scholarly journals Modeling Root Zone Effects on Preferred Pathways for the Passive Transport of Ions and Water in Plant Roots

2016 ◽  
Vol 7 ◽  
Author(s):  
Kylie J. Foster ◽  
Stanley J. Miklavcic
Keyword(s):  
Root Zone ◽  
Plant Roots ◽  
Passive Transport ◽  
Transport Of Ions

scholarly journals Effect of Nematodes on Rhizosphere Colonization by Seed-Applied Bacteria

2004 ◽  
Vol 70 (8) ◽  
pp. 4666-4671 ◽  
Author(s):  
Oliver G. G. Knox ◽  
Ken Killham ◽  
Rebekka R. E. Artz ◽  
Chris Mullins ◽  
Michael Wilson
Keyword(s):  
Pseudomonas Fluorescens ◽  
Water Flow ◽  
Soil Biota ◽  
Plant Roots ◽  
Soil Nematodes ◽  
Passive Transport ◽  
Commercial Products ◽  
Rhizosphere Colonization ◽  
Physical Conditions ◽  
Bacterial Movement

ABSTRACT There is much interest in the use of seed-applied bacteria for biocontrol and biofertilization, and several commercial products are available. However, many attempts to use this strategy fail because the seed-applied bacteria do not colonize the rhizosphere. Mechanisms of rhizosphere colonization may involve active bacterial movement or passive transport by percolating water or plant roots. Transport by other soil biota is likely to occur, but this area has not been well studied. We hypothesized that interactions with soil nematodes may enhance colonization. To test this hypothesis, a series of microcosm experiments was carried out using two contrasting soils maintained under well-defined physical conditions where transport by mass water flow could not occur. Seed-applied Pseudomonas fluorescens SBW25 was capable of rhizosphere colonization at matric potentials of −10 and −40 kPa in soil without nematodes, but colonization levels were substantially increased by the presence of nematodes. Our results suggest that nematodes can have an important role in rhizosphere colonization by bacteria in soil.

scholarly journals Root-associated microbiomes of wheat under the combined effect of plant development and nitrogen fertilization

Microbiome ◽  
2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Shuaimin Chen ◽  
Tatoba R. Waghmode ◽  
Ruibo Sun ◽  
Eiko E. Kuramae ◽  
Chunsheng Hu ◽  
...  
Keyword(s):  
Community Structure ◽  
Plant Growth ◽  
Microbial Communities ◽  
Root Zone ◽  
N Fertilization ◽  
Plant Roots ◽  
Growth Stages ◽  
Ripening Stages ◽  
N Input

Abstract Background Plant roots assemble microbial communities both inside the roots and in the rhizosphere, and these root-associated microbiomes play pivotal roles in plant nutrition and productivity. Although it is known that increased synthetic fertilizer input in Chinese farmlands over the past 50 years has resulted in not only increased yields but also environmental problems, we lack a comprehensive understanding of how crops under elevated nutrient input shape root-associated microbial communities, especially through adjusting the quantities and compositions of root metabolites and exudates. Methods The compositions of bacterial and fungal communities from the roots and rhizosphere of wheat (Triticum aestivum L.) under four levels of long-term inorganic nitrogen (N) fertilization were characterized at the tillering, jointing and ripening stages. The root-released organic carbon (ROC), organic acids in the root exudates and soil organic carbon (SOC) and soil active carbon (SAC) in the rhizosphere were quantified. Results ROC levels varied dramatically across wheat growth stages and correlated more with the bacterial community than with the fungal community. Rhizosphere SOC and SAC levels were elevated by long-term N fertilization but varied only slightly across growth stages. Variation in the microbial community structure across plant growth stages showed a decreasing trend with N fertilization level in the rhizosphere. In addition, more bacterial and fungal genera were significantly correlated in the jointing and ripening stages than in the tillering stage in the root samples. A number of bacterial genera that shifted in response to N fertilization, including Arthrobacter, Bacillus and Devosia, correlated significantly with acetic acid, oxalic acid, succinic acid and tartaric acid levels. Conclusions Our results indicate that both plant growth status and N input drive changes in the microbial community structure in the root zone of wheat. Plant growth stage demostrated a stronger influence on bacterial than on fungal community composition. A number of bacterial genera that have been described as plant growth-promoting rhizobacteria (PGPR) responded positively to N fertilization, and their abundance correlated significantly with the organic acid level, suggesting that the secretion of organic acids may be a strategy developed by plants to recruit beneficial microbes in the root zone to cope with high N input. These results provide novel insight into the associations among increased N input, altered carbon availability, and shifts in microbial communities in the plant roots and rhizosphere of intensive agricultural ecosystems.

