Zea mays roots

COt concentrations have been rising steadily over the last 40 years and are expected to continue to rise, though the magnitude of the increase is uncertain (222). This could be expected to have important consequences for photosynthesis and hence exudation. However, Whipps (13) reported that the loss of a,ssimilated carbon from Zea mays roots was unaffected by atmospheric CO concentrations up to 1000 )il r. In contrast, Norby et al., (223) found that carbon allocation to roots and root exudation increased in Liriodendron tuUpifera grown in the presence of elevated CO levels. In Pimts echinata seedlings, there was increased exudation under elevated CO after 34 weeks but not after 41 weeks (224). 

Freeze etching of stelar tissue in Zea mays roots has demonstrated the association of globular complexes with the ends of nascent microfibrils. The results support a model for the synthesis of cellulose in which an enzyme complex in the granule adds D-glucopyranosyl residues to the developing end of a microfibril. The ultrastructure of the cellulosic network of the primary cell wall of pine wood and its development during the formation of tracheids have been studied by electron microscopy. ... 

Luster, D. G., and Buckout, T. J., 1988, Multiple electron transport activities in plasma membranes from maize Zea mays) roots, Physiol. Plant. 73 339-347. 

Fig. 6.4.3. Electron micrographs of suberized walls of Solarium tuberosum tuber periderm (1), bundle sheaths of Zea mays (courtesy of Dr. T.R O Brien) (2), the chalazal region of the inner seed coat of Citrus paradisi (3), hypodermis in Zea mays root grown in Mg -deficient medium (4), and idioblast from Agave americana leaf (5). Arrowheads, LS = lamellar suberin...

Stress seems to affect suberization. Salt stress due to mineral deficiencies can result in changes in suberization. For example, magnesium deficiency caused the hypodermis (Fig. 6.4.3) and endodermis of Zea mays roots to have more heavily suberized cell walls (372), whereas iron deficiency in Phaseolus vulgaris led to a drastic decrease in suberin deposition in the roots (412). Mechanical stress in the form of physical impedance to root growth caused increased suberization in the walls of endodermal cells of Hordeum vulgare roots (497). 

Clarkson D T, Robards A W, Stephens J E, Stark M 1987 Suberin lamellae in the hypodermis of maize Zea mays) roots development and factors affecting the permeability of hypodermal layers. Plant Cell Environ 10 83-93... 

D. L. Jones and P. R. Darrah, Influx and efflux of organic acids across the. soil-root interface of Zea mays L. and its implications in rhizosphere C flow. Plant Soil 173 103 (1995). 

R. Schonwitz and H. Ziegler, Exudation of water soluble vitamins and some carbohydrates by intact roots of maize seedlings Zea mays L.) into a mineral nutrient solution. Z. Planzenphysiol. 107 1 (1982). 

J. L. Morel, M. Mench, and A. Guckert, Measurement of Pb, Cu and Cd binding with mucilage exudates from maize (Zea mays L.) roots. Biol. Pertil. Soils 2 29 (1986). 

M. Mench and E. Martin, Mobilization of cadmium and other metals from two soils by root exudates of Zea mays L., Nicotiana tabacum L. and Nicotiana rustica L. Plant Soil I32 %1 (1991). 

P. H. Saglio, M. C. Drew, and A. Pradet, Metabolic acclimation to anoxia induced by low (2-4kPa partial pressure) oxygen pre-treatment (hypoxia) in root tips of Zea mays, Plant Physiology S6 61 (1988). 

J. D. Everard and M. C. Drew. Mechanisms of inhibition of water movement in anaerobically treated roots of Zea mays. Journal of Experimental Botany 38 1154 (1987). 

ZmVP14 Zea mays AAB62181 Schwartz et al. (1997) Leaf, root, embryo... 

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