AUTHOR=Zhu Feifei , Dai Luming , Hobbie Erik A. , Koba Keisuke , Liu Xueyan , Gurmesa Geshere A. , Huang Shaonan , Li Shanlong , Li Yinghua , Han Shijie , Fang Yunting 

TITLE=Uptake Patterns of Glycine, Ammonium, and Nitrate Differ Among Four Common Tree Species of Northeast China

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00799

DOI=10.3389/fpls.2019.00799

ISSN=1664-462X

ABSTRACT=<p>Fundamental questions of how plant species within secondary forests and plantations in northeast China partition limited nitrogen (N) resource remain unclear. Here we conducted a <sup>15</sup>N tracer greenhouse study to determine glycine, ammonium, and nitrate uptake by the seedlings of two coniferous species, <italic>Pinus koraiensis</italic> (<italic>Pinus</italic>) and <italic>Larix keampferi</italic> (<italic>Larix</italic>), and two broadleaf species, <italic>Quercus mongolica</italic> (<italic>Quercus</italic>) and <italic>Juglans mandshurica</italic> (<italic>Juglans</italic>), that are common in natural secondary forests in northeast China. Glycine contributed 43% to total N uptake of <italic>Pinus</italic>, but only 20, 11, and 21% to N uptake by <italic>Larix, Quercus</italic>, and <italic>Juglans</italic>, respectively (whole plant), whereas nitrate uptake was 24, 74, 88, and 68% of total uptake for these four species, respectively. Retention of glycine carbon versus nitrogen in <italic>Pinus</italic> roots indicated that 36% of glycine uptake was retained intact. Nitrate was preferentially used by <italic>Larix, Quercus</italic>, and <italic>Juglans</italic>, with nitrate uptake constituting 68∼88% of total N use by these three species. These results demonstrated that these dominant tree species in secondary forests in northeast China partitioned limited N resource by varying uptake of glycine, ammonium and nitrate, with all species, except <italic>Pinus</italic>, using nitrate that are most abundant within these soils. Such N use pattern may also provide potential underlying mechanisms for the higher retention of deposited nitrate than ammonium into aboveground biomass in these secondary forests.</p>