Graphene oxide affects growth and physiological indexes in Larix olgensis seedlings and the soil properties of Haplic Cambisols in Northeast China.

Abstract

Changbai larch (Larix olgensis A. Henry) seedlings growing in a Haplic Cambisol and receiving 0 (Ck), 25, 50, 100, 250, or 500mgL-1 graphene oxide (GO) were incubated for 30, 40, or 50days, and the effects of applying GO on the growth and physiological characteristics of the seedlings and soil chemical properties and enzyme activities were investigated. The superoxide anion (except for 25mgL-1 at 40days and 50mgL-1 at 50days) and hydrogen peroxide contents of the leaves increased at 25-100mgL-1 GO; however, superoxide dismutase (SOD) and peroxidase (POD) (except for 100mgL-1 at 50days) activities, soluble protein (except for 100mgL-1 at 30 and 40days), proline (except for 100mgL-1 at 50days), as well as seedling biomass (except for stems at 25-100mgL-1, and leaves and roots at 50-100mgL-1 for 30days) all decreased. However, when the seedlings were exposed to 250-500mgL-1 GO, especially at 40 and 50days, these trends for tree growth and physiological parameters were reversed, suggesting the beneficial effect of GO at high concentrations on the seedlings. GO decreased the organic matter, alkali-hydrolyzale nitrogen, available phosphorus, and potassium contents of the soil at 40 and 50days (except for available phosphorus at 50days), as well as the acid phosphatase, urease (except for 30days), dehydrogenase, and catalase activities (except for 30 and 40days); thus, GO may inhibit nitrogen and phosphorus cycling in Haplic Cambisols (except for nitrogen at 30days).