Record ID No. |
3786 |
Author(s) |
Ngwene, B., Gabriel, E., George, E. , 2012 |
Affiliation |
Leibniz-Institute of Vegetable and Ornamental Crops Grossbeeren and Erfurt e.V., Theodor-Echtermeyer-Weg 1, Grossbeeren, 14979, Germany |
Title |
Influence of different mineral nitrogen sources (NO3--N vs. NH 4+ -N) on arbuscular mycorrhiza development and N transfer in a Glomus intraradices-cowpea symbiosis |
Source. Vol.(no):Page |
Mycorrhiza, pp. 1-11. |
Categories |
Arbuscular Mycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Nitrogen metabolism |
Host |
Vigna unguiculata |
Organism |
Glomus intraradices |
Country |
Germany, Europe |
Abstracts |
Labeled nitrogen (15 N) was applied to a soil-based substrate in order to study the uptake of N by Glomus intraradices extraradical mycelium (ERM) from different mineral N (NO3- vs. NH4+) sources and the subsequent transfer to cowpea plants. Fungal compartments (FCs) were placed within the plant growth substrate to simulate soil patches containing root-inaccessible, but mycorrhiza-accessible, N. The fungus was able to take up both N-forms, NO3- and NH4+. However, the amount of N transferred from the FC to the plant was higher when NO3- was applied to the FC. In contrast, analysis of ERM harvested from the FC showed a higher 15 N enrichment when the FC was supplied with 15NH4+ compared with 15NO3-. The 15 N shoot/root ratio of plants supplied with 15NO3- was much higher than that of plants supplied with 15NH4+, indicative of a faster transfer of 15NO3- from the root to the shoot and a higher accumulation of 15NH4+ in the root and/or intraradical mycelium. It is concluded that hyphae of the arbuscular mycorrhizal fungus may absorb NH4+ preferentially over NO3- but that export of N from the hyphae to the root and shoot may be greater following NO3- uptake. The need for NH4+ to be assimilated into organically bound N prior to transport into the plant is discussed. |