Wheat roots

After this, we demonstrated the ability of wheat anionic POs to bind to the chitin of the cell walls of fungal pathogens. We called these POs "chitin-binding POs" (Maksimov et al., 2003). We were the first to demonstrate the binding of the anionic PO of wheat root to chitin (Maksimov et al., 1994). Besides this, we observed that in some species the activity of POs was increased in the unbound Armoracia rustkana, Lagenaria siceraria) or eluted Pisum sativum, Galega orientalis, Brassica oleraceae) fractions of proteins after interaction with chitin. 

Fig. 6. Effect of the degree of chitin acetylation (%) on the interaction between chitin and chitin-specific wheat POs (A) (U/ mg protein) (Maksimov et al., 2005) (B) PAAG after lEF of PO fractions from wheat roots (a) not bound to high-acetylated (b) and low-acetylated chitosan (c) (Khairullin et al., 2000). Designations (1) 12% (2) 23% (3) 37% (4) 45% (5) 65%.

Fig. 7. PAAG densitogram after lEF of the PO fraction of wheat roots absorbed by the...

Pritchard, J., Tomos, A.D. Wyn Jones, R.G. (1987). Control of wheat root elongation growth. I. Effects of ions on growth rate, wall rheology and cell water relations. Journal of Experimental Botany, 38, 948-59. 

Table 4. Wheat root seedling elongation (30 replicates), tip turgor pressure (4 mm, >10 replicates) and tip tensiometric plasticity (2-7 mm, >10 replicates) following various growth altering treatments...

Fig. 1. Decline in tensiometric extensibility of live wheat root tips (2-7 mm) following excision from the plant. Each point is the mean of 10 determinations performed on methanol-killed tissue.

Tao, S. et al.. Use of sequential ASE extraction to evaluate the bioavailabdity of DDT and its metabolites to wheat roots in soils with various organic carbon contents, Sci. Total Environ., 320, 1, 2004. 

Maurhofer M, E Baehler, R Nitz, V Martinez, C Keel (2004) Cross talk between 2,4-diacetylphloroglucinol-producing biocontrol pseudomonads on wheat roots. Appl Environ Microbiol 70 1990-1998. 

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P. R. Ryan, E. Delhaize, and P. J. Randall, Characterization of Al-stimulated efflux of malate from the apices of Al-tolerant wheat roots. PUmui 796 103 (1995). 

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J. W. L. Van Vuurde and B. Schippers, Bacterial colonisation of seminal wheat roots. Soil Biology and Biochemistiy 12 559 (1980). 

E. Slesak and J. Jurek, Effects of potassium humate on electric potentials of wheat roots. Acta Univ. Wrati.sl. 37 13 (1988). 

G. Concheri, S. Nardi, F. Reniero, and G. Dell Agnola, The effects of humic substances within the Ah horizon of a calcic luvisol on morphological changes related to invertase and peroxidase activities in wheat roots. Plant Soil 179 65 (1996). 

The recent report of wave-like patterns of bacteria and water soluble carbon associated with wheat roots (58) which were not strongly correlated with each other or with lateral root formation pose a challenge for models. So do the reports of highly dynamic and erratic population fluctuations of individual pseudomonad clones on sugar beet roots (59). 

Z. Rengel, G. Ross, and P. Hinsch, Plant genotype and micronutrient status influence colonization of wheat roots by soil bacteria. J. Plain Niilr. 21 99 (1998). 

B. M. McDougall. and A. D. Rovira, Sites of exudation of C-labelled compounds from wheat roots. New Phyiol. 69 999 (1970). 

T. Katterer, A-C. Hansson, and O. Andren, Wheat root biomass and nitrogen dynamics—effects of daily irrigation and fertili.sation. Plant Soil 151 21 (1993). 

Fester, T., W. Maier et al. (1999). Accumulation of secondary compounds in barley and wheat roots in response to inoculation with an arbuscular mycorrhizal fungus and co-inoculation with rhizosphere bacteria. Mycorrhiza 8(5) 241-246. 

Wheat root Al, Si and others Aluminum/silicon interactions (52)... 

Zhu, Y.G., Shaw, G., Nisbet, A.F., and Willkins, B.T., 1999, Effect of external potassium supply on compartmentation and flux characteristics of radiocaesium in intact spring wheat roots. Ann. Bot. 84 639-644. 

Two cases will be presented to illustrate the difficulty in establishing allelopathy and in linking the agent to poor crop growth. Specifically, the role of phenolic acids and the role of toxin-producing pseudomonads colonizing wheat roots will be examined. 

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