Phosphorus fertiliser application mitigates the negative effects of microplastic on soil microbes and rice growth.

Soil microplastics (MPs) have attracted widespread attention recently. Most studies have explored how soil MPs affect the soil's physicochemical parameters, matter circulation, and soil microbial community assembly. Similarly, a key concern in agricultural development has been the use of phosphorus (P) fertiliser, which is essential for plant health and development. However, the relationship between MPs and phosphate fertilisers and their effects on the soil environment and plant growth remains elusive. This study assessed the influence of adding low-density polyethylene MPs (1%) with different phosphate fertiliser application rates on microbial communities and rice biomass. Our results showed that MPs changed the structure of soil bacterial and phoD-harbouring microbial communities in the treatment with P fertiliser at the same level and suppressed the interactions of phoD-harbouring microorganisms. In addition, we found that MPs contamination inhibited rice growth; however, the inclusion of P fertiliser in MP-contaminated soils reduced the inhibitory action of MPs on rice growth, probably because the presence with P fertiliser promoted the uptake of NO3--N by rice in MP-contaminated soils. Our results provide further insights into guiding agricultural production, improving agricultural management, and rationally applying phosphate fertilisers in the context of widespread MPs pollution and global P resource constraints.

[Temporal-spatial Distribution of Nitrogen and Phosphorus Nutrients in Lake Taihu Based on Geostatistical Analysis].

It is of great significance to investigate the spatio-temporal variation in nitrogen and phosphorus nutrients as a mechanism for controlling the sudden increase of algae in eutrophic water. Based on the geostatistical analysis, we studied the sources and occurring forms of nitrogen and phosphorus in different areas of Lake Taihu-a large shallow and eutrophic lake in China. We also examined the spatial distribution of the type of nutrient restriction and its reason by monitoring the sites seasonally from August 2014 to May 2015. The results showed that:① The concentrations of soluble nitrogen and phosphorus were higher in the winter than in other seasons, and they gradually decreased spatially from the northwest to southeast. The concentrations of particulate nitrogen, phosphorus, and chlorophyll a were highest in the summer, and the high-concentration regions in the winter and other seasons were located in the southern and northwestern parts of the lake, respectively. ② The composition of nitrogen and phosphorus in algae-and macrophyte-dominated regions changed substantially with the seasonal change. The algae-dominated regions were dominated by nitrate nitrogen and organic phosphorus in the winter and particulate nitrogen and phosphorus during the other seasons. However, the macrophyte-dominated region was dominated by particulate nitrogen and phosphorus in the winter and ammonia, organic nitrogen, and phosphorus during the other seasons. ③ The ratios of total nitrogen to total phosphorus in the algae-dominated region were greater than 16:1 in the autumn and winter but less than 16:1 in the summer and spring. Meanwhile, the ratios of total nitrogen to total phosphorus in the macrophyte-dominated region increased from less than 16:1 in the autumn and winter to more than 16:1 in the summer and spring. In the algae-dominated region, the spatial variation in the dissolved total nitrogen to total phosphorus ratio was consistent with the ratio of total nitrogen to total phosphorus. In the macrophyte-dominated region, the dissolved total nitrogen to total phosphorus ratio increased from less than 16:1 in the autumn to more than 16:1 in the summer, winter, and spring. The temporal and spatial variation in the ratio of particulate nitrogen to phosphorus was not significant (P>0.05), and this ratio was less than and greater than 16 in algae-and macrophyte-dominated regions, respectively.

[Assessment of genetic diversity of Rehmannia glutinosa germplasm detected by RAPDs and ISSRs].

RAPD and ISSR markers were used to assess the germplasm genetic diversity among 10 individuals of Rehmannia glutinosa, including 8 cultivars and 2 virus-free lines micropropagated by tip tissue culture. 17 RAPD primers and 10 ISSR primers, with polymorphic and informative patterns, were selected from a total of 80 RAPD ones and 44 ISSR ones to determine these individuals' genetic diversity. The 17RAPD primers and 10 ISSR primers generated 177RAPDfragments and 110 fragments, respectively. The number of effective loci, the percentage of polymorphic loci, Shannon's Information index (I) and effective number of alleles (Ne) is in turn109, 61.58%, 0.3135, 1.3641 for RAPD makers, and 79, 71.82 %, 0.3577 and 1.4037 for ISSR markers; Jaccard's genetic similarity matrice and dendrograms for the 10 individuals were formed based on RAPD and ISSR-generated polymorphic bands. In dendrograms, they could be divided into two groups: one group containing six individuals such as Zupei 85.5, Datian 85.5, jinzhuangyuan, Jinbai, Zupei 9302 and Datian9302; the other composed of 4 ones such as Beijing No.1, Dahongpao, Dihuang 9104 and wild dihuang; the correlation coefficient of 0.649 between RAPD and ISSR markers GSs indicated that these two markers were significantly correlated. The results revealed that RAPD and ISSR markers were suitable for assessment of germplasm genetic diversity of Rehmannia glutinosa, and ISSR marker was superior to RAPD marker.