Alleviating effects of silicon on cadmium toxicity in ginger (Zingiber officinale Roscoe)

Abstract

Heavy metal pollution was a serious problem for ginger cultivation. This study assessed the effects of the three treatments Si0 (0), Si1 (1 g kg-1), and Si2 (2 g kg-1) on the reduction of cadmium (2 mg kg-1 Cd) toxicity in Zingiber officinale Rosc. via growth modulation, photosynthetic efficiency, and antioxidant defense. Morphology indexes, Cd (cadmium) content, Cd transfer and absorption coefficient, photosynthesis, and antioxidant enzyme activities under Cd stress were determined. On day 120 of the experiment, plant height had increased by 18.8% and 24.7% under the Si1 and Si2 treatments compared with the CK treatment. Meanwhile, the fresh weight of the rhizomes in Si1 and Si2 had increased by 14.3% and 19.5% in comparison with the Si0 treatment. Also, the yield of ginger improved dramatically under the Si1 and Si2 treatments. These treatments had increased by 14.3% and 19.5% compared with the CK treatment. The Cd content of the mother-ginger, son-ginger, and grandson-ginger decreased by 27.6%, 35.5%, and 51.2%, respectively, under 2 mg kg-1 Cd stress in the Si2 treatment. The Cd transfer was inhibited from the underground to the aboveground in the high-concentration Si treatment (Si2). When 1 g kg-1 and 2 g kg-1 Si was added to the soil, the leaf photosynthetic rate increased by 15.1% and 26.9% compared with the CK treatment at 11:00 am, respectively. Soil conditioner Si alleviated the harmful effects of Cd stress on ginger plants.