scholarly journals Produksi Benih Kentang Sistem Aeroponik dan Root Zone Cooling dengan Pembedaan Tekanan Pompa di Dataran Rendah

2017 ◽  
Vol 44 (3) ◽  
pp. 299
Author(s):  
Eni Sumarni ◽  
Arief Sudarmaji ◽  
Herry Suhardiyanto ◽  
Dan Satyanto Krido Saptomo
Keyword(s):  
Potato Tuber ◽  
Root Zone ◽  
Block Design ◽  
Plant Roots ◽  
Growth And Yield ◽  
Potato Tubers ◽  
Orthogonal Contrasts ◽  
Cooling Temperature ◽  
Randomized Block Design ◽  
Pump Pressure

<p>ABSTRACT<br /><br />Nutrition  pumps  pressure is important in aeroponic. Optimal  pump  pressure produces well oxygenation, so that increases the dissolved oxygen content in the nutrition. It is good for plant roots. The purpose of this study was to determine pump pressure on the growth and yield  potato seeds grown in aeroponics in lowland 125 m asl with root zone cooling. This study used a randomized block design non factorial. Data were analyzed using analysis of variance followed by a further test of orthogonal contrasts at the level of α = 5%. Results showed that different pump pressure on the provision of nutrient, temperature cooling in the root zone gave different results on the number of potato tubers per plant and weight per tuber in each variety. Root zone cooling temperature 15 °C, the pump pressure&gt; 1.5 atm produce highest number of tubers per plant, i.e. 11.8 tuber of Granola variety and 8.2 tuber of Atlantic variety.  The was no tuber produced from control (without referigeration). The highest weights per tuber (10.35 and 5.01 g for Atlantic and Granola variety, respectively) were reached with cooling temperature at 15 °C and the pump pressure &gt; 1.5 atm.<br /><br />Keywords: evaporative cooling, hydroponics, potato, tuber, variety     <br /><br /></p>

Active and passive transport of ions in erythrocyte membranes under the influence of low temperatures

Cryobiology ◽  
1978 ◽  
Vol 15 (6) ◽  
pp. 706
Author(s):  
A.K. Gulevski ◽  
V.I. Lugovoi ◽  
N.R. Guseva ◽  
G.F. Zhegunov ◽  
L.N. Kuzmina ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Erythrocyte Membranes ◽  
Passive Transport ◽  
Transport Of Ions

scholarly journals Accumulation and dynamics of manganese in raspberry

2019 ◽  
Vol 113 (2) ◽  
pp. 221
Author(s):  
Senad MURTIĆ ◽  
Emir ŠAHINOVIĆ ◽  
Hamdija ČIVIĆ ◽  
Emina SIJAHOVIĆ
Keyword(s):  
Atomic Absorption Spectroscopy ◽  
Manganese Oxides ◽  
Scientific Literature ◽  
Root Zone ◽  
Ph Value ◽  
Ore Deposits ◽  
Plant Roots ◽  
Food Crops ◽  
Manganese Ore ◽  
Good Ability

<p>The aim of this study was to evaluate the dynamics of Mn in ‘soil - raspberry’ system on the area around the manganese ore deposits Radostovo in Bužim municipality. Atomic absorption spectroscopy was used to determine the concentration of Mn in soil and plant samples. Fe, Zn and Cu concentration in soil and raspberry plants was also subject of analysis, since these elements have antagonistic relationship with Mn in soils. The concentration of available Mn in soils was low, although the total Mn in the same soils exceeded the Mn toxic values noted in the scientific literature. The chemical and physical properties of the examined soils characterized by a relatively high pH value and good ability to store root-zone air certainly contributed to the decreasing release of available Mn<sup>2+</sup> from manganese oxides in soils as well as Mn<sup>2+</sup> oxidation to insoluble Mn<sup>3+</sup> or Mn<sup>4+</sup> ions, resulting in low uptake of Mn by plant roots. The results of study also showed that the absorbed Mn mostly accumulates in leaves and roots of raspberry, and much less in the stem and fruits. That rule in Mn distribution within raspberry plant is in fact identical to all food crops.</p>

EFFECT OF PLANT ROOTS ON CHEMICAL AND BIOCHEMICAL PROPERTIES OF SURROUNDING DISCRETE SOIL ZONES

1988 ◽  
Vol 68 (2) ◽  
pp. 233-242 ◽  
Author(s):  
J. F. DORMAAR
Keyword(s):  
Root Zone ◽  
Chemical Properties ◽  
Outer Zone ◽  
Bouteloua Gracilis ◽  
Biochemical Properties ◽  
Plant Roots ◽  
Grass Species ◽  
Detailed Knowledge ◽  
Blue Grama ◽  
Wheat Field

