Submitted to: Biology and Fertility of Soils
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/18/2009
Publication Date: 6/2/2009
Publication URL: hdl.handle.net/10113/35752
Citation: Reeve, J., Smith, J.L., Carpenter-Boggs, L., Reganold, J.P. 2009. Glycine, Nitrate, and Ammonium Uptake by Classic and Modern Wheat Varieties in a Short-Term Microcosm Study. Biology and Fertility of Soils. Available www.springerlink.com/content/r3261800q32ut474/fulltext.pdf. [doi: 10.1007/s00374-009-0383-x.]. Interpretive Summary: The production of organically grown fruits and vegetables in the United States is doubling every 3 years. This trend is also mirrored worldwide. However, there are limits to production and food quality due to the regulation that specifies that certified organic production can only use organic fertilizers. The problem is that using organic based fertilizer limits the availability of nitrogen, a critical plant nutrient. This study focused on the plant uptake of an organic nitrogen compound (glycine). These types of compounds are abundant in organic materials such as compost, manures and food processing waste. We tested this potential organic nitrogen source on old and new wheat varieties. We found that all wheat varieties tested took up glycine-N but in small amounts of the total N uptake (4-8%). The newer wheat varieties took up more organic N than the older varieties and also transferred more to the plant shoots. These results could have significance in the development of varieties adapted to organic and low-input systems.
Technical Abstract: Abstract Plants take up nitrogen principally in the form of nitrate and ammonium; however, evidence is growing that they can also use organic N in the form of amino acids. Selecting varieties that better use organic N could be important in maximizing productivity in organic and low-input systems because these varieties may access a wider pool of available nutrients. We tested amino acid-N uptake by wheat (Triticum aestivum L.) seedlings over 24 h over a range of soil glycine concentrations. Wheat was grown in 5 ml pipette tips for 10 days prior to labeling with 14C-labeled glycine. In a second experiment, uptake of amino acid-N relative to nitrate and ammonium was tested in three pre-1940 wheat varieties (Arco, Idaed, and Red Fife), three modern varieties (Alpowa, Madsen, and Zak), and one perennial wheat variety (unreleased). Glycine-N was detected in all shoots (with the exception of the lowest soil concentration) and increased with increasing soil concentration. There were few differences in uptake between individual varieties tested but seedlings of modern varieties were more efficient at capturing organic N than classic varieties. Glycine-N constituted between 3.9% and 8.1% of total N uptake over 24 h and constituted a significantly greater proportion of total N in perennial wheat than annual wheat varieties. These results show that there may be sufficient varietal differences in organic N uptake in wheat to warrant selection for this trait in breeding programs targeted to improving N use efficiency.