Intensive agriculture uses a lot of nitrogen fertilizers to increase crop productivity. These crops are in competition with soil-denitrifying microorganisms that assimilate nitrogen in the form of nitrate and transform it into N₂O, a greenhouse gas, or N₂. However, certain plant species exude secondary metabolites, called procyanidins, which inhibit denitrifiers and increase the nitrate pool in the soil available for plant nutrition. This phenomenon is called biological denitrification inhibition. Previously, we showed that the addition of exogenous procyanidins to a lettuce crop induces denitrifier inhibition and increases nitrate content in the soil, affecting lettuce morphological traits. Here, the effects of procyanidin amendments in the field on a more long-term and nitrogen-consuming crop species such as celery were tested. The effects of procyanidin amendment on celery growth with those of conventional ammonium nitrate amendments were, therefore, compared. Denitrification activity, nitrate concentration, the abundance of denitrifying bacteria in the soil, and traits related to celery growth were measured. It was shown that the addition of procyanidins inhibits denitrifiers and increases the soil nitrate level, inducing an improvement in celery morphological traits. In addition, procyanidin amendment induces the lowest nitrogen concentration in tissues and reduces N₂O emissions.

中文翻译：

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田间生物反硝化抑制（BDI）是否会导致长期种植的重瓣芹菜的植物生长和营养增加？

集约化农业使用大量的氮肥来提高农作物的生产力。这些作物与土壤硝化微生物竞争，后者会将硝酸盐形式的氮吸收并转化为N ₂ O，温室气体或N ₂。但是，某些植物物种散布着称为原花青素的次生代谢产物，这些代谢产物抑制反硝化剂并增加土壤中的硝酸盐库，可用​​于植物营养。这种现象称为生物反硝化抑制。以前，我们表明向莴苣作物中添加外源原花青素会诱导反硝化剂抑制并增加土壤中的硝酸盐含量，从而影响莴苣的形态特征。在这里，测试了原花青素改良剂在田间对更长期和耗氮的农作物如芹菜的影响。因此，比较了原花青素修饰物与传统硝酸铵修饰物对芹菜生长的影响。反硝化活性，硝酸盐浓度，土壤中反硝化细菌的含量，测定芹菜的生长性状。结果表明，原花青素的添加会抑制反硝化作用并增加土壤硝酸盐含量，从而导致芹菜形态性状的改善。此外，花青素修饰剂可诱导组织中最低的氮浓度并减少氮₂ O排放。