Root architecture

These plant responses are largely controlled by the internal status of plant (40). On the other hand, it has been shown that the occurrence of nutrient-rich patches in the soil can trigger changes in root architecture and also in the capacity for nutrient acquisition (46,47). Recent results indicate that this behavior is dependent not only on internal (metabolic) signals but also on the capacity to sense... 

H. Zhang, and B. G. Forde, An Arabidopsis MADS box gene that controls nutrient-induced changes in root architecture. Science 279 401 (1998). 

J. Lynch, Root architecture and plant productivity. Plant Phy.siol. 109 1 (1995). 

G. M. Bernston, Modelling root architecture are there tradeoffs between efficiency and potential of resource acquisition New Phyiol. /27 483 (1994). 

Such an analysis indicates that the zero-sink assumption must be used with extreme caution if accurate flux calculations are required at the local root level. Potassium, for example, is close to the limiting value of A, for the zero sink assumption to be fulfilled, and simulations with larger roots or larger buffer powers could well lead to inaccurate simulation results. Any zero-sink model involving nitrate should be treated with some suspicion. The zero-sink assumption is also widely used in root architecture models (see later). 

Figure 11 Root systems as simulated by the computer program Simroot. The systems display herriitgbone architecture (a) dichotomous architecture (b) and bean root architecture (c). The bean root system (c) is shown in

Kirk GJD, Le van Du. 1997. Changes in rice root architecture, porosity, and oxygen and proton release under phosphorus deficiency. New Phytologist 135 191-200. 

Evaluating and exploiting gene bank material can be of use because required characteristics might have disappeared by selection under modern, high input conditions, such as low-input tolerance and deep or intensive root architecture (Foulkes et al. 1998 De Melo 2003). This is a relatively low cost method to develop valuable accessions. 

Lopez-Bucio, J., Cruz-Ramrrez, A., and Herrera-Estrella, L. (2003).The role of nutrient availability in regulating root architecture. Curr. Opin. Plant Biol. 6, 280-287. 

Schwartz, C., Morel, J. L., Saumier, S., Whiting, S. N., and Baker, A. J. M. (1999). Root architecture of the Zn-hyperaccumulator plant Thlaspi caerulescens as affected by metal origin, content and localisation in soil. Plant Soil 208, 103-115. 

Especially the dependence on the mineralisation dynamics of a low-input of slow-releasing organic stable or green manure makes the nutrient flow in different soils less controllable, and requires varieties adapted to such soil fertility management. Deep, intensive root architecture may contribute to a more efficient capturing of water and nutrients (Lees and Gahoonia, 2004). Experiments have also shown that varieties may differ in efficiency of nutrient uptake and use (Baresel et al., 2005). The ability to interact with beneficial soil micro-organisms can support this efficiency (Bosco et al., 2006). 

SLs have been shown to regulate not only shoot but also root architecture by controlling lateral root formatiOTi and root-hair elongation in a MAX2 dependent manner [12-14,89]. As in the regulation of shoot architecture, SL-auxin cross talk seems to be involved in these root responses. 

Role as cancer preventive agents, 3448 The Role of cytokinins in planta, 969 The Role of purine alkaloids in Planta, 965 Rol genes, 2774, 2948 Root architecture, 3585 ROOTec bioactives Ltd, 2779 Root exudates, 1566... 

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