, totaling 24 plots for each experiment. The water added to compensate for the water - depth loss due to evapotranspiration (WCET) was the brackish water of each treatment in Experiment I and the local water without modifications in Experiment II. The increase in the salinity of the water used for the nutrient solution preparation reduced the foliar phosphorus and potassium contents and increased the chloride and sodium contents, regardless of the WCET. Foliar nitrogen, calcium, magnesium and sulfur contents were not affected by increasing the water salinity used for the nutrient solution preparation.

scholarly journals Growth and mineral nutrition of Solanum americanum

2010 ◽  
Vol 28 (2) ◽  
pp. 293-299 ◽  
Author(s):  
S. Bianco ◽  
L.B. Carvalho ◽  
M.S. Bianco
Keyword(s):  
Experimental Design ◽  
Nutrient Solution ◽  
Mineral Nutrition ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Perennial Crops ◽  
Greenhouse Trial ◽  
Matter Production ◽  
Solanum Americanum ◽  
Experimental Stage

A greenhouse trial was carried out from November 1995 to April 1996 at FCAV/UNESP, Brazil, aiming to study the dry matter production and the accumulation and distribution of macronutrients in Solanum americanum, an important weed for annual and perennial crops in Brazil. The plants were grown in seven liter pots with sand substrate, irrigated daily with Hoagland & Arnon nutrient solution. The experimental design was completely randomized with four replicates. The treatments corresponded to evaluation times at 14 day intervals, beginning 21 days after emergence (DAE). In each evaluation, the plants of four pots were analyzed for dry matter production and macronutrient content. S. americanum had a small dry matter and macronutrient accumulation at the beginning of the experimental stage, increasing after 77 DAE and reaching the maximum theoretical value at 142, 142, 164, 149, 140, 149 and 152 DAE, for dry matter, N, P, K, Ca, Mg, and S, respectively. K and N were the most accumulated macronutrients for S. americanum plants.

scholarly journals Water and phosphorus uptake by upland rice root systems unraveled under multiple scenarios: linking a 3D soil-root model and data

2020 ◽  
Author(s):  
Trung Hieu Mai ◽  
Pieterjan De Bauw ◽  
Andrea Schnepf ◽  
Roel Merckx ◽  
Erik Smolders ◽  
...  
Keyword(s):  
Upland Rice ◽  
Phosphorus Uptake ◽  
Root Systems ◽  
Multiscale Model ◽  
P Uptake ◽  
Water Dynamics ◽  
Small Scale ◽  
P Availability ◽  
P Deficiency ◽  
Plant P Uptake

AbstractBackground and aimsUpland rice is often grown where water and phosphorus (P) are limited and these two factors interact on P bioavailability. To better understand this interaction, mechanistic models representing small-scale nutrient gradients and water dynamics in the rhizosphere of full-grown root systems are needed.MethodsRice was grown in large columns using a P-deficient soil at three different P supplies in the topsoil (deficient, suboptimal, non-limiting) in combination with two water regimes (field capacity versus drying periods). Root architectural parameters and P uptake were determined. Using a multiscale model of water and nutrient uptake, in-silico experiments were conducted by mimicking similar P and water treatments. First, 3D root systems were reconstructed by calibrating an architecure model with observed phenological root data, such as nodal root number, lateral types, interbranch distance, root diameters, and root biomass allocation along depth. Secondly, the multiscale model was informed with these 3D root architectures and the actual transpiration rates. Finally, water and P uptake were simulated.Key resultsThe plant P uptake increased over threefold by increasing P and water supply, and drying periods reduced P uptake at high but not at low P supply. Root architecture was significantly affected by the treatments. Without calibration, simulation results adequately predicted P uptake, including the different effects of drying periods on P uptake at different P levels. However, P uptake was underestimated under P deficiency, a process likely related to an underestimated affinity of P uptake transporters in the roots. Both types of laterals (i.e. S- and L-type) are shown to be highly important for both water and P uptake, and the relative contribution of each type depend on both soil P availability and water dynamics. Key drivers in P uptake are growing root tips and the distribution of laterals.ConclusionsThis model-data integration demonstrates how multiple co-occurring single root phene responses to environmental stressors contribute to the development of a more efficient root system. Further model improvements such as the use of Michaelis constants from buffered systems and the inclusion of mycorrhizal infections and exudates are proposed.

