Hair root

Various techniques for collection of root exudates are associated with the risk of root injury by rupture of root hairs and epidermal cells or rapid change of the environmental conditions (e.g., temperature, pH, oxygen availability) during transfer of root systems into trap solutions, application of absorbtion materials onto the root surface, and preparation of root systems for exudate collection. The possible impact of those stress treatments may be assessed by measuring parameters of plant growth in plants either. subjected or not subjected to the collection procedure (6) and by comparing exudation patterns after exposure of roots to the handling procedures with different intensity. 

Polyvinyl chloride cylinders -1- nylon gauze -1- device for continuous water supply Soil slices at measurable distance from soil-root interface. High bulk density of soil sampled. Nutrient uptake through an induced root hairs surface. Study of rhizosphere effect over a time and distance gradient from the soil-root interface. 47, 67, 127-129... 

Z. Banfalvi and A. Kondorosi, Production of root hair deformation factors by Rhizohium meliloti nodulation genes in Escherichia coli H.mD (NocM) is involved in the plant host-specific modification of the NodABS-factor. Plant Mol. Biol. 13 1 (1989). 

T. Beguiristain and F. Lapeyrie, Host plant stimulates hypaphorine accumulation in Pisolithus tinctorius hyphae during ectomycorrhizal infection while excreted fungal hypaphorine controls root hair development. New Phytol. 136 525 (1997). 

The classic Barber-Cushman model treats the root surface as a smooth solid cylinder. Yet many experimental studies have shown that root hairs are important for the uptake of some nutrients, e.g., P (25,26). Various mathematical models for root hairs have been used (5,27,28), which all differ slightly in the way in which root hairs are modeled. Most authors conclude that root hairs make a substantial contribution to uptake, particularly for relatively immobile nutrients. 

T. S. Gahoonia, D. Care, and N. E. Nielsen, Root hairs and phosphorus acquisition of wheat and barley cultivars. Plant Soil 797 181 (1997). 

S. Itoh and S. A. Barber. A numerical solution of whole plant uptake for soil-root uptake including root hairs. Plant Soil 70 403 (1983). 

J. S. Gcelhoed. L. J. M. Sipko, and G. R. Findernegg, Modelling zero sink nutrient uptake by roots with root hairs from. soil compari.son of two models. Soil Sci. 162 544 (1997). 

In addition to reduction in root length, seedlings exposed to all concentrations of polar peak 1B displayed both an increase in root hairs and chlorosis at the tips of the cotyledons. The severity of these symptoms increased with the dosage. 

Goedhart, J, Hink, M. A, Visser, A. J, Bisseling, T. and Gadella, T. W, Jr. (2000). In vivo fluorescence correlation microscopy (FCM) reveals accumulation and immobilization of Nod factors in root hair cell walls. Plant J. 21, 109-19. 

Wymer, C. L., Bibikova, T. N. and Gilroy, S. (1997). Cytoplasmic free calcium distributions during the development of root hairs of Arabidopsis thaliana. Plant J. 12, 427-39. 

Observations Figure 2 shows confocal images of 48 h tomato roots exposed to S. deppei aqueous leachate and then stained with DCFDA. A higher fluorescence is observed in treated-root hairs. 

The content of total and individual ginsenosides does not only vary between plant organs and species. In particular, the content of ginsenosides in ginseng roots also depends on growing conditions and age of the roots, and internal root size (root hairs, lateral roots, and main roots) (Christensen et al, 2006 Court et ah, 1996b Soldati and Tanaka, 1984 Wills and Stuart, 2001). 

TABLE 1.2 The content of ginsenosides (mg/kg fresh weight) in different root sections [diameter 0.5-2.5 mm (root hairs) 5.0-10.0 mm (lateral) 15.0-20.0 and >20.0-38.0 mm (main roots)] of fresh roots from 6-year-old Panax quinquefolium (American ginseng) plants grown in Denmark (Christensen et ai, 2006)... 

FIGURE 1.9 Ginseng roots from 6-year-old American ginseng plants (Panax quinquefo-lium) grown in Denmark with root hairs, lateral roots, and main roots. Ginseng roots within the same species may not only differ in content of ginsenosides but also in root size. 

---