Plant-microbe competition: does injection of isotopes of C and N into the rhizosphere effectively characterise plant use of soil N?
Plant-microbe competition: does injection of isotopes of C and N into the rhizosphere effectively characterise plant use of soil N?
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DOI：
10.1111/nph.15433
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发表时间：
2019-01-01
期刊：
影响因子：
9.4
通讯作者：
Jones, Davey L.
中科院分区：
文献类型：
--
作者：
Hill, Paul W.;Jones, Davey L.
尽管在过去的25年里受到了相当大的关注，但早期蛋白质分解产品对植物氮(N)营养的重要性仍然不确定。用N-15、C-13和C-14标记的无机氮和氨基酸(L-丙氨酸)根际注射，追赶时间从1min到24h，研究了根(Triticum Aestivum)与土壤微生物竞争氨基酸的持续时间。我们进一步研究了L丙氨酸的微生物修饰对植物碳(C)和氮回收的影响。从碳同位素的恢复中，完整的丙氨酸摄取量是添加的0.2-1.3%。土壤微生物似乎在1min内从土壤溶液中去除丙氨酸，并在5min内释放足够的NH4+，以满足所有植物N-15的恢复(超过24h)。微生物产生的无机酸或酮酸C占C和N标记的共位似乎是完整摄取的合理衡量标准。微生物修饰C的潜在干扰可能是温和的，但可能会随着追逐时间的延长而增加。同样，L-丙氨酸在土壤中的竞争在几分钟内就完成了，而以相同速率添加的NO3-在土壤中持续了24小时，这表明较长的追逐周期会对结果产生偏差，无法准确地模拟土壤过程。
Despite considerable attention over the last 25 yr, the importance of early protein breakdown products to plant nitrogen (N) nutrition remains uncertain. We used rhizosphere injection of N-15-, C-13- and C-14-labelled inorganic N and amino acid (l-alanine), with chase periods from 1 min to 24 h, to investigate the duration of competition for amino acid between roots (Triticum aestivum) and soil microorganisms. We further investigated how microbial modification of l-alanine influenced plant carbon (C) and N recovery. From recovery of C isotopes, intact alanine uptake was 0.2-1.3% of added. Soil microbes appeared to remove alanine from soil solution within 1 min and release enough NH4+ to account for all plant N-15 recovery (over 24 h) within 5 min. Microbially generated inorganic or keto acid C accounted for Co-location of C and N labels appears a reasonable measure of intact uptake. Potential interference from microbially modified C is probably modest, but may increase with chase period. Similarly, competition for l-alanine is complete within a few minutes in soil, whereas NO3- added at the same rate is available for > 24 h, indicating that long chase periods bias outcomes and fail to accurately simulate soil processes.