Variation of Soil Bacterial Communities during Lettuce Continuous Cropping

Abstract

The variation of bacterial community in lettuce continuous cropping was determined by high throughput sequencing. During the continuous planting of lettuce, the richness and diversity of bacterial communities in the soil increased, and the ACE index and Chao index increased by 40.21 % and 36.91 %, respectively. The proportion of Actinobacteria, Chloroflexi, Firmicutes and Nitrospirae in the soil increased, while the abundance of Acidobacteria, Bacteroidetes, Gemmatimonadetes, Planctomycetes and Proteobacteria gradually declined. And the abundance in the soil accounting for 1 % of the dominant bacterial genera increased to 11, among them, Anaerolinea, Bacillus, Nitrosomonas, and Xanthomonas etc became the dominant bacterium genus in the soil after lettuce continuous cropping. After the lettuce had been planted 8 times, the yield decreased by 21.20 % compared to the first harvest. Lettuce continuous cropping had an effect on bacterial community and lettuce yield to some extent.

Control of the Porous Structure of Polystyrene Particles Obtained by Nonsolvent Induced Phase Separation

“…Porosity may be achieved in different classes of structures, such as large monoliths, 1 thin membranes, 9 or microspheres. 10 There are a number of synthetic methods for producing organic porous materials. 11,2 In particular, porous polymers can be obtained by exploiting the process of phase separation of an initially homogeneous polymer solution.…”