Low-Cadmium Wheat Cultivars Limit the Enrichment, Transport and Accumulation of Cadmium

Abstract

Low-cadmium (Cd) accumulating wheat cultivars (LAWC-Cds) can effectively reduce the total Cd content in wheat grains (Grain-Cd). Thirteen LAWC-Cds were planted in three fields to study the enrichment, transport, and accumulation patterns of Cd in LAWC-Cds. Compared with the soil properties before planting, the soil pH and the total Cd content in the soil decreased, while the Cd content in the diethylenetriaminepentaacetic acid extract, soil conductivity, and soil organic matter increased at wheat maturity. The Cd enrichment capacity of the different organs of wheat decreased in the following order: root > leaf > rachis > stem > glume > grain. The dynamics of Cd accumulation in roots affected Grain-Cd, and these factors were negatively correlated. The Cd content and Cd accumulation in all organs of LAWC-Cds showed strong negative correlations with the lengths of the first and second internodes and highly significant positive correlations with both grains per spike and awn length. Structural equation modeling showed that the Cd content of wheat organs had the most direct effect (0.639) in determining Grain-Cd, and soil properties had the largest effect (0.744) in influencing Grain-Cd. This study is important for screening wheat cultivars with stable low Cd-accumulation characteristics.