A Nutrient Requirement for Optimum Water Absorption by Intact Root Systems

Nature ◽  
1963 ◽  
Vol 199 (4888) ◽  
pp. 93-94 ◽  
Author(s):  
D. H. DREW
Keyword(s):  
Water Absorption ◽  
Root Systems ◽  
Nutrient Requirement ◽  
Intact Root ◽  
Optimum Water

Conversaziones 1974

1975 ◽  
Vol 29 (2) ◽  
pp. 163-171
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Cell Walls ◽  
Structural Changes ◽  
Vascular Tissue ◽  
Root Systems ◽  
Plant Roots ◽  
Tracer Studies ◽  
Water Move ◽  
Intact Root

CONVERSAZIONES were held this year on 9 May and 27 June. At the first conversazione twenty-seven exhibits and two films were shown. The fine structure of plant roots in relation to transport of nutrient ions and water was demonstrated by Dr D. T. Clarkson of the A.R.C. Letcombe Laboratory, Wantage and Dr A. W. Robards of the Department of Biology, University of York. Two major pathways by which nutrients and water move radially across the cortex towards the central vascular tissue have been distinguished by the use of tracer studies of adsorption by different zones of intact root systems, microautoradiography and electron microscopy. Movement can be apoplastic through cell walls, or symplastic between cells joined by plasmodesmata. As the root ages, structural changes in the endodermis reduce movement in the former pathway but the symplast is not interrupted by the elaboration of endodermal walls because plasmodesmatal connexions remain intact. These observations help explain the contrasting extent to which different ions and water reach the shoot from young and mature parts of root systems.

scholarly journals Evidence of Association of Salmonellae with Tomato Plants Grown Hydroponically in Inoculated Nutrient Solution

2002 ◽  
Vol 68 (7) ◽  
pp. 3639-3643 ◽  
Author(s):  
Xuan Guo ◽  
Marc W. van Iersel ◽  
Jinru Chen ◽  
Robert E. Brackett ◽  
Larry R. Beuchat
Keyword(s):  
Nutrient Solution ◽  
Root Systems ◽  
Plant Roots ◽  
Tomato Plants ◽  
Agronomic Practices ◽  
Stems And Leaves ◽  
Pathogen Populations ◽  
Hoagland Nutrient Solution ◽  
Hydroponically Grown ◽  
Intact Root

ABSTRACT The possibility of uptake of salmonellae by roots of hydroponically grown tomato plants was investigated. Within 1 day of exposure of plant roots to Hoagland nutrient solution containing 4.46 to 4.65 log10 CFU of salmonellae/ml, the sizes of the pathogen populations were 3.01 CFU/g of hypocotyls and cotyledons and 3.40 log10 CFU/g of stems for plants with intact root systems (control) and 2.55 log10 CFU/g of hypocotyls and cotyledons for plants from which portions of the roots had been removed. A population of ≥3.38 log10 CFU/g of hypocotyls-cotyledons, stems, and leaves of plants grown for 9 days was detected regardless of the root condition. Additional studies need to be done to unequivocally demonstrate that salmonellae can exist as endophytes in tomato plants grown under conditions that simulate commonly used agronomic practices.

Soil and plant resistances to water absorption by plant root systems

1979 ◽  
Vol 30 (2) ◽  
pp. 279 ◽  
Author(s):  
GJ Burch
Keyword(s):  
Water Absorption ◽  
Root System ◽  
Soil Water ◽  
Water Movement ◽  
Plant Root ◽  
Unit Length ◽  
Water Flux ◽  
Soil Water Potential ◽  
Root Systems ◽  
Soil Resistance

