Abstract
We investigated the impacts of graphene application at different concentrations on the growth and physiological characteristics of Changbai larch (Larix olgensis A. Henry) seedlings and the chemical properties and enzyme activities of Haplic Cambisols under these seedlings. The aim is to evaluate the environmental effects of graphene on the afforestation species and the zonal forest soils of Northeast China. Seedlings receiving 0 (CK), 25, 50, 100, 250, or 500 mg L−1 graphene were incubated for 30, 40, or 50 days. Low concentrations (25–50 mg L−1) of graphene increased the dry masses of root, stem, and leaf; however, high concentrations (100–500 mg L−1) inhibited them. Compared with those under 0 mg L−1 graphene, the root length, surface area, volume, and average diameter all increased during the early stages of incubation (i.e., 30 and 40 days) under low concentration of graphene (<50 or 100 mg L−1) and decreased at higher graphene concentration (>100 mg L−1); at 50 days, they were significantly inhibited. At 30 days, graphene decreased superoxide dismutase (SOD) and peroxidase (POD) activities, as well as pigment, soluble protein, and proline contents, and the decline increased with increasing graphene concentration; at 40 and 50 days, the above parameters increased initially and then decreased, reaching a maximum at 50 mg L−1. The changes in relative conductivity and malondialdehyde (MDA), superoxide anion and hydrogen peroxide contents were the opposite of those in the physiological indexes mentioned above. Therefore, graphene caused different degrees of oxidative stress in L. olgensis seedlings. At 30 days, graphene generally increased the organic matter, hydrolytic nitrogen, and available phosphorus and potassium contents of Haplic Cambisols, but these parameters decreased at 40 and 50 days. Graphene generally decreased acid phosphatase, urease, dehydrogenase, and catalase activities. Therefore, when graphene reaches a certain content level in this soil, it may also affect nitrogen and phosphorus cycling.
Highlights
Nanomaterials are usually defined as particles with a particle size of 1–100 nm and are known as ultrafine particles [1]
The seedling biomass declined at high graphene concentration butThe wasseedling promoted at low concentration, and the graphene concentration (Figure 1)
This study is the first to provide experimental evidence revealing the interrelations between graphene and L. olgensis seedlings and Haplic Cambisols in Northeast China
Summary
Nanomaterials are usually defined as particles with a particle size of 1–100 nm and are known as ultrafine particles [1]. Graphene is the thinnest and toughest two-dimensional nanomaterial in the world [3,4] and has a thickness of only 0.34 nm, a specific surface area of 2630 m2 g−1 , and thermal conductivity of 5000 W m−1 K−1 [5,6,7,8]. These special properties make it appropriate for widespread application in environmental applications [9], electronics [10], information technology, optics [11], Forests 2020, 11, 258; doi:10.3390/f11030258 www.mdpi.com/journal/forests. Its use may have some impacts or potential risks to ecosystems [17], especially for the soil and plants
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
