Chemotaxonomic variation in volatile component contents and their correlation between climate factors in Chinese prickly ash peels (Zanthoxylum bungeanum Maxim.).

In this study, we analyzed the characteristics of volatile compounds of Chinese prickly ash peels with different climate conditions and their correlation. The data revealed that the contents of limonene and linalool in peels from southwest and northwest regions were higher, and the aroma was stronger, while the contents of ß-myrcene and (E)-ocimene in them from north, east and central China were higher, and the spicy flavor was heavier. Hierarchical cluster analysis demonstrated that the classification had geographical continuity. Through the correlation analysis and path analysis, it was found that the contents of volatile compounds were closely related to the climatic factors. The influence of wind speed and annual average temperature on volatile substances was greater than that of annual average precipitation and annual sunshine duration. This enriched the effect of climatic factors on the accumulation of volatile substances, and promoted the agriculture practices in area having similar climate conditions.

Carcinogenic and mutagenic potencies for different PAHs sources in coastal sediments of Shandong Peninsula.

In this study, sources of PAHs in coastal sediments of Shandong Peninsula were apportioned using the chemical mass balance (CMB) model, and source apportionment of carcinogenic and mutagenic potencies was conducted combining CMB with the formula of benzo(a)pyrene carcinogenic equivalent (BaPTEQ) and BaP mutagenic equivalent (BaPMEQ) concentration. Total concentrations of sixteen PAHs in sediment ranged from 181.2 ng g(-1) to 303.6 ng g(-1), and concentrations of eight carcinogenic PAHs (cPAHs) varied from 98.8 ng g(-1) to 141.1 ng g(-1). The BaP played a dominant role for carcinogenic and mutagenic potencies of PAHs, although the IND showed the highest concentration level. The vehicular sources made the highest contribution to BaPTEQ (57.7%) and BaPMEQ (55.5%), while petrogenic source, the highest contributor for PAHs (39.4%), provided the lowest contribution to BaPTEQ (1.1%) and BaPMEQ (1.5%). Besides, the ecotoxicological evaluation, based on Sediment Quality Guidelines (SQGs), showed low ecological risks generally.

[Effects of tillage and mulching on orchard soil moisture content and temperature in Loess Plateau].

A field experiment was conducted to study the effects of different tillage system (no-tillage, rotary tillage, and plow tillage) and mulching (straw mulch, sod mulch, and film mulch) on the orchard soil moisture content and temperature in Loess Plateau. Under different tillage system, the soil moisture content in 0-1 m layer differed significantly in May, with the sequence of no-tillage (14.28%) > rotary tillage (14.13%) > plow tillage (13.57%), but had less difference in September. Straw mulch induced significantly higher soil moisture content than sod mulch, film mulch, and no-mulch. Among the treatments tillage plus mulching, no-tillage plus straw mulch resulted in the greatest soil water storage. The average soil temperature at daytime was in order of film mulch > no-mulch > sod mulch > straw mulch, and the change range of soil temperature was no-mulch > film mulch > sod mulch > straw mulch. Soil water storage under different mulching treatments was not always negatively correlated with soil temperature, but depended on the water conservation effect and heat-preserved capacity of mulching material. Above all, the main conservation tillage system for the orchards in Loess Plateau would be no tillage plus straw mulch.