A study of water absorption by root systems of two herbage species, white clover (Trifolium repens L.) and tall fescue (Festuca arundinacea Schreb.), was used to partition the resistances to water flux between the soil and plant. A large and almost constant plant resistance influenced the pattern of water absorption until the soil resistance reached about 1.5 x 103 MPa s cm-3. This corresponded to an extraction of almost 80% of the available soil water. Water absorption from progressively deeper soil layers showed no evidence of any substantial resistance to water flux through the root xylem. Therefore, in wet soils, water movement into and through a root system is predominantly influenced by a large resistance to the radial water flux through root tissues outside the xylem. The radial resistance values for unit (cm) length of root were 6.49 x 106 and 6.54 x 106 MPa s cm-2 for clover and fescue respectively. A model of water uptake has been described which introduces two modified parameters for integrating the soil water potential (ψ) and the soil-root conductance (κ), over an entire root system. This study, along with other evidence from the literature, would indicate that for unit length of root the radial resistance to water absorption is reasonably similar, not only for an entire root system but also for a number of different species. An underestimation of the radial soil resistance (Rsr) to water absorption suggests that a root contact resistance (Rc) exists which could be due to the shrinkage of the soil or root, or both, with drying of the soil. This effect caused an increase in resistance to water absorption of about 48 x Rsr for fescue and 71 x Rsr for clover. This difference in Rc between the two species was attributed to a contrast in root morphology, especially a difference in the average root diameters of the two species.

Root Absorption of Water and Physiological Responses to Water Deficits by Festuca arundinacea Schreb. And Trifolium repens L

1978 ◽  
Vol 5 (6) ◽  
pp. 859 ◽  
Author(s):  
GJ Burch ◽  
GG Johns
Keyword(s):  
Water Absorption ◽  
Root System ◽  
Soil Water ◽  
Water Uptake ◽  
Leaf Senescence ◽  
Soil Profile ◽  
Festuca Arundinacea ◽  
Physiological Responses ◽  
Root Systems ◽  
Two Parameters

A study of water uptake by white clover (Trifoliurn repens) and tall fescue (Festuca arundinacea cv. Demeter) examined their comparative physiological responses to water deficits and the pattern of water absorptioil by their root systems. Fescue had more deep roots than clover and extracted more water from deep soil layers, finally resulting in a drier soil profile. Poor control of leaf transpiration in clover resulted in low leaf water potentials and increased leaf senescence; in fescue, better stomatal control and higher leaf water potentials prolonged its period of active growth. The relationships between soil water content, transpiration rate and pattern of water absorption by both root systems were compared using an existing theory of water uptake. Two parameters for integrating soil water potential and soil conductance down the soil profile gave more consistent relationships with the transpiration rates of fescue than with those of clover. These two parameters may be less able to account for the pattern of soil water absorption by a clover root system and a possible explanation for this effect is discussed. Relative canopy conductance ratios gave similar relationships with the relative transpiration ratios for fescue and clover. Therefore, leaf senescence in clover was apparently important for balancing its rates of transpiration and water uptake. In contrast, fescue was able to rely upon its more extensive root system, effective stomatal control and ability to roll leaves to regulate its water balance.

A Method for Simulating Subsurface Disposal of Herbicides

Weed Science ◽  
1977 ◽  
Vol 25 (4) ◽  
pp. 368-372
Author(s):  
J.M. Cupello ◽  
A.L. Young ◽  
J.C.H. Smith
Keyword(s):  
Acetic Acid ◽  
Plant Height ◽  
Control Plant ◽  
Soil Layer ◽  
Root Systems ◽  
Butyl Esters ◽  
Phenoxy Herbicides ◽  
Dichlorophenoxy Acetic Acid ◽  
Subsurface Injection ◽  
Intact Root

Specially designed growth boxes were used to simulate field subsurface injection of phenoxy herbicides. Sorghum (Sorghum vulgarePers.) seedlings were grown in stainless steel containers (inserts) which were placed in plexiglass boxes containing a soil layer that had received 2,240 kg/ha of a 50:50 mixture of then-butyl esters of 2,4-D [(2,4-dichlorophenoxy)-acetic acid] and 2,4,5-T [(2,4,5-trichlorophenoxy)-acetic acid]. Plant height data were collected periodically for all treatments. Subsurface herbicide application to both intact and cut root systems significantly altered root growth. Plants with treated, intact root systems showed retarded growth which became more pronounced with time. Plants whose root systems were treated, and cut on day 22, showed an initial acceleration of growth; a trend which eventually reversed itself and resulted in control plant height exceeding that of treated plants.

