Variations in Root Characteristics and Cadmium Accumulation of Different Rice Varieties under Dry Cultivation Conditions

Overview

This pot experiment investigated cadmium accumulation and root characteristics of five rice genotypes under dry cultivation conditions at two cadmium levels (0 and 10 mg per kg soil). Cadmium concentration in rice organs decreased in the order roots > shoots > grains, and across three developmental periods in the order maturity > booting > tillering. The lowest bioaccumulation factor (BCF) and translocation factor (TF) were found in Yunjing37 (YJ37) under cadmium stress. YJ37 was screened as a low cadmium-accumulating variety; the concentration of cadmium (DCB-Cd) was lowest in DHY34 at maturity.

The study provides evidence that genotypic differences in root morphology, iron plaque formation, and anatomy affect cadmium accumulation in rice under dry cultivation, supporting variety selection as a mitigation strategy.

Key numbers

Cadmium inhibition rates on root length: DHY34 (41.80%), DHY918 (5.09%), DHY615 (40.95%), YJ37 and YY673 (10.51%) (p. 1 abstract).

Stele diameter: DHY615 decreased the most; YY673 decreased the least. Rates of change: -21.50, -14.29, -5.86, -26.35% (p. 1 abstract).

Iron plaque cadmium (DCB-Fe): highest in YJ37; cadmium in plaque (DCB-Cd) lowest in DHY34 (p. 1 abstract).

Average reduction in rice shoot cadmium under flooded vs non-flooded conditions was 42.26% (cited from reference [21], not original data from this study) (p. 10).

Evidence Fitness

EF-3 (modeled or limited evidence). Pot experiment with artificially spiked cadmium (10 mg per kg, well above typical agricultural soils). Provides genotype-specific cadmium accumulation data under dry cultivation, relevant to variety selection for low-cadmium rice. Not representative of market rice concentrations.

Methods

Pot experiment, greenhouse, Yunnan Agricultural University. Five rice genotypes, two cadmium levels, three developmental stages. Iron plaque extracted by dithionite-citrate-bicarbonate (DCB) method. Cadmium measured in roots, shoots, grains, and rhizosphere soil.

LOD/LOQ: not reported in abstract. CRM/Recovery: not reported in abstract.

Implications

Certification: Supports the principle that variety selection (low-cadmium cultivars) is a viable mitigation approach for dry cultivation rice, particularly in cadmium-contaminated regions. YJ37 identified as a low-accumulator.

Courses: Demonstrates that root morphology and iron plaque formation are mechanistic determinants of genotypic differences in cadmium accumulation under dry cultivation.

Provenance notes

Open access (CC BY 4.0). MDPI journal (Plants). Deposit: HMI-MIT-rice.

Related evidence

• Rice

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