Chloride Improves Nitrate Utilization and NUE in Plants

Abstract

Chloride (Cl -) has traditionally been considered harmful to agriculture because of its toxic effects in saline soils and its antagonistic interaction with nitrate (NO 3 -), which impairs NO 3 -nutrition. It has been largely believed that Cl -antagonizes NO 3 uptake and accumulation in higher plants, reducing crop yield. However, we have recently uncovered that Cl -has new beneficial macronutrient functions that improve plant growth, tissue water balance, plant water relations, photosynthetic performance, and water-use efficiency. The increased plant biomass indicates in turn that Cl - may also improve nitrogen use efficiency (NUE). Considering that N availability is a bottleneck for the growth of land plants excessive NO 3 -fertilization frequently used in agriculture becomes a major environmental concern worldwide, causing excessive leaf NO 3 -accumulation in crops such as vegetables, which poses a potential risk to human health. New farming practices aimed to enhance plant NUE by reducing NO 3