[Effects of Biodegradable Film Raw Material Particles on Soil Properties, Wheat Growth, and Nutrient Absorption and Transportation].

Biodegradable plastic film is one of the effective ways to solve the problem of white pollution in agriculture. However, its impacts on soil-plant systems are not well documented. In order to provide a basis for the safety evaluation of large-scale application of biodegradable plastic film, pot experiments were conducted to investigate the effects of the types(H, S, and X) and doses(2.5, 10, and 40 g·kg-1) of biodegradable film raw material particles on the soil physiochemical properties, biological properties, growth, and nutrient absorption by wheat (Triticum aestivum L.). The results showed that three types of biodegradable film raw material particles significantly increased soil pH but had no significant effect on soil organic matter content; medium-high doses of H and low-medium doses of S plastic particles had a positive effect on soil nitrification and soil nitrogen availability, whereas X film particles had an inhibitory effect. H film particles increased soil available phosphorus content, and S and X had no significant effect. X film particles increased the content of soil available potassium, but S and H had no significant effect. The effects of three types of biodegradable raw material particles on soil enzyme activities varied with the types and doses of plastic film and enzyme types. With the increase in the doses of plastic film particles, the activities of three kinds of soil enzymes showed a downward trend. Except for the low and medium doses of the S treatment, the other treatments inhibited the growth of wheat, in which X film particles had the greatest inhibitory effect on the biomass of wheat roots, stems, leaves, and grain; with the increase in the doses of film particles, the inhibition effect of wheat biomass was more obvious. For wheat nutrients, the absorption of nitrogen was promoted at low doses and inhibited at high doses, and the three types of film particles inhibited the absorption of phosphorus and potassium. There were significant differences in the distribution ratio of nitrogen and phosphorus between the stems, leaves, and grains of wheat by all the film particles; however, there was no significant difference in the distribution ratio of potassium between those treatments. Correlation analysis showed that wheat biomass was the main factor affecting wheat nutrient accumulation.

Amycolatopsis xylanica sp. nov., isolated from soil.

An actinomycete, designated CPCC 202699(T), was isolated from soil in Qinghai province, China, and its taxonomic status was established. Strain CPCC 202699(T) contained meso-diaminopimelic acid in its peptidoglycan, arabinose and galactose as the diagnostic sugars in whole-cell hydrolysates, a phospholipid pattern consisting mainly of phosphatidylethanolamine, phosphatidylmethylethanolamine and phosphatidylcholine, MK-9(H(4)) as the predominant menaquinone and iso-C(16 : 0) (18.8 %), iso-C(15 : 0) (18.1 %), iso-C(14 : 0) (14.2 %), C(16 : 1) cis9 (10.9 %) and C(17 : 1) cis9 (10.3 %) as the major fatty acids. In the phylogenetic tree based on 16S rRNA gene sequences, strain CPCC 202699(T) formed a separate branch within the genus Amycolatopsis. However, strain CPCC 202699(T) showed low 16S rRNA gene sequence similarities (<97.0 %) with type strains of species with validly published names in the genus Amycolatopsis. On the basis of genotypic and phenotypic differences from the closest phylogenetic neighbours of strain CPCC 202699(T), a novel species, Amycolatopsis xylanica sp. nov., is proposed. The type strain is CPCC 202699(T) (=DSM 45285(T) =KCTC 19581(T) =CCM 7627(T)).