Effects of intercropping on Se accumulation and growth of pakchoi, lettuce and radish.

Selenium is one of the most basic trace elements in the human body. It is necessary to improve the selenium content in agricultural products through agricultural planting technology to ensure that human nutrition and health need selenium. Therefore, our research passed the effect of intercropping on the growth and selenium accumulation of pakchoi, lettuce and radish were studied through pot experiments to determine whether intercropping of the three crop species can improve their selenium accumulation ability. The results showed that intercropping increased the root and shoot biomass of pakchoi and radish compared with the monocultures, while the biomass of roots and shoots decreased in other intercropping combinations. Intercropping also affected the photosynthetic pigment content of the three crop species. Specifically, the photosynthetic pigments increased in pakchoi and decreased in radish after intercropping. Notably, intercropping the three crop species together increased the SOD (superoxide dismutase) activities of the three crops compared with the monocultures. Meanwhile, intercropping radish with lettuce significantly increased the activities of SOD and CAT (catalase) in radish. Intercropping also increased the soluble sugar content in pakchoi and soluble protein content of radish relative to the monocultures. Furthermore, intercropping decreased the selenium content and the bioconcentration factor of the roots of the three vegetable crops, but improved the shoot selenium content, the bioconcentration factor and the transport factor of Se in pakchoi and radish. In conclusion, intercropping combination of pakchoi and radish can improve selenium accumulation in the edible parts of the crops, which is significant for efficient production of selenium-enriched vegetables.

This research is significant because this study provides some basis for improving the selenium content of plants and efficient production of pakchoi and radish. Under the condition of selenium application in soil, the intercropping of pakchoi and lettuce can promote the growth of both and improve their selenium enrichment ability.

Preparation of flexible and UV-blocking films from lignin-containing cellulose incorporated with tea polyphenol/citric acid.

Lignin-containing bamboo cellulose, fractionated from a pilot-scale microwave liquefaction of bamboo was dissolved in tetrabutylammonium acetate/dimethyl sulfoxide (TBAA/DMSO) for the fabrication of highly flexible, transparent and UV-blocking films. Tea polyphenol (TP) or citric acid (CA) was added during the dissolving process in order to modify the film's properties. The results showed that the addition of TP obviously improved the elongation at break (triple that of the control) and UV-blocking ability of the films. Both the addition of TP and CA could increase the water contact angle of the films. The films incorporated with TP and CA were much more thermal stable than previously reported similar films. The proposed film fabrication mechanism revealed that stable hydrogen bonds formed between the lignin-cellulose matrix and TP/CA, resulting in the enhancement on the properties of the films. This present study showed that lignin-containing cellulose with the incorporation of TP/CA had great potential in the preparation of films in place of plastic.

Characterization of Ethyl Acetate and Trichloromethane Extracts from Phoebe zhennan Wood Residues and Application on the Preparation of UV Shielding Films.

In this work, ethyl acetate (EA) and trichloromethane (TR) extracts were extracted from Phoebe zhennan wood residues and the extracts were then applied to the preparation of UV shielding films (UV-SF). The results revealed that substances including olefins, phenols and alcohols were found in both EA and TR extracts, accounting for about 45% of all the detected substances. The two extracts had similar thermal stability and both had strong UV shielding ability. When the relative percentage of the extract is 1 wt% in solution, the extract solution almost blocked 100% of the UV-B (280-315 nm), and UV-A (315-400 nm). Two kinds of UV-SF were successfully prepared by adding the two extracts into polylactic acid (PLA) matrix. The UV-SF with the addition of 24 wt% of the extractive blocked 100% of the UV-B (280-315 nm) and more than 80% of the UV-A (315-400 nm). Moreover, the UV shielding performance of the UV-SF was still stable even after strong UV irradiation. Though the addition of extracts could somewhat decrease the thermal stability of the film, its effect on the end-use of the film was ignorable. EA extracts had less effect on the tensile properties of the films than TR extracts as the content of the extract reached 18%. The results of this study could provide fundamental information on the potential utilization of the extracts from Phoebe zhennan wood residues on the preparation of biobased UV shielding materials.

Cadmium-accumulator straw application alleviates cadmium stress of lettuce (Lactuca sativa) by promoting photosynthetic activity and antioxidative enzyme activities.

The effects of application of straw derived from cadmium (Cd) accumulator plants (Siegesbeckia orientalis, Conyza canadensis, Eclipta prostrata, and Solanum photeinocarpum) on growth and Cd accumulation of lettuce plants grown under Cd exposure were studied. Treatment with straw of the four Cd-accumulator species promoted growth, photosynthesis, and soluble protein contents and enhanced the activities of peroxidase in leaves of lettuce seedlings. The biomass of shoot of lettuce from high to low in turn is the treatment of C. canadensis straw > S. photeinocarpum straw > S. orientalis > E. prostrata > Control. The Cd content in edible parts (shoots) of the lettuce plants was significantly decreased in the presence of straw from the Cd-accumulator species, except the presence of the straw of E. prostrata. And, the greatest reduction in Cd content in shoots was 27.09% in the S. photeinocarpum straw treatment compared with that of the control. Therefore, application of straw of S. orientalis, C. canadensis, and S. photeinocarpum can promote the growth of lettuce seedlings, and decrease their Cd accumulation, when grown in Cd-contaminated soil, which is beneficial for production of lettuce safe for human consumption.