Nitrogen translocation

E. Liljeroth, P. Kuiknian, and J. A. Van Veen, Carbon translocation to the rhizo-sphere of maize and wheat and influence on the turnover of native soil organic-matter at different soil nitrogen levels. Plant Soil 161 233 (1994). 

E. Liljeroth, J. A. Van Veen, and H. J. Miller, As.similate translocation to the rhizosphere of two wheat lines and subsequent utilization by rhizosphere microorganisms at two soil nitrogen concentrations. Soil Biology and Biochemistry 22 1015 (1990). 

Figure 11 The different steps of nitrogen metabolism in the extraradical hyphae, ccto-mycorrhizal roots, and roots of the host plant. I, absorption 2, assimilation 3. storage 4. translocation A, extramatrical hyphae B. ectomycorrhizal sheath C, Hartig net D, root cortical cells AA amino. acids.

Finlay, R. D., Ek, FI., Odham, G., and Soderstrom, B. Mycelium uptake, translocation and assimilation of nitrogen from N-labelled ammonium by Pintis. sylvestris plants infected with four different ectomycorrhizal fungi. New Phytol. //0 59-66 (1988). 

Alkaloids are translocated in the phloem sap like other photo-synthates, and QA contribute about 8 % to the overall nitrogen. 

Mineralization often has the initial effect (e.g., immediately after leaffall) of immobilizing N (36). In ecosystems where plant growth is limited by the availability of N, mineralization is also limited by N in the sense that addition of N to the leaflitter speeds decay and increases the rate at which N is immobilized by decomposers (37, 38). This initial immobilization period is marked by a net increase in the N content of leaflitter. Nitrogen limitation of decomposition follows in part from the low N content typical of litter, which arises from the translocation of N out of leaves during senescence. The immobilization phase of mineralization is followed by a period of slow release of inorganic N from the soil microbial pool (36). 

Measurements will be made of the form and levels of elements in soil, movement of elements to plant roots, uptake of elements by plant roots, and translocation to above-ground, and edible portions of plants. The elements to be studied include magnesium, calcium, potassium, zinc, phosphorous, nitrogen, iron, manganese, copper, and aluminum. 

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