scholarly journals A Wet Excavation Method for Root/Shoot Studies of Pearl Millet on the Sandy Soils of the Sahel

1994 ◽  
Vol 30 (3) ◽  
pp. 329-336 ◽  
Author(s):  
M. V. K. Sivakumar ◽  
S. A. Salaam
Keyword(s):  
Pearl Millet ◽  
Pennisetum Glaucum ◽  
Plant Root ◽  
Sandy Soils ◽  
Root Systems ◽  
Rooting Depth ◽  
Exponential Growth Rate ◽  
Promising Technique ◽  
Rapid Removal ◽  
Intact Root

SUMMARYRoot/shoot relations of two cultivars of pearl millet (Pennisetum glaucum) were studied on a sandy soil at Sadore in Niger using a wet excavation method. For the first 10 days after emergence (DAE), the length of the seminal root showed an exponential growth rate while plant height increased more or less linearly. The maximum rooting depth for millet was 168 cm and the maximum number of root axes and primary laterals, 172 per plant. Root length continued to increase up to 75 DAE, the maximum length exceeding 5000 cm per plant. The proportion of total day matter accumulated in the roots decreased from 30% in the early stages to less than 20% by maturity. The wet excavation method is a promising technique for the rapid removal of intact root systems of pearl millet from the sandy soils of the Sahel.

Sprouting capacity from intact root systems ofCirsium arvenseandSonchus arvensisdecrease in autumn

Weed Research ◽  
2013 ◽  
Vol 53 (3) ◽  
pp. 183-191 ◽  
Author(s):  
L Andersson ◽  
U Boström ◽  
J Forkman ◽  
I Hakman ◽  
J Liew ◽  
...  
Keyword(s):  
Root Systems ◽  
Sprouting Capacity ◽  
Intact Root

scholarly journals Mycorrhizal Influence on Transpiration Rates of Detached Leaves of Cowpea, Rose, and Geranium Exposed to Varying Levels of Abscisic Acid (ABA), pH, Calcium, and Phosphorus

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 647e-647
Author(s):  
Craig D. Green ◽  
Ann Stodola ◽  
Robert M. Augé
Keyword(s):  
Mycorrhizal Fungi ◽  
Root Systems ◽  
Residual Effects ◽  
Soil Drying ◽  
Chemical Signal ◽  
Test Species ◽  
Leaf Transpiration ◽  
Detached Leaves ◽  
Stomatal Sensitivity ◽  
Intact Root

Mycorrhizal colonization can alter stomatal behavior of host leaves during drought. This may be related to an altered production or reception of a chemical signal of soil drying. We tested whether intact root systems were required to observe a mycorrhizal effect on leaf transpiration (E), or whether some residual mycorrhizal influence on leaves could affect E of foliage detached from root systems. Transpiration assays were performed in the presence of several possible candidates for a chemical signal of soil drying. In detached leaves of Vigna unguiculata (cowpea), colonization interacted significantly with ABA and pH in regulating transpiration. Colonization affected E of detached Rosa hybrida (rose) leaves but had no effect on E of detached leaves of Pelargonium hortorum (geranium). In each species tested, increasing the ABA concentration decreased E. In cowpea, calcium appeared to alter stomatal sensitivity to ABA, as well as regulate stomatal activity directly. The pH of the feeding solution affected E in rose, but did not change E independently in cowpea or geranium. Adding phosphorus to the feeding solution did not alter E or the apparent sensitivity of stomata to ABA in any of the test species. Colonization of roots by mycorrhizal fungi can result in residual effects in detached leaves, that can alter the stomatal reception of chemical signals in both rose and cowpea.

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