scholarly journals Comparison of Root System Morphology of Cucurbit Rootstocks for Use in Watermelon Grafting

2018 ◽  
Vol 28 (5) ◽  
pp. 629-636 ◽  
Author(s):  
Matthew B. Bertucci ◽  
David H. Suchoff ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Christopher C. Gunter ◽  
...  
Keyword(s):  
Root System ◽  
Surface Area ◽  
Root Length ◽  
Dry Weight ◽  
Root Systems ◽  
Root Surface ◽  
Root Diameter ◽  
Root Surface Area ◽  
Diameter Class ◽  
Main Effect

Grafting of watermelon (Citrullus lanatus) is an established production practice that provides resistance to soilborne diseases or tolerance to abiotic stresses. Watermelon may be grafted on several cucurbit species (interspecific grafting); however, little research exists to describe root systems of these diverse rootstocks. A greenhouse study was conducted to compare root system morphology of nine commercially available cucurbit rootstocks, representing four species: pumpkin (Cucurbita maxima), squash (Cucurbita pepo), bottle gourd (Lagenaria siceraria), and an interspecific hybrid squash (C. maxima × C. moschata). Rootstocks were grafted with a triploid watermelon scion (‘Exclamation’), and root systems were compared with nongrafted (NG) and self-grafted (SG) ‘Exclamation’. Plants were harvested destructively at 1, 2, and 3 weeks after transplant (WAT), and data were collected on scion dry weight, total root length (TRL), average root diameter, root surface area, root:shoot dry-weight ratio, root diameter class proportions, and specific root length. For all response variables, the main effect of rootstock and rootstock species was significant (P < 0.05). The main effect of harvest was significant (P < 0.05) for all response variables, with the exception of TRL proportion in diameter class 2. ‘Ferro’ rootstock produced the largest TRL and root surface area, with observed values 122% and 120% greater than the smallest root system (‘Exclamation’ SG), respectively. Among rootstock species, pumpkin produced the largest TRL and root surface area, with observed values 100% and 82% greater than those of watermelon, respectively. These results demonstrate that substantial differences exist during the initial 3 WAT in root system morphology of rootstocks and rootstock species available for watermelon grafting and that morphologic differences of root systems can be characterized using image analysis.

Influence of Tylenchorhynchus ewingi on growth of loblolly pine seedlings, and host suitability of legumes and small grains

Nematology ◽  
2012 ◽  
Vol 14 (4) ◽  
pp. 417-425 ◽  
Author(s):  
Stephen W. Fraedrich ◽  
Michelle M. Cram ◽  
Zafar A. Handoo ◽  
Stanley J. Zarnoch
Keyword(s):  
Pearl Millet ◽  
Loblolly Pine ◽  
Cover Crops ◽  
Root Systems ◽  
Forest Tree ◽  
Initial Population ◽  
Severe Damage ◽  
Pine Seedlings ◽  
Small Grains ◽  
Production Losses

Tylenchorhynchus ewingi, a stunt nematode, causes severe injury to slash pine seedlings and has been recently associated with stunting and chlorosis of loblolly pine seedlings at some forest tree nurseries in southern USA. Experiments confirmed that loblolly pine is a host for T. ewingi, and that the nematode is capable of causing severe damage to root systems. Initial population densities as low as 60 nematodes (100 cm3 soil)−1 were sufficient to damage the root systems of loblolly pine seedlings. Populations of T. ewingi increased on pine from two- to 16-fold, depending on the initial population density. Evaluations of various cover crops used in southern forest tree nurseries indicated that legumes, rye and several varieties of sorghum were excellent hosts for T. ewingi. Other small grains such as ryegrass, oats and wheat were poorer hosts. A cultivar of pearl millet was a non-host for T. ewingi, and a cultivar of brown top millet appeared to be either a very poor host or a non-host. Nurseries that have seedling production losses caused by T. ewingi should consider rotating with non-host cover crops such as pearl millet or leaving fields fallow as part of their pest management programme.

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