The chemical and biochemical properties within and immediately adjacent to the root zone of two grass species were studied over a 5-wk period. The experiment utilized a simple container comprising five sandwiched compartments giving a center or "rhizosphere" zone, two intermediate zones, and two outer zones. Soil samples were taken from an Orthic Brown, Dark Brown, and Black Chernozemic Ah horizon and from the Orthic Dark Brown Chernozemic Ap horizons of the unfertilized part of a continuous wheat field and the fallow field of a wheat-fallow rotation, both under cultivation for 70 yr. The two grasses were blue grama (Bouteloua gracilis (H.B.K.) Lag.) and rye (Secale céréale L. 'Frontier'). High root densities were achieved by the end of the study, especially with the blue grama. Changes in pH over time were slight but consistent; they decreased in the Black Chernozemic soil and increased in the other soils. A redistribution of labile phosphorus was caused by the presence of the plant roots. The Orthic Dark Brown Ah and Ap horizon soils reacted differently to the conditions of the study. Monosaccharides always increased in the rhizosphere zone and generally decreased in the zone adjacent to the rhizosphere zone in the case of rye and in the outside zone in the case of blue grama. The ratio galactose + mannose/arabinose + xylose always increased towards the outer zone. Although the presence of roots influenced the measured chemical properties of the soil surrounding them, there were no overall common trends. The results, even in this simplified system, demonstrated complex and interrelated effects (P < 0.01) of soil type, plant species, and time on the biochemical dynamics in and near the rhizosphere. The properties of rhizosphere soil are system specific. To interpret the processes within the system, detailed knowledge of the soil organic matter, the physiology of the species root, and the effect on each other is obligatory. Key words: Rhizosphere, Chernozemic Ah/Ap horizons, blue grama, rye, monosaccharides

PHOSPHATE-DISSOLVING MICROORGANISMS ON SEED AND IN THE ROOT ZONE OF PLANTS

1962 ◽  
Vol 40 (9) ◽  
pp. 1181-1186 ◽  
Author(s):  
H. Katznelson ◽  
E. A. Peterson ◽  
J. W. Rouatt
Keyword(s):  
Strong Evidence ◽  
Root Zone ◽  
Red Clover ◽  
Crop Plants ◽  
Plant Roots ◽  
Selective Effect ◽  
Cereal Seed ◽  
Percentage Incidence

A high proportion (40–70%) of the bacteria on most of the seed tested solubilized phosphate precipitated in agar; flax and red clover were two striking exceptions with 11% and 24% respectively. The percentage incidence of these bacteria was considerably lower on the roots and in the rhizosphere of four out of the five crop plants studied than on their seed, being in the order of 10%. There was no strong evidence of a selective effect of plant roots on these organisms although barley appeared to favor them and oats to repress them somewhat.Phosphate-dissolving fungi were readily isolated from seed and plant roots. Cereal seed carried surprisingly few such fungi whereas grasses and clover had greater numbers. The phosphate-dissolving fungi isolated most frequently were species of Penicillium, Aspergillus, and Rhizopus; in addition, Candida, Oidiodendron, and Pseudogymnoascus species were isolated from roots and root-free soil.

On the structural organization of biological pumps and channels

1984 ◽  
Vol 42 ◽  
pp. 138-141
Author(s):  
G. Zampighi ◽  
M. Kreman
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Plasma Membranes ◽  
Transport Proteins ◽  
Molecular Organization ◽  
Passive Transport ◽  
Concentration Gradients ◽  
Cell Functions ◽  
Natural Concentration ◽  
Active Transport System

The plasma membranes of most animal cells contain transport proteins which function to provide passageways for the transported species across essentially impermeable lipid bilayers. The channel is a passive transport system which allows the movement of ions and low molecular weight molecules along their concentration gradients. The pump is an active transport system and can translocate cations against their natural concentration gradients. The actions and interplay of these two kinds of transport proteins control crucial cell functions such as active transport, excitability and cell communication. In this paper, we will describe and compare several features of the molecular organization of pumps and channels. As an example of an active transport system, we will discuss the structure of the sodium and potassium ion-activated triphosphatase [(Na+ +K+)-ATPase] and as an example of a passive transport system, the communicating channel of gap junctions and lens junctions.

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