Cadmium Treatment Affected the Growth and Physiology of Larix Olgensis Seedlings, the Chemical Properties of Haplic Cambisols and Toxicity Threshold Determination

Modern industry and agriculture have exacerbated soil heavy metal pollution, with cadmium (Cd) being one of the most common, toxic, and widely distributed pollutants. Our aim is to evaluate the environmental impacts of Cd on the afforestation species and zonal forest soil of northeastern China. Changbai larch (Larix olgensis A. Henry) seedlings receiving 0 (Ck), 1, 5, 25, 50, 75, or 100 mg L− 1 Cd treatment were incubated for 30, 40, or 50 days. Then, we investigated the growth and physiological characteristics of the seedlings, chemical properties of Haplic Cambisols under these seedlings and calculated the toxicity threshold. Partial Cd treatment significantly improved the relative conductivity, malondialdehyde, superoxide anion and hydrogen peroxide of seedlings and reduced leaf, stem and root dry mass at 30 days and root growth. Cd treatment reduced the soil pH value to a certain extent, generally improved the effectiveness of nitrogen, phosphorus and potassium nutrients, and significantly increased the content of available Cd. The EC10 values of the aboveground parts were higher than those of the roots, and the EC10 values of both reached a maximum at 50 days, reaching 2.07 and 1.15 mg L− 1, respectively. Partial Cd treatment had a significant impact on the growth physiology of seedlings and chemical properties of soil and varied with its concentration. Although the exact mechanism of the Cd treatment response is difficult to infer, this study clearly estimates the toxicity threshold of Cd-contaminated soil when the biomass of the plant is reduced by 10