scholarly journals The Interaction between Osmotic- and Pressure-induced Water Flow in Plant Roots

1975 ◽  
Vol 55 (5) ◽  
pp. 917-922 ◽  
Author(s):  
Edwin L. Fiscus
Keyword(s):  
Water Flow ◽  
Plant Roots

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.

Modeling water flow in cropped soils: Water uptake by plant roots

1995 ◽  
Vol 21 (5) ◽  
pp. 705-709 ◽  
Author(s):  
T.C. Janz ◽  
R.J. Stonier
Keyword(s):  
Water Flow ◽  
Water Uptake ◽  
Plant Roots

Interaction Between Plant Roots and Soil Water Flow in Response to Preferential Flow Paths in Northern China

2016 ◽  
Vol 28 (2) ◽  
pp. 648-663 ◽  
Author(s):  
Yinghu Zhang ◽  
Jianzhi Niu ◽  
Mingxiang Zhang ◽  
Zixing Xiao ◽  
Weili Zhu
Keyword(s):  
Soil Water ◽  
Water Flow ◽  
Preferential Flow ◽  
Northern China ◽  
Plant Roots ◽  
Flow Paths ◽  
Preferential Flow Paths ◽  
Soil Water Flow

scholarly journals The Action of Abscisic Acid on Ion Uptake and Water Flow in Plant Roots

1972 ◽  
Vol 25 (6) ◽  
pp. 1125 ◽  
Author(s):  
WJ Cram ◽  
MG Pitman
Keyword(s):  
Abscisic Acid ◽  
Water Flow ◽  
Ion Uptake ◽  
Plant Roots ◽  
Maximum Effect ◽  
Total Uptake ◽  
Maize Roots

Abscisic acid was shown to inhibit transport of potassium and chloride from the cut ends of excised barley and maize roots. Transport to the shoot of intact barley seedlings was also inhibited. Total uptake into the excised root of barley did not appear to be affected by abscisic acid. There was an increase in tracer accumulated in the root accompanying the reduction in transport from the cut end. Concentrations of abscisic acid above 10-6M produced the maximum effect.

Water Flow in Desert Soils Near Buried Waste Repositories

1999 ◽  
Author(s):  
A. W. Warrick ◽  
L. Pan
Keyword(s):  
Water Flow ◽  
Sand Dunes ◽  
National Research Council ◽  
Desert Soil ◽  
Plant Roots ◽  
Combined Processes ◽  
Simple Analytical Expression ◽  
Desert Soils ◽  
Chemical Wastes ◽  
Arid And Semiarid

Desert soils are frequently considered the safest choice for storing radioactive and chemical wastes (Winograd, 1974; National Research Council, 1976, 1995; Gee et al., 1992; IT Corporation, 1994). The reason is that nearly all rainwater that percolates into a desert soil is assumed to be taken up by plant roots and transpired back into the atmosphere. However, there is still recharge occurring in desert areas, although the magnitude of this recharge can vary greatly from one area to another (Rockhold et al., 1995). Therefore, proper siting of waste-disposal facilities is extremely important. This requires a good understanding of the factors that affect recharge and that minimize water flow through the waste layer. For a brief discussion of recharge in arid and semiarid regions, as well as an introduction to eight comprehensive papers on the topic, see Gee and Tyler (1994). This chapter has two major thrusts. The first part examines field measurements that have been made of the amounts of water that pass below the root zone to deeper depths in arid (and semiarid) environments. Also, some historical precipitation records are examined. The second part deals with modeling water flow in sloping, layered soils as might occur naturally or in cover designs that use capillary barriers. A simple analytical expression is presented for pressure-head distribution and diversion. This is followed by results from numerical modeling in order to test the effects of more complex boundary conditions, including steady versus nonsteady rainfall. Most rainwater that percolates into a desert soil is taken up by plant roots and transpired back into the atmosphere (Phillips, 1994). In addition, there is considerable surface evaporation. The combined processes of transpiration and evaporation, plus the lack of rainfall, cause desert soils to be dry most of the time. Furthermore, many of these soils are dry to great depths. However, not all desert soils are dry. Soils with minimal or no vegetation may contain considerably more water than soils with vegetation. Shifting sand dunes with deep, uniform sandy soils and minimal vegetation are often quite moist (Berndtsson and Chen, 1994).

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